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Jalili S, Keshavarz M. Zirconia (1 1 0) surface adsorption behavior – A density functional theory study. COMPUT THEOR CHEM 2020. [DOI: 10.1016/j.comptc.2020.112702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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2
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Sridar S, Churchward MA, Mushahwar VK, Todd KG, Elias AL. Peptide modification of polyimide-insulated microwires: Towards improved biocompatibility through reduced glial scarring. Acta Biomater 2017; 60:154-166. [PMID: 28735029 DOI: 10.1016/j.actbio.2017.07.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/01/2017] [Accepted: 07/18/2017] [Indexed: 01/12/2023]
Abstract
The goal of this study is to improve the integration of implanted microdevices with tissue in the central nervous system (CNS). The long-term utility of neuroprosthetic devices implanted in the CNS is affected by the formation of a scar by resident glial cells (astrocytes and microglia), limiting the viability and functional stability of the devices. Reduction in the proliferation of glial cells is expected to enhance the biocompatibility of devices. We demonstrate the modification of polyimide-insulated microelectrodes with a bioactive peptide KHIFSDDSSE. Microelectrode wires were functionalized with (3-aminopropyl) triethoxy silane (APTES); the peptide was then covalently bonded to the APTES. The soluble peptide was tested in 2D mixed cultures of astrocytes and microglia, and reduced the proliferation of both cell types. The interactions of glial cells with the peptide-modified wires was then examined in 3D cell-laden hydrogels by immunofluorescence microscopy. As expected for uncoated wires, the microglia were first attracted to the wire (7days) followed by astrocyte recruitment and hypertrophy (14days). For the peptide-treated wires, astrocytes coated the wires directly (24h), and formed a thin, stable coating without evidence of hypertrophy, and the attraction of microglia to the wire was significantly reduced. The results suggest a mechanism to improve tissue integration by promoting uniform coating of astrocytes on a foreign body while lessening the reactive response of microglia. We conclude that the bioactive peptide KHIFSDDSSE may be effective in improving the biocompatibility of neural interfaces by both reducing acute glial reactivity and generating stable integration with tissue. STATEMENT OF SIGNIFICANCE The peptide KHIFSDDSSE has previously been shown in vitro to both reduce the proliferation of astrocytes, and to increase the adhesion of astrocyte to glass substrates. Here, we demonstrate a method to apply uniform coatings of peptides to microwires, which could readily be generalized to other peptides and surfaces. We then show that when peptide-modified wires are inserted into 3D cell-laden hydrogels, the normal cellular reaction (microglial activation followed by astrocyte recruitment and hypertrophy) does not occur, rather astrocytes are attracted directly to the surface of the wire, forming a relatively thin and uniform coating. This suggests a method to improve tissue integration of implanted devices to reduce glial scarring and ultimately reduce failure of neural interfaces.
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Affiliation(s)
- Sangita Sridar
- Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta, AB, Canada
| | - Matthew A Churchward
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB T6G 2G3, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta, AB, Canada
| | - Vivian K Mushahwar
- Division of Physical Medicine and Rehabilitation, University of Alberta, Edmonton, AB T6G 2E1, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta, AB, Canada
| | - Kathryn G Todd
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB T6G 2G3, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta, AB, Canada
| | - Anastasia L Elias
- Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada; Alberta Innovates-Health Solutions Interdisciplinary Team in Smart Neural Prostheses (Project SMART), University of Alberta, AB, Canada.
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Rashkow JT, Talukdar Y, Lalwani G, Sitharaman B. In Vivo Hard and Soft Tissue Response of Two-Dimensional Nanoparticle Incorporated Biodegradable Polymeric Scaffolds. ACS Biomater Sci Eng 2017; 3:2533-2541. [DOI: 10.1021/acsbiomaterials.7b00425] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jason T. Rashkow
- Department of Biomedical
Engineering, Stony Brook University, Stony Brook, New York 11794-5281, United States
| | - Yahfi Talukdar
- Department of Biomedical
Engineering, Stony Brook University, Stony Brook, New York 11794-5281, United States
| | - Gaurav Lalwani
- Department of Biomedical
Engineering, Stony Brook University, Stony Brook, New York 11794-5281, United States
| | - Balaji Sitharaman
- Department of Biomedical
Engineering, Stony Brook University, Stony Brook, New York 11794-5281, United States
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Soluble eggshell membrane: A natural protein to improve the properties of biomaterials used for tissue engineering applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 67:807-821. [DOI: 10.1016/j.msec.2016.05.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 04/18/2016] [Accepted: 05/01/2016] [Indexed: 02/07/2023]
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Pountos I, Panteli M, Lampropoulos A, Jones E, Calori GM, Giannoudis PV. The role of peptides in bone healing and regeneration: a systematic review. BMC Med 2016; 14:103. [PMID: 27400961 PMCID: PMC4940902 DOI: 10.1186/s12916-016-0646-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Bone tissue engineering and the research surrounding peptides has expanded significantly over the last few decades. Several peptides have been shown to support and stimulate the bone healing response and have been proposed as therapeutic vehicles for clinical use. The aim of this comprehensive review is to present the clinical and experimental studies analysing the potential role of peptides for bone healing and bone regeneration. METHODS A systematic review according to PRISMA guidelines was conducted. Articles presenting peptides capable of exerting an upregulatory effect on osteoprogenitor cells and bone healing were included in the study. RESULTS Based on the available literature, a significant amount of experimental in vitro and in vivo evidence exists. Several peptides were found to upregulate the bone healing response in experimental models and could act as potential candidates for future clinical applications. However, from the available peptides that reached the level of clinical trials, the presented results are limited. CONCLUSION Further research is desirable to shed more light into the processes governing the osteoprogenitor cellular responses. With further advances in the field of biomimetic materials and scaffolds, new treatment modalities for bone repair will emerge.
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Affiliation(s)
- Ippokratis Pountos
- Department of Trauma & Orthopaedics, School of Medicine, University of Leeds, Leeds, UK
| | - Michalis Panteli
- Department of Trauma & Orthopaedics, School of Medicine, University of Leeds, Leeds, UK
| | | | - Elena Jones
- Unit of Musculoskeletal Disease, Leeds Institute of Rheumatic and Musculoskeletal Medicine, St. James University Hospital, University of Leeds, LS9 7TF, Leeds, UK
| | - Giorgio Maria Calori
- Department of Trauma & Orthopaedics, School of Medicine, ISTITUTO ORTOPEDICO GAETANO PINI, Milan, Italy
| | - Peter V Giannoudis
- Department of Trauma & Orthopaedics, School of Medicine, University of Leeds, Leeds, UK. .,NIHR Leeds Biomedical Research Unit, Chapel Allerton Hospital, LS7 4SA Leeds, West Yorkshire, Leeds, UK.
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Trubiani O, Orsini G, Caputi S, Piatelli A. Adult Mesenchymal Stem Cells in Dental Research: A New Approach for Tissue Engineering. Int J Immunopathol Pharmacol 2016; 19:451-60. [PMID: 17026831 DOI: 10.1177/039463200601900301] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Many adult tissues contain a population of stem cells that have the ability to regenerate after trauma, disease or aging. Recently, there has been great interest in mesenchymal stem cells and their roles in maintaining the physiological structure of tissues. The studies on stem cells are thought to be very important and, in fact, it has been shown that this cell population can be expanded ex vivo to regenerate tissues not only of the mesenchymal lineage, such as intervertebral disc cartilage, bone and tooth-associated tissues, but also other types of tissues. Several studies have focused on the identification of odontogenic progenitors from oral tissues, and it has been shown that the mesenchymal stem cells obtained from periodontal ligament and dental pulp could have similar morphological and phenotypical features of the bone marrow mesenchymal cells. In fact a population of homogeneous human mesenchymal stem cells derived from periodontal ligament and dental pulp, and proliferating in culture with a well-spread morphology, can be recovered and characterized. Since these cells are considered as candidates for regenerative medicine, the knowledge of the cell differentiation mechanisms is imperative for the development of predictable techniques in implant dentistry, oral surgery and maxillo-facial reconstruction. Thus, future research efforts might be focused on the potential use of this cell population in tissue engineering. Further studies will be carried out to elucidate the molecular mechanisms involved in their maintenance and differentiation in vitro and in vivo.
