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Zare M, Bigham A, Zare M, Luo H, Rezvani Ghomi E, Ramakrishna S. pHEMA: An Overview for Biomedical Applications. Int J Mol Sci 2021; 22:6376. [PMID: 34203608 PMCID: PMC8232190 DOI: 10.3390/ijms22126376] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 12/31/2022] Open
Abstract
Poly(2-hydroxyethyl methacrylate) (pHEMA) as a biomaterial with excellent biocompatibility and cytocompatibility elicits a minimal immunological response from host tissue making it desirable for different biomedical applications. This article seeks to provide an in-depth overview of the properties and biomedical applications of pHEMA for bone tissue regeneration, wound healing, cancer therapy (stimuli and non-stimuli responsive systems), and ophthalmic applications (contact lenses and ocular drug delivery). As this polymer has been widely applied in ophthalmic applications, a specific consideration has been devoted to this field. Pure pHEMA does not possess antimicrobial properties and the site where the biomedical device is employed may be susceptible to microbial infections. Therefore, antimicrobial strategies such as the use of silver nanoparticles, antibiotics, and antimicrobial agents can be utilized to protect against infections. Therefore, the antimicrobial strategies besides the drug delivery applications of pHEMA were covered. With continuous research and advancement in science and technology, the outlook of pHEMA is promising as it will most certainly be utilized in more biomedical applications in the near future. The aim of this review was to bring together state-of-the-art research on pHEMA and their applications.
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Affiliation(s)
- Mina Zare
- Center for Nanotechnology and Sustainability, Department of Mechanical Engineering, National University of Singapore, Singapore 117581, Singapore;
| | - Ashkan Bigham
- Institute of Polymers, Composites and Biomaterials—National Research Council (IPCB-CNR), Viale J.F. Kennedy 54—Mostra d’Oltremare pad. 20, 80125 Naples, Italy;
| | - Mohamad Zare
- Health Science Center, Xi’an Jiaotong University, Xi’an 710061, China;
| | - Hongrong Luo
- National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China;
| | - Erfan Rezvani Ghomi
- Center for Nanotechnology and Sustainability, Department of Mechanical Engineering, National University of Singapore, Singapore 117581, Singapore;
| | - Seeram Ramakrishna
- Center for Nanotechnology and Sustainability, Department of Mechanical Engineering, National University of Singapore, Singapore 117581, Singapore;
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Xu P, Cao J, Feng X, Gao Q, Lee SY, Ye J. Facile fabrication of elastic, macro-porous, and fast vascularized silicone orbital implant. J Biomed Mater Res B Appl Biomater 2020; 109:765-774. [PMID: 33131193 DOI: 10.1002/jbm.b.34742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 09/10/2020] [Accepted: 09/30/2020] [Indexed: 11/07/2022]
Abstract
Orbital implants with interconnected porous architecture had gained prominence, as they were capable of being colonized by fibrovascular tissue and minimizing complications. However, mechanical properties of orbital implant had received little attention among existing design philosophy. Herein, a compliant porous silicone scaffold was developed by gelatin porogen-leaching method and used as the orbital implant in this study. The silicone scaffolds exhibited desired microstructure and simulated mechanical properties, including high porosity of ~90%, suitable pore size of 280-450 μm, reduced modulus of 50.1 ± 11.7 KPa, and excellent elasticity. in vitro results showed that the porous silicone scaffolds did not exhibit noticeable cytotoxicity and were favorable for both adhesion and proliferation of human vascular ECs. The porous silicone scaffold was easy to be manipulated when implanted into the anophthalmic sockets of rabbits. The implanted scaffolds provided satisfactory volume replacement and induced extensive fibro-vascularization, showing desirable orbital reconstruction effects. Therefore, our novel porous silicone scaffolds may be promising substitutes for current orbital implants.
