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Kiel S, Klein M, Kroupitski Y, Peiper UM, Sela Saldinger S, Poverenov E. Air-ozonolysis activation of polyolefins versus use of laden finishing to form contact-active nonwoven materials. Sci Rep 2021; 11:10798. [PMID: 34031478 PMCID: PMC8144365 DOI: 10.1038/s41598-021-90218-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 05/07/2021] [Indexed: 11/08/2022] Open
Abstract
Two synthetic approaches were explored for modification of the polyolefins polyethylene/polypropylene (PE/PP) to form contact-active nonwoven materials. In the first approach, polymer surfaces were activated by O2-free air-ozonolysis, and then the active agent (trimethoxysilyl) propyl-octadecyl-dimethyl-ammonium chloride (C18-TSA) was covalently bound. In the second approach, the active agent was directly conjugated to the commercial 'finishing' that was then applied to the polymer. The chemical, physical and microscopic properties of the modified polymers were comprehensively studied, and their active site density was quantified by fluorescein sodium salt-cetyltrimethylammonium chloride reaction. The antimicrobial activity of the prepared nonwovens against Bacillus subtilis (Gram-positive) and Salmonella enterica (Gram-negative), and their stability at various pHs and temperatures were examined. The two approaches conferred antimicrobial properties to the modified polymers and demonstrated stable linkage of C18-TSA. However, the performance of the nonwovens formed by the first approach was superior. The study suggests two feasible and safe pathways for the modification of polyolefins to form contact-active nonwoven materials that can be further applied in various fields, such as hygiene products, medical fabrics, sanitizing wipes, and more.
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Affiliation(s)
- Stella Kiel
- Department of Food Science, Agro-Nanotechnology and Advanced Materials Research Center, Agricultural Research Organization, The Volcani Center, 7505101, Rishon Lezion, Israel
| | - Miri Klein
- Department of Food Science, Agro-Nanotechnology and Advanced Materials Research Center, Agricultural Research Organization, The Volcani Center, 7505101, Rishon Lezion, Israel
| | - Yulia Kroupitski
- Department of Food Science, Agro-Nanotechnology and Advanced Materials Research Center, Agricultural Research Organization, The Volcani Center, 7505101, Rishon Lezion, Israel
| | - Uri M Peiper
- Department of Agricultural Engineering, Agricultural Research Organization, The Volcani Center, 7505101, Rishon Lezion, Israel
| | - Shlomo Sela Saldinger
- Department of Food Science, Agro-Nanotechnology and Advanced Materials Research Center, Agricultural Research Organization, The Volcani Center, 7505101, Rishon Lezion, Israel
| | - Elena Poverenov
- Department of Food Science, Agro-Nanotechnology and Advanced Materials Research Center, Agricultural Research Organization, The Volcani Center, 7505101, Rishon Lezion, Israel.
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2
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Hazer B, Ashby RD. Synthesis of a novel tannic acid-functionalized polypropylene as antioxidant active-packaging materials. Food Chem 2020; 344:128644. [PMID: 33246682 DOI: 10.1016/j.foodchem.2020.128644] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/06/2020] [Accepted: 11/11/2020] [Indexed: 12/26/2022]
Abstract
This work focuses on the synthesis of novel tannin-functionalized polypropylene copolymers that are designed to inhibit the oxidation of vegetable oils for potential use as packaging materials. An empty glass Petri dish (control), a chlorinated polypropylene-coated glass Petri dish (control) and a series of the tannin-functionalized polypropylene coated glass Petri dishes overlaid with linseed oil were exposed to air and additional white light. Oligomerization of the oxidized linseed oil was assessed by measuring the flow properties of the exposed oil using a viscometer. The antioxidant effect of the tannic acid grafted polypropylene copolymers (PP-Tann) retarded oligomerization of the linseed oil. The molar mass of the linoleic acid overlaid onto the PP-Tann films was the lowest among the tested samples after each time period indicating that tannin-grafted polypropylene may be a promising packaging material for vegetable oils.
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Affiliation(s)
- Baki Hazer
- Kapadokya University, Department of Aircraft Airflame Engine Maintenance, Mustafapaşa, Kasabası 50420, Ürgüp, Turkey; Zonguldak Bülent Ecevit University, Department of Chemistry, 67100 Zonguldak, Turkey.
| | - Richard D Ashby
- USDA ARS, East. Reg. Res. Ctr, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA.
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3
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Majchrzycka K, Okrasa M, Jachowicz A, Szulc J, Brycki B, Gutarowska B. Application of Biocides and Super-Absorbing Polymers to Enhance the Efficiency of Filtering Materials. Molecules 2019; 24:E3339. [PMID: 31540285 PMCID: PMC6767095 DOI: 10.3390/molecules24183339] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 11/16/2022] Open
Abstract
Studies on the functionalization of materials used for the construction of filtering facepiece respirators (FFRs) relate to endowing fibers with biocidal properties. There is also a real need for reducing moisture content accumulating in such materials during FFR use, as it would lead to decreased microorganism survival. Thus, in our study, we propose the use of superabsorbent polymers (SAPs), together with a biocidal agent (biohalloysite), as additives in the manufacturing of polypropylene/polyester (PP/PET) multifunctional filtering material (MFM). The aim of this study was to evaluate the MFM for stability of the modifier's attachment to the polymer matrix, the degree of survival of microorganisms on the nonwoven, and its microorganism filtration efficiency. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to test the stability of the modifier's attachment. The filtration efficiency was determined under conditions of dynamic aerosol flow of S. aureus bacteria. The survival rates (N%) of the following microorganisms were assessed: Escherichia coli and Staphylococcus aureus bacteria, Candida albicans yeast, and Aspergillus niger mold using the AATCC 100-2004 method. FTIR spectrum analysis confirmed the pre-established composition of MFM. The loss of the active substance from MFM in simulated conditions of use did not exceed 0.02%, which validated the stability of the modifier's attachment to the PP/PET fiber structure. SEM image analysis verified the uniformity of the MFM structure. Lower microorganism survival rates were detected for S. aureus, C. albicans, and E. coli on the MFM nonwoven compared to control samples that did not contain the modifiers. However, the MFM did not inhibit A. niger growth. The MFM also showed high filtration efficiency (99.86%) against S. aureus bacteria.
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Affiliation(s)
- Katarzyna Majchrzycka
- Department of Personal Protective Equipment, Central Institute for Labour Protection-National Research Institute, 90-133 Łódź, Poland.
| | - Małgorzata Okrasa
- Department of Personal Protective Equipment, Central Institute for Labour Protection-National Research Institute, 90-133 Łódź, Poland.
| | - Anita Jachowicz
- Institute of Fermentation Technology and Microbiology, Lodz University of Technology, 90-924 Łódź, Poland.
| | - Justyna Szulc
- Institute of Fermentation Technology and Microbiology, Lodz University of Technology, 90-924 Łódź, Poland.
| | - Bogumił Brycki
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, 60-780 Poznań, Poland.
| | - Beata Gutarowska
- Institute of Fermentation Technology and Microbiology, Lodz University of Technology, 90-924 Łódź, Poland.
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Liu X, Miller AL, Xu H, Waletzki BE, Lu L. Injectable Catalyst-Free Poly(Propylene Fumarate) System Cross-Linked by Strain Promoted Alkyne-Azide Cycloaddition Click Chemistry for Spine Defect Filling. Biomacromolecules 2019; 20:3352-3365. [PMID: 31398020 PMCID: PMC9009285 DOI: 10.1021/acs.biomac.9b00133] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A new PPF-BCN/hyPCL32-N3 injectable system that can be cross-linked by catalyst-free, strain promoted alkyne-azide cycloaddition (SPAAC) click chemistry was developed for tissue engineering applications. The system consisted of two components: PPF-BCN, poly(propylene fumarate) (PPF) functionalized with (1R,8S,9s)-bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN-OH), and hyPCL32-N3, a hyper-branched 32-arm poly(ε-caprolactone) (PCL) dendrimer functionalized with azide as the cross-linker core. Fast SPAAC click reaction allowed the desired gelation of the system without using any toxic initiator or catalyst. Compared to the conventional injectable formulation, e.g., poly(methyl methacrylate) (PMMA), our PPF-BCN/hyPCL32-N3 (abbreviated as PFCL-Click) injectable system showed enhanced biocompatibility and low heat generation during cross-linking. After reaction, the cross-linked PFCL-Click scaffolds supported excellent proliferation and differentiation of preosteoblast cells on the surface. The PFCL-Click system can be successfully injected into vertebral bodies of rabbit spine and can be monitored by X-ray imaging after incorporating zirconium dioxide (ZrO2) powder. With these unique advantages, this injectable system has promising potential for bone defect repair and other tissue engineering and regenerative medicine applications.