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Affiliation(s)
- O Trubiani
- Department of Stomatology and Oral Science, Ce.SI. Foundation G. d'Annunzio, Chieti, Italy
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Amjadian S, Seyedjafari E, Zeynali B, Shabani I. The synergistic effect of nano-hydroxyapatite and dexamethasone in the fibrous delivery system of gelatin and poly(l-lactide) on the osteogenesis of mesenchymal stem cells. Int J Pharm 2016; 507:1-11. [PMID: 27107902 DOI: 10.1016/j.ijpharm.2016.04.032] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 04/12/2016] [Accepted: 04/13/2016] [Indexed: 02/06/2023]
Abstract
Recently, electrospun nanofibrous scaffolds are vastly taken into consideration in the bone tissue engineering due to mimicking the natural structure of native tissue. In our study, surface features of nanofibers were modified through simultaneous electrospining of the synthetic and natural polymers using poly l-lactide (PLLA) and gelatin to fabricate the hybrid scaffold (PLLA/gelatin). Then, hydroxyapatite nanoparticles (nHA) were loaded in electrospun PLLA nanofibers (PLLA,nHA/gelatin) and also dexamethasone (DEX) was incorporated in these fibers (PLLA,nHA,DEX/gelatin) in the second experiment. Fabricated nanofibrous composite scaffolds were characterized via SEM, FTIR spectroscopy, contact angle, tensile strength measurements, DEX release profile and MTT assay. After seeding adipose derived mesenchymal stem cells, osteoinductivity and osteoconductivity of fabricated scaffolds were analyzed using common osteogenic markers such as alkaline phosphatase activity, calcium depositions and gene expression. These results confirmed that all properties of nanofibers were improved by modifications. Moreover, osteogenic differentiation of stem cells increased in PLLA,nHA/gelatin group in comparison with PLLA/gelatin. The sustained release of DEX was obtained from PLLA,nHA,DEX/gelatin which subsequently led to more osteogenic differentiation. Taken together, PLLA,nHA,DEX/gelatin showed significant potential to support the stem cell proliferation and ostogenic differentiation, and can be a good candidates for tissue engineering and regenerative medicine applications.
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Affiliation(s)
- Sara Amjadian
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran; School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Ehsan Seyedjafari
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran.
| | - Bahman Zeynali
- School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Iman Shabani
- Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
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Abstract
Since Brånemark discovered the favorable effects of titanium in bone healing in 1965, titanium has emerged as the gold standard bulk material for present-time dental implantology. In the course of years researchers aimed for improvement of the implants performance in bone even at compromised implant sites and multiple factors were investigated influencing osseointegration. This review summarizes and clarifies the four factors that are currently recognized being relevant to influence the tissue-implant contact ratio: bulk materials and coatings, topography, surface energy, and biofunctionalization. The macrodesigns of bulk materials (e.g., titanium, zirconium, stainless steel, tantalum, and magnesium) provide the mechanical stability and their influence on bone cells can be additionally improved by surface treatment with various materials (calcium phosphates, strontium, bioglasses, diamond-like carbon, and diamond). Surface topography can be modified via different techniques to increase the bone-implant contact, for example, plasma-spraying, grit-blasting, acid-etching, and microarc oxidation. Surface energy (e.g., wettability and polarity) showed a strong effect on cell behavior and cell adhesion. Functionalization with bioactive molecules (via physisorption, covalent binding, or carrier systems) targets enhanced osseointegration. Despite the satisfying clinical results of presently used dental implant materials, further research on innovative implant surfaces is inevitable to pursuit perfection in soft and hard tissue performance.
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Molecular dynamics simulations of collagen adsorption onto grooved rutile surface: The effects of groove width. Colloids Surf B Biointerfaces 2014; 121:150-7. [DOI: 10.1016/j.colsurfb.2014.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/10/2014] [Accepted: 06/02/2014] [Indexed: 11/18/2022]
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Gomillion CT, Lakhman RK, Kasi RM, Weiss RA, Kuhn LT, Goldberg AJ. Lithium-end-capped polylactide thin films influence osteoblast progenitor cell differentiation and mineralization. J Biomed Mater Res A 2014; 103:500-10. [PMID: 24733780 DOI: 10.1002/jbm.a.35190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 03/18/2014] [Accepted: 03/26/2014] [Indexed: 11/08/2022]
Abstract
End-capping by covalently binding functional groups to the ends of polymer chains offers potential advantages for tissue engineering scaffolds, but the ability of such polymers to influence cell behavior has not been studied. As a demonstration, polylactide (PLA) was end-capped with lithium carboxylate ionic groups (hPLA13kLi) and evaluated. Thin films of the hPLA13kLi and PLA homopolymer were prepared with and without surface texturing. Murine osteoblast progenitor cells from collagen 1α1 transgenic reporter mice were used to assess cell attachment, proliferation, differentiation, and mineralization. Measurement of green fluorescent protein expressed by these cells and xylenol orange staining for mineral allowed quantitative analysis. The hPLA13kLi was biologically active, increasing initial cell attachment and enhancing differentiation, while reducing proliferation and strongly suppressing mineralization, relative to PLA. These effects of bound lithium ions (Li(+) ) had not been previously reported, and were generally consistent with the literature on soluble additions of lithium. The surface texturing generated here did not influence cell behavior. These results demonstrate that end-capping could be a useful approach in scaffold design, where a wide range of biologically active groups could be employed, while likely retaining the desirable characteristics associated with the unaltered homopolymer backbone.
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Affiliation(s)
- Cheryl T Gomillion
- Department of Reconstructive Sciences, Center for Biomaterials, University of Connecticut Health Center, Farmington, Connecticut, 06030
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11
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Wu TY, Zhou ZB, He ZW, Ren WP, Yu XW, Huang Y. Reinforcement of a new calcium phosphate cement with RGD-chitosan-fiber. J Biomed Mater Res A 2013; 102:68-75. [PMID: 23606446 DOI: 10.1002/jbm.a.34669] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 02/15/2013] [Indexed: 11/06/2022]
Abstract
Calcium phosphate cement (CPC) has been widely used in orthopedic and dental applications. A critical limitation of CPC is low strength and high susceptibility to severe fracture. Surgeons can use it only to reconstruct non-stress bearing bone, raising the need for a tougher new generation of CPC. Fibers have been used as a reinforcement of CPC to improve the strength of a pure CPC scaffold. The RGD peptides (Arg-Gly-Asp) have been used to improve the biocompatibility of the scaffold, via physical adsorption. The purpose of this study was to develop a novel CPC scaffold reinforced by RGD peptide-bearing chitosan fibers (RGD-fiber-CPC). Our data showed that the RGD-fiber-CPC scaffold had an increased flexural strength, and stimulated new bone formation in an animal model. The RGD-fiber-CPC is a novel bone graft substitute in orthopedic surgery.
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Affiliation(s)
- Tian-Yi Wu
- Department of Orthopedic Surgery, Shanghai Sixth People's Hospital, Shanghai Jiaotong University, Shanghai 200011, China; Department of Orthopaedic Surgery, 2nd Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing 210011, China
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12
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Tamada Y. Modification of Fibroin Film with A Chimera Fibroin Fragment for Improvement of Cell Adhesion. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-530-27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractSilk fibroin is a naturally occurring structural protein with good mechanical properties used in a variety of forms, such as powder, fiber, film, and gel. Although silk fibroin is potentially suitable for use in tissue engineering, it lacks cell regulation functions such as cell adhesion, growth, metabolism, and differentiation. The immobilization of biologically active molecules such as proteins and peptides has been reported as promising in controlling cell behavior. Silk fibroin's phase transition is characterized by a conformational change of protein from a random coil to a beta sheet. During phase transition, biological molecules can be stably entrapped in silk fibroin without the use of chemicals. We designed a novel immobilization using this phase transition mechanism with a chimera fibroin fragment. The chimera fibroin fragment was constructed by linking a bioactive peptide to fibroin fragments including crystal regions. In the first study, a synthetic oligonucleotide encoding Arg-Gly-Asp peptide which promotes cell adhesion, was fused to the fibroin fragment gene through inframe gene fusion, and the chimera fibroin (RGD-fibroin) gene was expressed by E.coli. This paper discusses RGD-fibroin construction, and the results of cell adhesion on fibroin films containing RGD-fibroin.