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Affiliation(s)
- Peifang Xu
- Department of Ophthalmology, The Second Affiliated Hospital of Zhejiang University, College of Medicine, Hangzhou, China
| | - Jing Cao
- Department of Ophthalmology, The Second Affiliated Hospital of Zhejiang University, College of Medicine, Hangzhou, China
| | - Xue Feng
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China
| | - Qi Gao
- Department of Ophthalmology, The Second Affiliated Hospital of Zhejiang University, College of Medicine, Hangzhou, China
| | - Sang Yeul Lee
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea
| | - Juan Ye
- Department of Ophthalmology, The Second Affiliated Hospital of Zhejiang University, College of Medicine, Hangzhou, China
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Hicks CR, Morrison D, Lou X, Crawford GJ, Gadjatsy A, Constable IJ. Orbital implants: potential new directions. Expert Rev Med Devices 2014; 3:805-15. [PMID: 17280545 DOI: 10.1586/17434440.3.6.805] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This article reviews orbital implants used to replace an eye after enucleation or evisceration. Advantages of implant placement are described, with discussion of implant and wrap material, and design features that affect clinical outcomes. Implants may be porous or nonporous, pegged for linkage with a cosmetic shell or unpegged, and may be wrapped with a covering material or tissue or unwrapped. Device shape, volume and material qualities affect tissue tolerance and the risk of exposure or extrusion. Limitations of currently available devices are discussed, with factors affecting surgeon and patient choice. Ideally, a device should be easy to insert, avoid the need for wrapping or adjunctive tissues, be light, biointegratable, comfortable after implantation and provide satisfactory orbital volume replacement, movement and cosmesis without requiring further surgery or pegging. This review briefly discusses developments in implant design and aspects of design that affect function, but is not a detailed clinical review; rather, it aims to stimulate thought on optimal design and discusses recent developments. Novel technology in the form of a prototype device with a soft, biointegratable anterior surface is described as an example of newer approaches.
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Affiliation(s)
- Celia R Hicks
- Department Biomaterials and Polymer Research, Lions Eye Institute, and Research Ophthalmologist, Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Australia.
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Improving the cellular invasion into PHEMA sponges by incorporation of the RGD peptide ligand: The use of copolymerization as a means to functionalize PHEMA sponges. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2013; 33:4917-22. [DOI: 10.1016/j.msec.2013.08.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 07/22/2013] [Accepted: 08/09/2013] [Indexed: 12/16/2022]
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Extruded, partially disintegrated, poly-HEMA orbital implant (AlphaSphere). Ophthalmic Plast Reconstr Surg 2013; 30:e86-91. [PMID: 24145907 DOI: 10.1097/iop.0b013e31829f3b5c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A 54-year-old diabetic man underwent enucleation for endophthalmitis. Secondary implantation of a 2-hydroxyethyl methacrylate (HEMA) sphere (AlphaSphere, Addition Technology) was performed 2 weeks later. Six weeks after insertion, noninfectious disintegration of sutured tissue planes represented by Tenon's capsule, rectus muscle, and conjunctiva occurred, requiring removal of the fragmenting implant before uncontrolled extrusion occurred. Histopathologic analysis revealed an absence of infectious pathogens and no tissue necrosis, but rather breakup of the implant material that elicited a granulomatous response with sparse T-lymphocytes and almost no polymorphonuclear leukocytes. This distinctively designed poly-HEMA orbital implant incited a dramatic and irreversible host tissue response. Investigation of other cases will be necessary to determine the frequency of such a complication and should include rigorous histopathologic techniques.
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Paterson SM, Shadforth AM, Brown DH, Madden PW, Chirila TV, Baker MV. The synthesis and degradation of collagenase-degradable poly(2-hydroxyethyl methacrylate)-based hydrogels and sponges for potential applications as scaffolds in tissue engineering. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012. [DOI: 10.1016/j.msec.2012.07.037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Paterson SM, Casadio YS, Brown DH, Shaw JA, Chirila TV, Baker MV. Laser scanning confocal microscopy versus scanning electron microscopy for characterization of polymer morphology: Sample preparation drastically distorts morphologies of poly(2-hydroxyethyl methacrylate)-based hydrogels. J Appl Polym Sci 2012. [DOI: 10.1002/app.38034] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Chirila TV, George KA, Abdul Ghafor WA, Pas SJ, Hill AJ. Sequential homo-interpenetrating polymer networks of poly(2-hydroxyethyl methacrylate): Synthesis, characterization, and calcium uptake. J Appl Polym Sci 2012. [DOI: 10.1002/app.36824] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Zainuddin, Chirila TV, Barnard Z, Watson GS, Toh C, Blakey I, Whittaker AK, Hill DJ. F2 excimer laser (157nm) radiation modification and surface ablation of PHEMA hydrogels and the effects on bioactivity: Surface attachment and proliferation of human corneal epithelial cells. Radiat Phys Chem Oxf Engl 1993 2011. [DOI: 10.1016/j.radphyschem.2010.07.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Degradable Hydrogels for Tissue Engineering – Part I: Synthesis by RAFT Polymerization and Characterization of PHEMA Containing Enzymatically Degradable Crosslinks. ACTA ACUST UNITED AC 2010. [DOI: 10.4028/www.scientific.net/jbbte.6.67] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A nonapeptide, which is sensitive to enzymatic digestion by collagenase, was modified by the covalent attachment of an acrylamido group at the terminal positions. The functionalized peptide was used as a crosslinking agent during polymerization of 2-hydroxyethyl methacrylate (HEMA). Reversible addition-fragmentation chain transfer (RAFT) method was used to obtain a polymer (PHEMA) with an average theoretical molecular weight of 4000 Da, containing enzymatically labile peptide crosslinks. The functionalized peptide was analyzed in detail by 1H and 13C nuclear magnetic resonance (NMR) spectrometry. The polymerization reaction was monitored by near infrared spectrometry, while the resulting polymer was analyzed by size exclusion chromatography and solid NMR spectrometry. The peptide-crosslinked PHEMA was subjected to an in-vitro degradation assay in the presence of collagenase. At the highest concentration of enzyme used in the study, a weight loss of 35% was recorded after 60 days of incubation in the collagenolytic medium. This suggests that crosslinking with enzymatically degradable peptides is a valid method for inducing biodegradability in polymers that otherwise are not degradable.
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Kim M, Foo LF, Uggen C, Lyman S, Ryaby JT, Moynihan DP, Grande DA, Potter HG, Pleshko N. Evaluation of early osteochondral defect repair in a rabbit model utilizing fourier transform-infrared imaging spectroscopy, magnetic resonance imaging, and quantitative T2 mapping. Tissue Eng Part C Methods 2010; 16:355-64. [PMID: 19586313 PMCID: PMC2945312 DOI: 10.1089/ten.tec.2009.0020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 07/07/2009] [Indexed: 02/03/2023] Open
Abstract
CONTEXT Evaluation of the morphology and matrix composition of repair cartilage is a critical step toward understanding the natural history of cartilage repair and efficacy of potential therapeutics. In the current study, short-term articular cartilage repair (3 and 6 weeks) was evaluated in a rabbit osteochondral defect model treated with thrombin peptide (TP-508) using magnetic resonance imaging (MRI), quantitative T2 mapping, and Fourier transform-infrared imaging spectroscopy (FT-IRIS). METHODS Three-mm-diameter osteochondral defects were made in the rabbit trochlear groove and filled with either TP-508 plus poly-lactoglycolidic acid microspheres or poly-lactoglycolidic acid microspheres alone (placebo). Repair tissue and adjacent normal cartilage were evaluated at 3 and 6 weeks postdefect creation. Intact knees were evaluated by magnetic resonance imaging for repair morphology, and with quantitative T2 mapping to assess collagen orientation. Histological sections were evaluated by FT-IRIS for parameters that reflect collagen quantity and quality, as well as proteoglycan (PG) content. RESULTS AND CONCLUSION There was no significant difference in volume of repair tissue at either time point. At 6 weeks, placebo repair tissue demonstrated longer T2 values (p < 0.01) than TP-508 did. Although both placebo and TP-508 repair tissue demonstrated longer T2 values than adjacent normal cartilage did, the 6-week T2 values of the TP-508 specimens were closer to those of the adjacent normal cartilage than were the placebo values. FT-IRIS analysis demonstrated a significant increase in collagen content, integrity, and PG content of the TP-508 repair tissue from 3 to 6 weeks (p < or = 0.05). In addition, the collagen and PG content of the TP-508 samples were closer to normal cartilage at 3 weeks than were the placebo samples. Further, there was a significant inverse correlation between the T2 relaxation values and collagen orientation in the normal cartilage. However, there were no significant correlations between T2 relaxation values and any FT-IRIS parameter in the repair tissue. Together, the data demonstrate that MRI and FT-IRIS assessment of cartilage repair tissue provide molecular information that furthers understanding of the cartilage repair process.