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Affiliation(s)
- Xifeng Liu
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - A. Lee Miller
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Hao Xu
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Brian E. Waletzki
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Lichun Lu
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA
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Li KT, Yang CN. Propylene Polymerization Catalyzed by Metallocene /Methylaluminoxane Systems on Rice Husk Ash. Molecules 2019; 24:molecules24081467. [PMID: 31013913 PMCID: PMC6514659 DOI: 10.3390/molecules24081467] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 11/18/2022] Open
Abstract
Silica generated from agricultural waste is more cost effective and environmentally friendly than silica from traditional commercial processes. In this study, spherical silica particles with a diameter of around 120 nm were fabricated from rice husk ash (RHA), and were used to support two bridged zirconcene complexes ((I) Me2Si(Ind)2ZrCl2 and (II) C2H4(Ind)2ZrCl2) for catalyzing propylene polymerization to produce polypropylene (PP) in a temperature range of 40–70 °C and in a solution methylaluminoxane (MAO) range of 0.1–0.6 wt%. Due to its small particle size, RHA-supported catalyst exhibited much higher activity than micro-sized commercial silica-supported catalyst. At the optimum polymerization temperature of 55 °C and with increasing MAO concentration, polymer yield increased proportionally with the increase of number average molecular weight. Compared to (I), (II) produced more polymer molecules but with much shorter chain length, ascribed to the differences of Zr loading and bridge structure. With increasing polymerization temperature, polymer molecular weight decreased rapidly and resulted in a significant change of PP assembly morphology (shape and size). At 55 °C, (I) produced uniform PP assemblies which had dumbbell-like structure with a smooth middle section and two fibrillar ends, while (II) produced spherical PP particles. The dumbbell middle part width was essentially identical to the Batchelor microscale proposed in turbulent mixing theory.
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Ray AS, Ghann WE, Tsoi PS, Szychowski B, Dockery LT, Pak YJ, Li W, Kane MA, Swaan P, Daniel MC. Set of Highly Stable Amine- and Carboxylate-Terminated Dendronized Au Nanoparticles with Dense Coating and Nontoxic Mixed-Dendronized Form. Langmuir 2019; 35:3391-3403. [PMID: 30712354 PMCID: PMC6499480 DOI: 10.1021/acs.langmuir.8b03196] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The synthesis of a novel poly(propyleneimine) (PPI) dendron in gram scale as well as its use in the formation of a highly stable, dendronized gold nanoparticle (AuNP)-based drug delivery platform is described herein. The AuNP-based platform is composed of three complementary parts: (i) a 15 nm AuNP core, (ii) a heterofunctional thioctic acid-terminated tetraethylene glycol spacer, and (iii) a third-generation PPI dendron with a unique protonation profile and diverse end-group functionalization that allows for further derivatization. The prepared dendronized AuNPs are able to withstand several rounds of lyophilization cycles with no sign of aggregation, are stable in phosphate-buffered saline and Hanks' buffer as well as in serum, and are resistant to degradation by glutathione exchange reactions. This nanocarrier platform displays a dense coating, with >1400 dendrons/AuNPs, which will enable very high payload. Furthermore, while amine-terminated AuNPs expectedly showed cytotoxicity against the MCF-7 breast cancer cell line from a NP concentration of 1 nM, the mixed monolayer AuNPs (coated with 40/60 amine/carboxylate dendrons) interestingly did not exhibit any sign of toxicity at concentrations as high as 15 nM, similar to the carboxylate-terminated AuNPs. The described dendronized AuNPs address the current practical need for a stable NP-based drug delivery platform which is scalable and easily conjugable, has long-term stability in solution, and can be conveniently formulated as a powder and redispersed in desired buffer or serum.
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Affiliation(s)
- Arunendra Saha Ray
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, Maryland 21250, United States
| | - William E. Ghann
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, Maryland 21250, United States
| | - Phoebe S. Tsoi
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, Maryland 21250, United States
| | - Brian Szychowski
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, Maryland 21250, United States
| | - Lance T. Dockery
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, Maryland 21250, United States
| | - Yewon J. Pak
- Department of Pharmaceutical Sciences, Center for Nanobiotechnology, University of Maryland, Baltimore, 20 Penn Street, Baltimore, Maryland 21201, United States
| | - Wenjing Li
- Mass Spectrometry Center, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States
| | - Maureen A. Kane
- Mass Spectrometry Center, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, United States
| | - Peter Swaan
- Department of Pharmaceutical Sciences, Center for Nanobiotechnology, University of Maryland, Baltimore, 20 Penn Street, Baltimore, Maryland 21201, United States
| | - Marie-Christine Daniel
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, Maryland 21250, United States
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7
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Malaekeh-Nikouei B, Rezaee M, Gholami L, Sanjar Mousavi N, Kazemi Oskuee R. Synthesis, characterization and evaluation of transfection efficiency of dexamethasone conjugated poly(propyleneimine) nanocarriers for gene delivery# . Pharm Biol 2018; 56:519-527. [PMID: 30270694 PMCID: PMC6171438 DOI: 10.1080/13880209.2018.1517183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/25/2018] [Accepted: 08/15/2018] [Indexed: 06/08/2023]
Abstract
CONTEXT Polypropylenimine (PPI), a cationic dendrimer with defined structure and positive surface charge, is a potent non-viral vector. Dexamethasone (Dexa) conveys to the nucleus through interaction with its intracellular receptor. OBJECTIVE This study develops efficient and non-toxic gene carriers through conjugation of Dexa at various percentages (5, 10 and 20%) to the fourth and the fifth generation PPIs (PPIG4s and PPIG5s). MATERIALS AND METHODS The 21-OH group of Dexa (0.536 mmol) was modified with methanesulfonyl chloride (0.644 mmol) to activate it (Dexa-mesylate), and then it was conjugated to PPIs using Traut's reagent. After dialysis (48 h) and lyophilization, the physicochemical characteristics of products (PPI-Dexa) including zeta potential, size, buffering capacity and DNA condensing capability were investigated and compared with unmodified PPIs. Moreover, the cytotoxicity and transfection activity of the Dexa-modified PPIs were assessed using Neuro2A cells. RESULTS Transfection of PPIG4 was close to PEI 25 kDa. Although the addition of Dexa to PPIG4s did not improve their transfection, their cytotoxicity was improved; especially in the carrier to DNA weight ratios (C/P) of one and two. The Dexa conjugation to PPIG5s enhanced their transfection at C/P ratio of one in both 5% (1.3-fold) and 10% (1.6-fold) Dexa grafting, of which the best result was observed in PPIG5-Dexa 10% at C/P ratio of one. DISCUSSION AND CONCLUSIONS The modification of PPIs with Dexa is a promising approach to improve their cytotoxicity and transfection. The higher optimization of physicochemical characteristics, the better cell transfection and toxicity will be achieved.
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Affiliation(s)
- Bizhan Malaekeh-Nikouei
- Nanotechnology Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehdi Rezaee
- Department of Medical Biotechnology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Leila Gholami
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Reza Kazemi Oskuee
- Targeted Drug Delivery Research Center, Institute of Pharmaceutical Technology, Mashhad University of Medical Sciences, Mashhad, Iran
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8
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Lin Z, Roman MJ, Decker EA, Goddard JM. Synthesis of Iminodiacetate Functionalized Polypropylene Films and Their Efficacy as Antioxidant Active-Packaging Materials. J Agric Food Chem 2016; 64:4606-4617. [PMID: 27243793 DOI: 10.1021/acs.jafc.6b01128] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The introduction of metal-chelating ligands to the food-contact surface of packaging materials may enable the removal of synthetic chelators (e.g., ethylenediamine tetra-acetic acid (EDTA)) from food products. In this study, the metal-chelating ligand iminodiacetate (IDA) was covalently grafted onto polypropylene surfaces to produce metal-chelating active-packaging films. The resulting films were able to chelate 138.1 ± 26 and 210.0 ± 28 nmol/cm(2) Fe(3+) and Cu(2+) ions, respectively, under acidic conditions (pH 3.0). The films demonstrated potent antioxidant efficacy in two model food systems. In an emulsified-oil system, the chelating materials extended the lag phase of both lipid hydroperoxide and hexanal formation from 5 to 25 days and were as effective as EDTA. The degradation half-life of ascorbic acid in an aqueous solution was extended from 5 to 14 days. This work demonstrates the potential application of surface-grafted chelating IDA ligands as effective antioxidant active food-packaging materials.
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Affiliation(s)
- Zhuangsheng Lin
- Department of Food Science, University of Massachusetts, Chenoweth Lab , 102 Holdsworth Way, Amherst, Massachusetts 01003, United States
| | - Maxine J Roman
- Department of Food Science, University of Massachusetts, Chenoweth Lab , 102 Holdsworth Way, Amherst, Massachusetts 01003, United States
| | - Eric A Decker
- Department of Food Science, University of Massachusetts, Chenoweth Lab , 102 Holdsworth Way, Amherst, Massachusetts 01003, United States
- Bioactive Natural Products Research Group, Department of Biochemistry, Faculty of Science, King Abdulaziz University , P.O. Box 80203, Jeddah 21589, Saudi Arabia
| | - Julie M Goddard
- Department of Food Science, University of Massachusetts, Chenoweth Lab , 102 Holdsworth Way, Amherst, Massachusetts 01003, United States
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Zavala-Lagunes E, Ruiz JC, Varca GHC, Bucio E. Synthesis and characterization of stimuli-responsive polypropylene containing N-vinylcaprolactam and N-vinylimidazole obtained by ionizing radiation. Mater Sci Eng C Mater Biol Appl 2016; 67:353-361. [PMID: 27287131 DOI: 10.1016/j.msec.2016.05.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 04/08/2016] [Accepted: 05/12/2016] [Indexed: 01/26/2023]
Abstract
Polypropylene films were grafted with thermo-responsive N-vinylcaprolactam and pH-responsive N-vinylimidazole polymers by means of gamma radiation using pre-irradiation and direct methods, in order to functionalize the films with thermo- and/or pH-responsiveness. The dependence of grafting yield on parameters such as co-monomer concentration, pre-irradiation dose, temperature, and reaction time was evaluated. The samples were characterized by Fourier transform infrared and X-ray photoelectron spectroscopies, differential scanning calorimetry, thermogravimetric analysis, swelling studies in different solvents, and water contact angle. The grafted copolymers presented thermo- and pH-sensitiveness, highlighting their potential as advanced biomaterials, capable of providing adequate environment for hosting and sustained release of antimicrobial drugs bearing cationic moieties, such as groups of diclofenac, while still exhibiting good cytocompatibility.