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Chen Y, Bilgen B, Pareta RA, Myles AJ, Fenniri H, Ciombor DM, Aaron RK, Webster TJ. Self-Assembled Rosette Nanotube/Hydrogel Composites for Cartilage Tissue Engineering. Tissue Eng Part C Methods 2010; 16:1233-43. [DOI: 10.1089/ten.tec.2009.0400] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Yupeng Chen
- Department of Chemistry, Brown University, Providence, Rhode Island
- Division of Engineering, Brown University, Providence, Rhode Island
| | - Bahar Bilgen
- Department of Orthopaedics, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Rajesh A. Pareta
- Division of Engineering, Brown University, Providence, Rhode Island
| | - Andrew J. Myles
- Department of Chemistry, National Institute for Nanotechnology, National Research Council, University of Alberta, Edmonton, Canada
| | - Hicham Fenniri
- Department of Chemistry, National Institute for Nanotechnology, National Research Council, University of Alberta, Edmonton, Canada
| | - Deborah McK. Ciombor
- Department of Orthopaedics, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Roy K. Aaron
- Department of Orthopaedics, Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Thomas J. Webster
- Division of Engineering, Brown University, Providence, Rhode Island
- Department of Orthopaedics, Warren Alpert Medical School, Brown University, Providence, Rhode Island
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Paletta JRJ, Bockelmann S, Walz A, Theisen C, Wendorff JH, Greiner A, Fuchs-Winkelmann S, Schofer MD. RGD-functionalisation of PLLA nanofibers by surface coupling using plasma treatment: influence on stem cell differentiation. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2010; 21:1363-1369. [PMID: 19943087 DOI: 10.1007/s10856-009-3947-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 11/16/2009] [Indexed: 05/28/2023]
Abstract
The aim of this study was to functionalize the surface of synthetic poly-(l-lactic) (PLLA) nanofibers with RGD peptide, in order to promote growth and osteogenic differentiation of human mesenchymal stem cells (hMSC) in vitro. The cRGD was coupled onto PLLA nanofibers using oxygen plasma combined with EDC/sulfo-NHS activation. Matrices were seeded with hMSC and cultivated over a period of 22 days under growth conditions and analyzed during the course of cultivation. The plasma activation of PLLA nanofibers resulted in a reduction of hydrophobicity as well as a formation of carboxyl groups on the surface of the fibers. Furthermore, maximum load, but not young's modulus was influenced by the treatment with oxygen plasma. When hMSC were cultured onto the cRGD functionalized scaffolds, cells showed no increased proliferation or cell density but an induction of genes associated with the osteoblast lineage. In brief, this study indicates that functional peptides of the extracellular matrix can be coupled onto PLLA nanofibers using plasma treatment in combination with EDC/sulfo-NHS treatment. These groups are accessible for the growing cell and mediate probably some osteoinductive properties of collagen nanofibers.
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Oliveira JM, Silva SS, Malafaya PB, Rodrigues MT, Kotobuki N, Hirose M, Gomes ME, Mano JF, Ohgushi H, Reis RL. Macroporous hydroxyapatite scaffolds for bone tissue engineering applications: physicochemical characterization and assessment of rat bone marrow stromal cell viability. J Biomed Mater Res A 2009; 91:175-86. [PMID: 18780358 DOI: 10.1002/jbm.a.32213] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this work, a new methodology is reported for developing hydroxyapatite (HA) scaffolds using an organic sacrifice template. The novelty of work consists of possibility of obtaining porous and highly interconnected scaffolds mimicking the sacrificial component. Our purpose consisted of evaluating the physicochemical properties of the HA scaffolds by means of Fourier transform infra-red spectroscopy, X-ray diffraction analysis, and scanning electron microscopy (SEM) attached with an X-ray detector. The HA scaffolds obtained possess a porosity of approximately 70%, and macropores diameter in the range of 50-600 microm. In contrast, results regarding the microcomputed tomography analysis have demonstrated both high pore uniformity and interconnectivity across the scaffolds. The compressive strength of the HA scaffolds was found to be 30.2 +/- 6.0 MPa. Bioactivity of the HA scaffolds was assessed by immersion into a simulated body fluid solution, in vitro. SEM observations have showed a deposition of apatite on the surface of the HA scaffolds, with a "cauliflower-like" morphology after 1 day, and tend to be more pronounced with the immersion time. The changes in calcium and phosphorus concentration were monitored by inductively-coupled plasma optical emission spectrometry. Cytotoxicity of the HA scaffolds was preliminarily investigated by carrying direct observation of mouse fibroblasts cells (L929 cell-line) death in the inverted microscope, and then cell viability was determined by means of carrying out a MTS assay. Complementarily, a luminescent cell viability assay based on the quantification of adenosine triphosphate was performed using rat bone marrow stromal cells (RBMSCs). A LIVE/DEAD assay and SEM analysis allowed the visualization of the RBMSCs adhesion and proliferation on the surface of the HA scaffolds. According to the results obtained from 3D architecture, mechanical properties, biocompatibility, and adhesion tests, it is suggested that HA scaffolds has potential to find applications in bone tissue engineering scaffolding.
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Affiliation(s)
- Joaquim M Oliveira
- Department of Polymer Engineering, 3B's Research Group-Biomaterials, Biodegradables, and Biomimetics, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.
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16
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Chen Y, Webster TJ. Increased osteoblast functions in the presence of BMP-7 short peptides for nanostructured biomaterial applications. J Biomed Mater Res A 2009; 91:296-304. [PMID: 18980196 DOI: 10.1002/jbm.a.32246] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
To improve bone regeneration around orthopedic biomaterials, researchers have attempted to combine growth factors on and in implants. Equally as exciting, greater bone growth has been demonstrated around nanoscaled materials (like helical rosette nanotubes or nanocrystalline hydroxyapatite) that mimic the geometry of the natural components of bone. To combine these two approaches, in this in vitro study, the ability of three short peptides [labeled for convenience: a or SNVILKKYRN, b or KPSSAPTQLN, and c or KAISVLYFDDS chosen from the larger bone morphogenetic protein-7 (BMP-7)] to promote osteoblast (bone-forming cells) functions were determined. Shorter peptides of BMP-7 are required for growth factor incorporation into nanoscale biomaterials because their sizes are in the nanometer regime. Results showed that of all the peptides, peptide b and the peptide combination a,b, enhanced osteoblast density the most after 5 days when compared with the controls (no growth factors). Furthermore, osteoblasts cultured with peptide b had a larger and more spread morphology than did controls. In addition, peptide c and its combinations (a, c; b, c; and a, b, c) increased osteoblast calcium deposition after 14 and 21 days compared with the controls. Since these peptides are much smaller than BMP-7, the results of this study provided information that peptides can be easily chemically functionalized onto nanoscaled biomaterials to improve bone growth. Thus, the present study elucidated that shorter peptides in BMP-7 was found to be more appropriate for inclusion in and on nanomaterials to promote osteoblast proliferation (peptide b and the peptide combination a,b) and osteoblast deposition of calcium-containing mineral (peptide c and the peptide combinations a,c; b,c; and a, b, c).