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Affiliation(s)
- Minwook Kim
- Musculoskeletal Imaging & Spectroscopy Laboratory, Hospital for Special Surgery, New York, New York
| | - Li F. Foo
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York
| | | | - Steven Lyman
- Outcomes Research, Hospital for Special Surgery, New York, New York
| | | | | | | | - Hollis G. Potter
- Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York
| | - Nancy Pleshko
- Musculoskeletal Imaging & Spectroscopy Laboratory, Hospital for Special Surgery, New York, New York
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Hicks CR, Werner L, Vijayasekaran S, Mamalis N, Apple DJ. Histology of AlphaCor skirts: evaluation of biointegration. Cornea 2006; 24:933-40. [PMID: 16227836 DOI: 10.1097/01.ico.0000160969.50706.7f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To report histologic findings in 14 AlphaCor artificial corneas implanted during clinical trials and subsequently explanted from human subjects following complications, so as to evaluate biointegration within the device skirt. METHODS Explants were fixed and sectioned in paraffin. Histologic findings related to the device skirt were compared with earlier histologic results from animal studies and correlated with clinical histories. RESULTS Two devices had been removed due to complications related to the optic alone, 11 following stromal melting overlying the biointegratable sponge skirt and 1 due to a retroprosthetic membrane. All devices demonstrated normal skirt porosity. Biointegration was similar to that found in animal studies but qualitatively appeared reduced in the affected areas in patients with overlying stromal melting prior to explantation. Patients with a longer history of melting prior to explantation demonstrated presence of inflammatory cells around the device. CONCLUSIONS Histologic findings of the AlphaCor skirt in humans are consistent with earlier animal studies. This study confirms that biointegration by host fibroblastic cells, with collagen deposition occurs after AlphaCor implantation in humans. In cases in which stromal melting had occurred, biointegration is seen to be reduced. On correlating preoperative clinical factors with biointegration observed histologically, preoperative vascularization appears not to be required for AlphaCor biointegration.
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Affiliation(s)
- C R Hicks
- Biomaterials Research Centre, Lions Eye Institute, University of Western Australia, Nedlands.
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Vijayasekaran S, Chirila TV, Robertson TA, Lou X, Fitton JH, Hicks CR, Constable IJ. Calcification of poly(2-hydroxyethyl methacrylate) hydrogel sponges implanted in the rabbit cornea: a 3-month study. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 2001; 11:599-615. [PMID: 10981676 DOI: 10.1163/156856200743896] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels have been used in the past as ocular implants. In a recent development, PHEMA sponges have shown suitable properties as materials for the peripheral component of an artificial cornea (keratoprosthesis). However, the propensity of PHEMA to calcify could threaten the long-term stability of the implanted devices. In an attempt to improve the understanding of the calcification mechanism, the dynamics, extent, and nature of calcified deposits within PHEMA sponges implanted in the cornea were investigated in this study, and the possible correlation between necrosis of cells and calcification was critically examined. Samples of a PHEMA sponge were implanted in rabbit corneas and explanted at predetermined time points (2, 4, and 12 weeks). The samples were examined by microscopy (light, transmission, scanning) and energy dispersive analysis of X-rays. Histological assessment and semiquantitative analysis of the amount of calcium deposited was performed using image analysis. An in vitro experiment was also performed by incubating sponge samples for 2 weeks in a solution of calcium and phosphate ions at a ratio similar to that in hydroxyapatite, in the absence of cells. Calcification was not seen in the 2- and 4-week explants, however, small deposits were detected in two of the 12-week explants, both within and on the sponge's constituent polymer particles. The deposit volumes represented 0.094% and 0.21%, respectively, of the total sponge volumes. Calcium deposits were present in large amounts both within the constituent polymer particles and on the surface of the sponges incubated in the abiotic calcifying solution. Cooperative mechanisms are suggested for the calcification of PHEMA sponges in vivo. The initial event may occur at a molecular level, when plasma proteins are adsorbed onto the polymer surface and bound through chelation to the calcium ions present in the medium. After their natural degradation, these structures may act as nucleation sites for calcium phosphate crystallization. Concurrently, the calcium ions can diffuse into the hydrogel particles and then the spontaneous precipitation of calcium phosphate may be caused by supersaturation due to the lower content of water in polymer, an effect which is likely predominant in vitro. The second event is the recruitment of phagocytic cells to clear calcium debris. Degeneration of these cells may then form nucleation sites for secondary calcification.
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Affiliation(s)
- S Vijayasekaran
- Department of Biomaterials and Polymer Research, University of Western Australia, Nedlands, Australia.
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