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Affiliation(s)
- Edgar Zavala-Lagunes
- Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, D.F. 04510, Mexico
| | - Juan-Carlos Ruiz
- División de Ciencias Básicas e Ingeniería, Depto. de Ingeniería de Procesos e Hidráulica, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No. 186, México, D.F. 09340, Mexico
| | - Gustavo H C Varca
- Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitária, 05508-000 São Paulo, SP, Brazil
| | - Emilio Bucio
- Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, D.F. 04510, Mexico.
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Thakur VK, Vennerberg D, Kessler MR. Green aqueous surface modification of polypropylene for novel polymer nanocomposites. ACS Appl Mater Interfaces 2014; 6:9349-9356. [PMID: 24841134 DOI: 10.1021/am501726d] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Polypropylene is one of the most widely used commercial commodity polymers; among many other applications, it is used for electronic and structural applications. Despite its commercial importance, the hydrophobic nature of polypropylene limits its successful application in some fields, in particular for the preparation of polymer nanocomposites. Here, a facile, plasma-assisted, biomimetic, environmentally friendly method was developed to enhance the interfacial interactions in polymer nanocomposites by modifying the surface of polypropylene. Plasma treated polypropylene was surface-modified with polydopamine (PDA) in an aqueous medium without employing other chemicals. The surface modification strategy used here was based on the easy self-polymerization and strong adhesion characteristics of dopamine (DA) under ambient laboratory conditions. The changes in surface characteristics of polypropylene were investigated using FTIR, TGA, and Raman spectroscopy. Subsequently, the surface modified polypropylene was used as the matrix to prepare SiO2-reinforced polymer nanocomposites. These nanocomposites demonstrated superior properties compared to nanocomposites prepared using pristine polypropylene. This simple, environmentally friendly, green method of modifying polypropylene indicated that polydopamine-functionalized polypropylene is a promising material for various high-performance applications.
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Affiliation(s)
- Vijay Kumar Thakur
- School of Mechanical and Materials Engineering, Washington State University , Pullman, Washington, United States
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12
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Li N, Yang X, Zhai G, Li L. Multifunctional pluronic/poly(ethylenimine) nanoparticles for anticancer drug. J Colloid Interface Sci 2010; 350:117-25. [PMID: 20598703 DOI: 10.1016/j.jcis.2010.06.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 05/31/2010] [Accepted: 06/02/2010] [Indexed: 11/17/2022]
Abstract
Nanoparticles consisting of a cross-linked cationic polymer network were prepared using Pluronic F127 and poly(ethylenimine) (PEI) and suggested as a drug delivery system for the anticancer drug Paclitaxel (PTX). In order to further improve the targeting capability of nanoparticles, folic acid (folate) was conjugated to the surface of nanoparticles. The characteristics were determined by various methods such as FT-IR for drug state in nanoparticles and DLS and TEM for particle size and morphology. The results found that the drug-loading content was increased when folate was connected to the surface of these nanoparticles. In vitro release experiments indicated that the PTX-loaded nanoparticles showed sustained release profiles compared to PTX solution, especially when nanoparticles were modified by folate. The cytotoxicity of PTX-loaded nanoparticles against cancer cell in vitro was remarkably higher than that of free drug and was better when folate, whose receptor was highly expressed in various tumors, was conjugated to the surface of these nanoparticles. The data demonstrated that this carrier-based approach to delivery of cytotoxic drugs may enhance tumor specificity and significantly reduce side effects related to systemic toxicity usually observed during cancer chemotherapy.
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Affiliation(s)
- Na Li
- Department of Pharmaceutics, School of Pharmacy, Shandong University, 44 Wenhuaxi Road, Jinan, Shandong Province 250012, China
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Chooi KW, Gray AI, Tetley L, Fan Y, Uchegbu IF. The molecular shape of poly(propylenimine) dendrimer amphiphiles has a profound effect on their self assembly. Langmuir 2010; 26:2301-2316. [PMID: 19860445 DOI: 10.1021/la9027282] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The shape of dendrimer amphiphiles has an unexpected effect on their self-assembly. A series of diaminobutane poly(propylenimine) generation 3 dendrimer (DAB-dendr-(NH(2))(16)) amphiphiles has been synthesized, bearing an average of five (PD5), three (PD3) and one (PD1) palmitoyl group(s) per dendrimer molecule. Additionally DAB-dendr-(NH(2))(16) was derivatized with a layer of poly(ethylene glycol) (PEG, degree of polymerization = 12) groups and conjugated to an average of 1 palmitoyl group at the PEG end (PPD1). A final amphiphile resulted from the conjugation of DAB-dendr-(NH(2))(16) with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-succinimidylpropionate (DSPE-PEG(3400)-SPA), i.e.: DPD5 (with 4 DSPE-PEG arms). The critical micellar concentration in aqueous media followed the trend: DPD5 < PD5 = PD3 < PD1 < PPD1 and amphiphiles eventually formed 10-20 nm monomolecular or multimolecular micelles and/or 200 nm spheres or tubules. Aggregation was entropy driven, as expected, for DPD5, PD5 and PD1 and enthalpy driven with the most hydrophilic compound PPD1, but was unexpectedly enthalpy driven for PD3. PD3 aggregates formed low capacity hydrophobic domains with a limited capacity for encapsulation of cyclosporine A; encapsulation levels (mole drug per mole polymer) were 0.099, 0.014, 0.099, and 0.735 for PD1, PD3, PD5, and DPD5 and, respectively. We conclude that star shaped amphiphiles such as PD3 are sterically hindered from self-assembling into high capacity hydrophobic domains in aqueous media. Amphiphile-membrane interactions were promoted by hydrophobic groups, but diminished by PEG moieties. DPD5 is the most suitable amphiphile for biomedical applications.
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Affiliation(s)
- Kar Wai Chooi
- Department of Pharmaceutics, The School of Pharmacy, University of London, London WC1N 1AX, UK
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14
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Zhang N, Cai ZY, Chang JB. [FTIR study on the synthesis of poly(propylene fumarate) and its copolymer]. Guang Pu Xue Yu Guang Pu Fen Xi 2010; 30:35-37. [PMID: 20302075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Poly(propylene fumarate) (PPF) is one kind of linear biodegradable polyester and the unsaturated double bonds along its main chain can be crosslinked with other olefinic monomers to form three-dimensional networks, and the networks can support tissues. In the present paper, firstly, the intermediate oligomer-bis (2-hydroxypropyl) fumarate (PFP) was synthesized, and then the unsaturated linear polyester PPF was synthesized with the oligomer PFP through melting condensation process. Additionally, on the base of the process, the oligomer bis(2-hydroxypropyl) sebacate (PSP) was synthesized by similar method and then a kind of new copolymer named poly(propylene fumarate-co-propylene sebacate) [P(PF-co-PS)] that comprised bis(2-hydroxypropyl) sebacate segments was synthesized with PFP and PSP by melting condensation. During the synthesis process, the structures of bis(2-hdroxypropyl) fumarate, bis(2-hydroxypropyl) sebacate, PPF and P(PF-co-PS) were characterized by FTIR The results shows that with the polymerization going along, oligomer bis (2-hydroxypropyl) fumarate and bis(2-hydroxypropyl) sebacate converted to PPF or P(PF-co-PS) gradually.
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Affiliation(s)
- Na Zhang
- College of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China.
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15
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Shalumon KT, Jayabalan M. Studies on biodegradation of crosslinked hydroxy terminated-poly(proplyene fumarate) and formation of scaffold for orthopedic applications. J Mater Sci Mater Med 2009; 20 Suppl 1:S161-S171. [PMID: 18584121 DOI: 10.1007/s10856-008-3503-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Accepted: 06/12/2008] [Indexed: 05/26/2023]
Abstract
Biodegradation of crosslinked-hydroxy terminated-poly(proplyene fumarate) (X-HTPPF) has been studied in simulated physiological media to assess the formation of porous scaffold structure for bone growth and remodeling in load bearing orthopedic applications. Variation in crosslink density and surface hydrophilicity of X-HTPPF are observed due to non-stoichiometric mass of reacting partners. These variations influence absorption of the medium and biodegradation during aging. Though the initial absorption of medium is relatively higher with the crosslinked polymer (PNVP1) having 63.6% HT-PPF and 36.4% comonomer n-vinyl pyrrolidone (NVP) during the initial period of aging, the weight loss due to subsequent degradation with time is relatively lesser. PNVP1 undergo slow degradation with formation of fibril structure on the surface. The present crosslinked material PNVP1 is a candidate for the load bearing orthopedic applications.