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Affiliation(s)
- Yupeng Chen
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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Dettin M, Herath T, Gambaretto R, Iucci G, Battocchio C, Bagno A, Ghezzo F, Di Bello C, Polzonetti G, Di Silvio L. Assessment of novel chemical strategies for covalent attachment of adhesive peptides to rough titanium surfaces: XPS analysis and biological evaluation. J Biomed Mater Res A 2009; 91:463-79. [DOI: 10.1002/jbm.a.32222] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Calcium Aluminate, RGD-Modified Calcium Aluminate, and β-Tricalcium Phosphate Implants in a Calvarial Defect. J Craniofac Surg 2009; 20:1538-43. [DOI: 10.1097/scs.0b013e3181b09c13] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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19
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Schofer MD, Boudriot U, Bockelmann S, Walz A, Wendorff JH, Greiner A, Paletta JRJ, Fuchs-Winkelmann S. Effect of direct RGD incorporation in PLLA nanofibers on growth and osteogenic differentiation of human mesenchymal stem cells. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2009; 20:1535-1540. [PMID: 19253014 DOI: 10.1007/s10856-009-3719-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 02/13/2009] [Indexed: 05/27/2023]
Abstract
The aim of this study was to functionalize synthetic poly-(L-lactic) (PLLA) nanofibers by direct incorporation of cRGD, in order to promote adhesion, growth and osteogenic differentiation of human mesenchymal stem cells (hMSC) in vitro. The cRGD was incorporated into PLLA nanofibers either by emulsion [PLLA-cRGD (d)] or suspension [PLLA-cRGD (s)]. Matrices were seeded with hMSC and cultivated over a period of 28 days under growth conditions and analyzed during the course. Although the mode of incorporation resulted in different distributions of the RGD peptide, it had no impact on the fiber characteristics when compared to corresponding unblended PLLA control fibers. However, hMSC showed better adherence on PLLA-cRGD (d). Nevertheless, this advantage was not reflected during the course of cultivation. Furthermore, the PLLA-cRGD (s) fibers mediated the osteogenic potential of collagen (determined as the expression and deposition of collagen and osteocalcin) to some extent. Further studies are needed in order to optimize the RGD distribution and concentration.
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Affiliation(s)
- Markus Dietmar Schofer
- Department of Orthopedics, University of Marburg, Baldingerstrasse, 35043, Marburg, Germany.
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Shapira L, Halabi A. Behavior of two osteoblast-like cell lines cultured on machined or rough titanium surfaces. Clin Oral Implants Res 2009; 20:50-5. [PMID: 19126108 DOI: 10.1111/j.1600-0501.2008.01594.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Two osteosarcoma-derived cell lines have been extensively used to investigate the biological events occurring on titanium surfaces: MG63 and Saos-2. However, the behavior of the two lines on different titanium surfaces has never been compared. AIM The aim of the present study was to compare the behavior of MG63 and Saos-2 cells on two different titanium surfaces, machined and rough (sandblasting and acid-etched). We compared cell proliferation and morphology, alkaline phosphatase (ALP) activity and secretion of osteocalcin (OC). RESULTS The most pronounced difference between the two cell lines was that ALP activity in the Saos-2 cells was 10-fold higher than in the MG63 cells. The proliferation rate of the MG63 cells was much higher than that of the Saos-2 cells at all the tested cell concentrations. MG-63 cells, but not Saos-2 cells, grown on rough surface titanium proliferated more rapidly than cells grown on machined surfaces. Morphological analysis revealed that Saos-2 cells and cells grown on the rougher surface, displayed a more mature phenotype. The level of OC secreted by the Saos-2 cells, but not the MG63 cells, were higher on the rough surface than on the machined surface. CONCLUSIONS This study shows that Saos-2 cells exhibit a more mature osteoblast phenotype, compared with that of MG63 cells, rendering them a good candidate for an in vitro model of osseointegration.
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Affiliation(s)
- Lior Shapira
- Department of Periodontology, Faculty of Dental Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
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Stadlinger B, Pilling E, Huhle M, Khavkin E, Bierbaum S, Scharnweber D, Kuhlisch E, Eckelt U, Mai R. Suitability of differently designed matrix-based implant surface coatings: An animal study on bone formation. J Biomed Mater Res B Appl Biomater 2008; 87:516-24. [DOI: 10.1002/jbm.b.31138] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Chen H, Yuan L, Song W, Wu Z, Li D. Biocompatible polymer materials: Role of protein–surface interactions. Prog Polym Sci 2008. [DOI: 10.1016/j.progpolymsci.2008.07.006] [Citation(s) in RCA: 452] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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23
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Yildirim ED, Yin X, Nair K, Sun W. Fabrication, characterization, and biocompatibility of single-walled carbon nanotube-reinforced alginate composite scaffolds manufactured using freeform fabrication technique. J Biomed Mater Res B Appl Biomater 2008; 87:406-14. [DOI: 10.1002/jbm.b.31118] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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24
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Zhang L, Ramsaywack S, Fenniri H, Webster TJ. Enhanced osteoblast adhesion on self-assembled nanostructured hydrogel scaffolds. Tissue Eng Part A 2008; 14:1353-64. [PMID: 18588485 DOI: 10.1089/ten.tea.2006.0436] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The objective of the current in vitro study was to improve properties of a commonly used hydrogel for implant applications by incorporating novel self-assembled helical rosette nanotubes (HRNs). Since traditional methods (such as autografts and allografts) used to treat bone defects present various disadvantages (such as donor tissue shortage, extensive inflammation, possible disease transmission, and poor new bone growth), which may lead to implant failure, much effort has been devoted to creating a novel bone substitute that biomimics the nanoscale features of natural bone in order to improve bone growth. HRNs (formed by chemically immobilizing two DNA base pairs) are a novel type of soft nanomaterial that biomimics natural nanostructured components of bone (such as collagen) since they are 3.5 nm in diameter and self-assemble into a helical structure in aqueous solutions. Because HRNs undergo a phase transition from a liquid to a viscous gel when heated to slightly above body temperatures or when added directly to serum-supplemented or serum-free media at body temperatures, they may provide an exciting therapy to heal bone fractures in situ. In this study, HRN-K1 (HRNs functionalized with lysine amino acids) was embedded in and coated on a model hydrogel [specifically, poly(2-hydroxyethyl methacrylate) or pHEMA]. The results of this study showed, for the first time, enhanced osteoblast (bone-forming cell) adhesion on HRN-K1 embedded in and coated on hydrogels compared to hydrogels without HRN-K1. Moreover, the results showed that embedding HRN-K1 into hydrogels can greatly decrease the polymerization time of pHEMA (especially at low temperatures). The presence of lysine in HRN-K1/hydrogels was shown to be one, but not only, property of HRN-K1 that enhanced osteoblast adhesion. In summary, the present results demonstrated that HRNs can improve properties of one particular hydrogel (pHEMA) and, thus, should be further investigated as a bone-healing material.
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Affiliation(s)
- Lijie Zhang
- Division of Engineering, Brown University, Providence, Rhode Island 02912, USA
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25
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Shi Z, Neoh KG, Kang ET, Poh C, Wang W. Bacterial adhesion and osteoblast function on titanium with surface-grafted chitosan and immobilized RGD peptide. J Biomed Mater Res A 2008; 86:865-72. [DOI: 10.1002/jbm.a.31648] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Sharon JL, Puleo DA. Immobilization of glycoproteins, such as VEGF, on biodegradable substrates. Acta Biomater 2008; 4:1016-23. [PMID: 18359670 PMCID: PMC2587396 DOI: 10.1016/j.actbio.2008.02.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 01/23/2008] [Accepted: 02/19/2008] [Indexed: 10/22/2022]
Abstract
Attachment of growth factors to biodegradable polymers, such as poly(lactide-co-glycolide) (PLGA), may enhance and/or accelerate integration of tissue engineering scaffolds. Although proteins are commonly bound via abundant amino groups, a more selective approach may increase bioactivity of immobilized molecules. In this research, exposed carboxyl groups on acid-terminated PLGA were modified with dihydrazide spacer molecules. The number of hydrazide groups available for subsequent attachment of protein was dependent on dihydrazide length, with shorter molecules present at significantly greater surface densities. The potent angiogenic glycoprotein vascular endothelial growth factor (VEGF) was oxidized with periodate and the aldehyde moieties allowed to react with the hydrazide-derivatized PLGA. Derivatization initially affected the amount of protein bound to the surfaces, but differences were substantially reduced following overnight incubation in saline. More importantly, use of shorter dihydrazide spacers significantly enhanced accessibility of immobilized VEGF for binding neutralizing antibody and soluble VEGF receptor. Furthermore, immobilized growth factor enhanced endothelial cell proliferation, with surfaces having the shortest and longest spacers stimulating greater effects. The present work has not only demonstrated an alternative approach to immobilizing growth factors on biodegradable materials, but the scheme can be used to alter the amount of protein bound as well as its availability for subsequent biointeractions.