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Affiliation(s)
- K T Shalumon
- Polymer Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695012, Kerala, India
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16
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Jayabalan M, Shalumon KT, Mitha MK. Injectable biomaterials for minimally invasive orthopedic treatments. J Mater Sci Mater Med 2009; 20:1379-1387. [PMID: 19160023 DOI: 10.1007/s10856-008-3683-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Accepted: 12/29/2008] [Indexed: 05/27/2023]
Abstract
Biodegradable and injectable hydroxy terminated-poly propylene fumarate (HT-PPF) bone cement was developed. The injectable formulation consisting HT-PPF and comonomer, n-vinyl pyrrolidone, calcium phosphate filler, free radical catalyst, accelerator and radiopaque agent sets rapidly to hard mass with low exothermic temperature. The candidate bone cement attains mechanical strength more than the required compressive strength of 5 MPa and compressive modulus 50 MPa. The candidate bone cement resin elicits cell adhesion and cytoplasmic spreading of osteoblast cells. The cured bone cement does not induce intracutaneous irritation and skin sensitization. The candidate bone cement is tissue compatible without eliciting any adverse tissue reactions. The candidate bone cement is osteoconductive and inductive and allow osteointegration and bone remodeling. HT-PPF bone cement is candidate bone cement for minimally invasive radiological procedures for the treatment of bone diseases and spinal compression fractures.
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Affiliation(s)
- M Jayabalan
- Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvanthapuram, India.
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17
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Kim SK, Kim HK, Lee MH, Yoon SW, Do Y. Novel Synthetic Strategy for Developing an Isospecific Unbridged Metallocene System for Propylene Polymerization. Chemistry 2007; 13:9107-14. [PMID: 17676573 DOI: 10.1002/chem.200700512] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
New unbridged zirconocenes functionalized with a Lewis base, [{1-(E-C(6)H(4))-3,4-Me(2)C(5)H(2)}(2)ZrCl(2)] (E = p-NMe(2) (3); p-OMe (4); p-SMe (5)) were prepared and their propylene polymerization behavior was examined. Under methylaluminoxane (MAO) activation at atmospheric monomer pressure, these complexes afford mixtures of polymers exhibiting multimelting transition temperatures and broad molecular weight distribution, whereas they produce completely atactic polypropylenes under [Ph(3)C][B(C(6)F(5))(4)] activation. Stepwise solvent extraction of the polymer mixtures reveals that the polymers consist of amorphous, moderately isotactic, as well as, highly isotactic portions and the weight ratio of each portion is dependent upon reaction temperature. The generation of rigid rac-like cationic active species in situ by the interaction between basic sites of catalysts and acidic sites of the [Me-MAO](-) counter anion is considered to be the origin of the observed isospecificity. Further investigation of bulk polymerization in liquid propylene shows not only a considerable increase of the isotactic portion of the obtained polypropylenes but also apparent isospecificity of 4 and 5/MAO systems even at high temperature. Variation of the Lewis basic center leads to a dramatic change in stereoselectivity of the catalyst in the decreasing order of 3>4>>5, in spite of their structural similarity.
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Affiliation(s)
- Seong Kyun Kim
- Department of Chemistry, School of Molecular Science BK-21, Center for Molecular Design and Synthesis, Polyolefin Materials Research Center, College of Natural Science, Korea Advanced Institute of Science and Technology, Daejeon, Korea
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18
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Tack F, Bakker A, Maes S, Dekeyser N, Bruining M, Elissen-Roman C, Janicot M, Janssen HM, De Waal BFM, Fransen PM, Lou X, Meijer EW, Arien A, Brewster ME. Dendrimeric poly(propylene-imines) as effective delivery agents for DNAzymes: dendrimer synthesis, stability and oligonucleotide complexation. J Control Release 2007; 116:e24-6. [PMID: 17718950 DOI: 10.1016/j.jconrel.2006.09.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- F Tack
- Oncology Discovery Research and Early Development, Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium
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19
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Abstract
The appearance of the gamma phase of a polypropylene-containing terpolymer prepared with a Ziegler-Natta catalyst was analyzed, and a novel strategy to make a polypropylene terpolymer which contains a high content of the gamma phase was experimentally sought. Wide-angle X-ray scattering and differential scanning calorimetry measurements have been conducted to investigate gamma-phase formation. Using a mixed flow of both elongational and shear components (a foaming process), we could introduce a lot of nuclei in the melt by flow-induced crystallization (FIC). The large number of nuclei accounting for the structural disorder during crystallite formation was ascribed to be the reason for gamma-phase formation in the terpolymer crystallization. A uniform distribution of defects in the melt crystallization was the key to obtaining a high content of the gamma phase.
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Affiliation(s)
- Soon Man Hong
- Polymer Hybrid Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul, Korea
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20
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Appelhans D, Zhong Y, Komber H, Friedel P, Oertel U, Scheler U, Morgner N, Kuckling D, Richter S, Seidel J, Brutschy B, Voit B. Oligosaccharide-Modified Poly(propyleneimine) Dendrimers: Synthesis, Structure Determination, and CuII Complexation. Macromol Biosci 2007; 7:373-83. [PMID: 17370276 DOI: 10.1002/mabi.200600260] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The multiple application of reductive amination on primary amino groups of first and second generation poly(propyleneimine) dendrimers is used as a one-pot approach to introduce twice the amount of the oligosaccharide units as surface groups, compared to initially present amino groups in the first and second generation dendrimers. This was proven by (1)H NMR, MALDI-TOF-MS, and LILBID-MS analysis. The size of these dendrimers was determined by the hydrodynamic radius using pulsed field gradient NMR and dynamic light scattering. Molecular modeling confirmed the presence of dense-shell dendrimers. These dendrimers exhibit a generation dependent Cu(II)/dendrimer ratio in an aqueous environment, highlighting these materials as possible metal-carrier systems with a well-defined oligosaccharide protection shell for application in a biological environment.
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Affiliation(s)
- Dietmar Appelhans
- Leibniz Institute of Polymer Research Dresden, Hohe Strasse 6, Dresden, Germany.
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21
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Liao E, Yaszemski M, Krebsbach P, Hollister S. Tissue-Engineered Cartilage Constructs Using Composite Hyaluronic Acid/Collagen I Hydrogels and Designed Poly(Propylene Fumarate) Scaffolds. ACTA ACUST UNITED AC 2007; 13:537-50. [PMID: 17319795 DOI: 10.1089/ten.2006.0117] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Our approach to cartilage tissue-engineering scaffolds combines image-based design and solid free-form (SFF) fabrication to create load-bearing constructs with user-defined parameters. In this study, 3-dimensional scaffolds with cubic and ellipsoidal pore architecture were fabricated using poly(propylene fumarate) (PPF). To increase seeding efficiency and cellular retention, hydrogels were used to deliver cells into the scaffolds. The first objective of this study was to evaluate the concentrations of composite hyaluronic acid (HyA) and collagen I hydrogels best able to stimulate proteoglycan synthesis in porcine chondrocytes in vitro and in vivo. The second objective was to evaluate the differences in extracellular matrix production due to pore geometry and scaffold design. For the in vitro assessment, chondrocytes were encapsulated in collagen I hydrogels with varying concentrations of HyA. Hydrogels were cultured for 1 and 2 weeks, and then the sulfated glycosaminoglycan (sGAG) content was quantified using a dimethyl-methylene blue assay. The concentration of HyA best able to increase ECM synthesis was 5% HyA/collagen I, or 0.23 mg/mL HyA. The results from the in vitro experiment were used as culture parameters for the in vivo analysis. Composite 5% HyA/collagen I or collagen I-only hydrogels were used to seed chondrocytes into SFF-fabricated scaffolds made of PPF with designed cubic or ellipsoidal pore geometry. The scaffolds were implanted subcutaneously in immunocompromised mice for 4 weeks. Histomorphometric analyses of sections stained with Safranin O were used to quantify the amount of ECM deposited by cells in the scaffolds. Scaffolds seeded with 5% HyA/collagen hydrogels had significantly greater areas of positive Safranin O staining (approximately 60%, compared with 30% for scaffolds with collagen I hydrogels only), indicating that greater numbers of chondrocytes retained their metabolic activity in the ectopic environment. These scaffolds also had greater stain intensities (corresponding to greater amounts of sGAG in the ECM) than their counterparts seeded with collagen I hydrogels alone. Significant differences in matrix production were not found between the scaffold pore designs. Overall, these results indicate that a combination of composite HyA hydrogels and designed SFF scaffolds could provide a functional tissue-engineered construct for cartilage repair with enhanced tissue regeneration in a load-bearing scaffold.
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Affiliation(s)
- Elly Liao
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
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22
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Lee KW, Wang S, Lu L, Jabbari E, Currier BL, Yaszemski MJ. Fabrication and Characterization of Poly(Propylene Fumarate) Scaffolds with Controlled Pore Structures Using 3-Dimensional Printing and Injection Molding. ACTA ACUST UNITED AC 2006; 12:2801-11. [PMID: 17518649 DOI: 10.1089/ten.2006.12.2801] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Poly(propylene fumarate) (PPF) is an injectable, biodegradable polymer that has been used for fabricating preformed scaffolds in tissue engineering applications because of in situ crosslinking characteristics. Aiming for understanding the effects of pore structure parameters on bone tissue ingrowth, 3-dimensional (3D) PPF scaffolds with controlled pore architecture have been produced in this study from computer-aided design (CAD) models. We have created original scaffold models with 3 pore sizes (300, 600, and 900 microm) and randomly closed 0%, 10%, 20%, or 30% of total pores from the original models in 3 planes. PPF scaffolds were fabricated by a series steps involving 3D printing of support/build constructs, dissolving build materials, injecting PPF, and dissolving support materials. To investigate the effects of controlled pore size and interconnectivity on scaffolds, we compared the porosities between the models and PPF scaffolds fabricated thereby, examined pore morphologies in surface and cross-section using scanning electron microscopy, and measured permeability using the falling head conductivity test. The thermal properties of the resulting scaffolds as well as uncrosslinked PPF were determined by differential scanning calorimetry and thermogravimetric analysis. Average pore sizes and pore shapes of PPF scaffolds with 600- and 900-microm pores were similar to those of CAD models, but they depended on directions in those with 300-microm pores. Porosity and permeability of PPF scaffolds decreased as the number of closed pores in original models increased, particularly when the pore size was 300 microm as the result of low porosity and pore occlusion. These results show that 3D printing and injection molding technique can be applied to crosslinkable polymers to fabricate 3D porous scaffolds with controlled pore structures, porosity, and permeability using their CAD models.
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Affiliation(s)
- Kee-Won Lee
- Tissue Engineering and Polymeric Biomaterials Laboratory, Departments of Orthopedic Surgery and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Dean D, Wolfe MS, Ahmad Y, Totonchi A, Chen JEK, Fisher JP, Cooke MN, Rimnac CM, Lennon DP, Caplan AI, Topham NS, Mikos AG. Effect of transforming growth factor beta 2 on marrow-infused foam poly(propylene fumarate) tissue-engineered constructs for the repair of critical-size cranial defects in rabbits. ACTA ACUST UNITED AC 2006; 11:923-39. [PMID: 15998232 DOI: 10.1089/ten.2005.11.923] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study investigates the osseointegration of poly(propylene fumarate) (PPF) with beta-tricalcium phosphate (beta-TCP) scaffolds in a critical-size (diameter, 1.6 cm), cranial defect in 4-month-old rabbits (n = 51), killed at 6 or 12 weeks. Two molecular weights of PPF were used to produce bilayer scaffolds with 0.5-mm solid external and 2.0-mm porous internal layers. The porous layer was infused with bone marrow aspirate, with half the animals receiving 0.8 microg of transforming growth factor beta2 (TGF-beta2). No foreign body or inflammatory response was observed externally or on histological examination of explants. Statistical analysis of histological areal and linear measures of new bone formation found significantly more bone at the later sacrifice time, followed by implants receiving TGF-beta2, followed by low molecular weight PPF implants. Approximately 40% of the explants were tested for incorporation strength with a one-point "push-in" test. Because no permanent fixation was used, implant strength (28.37-129.03 N; range, 6.4 to 29.0 lb of resistance) was due entirely to new bone formation. The strongest bone was seen in implants receiving TGF-beta2-infused marrow in animals killed at 12 weeks. These results support the use of PPF as an osteogenic substrate and future research into preoperative fabrication of critical size and supercritical-size cranial prosthetic implants.
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Affiliation(s)
- David Dean
- Department of Neurological Surgery and Research Institute, University Hospitals of Cleveland, Case Western Reserve University, Cleveland, Ohio 44106, USA.
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24
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Bellis E, Hajba L, Kovács B, Sándor K, Kollár L, Kokotos G. Three generations of alpha,gamma-diaminobutyric acid modified poly(propyleneimine) dendrimers and their cisplatin-type platinum complexes. ACTA ACUST UNITED AC 2006; 69:151-61. [PMID: 16624417 DOI: 10.1016/j.jbbm.2006.02.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2005] [Revised: 02/01/2006] [Accepted: 02/09/2006] [Indexed: 10/24/2022]
Abstract
Three generations of alpha,gamma-diaminobutyric acid modified poly(propyleneimine) dendrimers [DAB(AM)n, n = 4, 8, 16] containing 4, 8, 16 free amino groups were coupled with Boc-protected alpha,gamma-diaminobutyric acid (DABA) moieties in high yields. These modified dendrimers were deprotected and the chiral dendritic amines with 8, 16 and 32 amino groups on the surface were isolated in excellent yields. Dendrimers with cisplatin moieties at the periphery were obtained in the reaction of the free amine dendrimers and potassium tetrachloroplatinate(II). The highly insoluble complexes were isolated as hydrates and characterized by means of IR, TGA and elemental analysis.
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Affiliation(s)
- E Bellis
- University of Athens, Laboratory of Organic Chemistry, 15771 Athens, Greece
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25
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Lin CY, Schek RM, Mistry AS, Shi X, Mikos AG, Krebsbach PH, Hollister SJ. Functional bone engineering using ex vivo gene therapy and topology-optimized, biodegradable polymer composite scaffolds. ACTA ACUST UNITED AC 2005; 11:1589-98. [PMID: 16259612 DOI: 10.1089/ten.2005.11.1589] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Bone tissue engineering could provide an alternative to conventional treatments for fracture nonunion, spinal fusion, joint replacement, and pathological loss of bone. However, this approach will require a biocompatible matrix to allow progenitor cell delivery and support tissue invasion. The construct must also support physiological loads as it degrades to allow the regenerated tissue to bear an increasing load. To meet these complex requirements, we have employed topology-optimized design and solid free-form fabrication to manufacture biodegradable poly(propylene fumarate)/beta-tricalcium phosphate composites. These scaffolds were seeded with primary human fibroblasts transduced with an adenovirus expressing bone morphogenetic protein-7 and implanted subcutaneously in mice. Specimens were evaluated by microcomputed tomography, compressive testing, and histological staining. New bone was localized on the scaffold surface and closely followed its designed contours. Furthermore, the total stiffness of the constructs was retained for up to 12 weeks after implantation, as scaffold degradation and tissue invasion took place.
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Affiliation(s)
- Chia-Ying Lin
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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26
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Hedberg EL, Kroese-Deutman HC, Shih CK, Lemoine JJ, Liebschner MAK, Miller MJ, Yasko AW, Crowther RS, Carney DH, Mikos AG, Jansen JA. Methods: A Comparative Analysis of Radiography, Microcomputed Tomography, and Histology for Bone Tissue Engineering. ACTA ACUST UNITED AC 2005; 11:1356-67. [PMID: 16259591 DOI: 10.1089/ten.2005.11.1356] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This study focused on the assessment of radiography, microcomputed tomography, and histology for the evaluation of bone formation in a 15.0-mm defect in the rabbit radius after the implantation of a tissue-engineered construct. Radiography was found to be useful as a noninvasive method for obtaining images of calcified tissue throughout the time course of the experiment. With this method, however, image quality was low, making it difficult to obtain precise information about the location and quantity of the bone formed. Microcomputed tomography was used to create three-dimensional reconstructions of the bone (25-microm resolution). These reconstructions allowed for greater spatial resolution than the radiography, but did not allow for imaging of the implanted scaffold material or the surrounding, nonmineralized tissue. To visualize all materials within the defect area at the cellular level, histology was used. Histological analysis, however, is a destructive technique that did not allow for any further analysis of the samples. Each technique examined here has its own advantages and limitations, but each yields unique information regarding bone regeneration. It is only through the use of all three techniques that complete characterization of the bone growth and tissue/construct responses after implantation in vivo.
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27
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Zhao W, Yang D, Li Z, Xu T. [Progress in researches on the synthesis of poly (propylene fumarate) and its crosslinking characteristics]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2005; 22:381-4. [PMID: 15884560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Poly (propylene fumarate) is an unsaturated linear polyester, which degrades, in the presence of water, into propylene glycol and fumaric acid, and the degradation products can be cleared from the human body by normal metabolic processes. In this paper, different methods of the synthesis of PPF are listed, the crosslinking characteristics of polymerizing composite as well as the mechanical properties of cross-linked composite are discussed, and the potentialities of PPF composite used as particularly degradable polymeric cement for orthopedic application are reviewed.
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Affiliation(s)
- Wei Zhao
- School of Material Science and Engineering, Tianjin University, Tianjin 300072, China
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28
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Murugan E, Sherman RL, Spivey HO, Ford WT. Catalysis by hydrophobically modified poly(propylenimine) dendrimers having quaternary ammonium and tertiary amine functionality. Langmuir 2004; 20:8307-8312. [PMID: 15350107 DOI: 10.1021/la049420i] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Four different quaternary ammonium chloride-modified poly(propylenimine) (PPI) dendrimers were synthesized by alkylation of a PPI dendrimer having eight dimethylamino end groups with 1-bromooctane or 1-bromododecane. By varying the mole ratio of alkyl bromide to dendrimer, averages of 4-10 quaternary ammonium groups were formed. The new amphiphilic dendrimers are surface active and are micellar catalysts in water. The dendrimers have critical aggregation concentrations between 8.5 x 10(-4) and 9.0 x 10(-5) M. Decarboxylation of 6-nitrobenzisoxazole-3-carboxylate at 25 degrees C was 650 times faster than in water alone in the presence of a dendrimer quaternized with eight dodecyl chains at a concentration of 2.45 mM in quaternary ammonium groups. The order of the catalytic efficiency of the new dendrimers decreased with the length and number of hydrophobic alkyl groups in the order (C(12))(8) > (C(12))(4) > (C(8))(10) > (C(8))(5). The pseudo-first-order rate constants for basic hydrolysis of p-nitrophenyl hexanoate in pH 9.4 buffer at 30 degrees C using the (C(12))(8) and (C(12))(4) dendrimers were 26 and 13 times higher than those for hydrolysis with no dendrimer. The kinetic data were fit to a single-site binding model to evaluate the contributions of binding constants of reactants to the dendrimers and catalytic rate constants of the bound species to the overall catalytic activity.