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Affiliation(s)
- J. L. Sharon
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| | - D. A. Puleo
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY, USA
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27
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Self-assembled monolayer films of phosphonates for bonding RGD to titanium. Clin Orthop Relat Res 2008; 466:977-84. [PMID: 18224380 PMCID: PMC2504684 DOI: 10.1007/s11999-008-0117-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Accepted: 01/04/2008] [Indexed: 01/31/2023]
Abstract
Modification of the implant surface with the Arg-Gly-Asp tripeptide (RGD) putatively facilitates osteoblast attachment for improved implant fixation in the laboratory. We compared the histomorphometric and mechanical performance of titanium implants coated with RGD using a novel interface of self-assembled monolayers of phosphonates (RGD/SAMP) and implants coated with RGD using the more conventional thiolate-gold interface (RGD/thiolate-gold). We hypothesized RGD/SAMP-coated implants would show greater bone ongrowth and implant fixation than RGD/thiolate-gold-coated ones. We implanted an RGD/SAMP-coated implant in one femur and an RGD/thiolate-gold-coated in the contralateral femur of 60 rats. At 2, 4, and 8 weeks after implantation, 10 rats were sacrificed for histologic evaluation and another 10 for biomechanical testing. Bone-implant ongrowth and implant force-to-failure of the two implants were similar at all times. Although RGD/SAMP-coated implants did not show superior bone ongrowth and implant fixation, RGD/SAMP-coated implants have at least equally good histomorphometric and mechanical in vivo performance as RGD/thiolate-gold-coated ones. Additional in vivo characterization of self-assembled monolayer films of phosphonates as interface to bond RGD to titanium is needed to explore its full potential and seems justified based on the results of this study.
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Secchi AG, Grigoriou V, Shapiro IM, Cavalcanti-Adam EA, Composto RJ, Ducheyne P, Adams CS. RGDS peptides immobilized on titanium alloy stimulate bone cell attachment, differentiation and confer resistance to apoptosis. J Biomed Mater Res A 2008; 83:577-84. [PMID: 17503524 DOI: 10.1002/jbm.a.31007] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A major cause of implant failure in skeletal tissues is failure of osseointegration, often due to lack of adhesion of cells to the titanium (Ti) alloy interface. Since arginine-glycine-aspartic acid (RGD)-containing peptides have been shown to regulate osteoblast adhesion, we tested the hypothesis that, bound to a Ti surface, these peptides would promote osteoblasts differentiation, while at the same time inhibit apoptosis. RGDS and RGES (control) peptides were covalently linked to Ti discs using an APTS linker. While the grafting of both RGDS and RGES significantly increased Ti surface roughness, contact angle analysis showed that APTS significantly increased the surface hydrophobicity; when the peptides were tethered to Ti, this was reduced. To evaluate attachment, MC3T3-E1 osteoblast cells were grown on these discs. Significantly more cells attached to the Ti-grafted RGDS then the Ti-grafted RGES control. Furthermore, expression of the osteoblasts phenotype was significantly enhanced on the Ti-grafted RGDS surface. When cells attached to the Ti-grafted RGDS were challenged with staurosporine, an apoptogen, there was significant inhibition of apoptosis; in contrast, osteoblasts adherent to the Ti-grafted RGES were killed. It is concluded that RGD-containing peptides covalently bonded to Ti promotes osteoblasts attachment and survival with minimal changes to the surface of the alloy. Therefore, such modifications to Ti would have the potential to promote osseointegration in vivo.
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Affiliation(s)
- A G Secchi
- Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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29
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Fu J, Liang X, Chen Y, Tang L, Zhang QH, Dong Q. Oxidative stress as a component of chromium-induced cytotoxicity in rat calvarial osteoblasts. Cell Biol Toxicol 2007; 24:201-12. [PMID: 18027092 DOI: 10.1007/s10565-007-9029-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2007] [Accepted: 05/17/2007] [Indexed: 11/26/2022]
Abstract
It has been documented that medical prosthetic alloys release metal ions into surrounding tissues and cause cytotoxicity, but the mechanisms remain undefined. In that regard the cellular oxidative stress may be a common pathway in cellular responses to metal ions. The objective of this study was to approach the hypothesis that oxidative stress mediates chromium-induced cytotoxicity in rat calvarial osteoblasts. Osteoblasts were exposed to different concentrations of Cr6+ or Cr3+ (5-20 microM) in the presence or absence of the antioxidant N-acetyl-cysteine (NAC; 1-5 mM). Cellular viability, differentiation, and intracellular ultrastructural alterations were evaluated by MTT assay, alkaline phosphatase (ALP) activity assay, and transmission electron microscopy. Cellular oxidative stress was evaluated by intracellular reactive oxygen species (ROS) production. ROS production was monitored by the oxidation-sensitive fluorescent probe 2'7'-dichlorofluorescin diacetate (DCFH-DA). A time- and concentration- dependent increased cytotoxicity, time-dependent increased intracellular ROS production were indicated on exposure to Cr6+. Pretreatment of osteoblasts with 1-5 mM NAC afforded dose-dependent cytoprotective effects against Cr6+-induced cytotoxicity in osteoblasts. NAC decreased the level of intracellular ROS induced by Cr6+, too. While Cr3+ and NAC did not have any significant effects on osteoblasts (5-20 microM). These results suggest that oxidative stress is involved in Cr6+-induced cytotoxicity in osteoblasts, and NAC can provide protection for osteoblasts against Cr6+-induced oxidative stress. Cr3+ (5-20 microM) have no significant cytotoxicity in osteoblasts based on the results of this study.
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Affiliation(s)
- Jun Fu
- Key Laboratory of Oral Biomedical Engineering of Chinese Ministry of Education, West China College of Stomatology, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China
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30
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Lee MH, Adams CS, Boettiger D, Degrado WF, Shapiro IM, Composto RJ, Ducheyne P. Adhesion of MC3T3-E1 cells to RGD peptides of different flanking residues: detachment strength and correlation with long-term cellular function. J Biomed Mater Res A 2007; 81:150-60. [PMID: 17111408 DOI: 10.1002/jbm.a.31065] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We synthesized a series of RGD peptides and immobilized them to an amine-functional self-assembled monolayer using a modified maleimide-based conjugate technique that minimizes nonspecific interactions. Using a spinning disc apparatus, a trend in the detachment strength (tau(50)) of RGD peptides of different flanking residues was found: RGDSPK > RGDSVVYGLR approximately RGDS > RGES. Using blocking monoclonal antibodies, cellular adhesion to the peptides was shown to be primarily alpha(v)-integrin-mediated. In contrast, the tau(50) value of the cells on fibronectin (Fn)-coated substrates of similar surface density was 6-7 times higher and involved both alpha(5)beta(1) and alpha(v)beta(3) integrins. Cellular spreading was enhanced on RGD peptides after 1 h when compared to RGE and unmodified substrates. However, no significant differences were observed between the different RGD peptides. Long-term function of MC3T3-E1 cells was also evaluated by measuring alkaline phosphatase (ALP) activity and mineral deposition. Among the four peptides, RGDSPK exhibited the highest level of ALP activity after 11 days and mineralization after 15 days and reached comparable levels as Fn substrates after 15 and 24 days, respectively. These findings collectively illustrate both the advantages and limitations of enhancing cellular adhesion and function by the design of RGD peptides.
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Affiliation(s)
- Mark H Lee
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
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31
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Webster TJ, Ahn ES. Nanostructured biomaterials for tissue engineering bone. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2007; 103:275-308. [PMID: 17195467 DOI: 10.1007/10_021] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Advances in several critical research fields (processing, catalytic, optical, actuation, electrical, mechanical, etc.) have started to benefit from nanotechnology. Nano-technology can be broadly defined as the use of materials and systems whose structures and components exhibit novel and significantly changed properties when control is gained at the atomic, molecular, and supramolecular levels. Specifically, such advances have been found for materials when particulate size is decreased to below 100 nm. However, to date, relatively few advantages have been described for biological applications (specifically, those involving bone tissue engineering). This chapter elucidates several promising examples of how nanophase materials can be used to improve orthopedic implant applications. These include mechanical advantages as well as altered cell functions, leading to increased bone tissue regeneration on a wide range of nanophase materials including ceramics, polymers, metals, and composites thereof. Such advances were previously unimaginable with conventional materials possessing large micron-sized particulates.