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Affiliation(s)
- Eagambaram Murugan
- Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, USA
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29
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Wang JF, Wang L, Zhao ZR, Wang WQ, Chen T. Study on the distribution of active centers in novel low Ti-loading MgCl2-supported Ziegler-Natta catalyst. J Zhejiang Univ Sci 2004; 5:912-917. [PMID: 15236474 DOI: 10.1007/bf02947597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Novel MgCl2-supported Ziegler-Natta (Z-N) catalysts prepared using a new one-pot ball milling method can effectively control the amounts of Ti-loading in the catalysts. Complex GPC data on polypropylene synthesized by these novel catalysts were analyzed using the method of fitting the molecular weight distribution (MWD) curves with a multiple Flory-Schulz function. It was found that multiple active centers exist in these novel catalysts. Detailed study of the effects of the Ti-loadings in the catalysts on the distribution of the active centers showed that the Ti-loadings in the novel MgCl2-supported Z-N catalysts might affect the proportion of each type of active centers; and might be the main factor responsible for the effect of the Ti-loadings on the microstructure, the molecular weight and molecular weight distribution width of the resultant polymer, the catalytic activity and polymerization kinetics.
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Affiliation(s)
- Jian-Feng Wang
- State Key Lab of Polymer Reaction Engineering, College of Materials Science and Chemical Engineering, Zhejiang University, Hangzhou 310027, China
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Vicinelli V, Ceroni P, Maestri M, Lazzari M, Balzani V, Lee SK, Heyst Jv JV, Vogtle F. Photochemical and photophysical properties of a poly(propylene amine) dendrimer functionalised with E-stilbene units. Org Biomol Chem 2004; 2:2207-13. [PMID: 15280957 DOI: 10.1039/b404463k] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A second generation poly(propylene amine) dendrimer functionalized at the periphery with eight E-stilbene and eight 4-tert-butylbenzenesulfonyl units has been prepared. The absorption spectrum, fluorescence spectrum and decay, E<==>Z photoisomerization, and photocyclization of the Z-isomer of the stilbene units have been investigated in air equilibrated acetonitrile solutions. For comparison purposes, a reference compound of the peripheral dendrimer units, namely 4-tert-butyl-N-propyl-N-(4-styryl-benzyl)-benzenesulfonamide, has also been studied. The quantum yield of the E-->Z photoisomerization reaction (0.30) and the fluorescence quantum yield of the E isomer (0.014) are substantially smaller for the units appended to the dendrimer compared to those of the reference compound (0.50 and 0.046, respectively). The presence of a red tail and the biexponential decay of the emission band of the dendrimer indicate formation of excimers between the stilbene units appended at the poly(propylene amine) dendritic structure. Under the experimental conditions used (lambda(exc)= 313 nm), a Z/E photostationary state (around 9 : 1 for both reference compound and dendrimer ) is reached in the time scale of minutes. On continuing irradiation, other photoreactions take place in the time scale of hours: the stilbene moiety of compound undergoes photocyclization to phenanthrene (quantum yield 0.015), whereas in dendrimer photocyclization to phenanthrene is accompanied by other processes, including a photoreaction involving the internal amine groups.
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Affiliation(s)
- Veronica Vicinelli
- Dipartimento di Chimica "G. Ciamician", Universita di Bologna, via Selmi 2, I-40126 Bologna, Italy
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31
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Sillars DR, Landis CR. Catalytic propene polymerization: determination of propagation, termination, and epimerization kinetics by direct NMR observation of the (EBI)Zr(MeB(C6F5)3)propenyl catalyst species. J Am Chem Soc 2003; 125:9894-5. [PMID: 12914431 DOI: 10.1021/ja036393u] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Treatment of (EBI)ZrMe2 with B(C6F5)3 and 100 equiv of 1-hexene in toluene-d8 at -40 degrees C for 1 h, followed by addition of >5 equiv of propene, generates a living polypropene catalyst (3) with a polyhexene "tail". Upon further addition of propene, speciation of the catalyst and propagation kinetics are measured directly by NMR, yielding a propagation rate law that is first order in [propene] and [living catalyst] with a rate constant of 2.6 M-1 s-1 at -40 degrees C and the activation parameters DeltaH = 3.4(0.2) kcal/mol and DeltaS = -42(2) cal/(mol K). In the absence of propene, elimination of vinylidene-terminated polymer is observed with a first-order rate constant of 3.3 (0.5) x 10-5 s-1 at -40 degrees C and DeltaH = 12.9(1.4) kcal/mol and DeltaS = -23(5) cal/(mol K). Use of 1-13C-propene and 1,1-2H-2,3-13C-propene and 1H, 19F, and 13C NMR spectroscopy provide rigorous characterization of the living catalyst and enable the first direct observation of both 1,3-isomerization and chain-end epimerization processes at a metallocene catalyst. Isomerization and epimerization occur with rates that are similar to that of vinylidene termination and are consistent with previous mechanistic hypotheses featuring isomerization via a tertiary alkyl intermediate and switching between enantiofaces of the coordinated alkene.
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Affiliation(s)
- Douglass R Sillars
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, WI 53706, USA
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32
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Shung AK, Timmer MD, Jo S, Engel PS, Mikos AG. Kinetics of poly(propylene fumarate) synthesis by step polymerization of diethyl fumarate and propylene glycol using zinc chloride as a catalyst. J Biomater Sci Polym Ed 2002; 13:95-108. [PMID: 12003078 DOI: 10.1163/156856202753525963] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Diethyl fumarate and propylene glycol were reacted in the presence of a zinc chloride catalyst to synthesize poly(propylene fumarate) (PPF) over a period of 12 hours. The kinetics of the transesterification polymerization at 130 degrees C, 150 degrees C, and 200 degrees C were determined by gel permeation chromatography (GPC) analysis. The initial rate of polymerization at each temperature was quantified by calculating the rate of change of the number average molecular weight (Mn). At 200 degrees C, gelation of the PPF occurred after 4 h. GPC analysis of the reaction showed that PPF synthesized at 150 degrees C had a higher final Mn of 4600 (+/- 190) and a higher weight average molecular weight of 10500 (+/- 760) than at 130 degrees C (n = 3). The chemical structure of the PPF was verified by NMR and FT-IR analysis. This study demonstrated that the maximum Mn of PPF by a transesterification reaction is limited due to gelation of PPF at high temperature.
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Affiliation(s)
- Albert K Shung
- Department of Bioengineering, Rice University, Houston, TX 77251-1892, USA
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33
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Tanahashi K, Jo S, Mikos AG. Synthesis and characterization of biodegradable cationic poly(propylene fumarate-co-ethylene glycol) copolymer hydrogels modified with agmatine for enhanced cell adhesion. Biomacromolecules 2002; 3:1030-7. [PMID: 12217050 DOI: 10.1021/bm0200433] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We synthesized positively charged biodegradable hydrogels by cross-linking of agmatine-modified poly(ethylene glycol)-tethered fumarate (Agm-PEGF) and poly(propylene fumarate-co-ethylene glycol) (P(PF-co-EG)) to investigate the effect of the guanidino groups of the agmatine on hydrogel swelling behavior and smooth muscle cell adhesion to the hydrogels. The weight swelling ratio of these hydrogels at pH 7.0 increased from 279 +/- 4 to 306 +/- 7% as the initial Agm-PEGF content increased from 0 to 200 mg/g of P(PF-co-EG), respectively. The diffusional exponents, n, during the initial phase of water uptake were independent of the initial Agm-PEGF content and were determined to be 0.66 +/- 0.08, 0.71 +/- 0.07, and 0.60 +/- 0.05 for respective initial Agm-PEGF contents of 0, 100, and 200 mg/g. The heat of fusion of water present in the hydrogels increased from 214 +/- 11 to 254 +/- 4 J/g as the initial Agm-PEGF content increased from 0 to 200 mg/g. The number of adherent smooth muscle cells increased dose-dependently from 15 +/- 6 to 75 +/- 7% of the initial seeding density as the initial Agm-PEGF content increased from 0 to 200 mg/g. These results suggest that the incorporation of the guanidino groups of agmatine into P(PF-co-EG) hydrogels increases the hydrogel free water content and the total water content of the hydrogels and also enhances cell adhesion to the hydrogels.
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Affiliation(s)
- Kazuhiro Tanahashi
- Department of Bioengineering, Rice University, MS-142, P.O.Box 1892, Houston, TX 77251-1892, USA
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Behravesh E, Jo S, Zygourakis K, Mikos AG. Synthesis of in situ cross-linkable macroporous biodegradable poly(propylene fumarate-co-ethylene glycol) hydrogels. Biomacromolecules 2002; 3:374-81. [PMID: 11888325 DOI: 10.1021/bm010158r] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study describes a synthesis method of biodegradable macroporous hydrogels suitable as in situ cross-linkable biomaterials. Macroporous hydrogels were based on poly(propylene fumarate-co-ethylene glycol) and prepared via coupled free radical and pore formation reactions. Cross-linking was initiated by a pair of redox initiators, ammonium persulfate and L-ascorbic acid. Pores were formed by the reaction between L-ascorbic acid and sodium bicarbonate, a basic component, which evolved carbon dioxide. Sol fraction of the hydrogels was varied from 0.06 +/- 0.01 to 0.64 +/- 0.01. A stereological approach was used to analyze the morphological properties of the macroporous hydrogels by relating the morphological properties of thin sections to the original three-dimensional macroporous hydrogel. Prepared macroporous hydrogels had porosities between 0.43 +/- 0.08 and 0.84 +/- 0.02 and surface area densities between 55 +/- 3 and 108 +/- 7 cm(-1). Sodium bicarbonate concentration had the greatest effect on both the porosity and surface area density. The effect of copolymer formulation on the porosity and surface area density was insignificant. From thin sections of the macroporous hydrogels, the profile size distributions were determined as an estimate of the pore size distribution. Two formulations synthesized with varying L-ascorbic acid concentration of 0.05 and 0.1 M had median profile sizes of 50-100 and 150-200 microm, respectively. This novel synthesis method allows for the in situ cross-linking of biodegradable macroporous hydrogels with morpholological properties suitable for consideration as an injectable tissue engineering scaffold.
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Affiliation(s)
- Esfandiar Behravesh
- Department of Bioengineering, Rice University, MS-142, PO Box 1892, Houston, Texas 77251-1892, USA
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35
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Behravesh E, Shung AK, Jo S, Mikos AG. Synthesis and characterization of triblock copolymers of methoxy poly(ethylene glycol) and poly(propylene fumarate). Biomacromolecules 2002; 3:153-8. [PMID: 11866568 DOI: 10.1021/bm010137x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amphiphilic block copolymers were synthesized by transesterification of hydrophilic methoxy poly(ethylene glycol) (mPEG) and hydrophobic poly(propylene fumarate) (PPF) and characterized. Four block copolymers were synthesized with a 2:1 mPEG:PPF molar ratio and mPEGs of molecular weights 570, 800, 1960, and 5190 and PPF of molecular weight 1570 as determined by NMR. The copolymers synthesized with mPEG of molecular weights 570 and 800 had 1.9 and 1.8 mPEG blocks per copolymer, respectively, as measured by NMR, representing an ABA-type block copolymer. The number of mPEG blocks of the copolymer decreased with increasing mPEG block length to as low as 1.5 mPEG blocks for copolymer synthesized with mPEG of molecular weight 5190. At a concentration range of 5-25 wt % in phosphate-buffered saline, copolymers synthesized with mPEG molecular weights of 570 and 800 possessed lower critical solution temperatures (LCST) between 40 and 45 degrees C and between 55 and 60 degrees C, respectively. Aqueous solutions of copolymer synthesized with mPEG 570 and 800 also experienced thermoreversible gelation. The sol-gel transition temperature was dependent on the sodium chloride concentration as well as the mPEG block length. The copolymer synthesized from mPEG 570 had a transition temperature between 40 and 20 degrees C with salt concentrations between 1 and 10 wt %, while the sol-gel transition temperatures of the copolymer synthesized from mPEG molecular weight 800 were higher in the range 75-30 degrees C with salt concentrations between 1 and 15 wt %. These novel thermoreversible copolymers are the first biodegradable copolymers with unsaturated double bonds along their macromolecular chain that can undergo both physical and chemical gelation and hold great promise for drug delivery and tissue engineering applications.
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Affiliation(s)
- Esfandiar Behravesh
- Department of Bioengineering, Rice University, MS-142, P.O. Box 1892, Houston, Texas 77251-1892, USA
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Planas J, Kozlowski A, Harris JM, Tjerneld F, Hahn-Hägerdal B. Novel polymer-polymer conjugates for recovery of lactic acid by aqueous two-phase extraction. Biotechnol Bioeng 1999; 66:211-8. [PMID: 10578091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
A new family of polymer conjugates is proposed to overcome constraints in the applicability of aqueous two-phase systems for the recovery of lactic acid. Polyethylene glycol-polyethylenimine (PEI) conjugates and ethylene oxide propylene oxide-PEI (EOPO-PEI) conjugates were synthesized. Aqueous two-phase systems were generated when the conjugates were mixed with fractionated dextran or crude hydrolyzed starch. With 2% phosphate buffer in the systems, phase diagrams with critical points of 3.9% EOPO-PEI-3.8% dextran (DEX) and 3.5% EOPO-PEI-7.9% crude starch were obtained. The phase separation temperature of 10% EOPO-PEI solutions titrated with lactic acid to pH 6 was 35 degrees C at 5% phosphate, and increased linearly to 63 degrees C at 2% phosphate. Lactic acid partitioned to the top conjugate-rich phase of the new aqueous two-phase systems. In particular, the lactic acid partition coefficient was 2.1 in 10% EOPO-PEI-8% DEX systems containing 2% phosphate. In the same systems, the partitioning of the lactic acid bacterium, Lactococcus lactis subsp. lactis, was 0.45. The partitioning of propionic, succinic, and citric acids was also determined in the new aqueous two-phase systems.
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Affiliation(s)
- J Planas
- Department of Applied Microbiology, University of Lund, PO Box 124, SE-221 00 Lund, Sweden
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Abstract
The in vitro cytotoxicity and in vivo biocompatibility of poly(propylene fumarate-co-ethylene glycol) [P(PF-co-EG)] hydrogels were assessed in order to investigate the influence of poly(ethylene glycol) molecular weight and copolymer composition. These materials have application as injectable cardiovascular implants; cytotoxicity due to leachable products, as well as inflammation caused by the biomaterial itself, may ultimately affect the biocompatibility of the implant. We utilized a 7-day in vitro cytotoxicity assay to quantify cell density and cellular proliferation in the presence of copolymer films. The copolymer films exhibited slight to moderate cytotoxicity toward cultured endothelial cells, showing 20-86% viability relative to controls. Cell viability increased with an increasing weight percent of PEG or, to a lesser extent, the molecular weight of PEG. In vivo biocompatibility was assessed using a cage implantation model over a 21-day time period. This system was used to characterize the local cellular and humoral inflammatory response in the surrounding exudate, as well as the size and density of macrophages adherent to the material itself. All copolymer formulations exhibited excellent biocompatibility relative to controls with no significant differences in total leukocyte count among the different formulations. The in vivo inflammatory reaction displayed normal wound healing over 21 days as shown by a progressive decrease in both leukocyte concentration and enzymatic activity. The surface coverage of the copolymer films remained relatively constant from 7 to 21 days. There were no cells larger than 0.003 mm2, which was previously shown to be the threshold value for foreign-body giant cells. These data suggest that P(PF-co-EG) hydrogels have potential for use as injectable biomaterials.
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Affiliation(s)
- L J Suggs
- Institute of Biosciences and Bioengineering and Department of Chemical Engineering, Rice University, Houston, Texas 77251-1892, USA
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Peter SJ, Suggs LJ, Yaszemski MJ, Engel PS, Mikos AG. Synthesis of poly(propylene fumarate) by acylation of propylene glycol in the presence of a proton scavenger. J Biomater Sci Polym Ed 1999; 10:363-73. [PMID: 10189104 DOI: 10.1163/156856299x00423] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To synthesize high molecular weight poly(propylene fumarate) (PPF), fumaryl chloride and propylene glycol were reacted in the presence of potassium carbonate, which serves as a proton scavenger. Transesterification of the resulting low molecular weight oligomer led to a polymer with greater molecular weight than those from previous reaction methods without requiring the use of a catalyst. According to two-dimensional NMR, the backbone structure of this polymer was as expected and contained no byproducts formed by acid catalyzed addition across the fumarate double bond. Kinetic studies of the transesterification showed that the molecular weight reached a final Mn of 4900 (+/-700) and Mw of 9100 (+/-1300) after 16 h, while the polydispersity index remained below 1.8 throughout the reaction. Thus the PPF synthesized by the new method is of higher molecular weight and greater purity than our previously prepared material.
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Affiliation(s)
- S J Peter
- Department of Chemical Engineering, Rice University, Houston, TX 77005-1892, USA
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Lück M, Pistel KF, Li YX, Blunk T, Müller RH, Kissel T. Plasma protein adsorption on biodegradable microspheres consisting of poly(D,L-lactide-co-glycolide), poly(L-lactide) or ABA triblock copolymers containing poly(oxyethylene). Influence of production method and polymer composition. J Control Release 1998; 55:107-20. [PMID: 9795026 DOI: 10.1016/s0168-3659(98)00030-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Biodegradable particulate systems have been considered as parenteral drug delivery systems. The adsorption of plasma proteins on micro- and nanoparticles is determined by the surface properties and may, in turn, strongly influence the biocompatibility and biodistribution of both carriers. In the present study the influence of the polymer composition and the production method of microspheres on the in vitro plasma protein adsorption were investigated using two-dimensional electrophoresis (2-DE). Microparticles were prepared from poly(l-lactide) (l-PLA), poly(d,l-lactide-co-glycolide) (PLGA), and ABA triblock copolymers containing hydrophilic poly(oxyethylene) (B-blocks) domains connected to hydrophobic polyesters (A-blocks). Two different microencapsulation methods were employed, namely the w/o/w emulsion solvent evaporation method and the spray-drying technique. It could be demonstrated that the polymer composition and, especially, the encapsulation technique, influenced the interactions with plasma proteins significantly. For example, the percentages of several apolipoproteins in the plasma protein adsorption patterns of spray-dried PLGA- and l-PLA-particles were distinctly higher when compared to the adsorption patterns of the particles produced by the w/o/w-technique. Some adsorbed proteins were found to be characteristic or even specific for particles produced by the same method or consisting of identical polymers. Polyvinyl alcohol used as stabilizer in the w/o/w-technique may decisively influence the surface properties relevant for protein adsorption. The plasma protein adsorption on particles composed of ABA copolymers was drastically reduced when compared to microspheres made from pure polyesters. The adsorption patterns of ABA-particles were dominated by albumin. The plasma protein adsorption patterns detected on the different microspheres are likely to affect their in vivo performance as parenteral drug delivery systems.