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Affiliation(s)
- Thomas J Webster
- Division of Engineering and Orthopaedics, Brown University, Providence, RI 02912, USA.
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32
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Moura J, Teixeira LN, Ravagnani C, Peitl O, Zanotto ED, Beloti MM, Panzeri H, Rosa AL, de Oliveira PT. In vitro osteogenesis on a highly bioactive glass-ceramic (Biosilicate®). J Biomed Mater Res A 2007; 82:545-57. [PMID: 17311315 DOI: 10.1002/jbm.a.31165] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
One of the strategies to improve the mechanical performance of bioactive glasses for load-bearing implant devices has been the development of glass-ceramic materials. The present study aimed to evaluate the effect of a highly bioactive, fully-crystallized glass-ceramic (Biosilicate) of the system P(2)O(5)-Na(2)O-CaO-SiO(2) on various key parameters of in vitro osteogenesis. Surface characterization was carried out by scanning electron microscopy and Fourier transform infrared spectroscopy. Osteogenic cells were obtained by enzymatic digestion of newborn rat calvarial bone and by growing on Biosilicate discs and on control bioactive glass surfaces (Biosilicate) parent glass and Bioglass(R) 45S5) for periods of up to 17 days. All materials developed an apatite layer in simulated body fluid for 24h. Additionally, as early as 12 h under culture conditions and in the absence of cells, all surfaces developed a layer of silica-gel that was gradually covered by amorphous calcium phosphate deposits, which remained amorphous up to 72 h. During the proliferative phase of osteogenic cultures, the majority of cells exhibited disassembly of the actin cytoskeleton, whereas reassembly of actin stress fibers took place only in areas of cell multilayering by day 5. Although no significant differences were detected in terms of total protein content and alkaline phosphatase activity at days 11 and 17, Biosilicate supported significantly larger areas of calcified matrix at day 17. The results indicate that full crystallization of bioactive glasses in a range of compositions of the system P(2)O(5)-Na(2)O-CaO-SiO(2) may promote enhancement of in vitro bone-like tissue formation in an osteogenic cell culture system.
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Affiliation(s)
- João Moura
- Cell Culture Laboratory, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, CEP 14040-904, Ribeirão Preto, São Paulo, Brazil
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Seeley Z, Bandyopadhyay A, Bose S. Influence of TiO2 and Ag2O addition on tricalcium phosphate ceramics. J Biomed Mater Res A 2007; 82:113-21. [PMID: 17269142 DOI: 10.1002/jbm.a.31077] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Degradation of implanted ceramics allows for bone in-growth and eventual replacement with natural tissue. Calcium phosphate-based materials have gained the most significant attention because of their excellent biocompatibility and compositional similarities to natural bone. Adding various dopants to these ceramics significantly influences critical properties. In this study, tricalcium phosphate (TCP) compacts were fabricated via uniaxial compression with four compositions: (i) pure TCP, (ii) TCP with 1.0 wt % TiO(2), (iii) TCP with 0.5 wt % Ag(2)O, and (iv) ternary of TCP and 1.0 wt % TiO(2), and 0.5 wt % Ag(2)O. These compacts were sintered at 1250 degrees C for 4 h to obtain dense ceramic structures. Phase analyses were carried out using an X-ray diffractometer. The presence of TiO(2) in TCP improved densification and increased compression strength from 70 (+/-25) to 145 (+/-40) MPa. The ternary composition had the highest density and compression strength of 180 (+/-15) MPa. Human osteoblast cell growth behavior was studied using an osteoprecursor cell line (OPC 1) to assure that the biocompatibility of these ceramics was not altered due to the dopants. For long-term biodegradation studies, density, weight change, surface microstructure, and uniaxial compression strength were measured as a function of time in a simulated body fluid (SBF). Weight gain in SBF correlated strongly with precipitation viewed in the inter-connected pores of the samples. After 3 months in SBF, a 35% drop in compression strength was noticed for pure TCP, but for doped compositions, no strength loss was noticed.
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Affiliation(s)
- Zachary Seeley
- School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, USA
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Abstract
Repair of large bony defects still remains a challenge for surgeons. Hydroxyapatite (HA) is well known for its biocompatibility and osseoconduction properties in the osseous environment. In this study the biofunctionality of a newly developed scaffold comprising of collagen and HA, with variable macropores was examined. The biological response was evaluated using primary human osteoblast cells (HOBs). Cell infiltration, proliferation and differentiation were assessed. The results showed that HOBs were able to migrate from the collagen into the HA pores with greater cell migration and infiltration observed in those scaffolds with larger pores. Furthermore, it was shown that Alkaline Phosphatase, a differentiation marker for HOBs was enhanced as the average macropore size increased. This in vitro model provides a more relevant method of testing the biofunctionality and migration ability of cells at a trauma site following implantation in bone and cartilage.
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Jose B, Antoci V, Zeiger AR, Wickstrom E, Hickok NJ. Vancomycin covalently bonded to titanium beads kills Staphylococcus aureus. ACTA ACUST UNITED AC 2006; 12:1041-8. [PMID: 16183028 DOI: 10.1016/j.chembiol.2005.06.013] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 06/28/2005] [Accepted: 06/30/2005] [Indexed: 11/22/2022]
Abstract
Periprosthetic infections are life-threatening complications that occur in about 6% of medical device insertions. Stringent sterile techniques have reduced the incidence of infections, but many implant patients are at high risk for infection, especially the elderly, diabetic, and immune compromised. Moreover, because of low vascularity at the site of the new implant, antibiotic prophylaxis is often not effective. To address this problem, we designed a covalent modification to titanium implant surfaces to render them bactericidal. Specifically, we aminopropylated titanium, a widely used implant material and extended a tether by solid phase coupling of ethylene glycol linkers, followed by solid phase coupling of vancomycin. Vancomycin covalently attached to titanium still bound soluble bacterial peptidoglycan, reduced Staphylococcus aureus colony-forming units by 88% +/- 16% over 2 hr, and retained antibacterial activity upon a repeated challenge.
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Affiliation(s)
- Binoy Jose
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Sakaniwa D, Ohe T, Misumi T, Monjushiro H, Onoda A, Yamamura T. Covalent Immobilization of Metal-binding Motifs of Enzymes on Quartz Surface. [Ni(Cys-X2-Cys)2]2−of Hydrogenases. CHEM LETT 2005. [DOI: 10.1246/cl.2005.1634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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García AJ, Reyes CD. Bio-adhesive surfaces to promote osteoblast differentiation and bone formation. J Dent Res 2005; 84:407-13. [PMID: 15840774 DOI: 10.1177/154405910508400502] [Citation(s) in RCA: 226] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Binding of integrin adhesion receptors to extracellular matrix components, such as fibronectin and type I collagen, activates signaling pathways directing osteoblast survival, cell-cycle progression, gene expression, and matrix mineralization. Biomimetic strategies exploit these adhesive interactions to engineer bio-inspired surfaces that promote osteoblast adhesion and differentiation, bone formation, and osseointegration. These emerging initiatives focus on directing integrin binding through presentation of bio-adhesive motifs derived from extracellular matrices. These biomolecular approaches provide promising strategies for the development of biologically active implants and grafting substrates for enhanced bone repair.
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Affiliation(s)
- A J García
- Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, 315 Ferst Drive, 2314 Petit Biotechnology Building, Atlanta, GA 30332-0363, USA.
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Lee MH, Brass DA, Morris R, Composto RJ, Ducheyne P. The effect of non-specific interactions on cellular adhesion using model surfaces. Biomaterials 2005; 26:1721-30. [PMID: 15576146 DOI: 10.1016/j.biomaterials.2004.05.026] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Accepted: 05/12/2004] [Indexed: 12/24/2022]
Abstract
The contribution of non-specific interactions between cells and model functional surfaces was measured using a spinning disc apparatus. These model functional surfaces were created using self-assembled monolayers (SAM) of alkylsilanes terminated with epoxide, carboxyl (COOH), amine (NH(2)), and methyl (CH(3)) groups. These SAMs were characterized using ellipsometry, atomic force microscopy, contact angle goniometry, and X-ray photoelectron spectroscopy to confirm the presence of well-formed monolayers of expected physicochemical characteristics. All substrates also demonstrated excellent stability under prolonged exposure (up to 18 h) to aqueous conditions. The adhesion strength of K100 erythroleukemia cells to the functional substrates followed the trend: CH(3) < COOH approximately epoxide << NH(2). The NH(2) SAM surface exhibited nearly an order of magnitude greater adhesion strength than the other SAMs and this non-specific effect exceeded the adhesion measured when RGD tri-peptides were also immobilized on the surface. These findings illustrate the importance of substrate selection in quantitative studies of peptide-mediated cellular adhesion.
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Affiliation(s)
- Mark H Lee
- Department of Bioengineering, University of Pennsylvania, 120 Hayden Hall, 3320 Smith Walk, Philadelphia, PA 19104, USA.
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Grigoriou V, Shapiro IM, Cavalcanti-Adam EA, Composto RJ, Ducheyne P, Adams CS. Apoptosis and Survival of Osteoblast-like Cells Are Regulated by Surface Attachment. J Biol Chem 2005; 280:1733-9. [PMID: 15522882 DOI: 10.1074/jbc.m402550200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We tested the hypothesis that RGDS peptides regulate osteoblast survival in culture. Osteoblast-like MC3T3-E1 cells were allowed to attach to RGDS peptides that had been tethered to a silicone surface utilizing a previously described grafting technique. The RGDS-modified surface caused up-regulation of alpha(v)beta(3) integrin. We noted that there was an increase in expression of activated focal adhesion kinase and activated Akt. There was no change in the expression level of the anti-apoptotic protein Bcl-2, the pro-apoptotic protein Bad, or the inactivated form of Bad, pBad. Attachment to the RGDS-treated membrane completely abolished apoptosis induced by staurosporine, the Ca(2+).P(i) ion pair, and sodium nitroprusside. However, the surface modification did not interfere with apoptosis mediated by the free RGDS peptide or serum-free medium. When the activity of the phosphatidylinositol 3-kinase pathway was inhibited, RGDS-dependent resistance to apoptosis was eliminated. These results indicated that the binding of cells to RGDS abrogated apoptosis via the mitochondrial pathway and that the suppression of apoptosis was dependent on the activity of phosphatidylinositol 3-kinase.
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Affiliation(s)
- Vavara Grigoriou
- Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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40
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Siebers MC, ter Brugge PJ, Walboomers XF, Jansen JA. Integrins as linker proteins between osteoblasts and bone replacing materials. A critical review. Biomaterials 2005; 26:137-46. [PMID: 15207460 DOI: 10.1016/j.biomaterials.2004.02.021] [Citation(s) in RCA: 203] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2003] [Accepted: 02/03/2004] [Indexed: 12/25/2022]
Abstract
The adhesion of osteoblasts to substrates is mediated through proteins that have adsorbed to the substrate, providing integrins on the cell membrane with ligands to connect to. The integrins regulate cell behavior through bi-directional signaling pathways. This critical review has the purpose to consider the research that has been performed with osteoblasts, integrins, and bone replacing materials. Until now, most research has been done to investigate the integrin expression of osteoblasts in culture during cellular adhesion. However, it remains difficult to draw general conclusions from this research. Nevertheless, it can be concluded that the used substrates and protein or peptide coatings can influence the integrin expression and cellular behavior. Additional research has to be done to fully understand all the parameters involved in integrin expression, the adhesion of cells to substrates, and the subsequent cellular behavior. For this purpose, model substrates are under development. The signaling pathway is receiving more and more attention, but for biomaterial purposes, too little consideration is paid to the translation of the in vitro results to the in vivo situation, and to practical applications.
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Affiliation(s)
- M C Siebers
- Department of Biomaterials, College of Dental Science, University Medical Center Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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Mante FK, Little K, Mante MO, Rawle C, Baran GR. Oxidation of Titanium, RGD Peptide Attachment, and Matrix Mineralization of Rat Bone Marrow Stromal Cells. J ORAL IMPLANTOL 2004; 30:343-9. [PMID: 15641452 DOI: 10.1563/0.667.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
AbstractThe aim of this study was to compare the efficacy of attachment of arginine-glycine-aspartic acid (RGD) peptide to titanium surfaces oxidized by different methods. Titanium surfaces were treated as follows: (1) treatment A: passivation in nitric acid, (2) treatment B: heated in air at 400°C for 1 hour, (3) treatment C: immersed in 8.8 M H2O2/0.1 M HCl at 80°C for 30 minutes, and (4) treatment D: treated as in treatment C and then heated at 400°C for 1 hour. RGD was attached to titanium samples treated as in treatments A through D. The quantity of attached RGD was determined by an enzyme-linked immunoabsorbent assay. Mineralization of a rat bone marrow stromal cell (RMSC) culture on the titanium surfaces after 21 days was determined y atomic absorption spectroscopy. The treatments were ranked according to quantity of RGD attached as C, A, B, and D. Twenty-one days after RMSC culture, the degree of mineralization was significantly higher for treatment C than for treatments A, B, and D and for controls. The efficacy of RGD attachment varies with the oxidation treatment given to titanium. Oxidation in H2O2/0.1 M HCl at 80°C provided the best overall surface for RGD attachment as well as calcified matrix formation of RMSCs.
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Affiliation(s)
- Francis K Mante
- University of Pennsylvania School of Dental Medicine, 4001 Spruce Street, Philadelphia, PA 19104, USA.
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42
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El-Ghannam AR, Ducheyne P, Risbud M, Adams CS, Shapiro IM, Castner D, Golledge S, Composto RJ. Model surfaces engineered with nanoscale roughness and RGD tripeptides promote osteoblast activity. J Biomed Mater Res A 2004; 68:615-27. [PMID: 14986317 DOI: 10.1002/jbm.a.20051] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Cell adhesion to biomaterials is a prerequisite for tissue integration with the implant surface. Herein, we show that we can generate a model silica surface that contains a minimal-length arginine-glycine-aspartic acid (RGD) peptide that maintains its biological activity. In the first part of this study, attachment of MC3T3-E1 osteoblast-like cells was investigated on silicon oxide, amine terminated substrates [i.e., 3-aminopropyl triethoxysilane (APTS)], grafted RGD, and physisorbed RGD control. The APTS layer exhibited nanoscale roughness and presented amine functional groups for grafting a minimal RGD tripeptide devoid of any flanking groups or spacers. Contact angle measurements indicated that the hydrophobicity of the APTS surface was significantly lower than that of the surface with grafted RGD (RGD-APTS). Atomic force microscopy showed that surfaces covered with RGD-APTS were smoother (Ra = 0.71 nm) than those covered with APTS alone (Ra = 1.59 nm). Focusing mainly on cell morphology, experiments showed that the RGD-APTS hybrid provided an optimum surface for cell adhesion, spreading, and cytoskeletal organization. Discrete focal adhesion plaques were also observed consistent with successful cell signaling events. In a second set of experiments, smooth, monolayers of APTS (Ra = 0.1 nm) were used to prepare arginine-glycine-aspartic acid-serine (RGDS)-APTS and arginine-glycine-glutamic acid-serine (RGES)-APTS (control) substrates. Focusing mainly on cell function, integrin and gene expression were all enhanced for rate osteosarcoma cells on surfaces containing grafted RGDS. Both sets of studies demonstrated that grafted molecules of RGD(S) enhance both osteoblast-like cell adhesion and function.
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Affiliation(s)
- A R El-Ghannam
- Center for Bioactive Materials and Tissue Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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43
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Bagno A, Genovese M, Luchini A, Dettin M, Conconi MT, Menti AM, Parnigotto PP, Di Bello C. Contact profilometry and correspondence analysis to correlate surface properties and cell adhesion in vitro of uncoated and coated Ti and Ti6Al4V disks. Biomaterials 2004; 25:2437-45. [PMID: 14741609 DOI: 10.1016/j.biomaterials.2003.09.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A fundamental goal in the field of implantology is the design of specific devices able to induce a controlled and rapid "osseointegration". This result has been achieved by means of surface modifications aimed at optimizing implant-to-bone contact; furthermore, bone cell adhesion on implant surface has been directly improved by the application of biomolecules that stimulate new tissue formation, thus controlling interactions between biological environment and implanted materials. Actually, methods for biochemical factor delivery at the interface between implant surface and biological tissues are under investigation; a reliable technique is represented by the inclusion of biologically active molecules into biocompatible and biodegradable materials used for coating implant surface. This paper focuses the application of three polymeric materials already acknowledged in the clinical practice, i.e. poly-L-lactic acid (PLLA), poly-DL-lactic acid (PDLA), and sodium alginate hydrogel. They have been used to coat Ti (Ti2) and Ti6Al4V (Ti5) disks; their characteristics have been determined and their performances compared, with specific regard to the ability in allowing osteoblast adhesion in vitro. Moreover, profilometry data analysis permitted to identify a specific roughness parameter (peak density) which mainly controls the amount of osteoblast adhesion.