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Affiliation(s)
- M Lück
- Department of Pharmaceutics, Biopharmaceutics and Biotechnology, The Free University of Berlin, Kelchstrasse 31, D-12169 Berlin, Germany
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Suggs LJ, Kao EY, Palombo LL, Krishnan RS, Widmer MS, Mikos AG. Preparation and characterization of poly(propylene fumarate-co-ethylene glycol) hydrogels. J Biomater Sci Polym Ed 1998; 9:653-66. [PMID: 9686333 DOI: 10.1163/156856298x00073] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We describe the preparation and bulk characterization of a cross-linked poly(propylene fumarate-co-ethylene glycol), p(PF-co-EG), hydrogel. Eight block copolymer formulations were made varying four different design parameters including: poly(ethylene glycol) (PEG) molecular weight, poly(propylene fumarate) (PPF) molecular weight, copolymer molecular weight, and ratio of PEG to PPF. Two different cross-linking formulations were also tested, one with a cross-linking monomer and one without. The extent of the cross-linking reaction and the degree of swelling in aqueous solution were determined on copolymer formulations made without a cross-linking monomer. The values of molecular weight between cross-links, Mc ranged from 300 +/- 120 to 1190 +/- 320 as determined from swelling data (n = 3). The equilibrium volume swelling ratios, Q, varied from 1.5 +/- 0.1 to 3.0 +/- 0.1. This ratio was found to increase with increasing PEG content in the copolymer and decrease with increasing PPF molecular weight. The values for complex dynamic elastic moduli magnitudes of E*, ranged from 0.9 +/- 0.2 to 13.1 +/- 1.1 MPa for the formulations with the cross-linking monomer, N-vinyl pyrrolidinone (VP) (n = 3). The ultimate tensile stresses on the formulations made with VP ranged from 0.15 +/- 0.03 to 1.44 +/- 1.06 MPa, and tensile moduli ranged from 1.11 +/- 0.20 to 20.66 +/- 2.42 MPa (n = 5). All of the mechanical properties increased with increasing PPF molecular weight and decreased with increasing PEG content in the copolymer. These data show that the physical properties of p(PF-co-EG) hydrogels can be tailored for specific applications by altering the material composition.
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Affiliation(s)
- L J Suggs
- Cox Laboratory for Biomedical Engineering, Rice University, Houston, TX 77251-1892, USA
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Abstract
Nonionic block copolymers synthesized from ethylene oxide and propylene oxide were developed specifically for use as surfactants. Because the sizes and relative positions of the hydrophobic polyoxypropylene (POP) and hydrophilic polyoxyethylene (POE) blocks can be altered during synthesis, copolymers with significantly different surfactant characteristics can be produced. Copolymers of this type are currently used as excipients in a wide variety of pharmaceutical products where they act as emulsifying, wetting, thickening, stabilizing, and dispersing agents. Copolymers with unique physicochemical properties have recently been developed through the use of new manufacturing and purification techniques, and these copolymers are being used as drug-active and drug-delivery components. In this review, we summarize the current status of these new copolymers in terms of research and product development. This includes the use of new, high molecular weight copolymers as vaccine adjuvants and as vaccine-delivery vehicles. The use of purified, pharmaceutical-grade copolymers as anti-infectives and as antibiotic-delivery systems for the treatment of established bacterial and viral infections is also reviewed. These novel uses for copolymers are significantly different from the excipient uses common to this type of product and demonstrate the widespread utility of synthetic surfactant polymers.
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Abstract
Sulphonated polyisoprenes (SPIPs) having various molecular weights and sulphonate group contents were synthesized and their anticoagulant activities investigated. Prolongation of blood clotting time, prothrombin time and activated partial thromboplastin time were observed in the presence of SPIPs. The anticoagulant activity in blood was affected mainly by total sulphonate group concentration; however, the molecular weight of SPIPs also had an influence. Since thrombin time was prolonged by SPIPs for a condition which supplied enough thrombin to the assay system, interactions between fibrinogen and SPIPs may be one of the anticoagulant mechanisms of SPIPs.
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Affiliation(s)
- Y Tamada
- Japan Synthetic Rubber Co. Ltd., Tsukuba Research Laboratory, Ibaraki.
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43
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Peter SJ, Yaszemski MJ, Suggs LJ, Payne RG, Langer R, Hayes WC, Unroe MR, Alemany LB, Engel PS, Mikos AG. Characterization of partially saturated poly(propylene fumarate) for orthopaedic application. J Biomater Sci Polym Ed 1997; 8:893-904. [PMID: 9342654 DOI: 10.1163/156856297x00074] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A partially saturated linear polyester based on poly(propylene fumarate) (PPF) was synthesized for potential application in filling skeletal defects. The synthesis was carried out according to a two-step reaction scheme. Propylene glycol and fumaryl chloride were first combined to form an intermediate fumaric diester. The intermediate was then subjected to a transesterification to form the PPF-based polymer. This method allowed for production of a polymer with a number average molecular weight up to 1500 and a polydispersity index of 2.8 and below. The polymeric backbone structure was investigated through the use of FTIR and NMR. Kinetic studies of the transesterification allowed mapping of the molecular weight increase with reaction time. The final product was also characterized by thermal and solubility analysis.
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Affiliation(s)
- S J Peter
- Cox Laboratory for Biomedical Engineering, Rice University, Houston, TX 77005-1892, USA
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Abstract
The creep and wear behaviour of Chirulen, Hylamer and Enduron, materials which differ only in their manufacturing procedures, was examined and compared. Chirulen is manufactured by being pressed into form by plates, whereas Hylamer and Enduron are shaped by tubes. Hylamer differs from Enduron in that intermediate material processing is undertaken with the goal of improving the initial material. The wear and deformation rate was determined by means of the ring-on-disc testing device after 360,000 cycles and after 1.0 x 10(6) cycles, respectively. The static tests for the determination of wear were carried out at a contact stress of 5.62 MPa and a testing time of 100 h in analogy to the ring-on-disc tests. Chirulen and Hylamer demonstrated comparable wear with a tendency toward a lower wear rate in Hylamer, while Enduron presented a clearly higher wear rate.
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Affiliation(s)
- J Huber
- Klinikum Grosshadern, Ludwig-Maximilians-Universität München
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45
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Domb AJ, Manor N, Elmalak O. Biodegradable bone cement compositions based on acrylate and epoxide terminated poly(propylene fumarate) oligomers and calcium salt compositions. Biomaterials 1996; 17:411-7. [PMID: 8938235 DOI: 10.1016/0142-9612(96)89657-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The synthesis of biodegradable bone cement compositions is presented. These bone cement compositions can be applied as a putty-like mixture and harden to a strong material in a bone fracture. They degrade from the site of application to allow the ingrowth of new bone for complete healing of the bone fracture. The bone cement is composed of a solid particulate phase dispersed in an initially liquid polymeric phase, which can be hardened by cross-linking. The polymeric phase is a low-molecular-weight liquid poly(propylene fumarate) (PPF) containing double bonds available for cross-linking. The solid particulate phase consists of calcium carbonate and tricalcium phosphate. PPF oligomers of Mw = 1800 and Mn = 750 were prepared from the condensation of non-volatile bis(2-hydroxypropyl fumarate) and propylene-bis(hydrogen maleate) trimers. PPF terminated divinyl and diepoxide derivatives were obtained from the reactions between PPF diol and acryloyl chloride or epichlorhydrin, respectively. Putty-like cement compositions were prepared from a mixture of 30 wt% polymer phase containing benzoyl peroxide-dimethyl toluidine as polymerization catalyst and 70 wt% calcium salts. The divinyl and diepoxide terminated PPF oligomers provided a high strength composition of between 30 and 129 MPa which is suitable for bone cement applications. In vitro hydrolysis of the composites showed little weight loss with the compressive strength remaining above 20 MPa after 4 weeks in buffer solution. Compositions of the PPF oligomers cross-linked without calcium salts showed a gradual weight loss (10-65 wt% after 4 weeks) when placed in buffer solution followed by high water absorption (18-200 wt% after 4 weeks), with the epoxide terminated PPF being the least to degrade or absorb water.
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Affiliation(s)
- A J Domb
- The Hebrew University of Jerusalem, School of Pharmacy-Faculty of Medicine, Department of Pharmaceutical Chemistry, Jerusalem, Israel
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Affiliation(s)
- I N Topchieva
- Department of Chemistry, Moscow State University, Russia
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Abstract
Extruded filaments of unmodified polypropylene (PP) with and without antioxidant were implanted subcutaneously in hamsters in order to determine their rate of degradation. Specimens were removed periodically during a 5 month test period and analyzed by infrared spectroscopy and dynamic mechanical testing. The analyses show that degradation beigns to occur after only a few days. Although the reaction sequence is not known, several factors suggest that the in vivo degradation process is similar to autoxidation which occurs in air or oxygen. The infrared data indicate that the hydroxyl content of the implants increases at a rate of 0.061 mg/g polypropylene per day during the initiation phase of the reaction. An induction time of 108 days was extablished. Carbonyl bonds appear after an implantation time of 50--90 days and increase therafter. Mechanical tests indicate a decrease in the dynamic loss tangent, tan delta, during the first month of implantation for unmodified polypropylene. No change in the infrared spectra or tan delta was observed, however, for implants containing an antioxidant. Thus, it is apparent that polypropylene filaments implanted subcutaneously in hamsters degrade by an oxidation process which is retarded effectively by using an antioxidant. While the findings reported are specific to subcutaneous polypropylene implants, they suggest that degradation of other systems may involve similar processes. This notion suggests directions for further research on increasing the in vivo stability of synthetic polymers. Long-term effects of polymer implantation upon tissue were not studied in this work.
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