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Affiliation(s)
- Andrea Bagno
- Department of Chemical Process Engineering, University of Padova, via Marzolo 9, 35131 Pasova, Italy.
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Pham MT, Maitz MF, Reuther H, Muecklich A, Prokert F, Steiner G. Nucleation of calcium phosphate by surface-bound extracellular matrix. ACTA ACUST UNITED AC 2004; 71:16-24. [PMID: 15368251 DOI: 10.1002/jbm.a.30113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The native extracellular matrix (ECM) laid down on silicon and titanium surfaces by osteoblast-like SAOS-2 cells was exposed by selective removal of cells. This type of material surface ECM-Si, ECM-Ti was shown to promote the nucleation of calcium phosphate from a simulated body fluid (SBF). Microscopic and spectroscopic results revealed the effect was associated with a collagen fiber-free extracellular matrix.
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Affiliation(s)
- Minh Tan Pham
- Forschungszentrum Rossendorf e.V., Institut für Ionenstrahlphysik und Materialforschung, Postfach 510119, 01314 Dresden, Deutschland.
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Webster TJ, Waid MC, McKenzie JL, Price RL, Ejiofor JU. Nano-biotechnology: carbon nanofibres as improved neural and orthopaedic implants. NANOTECHNOLOGY 2004; 15:009. [PMID: 34911207 DOI: 10.1088/0957-4484/15/1/009] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2003] [Indexed: 06/14/2023]
Abstract
For the continuous monitoring, diagnosis, and treatment of neural tissue, implantable probes are required. However, sometimes such neural probes (usually composed of silicon) become encapsulated with non-conductive, undesirable glial scar tissue. Similarly for orthopaedic implants, biomaterials (usually titanium and/or titanium alloys) often become encapsulated with undesirable soft fibrous, not hard bony, tissue. Although possessing intriguing electrical and mechanical properties for neural and orthopaedic applications, carbon nanofibres/nanotubes have not been widely considered for these applications to date. The present work developed a carbon nanofibre reinforced polycarbonate urethane (PU) composite in an attempt to determine the possibility of using carbon nanofibres (CNs) as either neural or orthopaedic prosthetic devices. Electrical and mechanical characterization studies determined that such composites have properties suitable for neural and orthopaedic applications. More importantly, cell adhesion experiments revealed for the first time the promise these materials have to increase neural (nerve cell) and osteoblast (bone-forming cell) functions. In contrast, functions of cells that contribute to glial scar-tissue formation for neural prostheses (astrocytes) and fibrous-tissue encapsulation events for bone implants (fibroblasts) decreased on PU composites containing increasing amounts of CNs. In this manner, this study provided the first evidence of the future that CN formulations may have towards interacting with neural and bone cells which is important for the design of successful neural probes and orthopaedic implants, respectively.
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Affiliation(s)
| | - Michael C Waid
- Department of Biomedical Engineering, Purdue University, West Lafayette, IN 47907-1296, USA
| | - Janice L McKenzie
- Department of Biomedical Engineering, Purdue University, West Lafayette, IN 47907-1296, USA
| | - Rachel L Price
- Department of Biomedical Engineering, Purdue University, West Lafayette, IN 47907-1296, USA
| | - Jeremiah U Ejiofor
- Department of Biomedical Engineering, Purdue University, West Lafayette, IN 47907-1296, USA
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MacArthur BD, Please CP, Taylor M, Oreffo ROC. Mathematical modelling of skeletal repair. Biochem Biophys Res Commun 2004; 313:825-33. [PMID: 14706616 DOI: 10.1016/j.bbrc.2003.11.171] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Tissue engineering offers significant promise as a viable alternative to current clinical strategies for replacement of damaged tissue as a consequence of disease or trauma. Since mathematical modelling is a valuable tool in the analysis of complex systems, appropriate use of mathematical models has tremendous potential for advancing the understanding of the physical processes involved in such tissue reconstruction. In this review, the potential benefits, and limitations, of theoretical modelling in tissue engineering applications are examined with specific emphasis on tissue engineering of bone. A central tissue engineering approach is the in vivo implantation of a biomimetic scaffold seeded with an appropriate population of stem or progenitor cells. This review will therefore consider the theory behind a number of key factors affecting the success of such a strategy including: stem cell or progenitor population expansion and differentiation ex vivo; cell adhesion and migration, and the effective design of scaffolds; and delivery of nutrient to avascular structures. The focus will be on current work in this area, as well as on highlighting limitations and suggesting possible directions for future work to advance health-care for all.
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Affiliation(s)
- B D MacArthur
- University Orthopaedics, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK.
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Abstract
The development of biomaterials for tissue engineering applications has recently focused on the design of biomimetic materials that are capable of eliciting specific cellular responses and directing new tissue formation mediated by biomolecular recognition, which can be manipulated by altering design parameters of the material. Biomolecular recognition of materials by cells has been achieved by surface and bulk modification of biomaterials via chemical or physical methods with bioactive molecules such as a native long chain of extracellular matrix (ECM) proteins as well as short peptide sequences derived from intact ECM proteins that can incur specific interactions with cell receptors. The biomimetic materials potentially mimic many roles of ECM in tissues. For example, biomimetic scaffolds can provide biological cues for cell-matrix interactions to promote tissue growth, and the incorporation of peptide sequences into materials can also make the material degradable by specific protease enzymes. This review discusses the surface and bulk modification of biomaterials with cell recognition molecules to design biomimetic materials for tissue engineering. The criteria to design biomimetic materials such as the concentration and spatial distribution of modified bioactive molecules are addressed. Recent advances for the development of biomimetic materials in bone, nerve, and cardiovascular tissue engineering are also summarized.
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Affiliation(s)
- Heungsoo Shin
- Department of Bioengineering, Rice University, MS-142, P.O. Box 1892, Houston, TX 77251-1892, USA
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Hersel U, Dahmen C, Kessler H. RGD modified polymers: biomaterials for stimulated cell adhesion and beyond. Biomaterials 2003; 24:4385-415. [PMID: 12922151 DOI: 10.1016/s0142-9612(03)00343-0] [Citation(s) in RCA: 1722] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Since RGD peptides (R: arginine; G: glycine; D: aspartic acid) have been found to promote cell adhesion in 1984 (Cell attachment activity of fibronectin can be duplicated by small synthetic fragments of the molecule, Nature 309 (1984) 30), numerous materials have been RGD functionalized for academic studies or medical applications. This review gives an overview of RGD modified polymers, that have been used for cell adhesion, and provides information about technical aspects of RGD immobilization on polymers. The impacts of RGD peptide surface density, spatial arrangement as well as integrin affinity and selectivity on cell responses like adhesion and migration are discussed.
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Affiliation(s)
- Ulrich Hersel
- Institut für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstr. 4, D-85747, Garching, Germany
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50
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Abstract
Osteoblast-like SAOS-2 cells were allowed to synthesize and assemble their extracellular matrix (ECM) on titanium surfaces. After the selective removal of cells, Ti coated with a native ECM was obtained (ECM-Ti). The responses of SAOS-2 cells to ECM-Ti compared with those to peptide sequence RGDS- or fibronectin-immobilized Ti were examined, demonstrating the compositional and structural effects needed to trigger the native cell behavior.
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Affiliation(s)
- Minh T Pham
- Forschungszentrum Rossendorf e V, Institut für Ionenstrahlphysik und Materialforschung, Postfach 510119, 01314 Dresden, Deutschland.
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