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Lupu (Luchian) AM, Zaharescu T, Râpă M, Mariș M, Iovu H. Availability of PLA/SIS blends for packaging and medical applications.Part II: Contribution of stabilizer agents. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Effects of γ-radiation on structure and properties of poly(lactic acid) filaments. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Fromentin E, Aymes-Chodur C, Doizi D, Cornaton M, Miserque F, Cochin F, Ferry M. On the radio-oxidation, at high doses, of an industrial polyesterurethane and its pure resin. Polym Degrad Stab 2017. [DOI: 10.1016/j.polymdegradstab.2017.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Effects of electron beam irradiation on thermal and mechanical properties of poly(lactic acid) films. Polym Degrad Stab 2016. [DOI: 10.1016/j.polymdegradstab.2016.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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5
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Södergård A. Perspectives on Modification of Aliphatic Polyesters by Radiation Processing. J BIOACT COMPAT POL 2016. [DOI: 10.1177/0883911504048376] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Aliphatic polyesters have been studied mainly for medical applications, but also for other uses. Although the properties of different aliphatic polyesters are broad, there is a need for modifications to achieve desired material properties. Plasma modification of polymers has been applied to surface modification of polymers, while the bulk of the polymer remains unchanged. High energy radiation induced processing is an established technique that is used in polymer science. Radiation is used to initiate radical polymerizations and for modifications such as degradation, cross-linking, and graft-copolymerization. In this paper article radiation processing of aliphatic polyesters is reviewed. Included are synthetic polyesters, like polyglycolide, polylactide, poly(ε-caprolactone), poly(lactide-co-caprolactone) and two commonly occurring bacterial polyesters, polyhydroxybutyrate and poly(hydroxybutyrate- co-valerate). Relevant processing parameters as well as the effects and applications of the radiation modification are presented.
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Affiliation(s)
- Anders Södergård
- Turku Centre for Biomaterials, Turku University, Itäinen pitkäkatu 4 B, (PharmaCity), FIN-20520 Turku, Finland
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Bat E, Feijen J, Grijpma DW. Biodegradable Elastomeric Networks: Highly Efficient Cross-Linking of Poly(trimethylene carbonate) by Gamma Irradiation in the Presence of Pentaerythritol Triacrylate. Biomacromolecules 2010; 11:2692-9. [DOI: 10.1021/bm1007234] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Erhan Bat
- MIRA Institute for Biomedical Technology and Technical Medicine and Department of Polymer Chemistry and Biomaterials, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands and Department of Biomedical Engineering, University Medical Centre Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Jan Feijen
- MIRA Institute for Biomedical Technology and Technical Medicine and Department of Polymer Chemistry and Biomaterials, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands and Department of Biomedical Engineering, University Medical Centre Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Dirk W. Grijpma
- MIRA Institute for Biomedical Technology and Technical Medicine and Department of Polymer Chemistry and Biomaterials, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands and Department of Biomedical Engineering, University Medical Centre Groningen, University of Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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Ražem D, Katušin-Ražem B. The effects of irradiation on controlled drug delivery/controlled drug release systems. Radiat Phys Chem Oxf Engl 1993 2008. [DOI: 10.1016/j.radphyschem.2007.06.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Plikk P, Odelius K, Hakkarainen M, Albertsson AC. Finalizing the properties of porous scaffolds of aliphatic polyesters through radiation sterilization. Biomaterials 2006; 27:5335-47. [PMID: 16846641 DOI: 10.1016/j.biomaterials.2006.06.024] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Accepted: 06/29/2006] [Indexed: 11/28/2022]
Abstract
Porous scaffolds made of various L,L-lactide (LLA), 1,5-dioxepane-2-one (DXO) and epsilon-caprolactone (CL) copolymers were sterilized by EB- and gamma-irradiation. Differences in the comonomers, composition and the microstructure of the starting materials were used to influence the degradation mechanism and susceptibility towards irradiation and by this means to achieve sterilized scaffolds with predicted end-properties. The chemical changes and the formation of low-molecular-weight products were determined by SEC, 1H nuclear magnetic resonance (NMR), 13C NMR and gas chromatography-mass spectrometry (GC-MS). The degradation mechanism changed from random chain scission to cross-linking depending on the choice of monomers, the copolymer composition and the monomer sequences. Copolymerization of LLA with small amounts of CL or DXO increased the stability compared to that of the LLA homopolymer. Changing DXO to CL in a LLA copolymer also increased the stability. The type of radiation and the microstructure of the copolymer chains determined which of the monomer sequences were more prone to degrade. The most abundant low-molecular-weight product identified after sterilization was DXO monomer. Traces of LLA and CL monomers were also identified. Modification of the copolyester microstructure changed the degradation mechanism and the susceptibility towards irradiation. This allows the use of radiation sterilization to finalize the scaffold properties.
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Affiliation(s)
- Peter Plikk
- Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, Royal Institute of Technology, 100 44 Stockholm, Sweden
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Wuisman PIJM, Smit TH. Bioresorbable polymers: heading for a new generation of spinal cages. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2005; 15:133-48. [PMID: 16292588 PMCID: PMC3489405 DOI: 10.1007/s00586-005-1003-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 06/16/2005] [Accepted: 07/08/2005] [Indexed: 11/29/2022]
Abstract
The use of polymer-based bioresorbable materials is now expanding to the realm of spinal interbody fusion. Bioresorbable polymers have important advantages over metals, because they are temporary, much less stiff, and radiolucent. Most promising is a group of alpha-polyesters, in particular polylactide acids (PLAs). Their biocompatibility is excellent, and they have sufficient stiffness and strength to provide initial and intermediate-term stability required for bone healing. However, polylactides have characteristics that make them vulnerable to complications if not properly controlled. Degradation rate strongly depends on polymer type, impurities, manufacturing process, sterilization, device size, and the local environment. The fact that larger implants degrade faster is contra-intuitive, and should be considered in the design process. Also optimal surgical techniques, such as careful bone bed preparation, are required for a successful application of these materials. The purpose of this paper is to highlight the specific properties of these bioresorbable polymers and to discuss their potential and limitations. This is illustrated with early preclinical and clinical data.Bioresorbable cage technology is just emerging: their time-engineered degradation characteristics allow controlled dynamization in interbody applications, facilitating spinal fusion. Their radiolucency improves image assessment of fusion healing. Acceptance and use of bioresorbable implants may increase as further research and clinical studies report on their safety, efficacy, and proper usage.
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Affiliation(s)
- P I J M Wuisman
- Department of Orthopaedic Surgery, Vrije Universiteit Medical Centre, 1007 MB Amsterdam, The Netherlands.
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Bushell JA, Claybourn M, Williams HE, Murphy DM. An EPR and ENDOR study of gamma- and beta-radiation sterilization in poly (lactide-co-glycolide) polymers and microspheres. J Control Release 2005; 110:49-57. [PMID: 16290120 DOI: 10.1016/j.jconrel.2005.09.009] [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] [Received: 06/28/2005] [Revised: 06/28/2005] [Accepted: 09/20/2005] [Indexed: 10/25/2022]
Abstract
EPR/ENDOR spectroscopy was used to characterise the free radicals generated in a series of PLGA raw polymers and microspheres (with lactide:glycolide compositions of (75:25), (65:35) and (50:50)) after exposure to gamma (gamma-) and electron beam (beta-) irradiation at room temperature. Both sets of irradiated samples produced analogous EPR spectra, indicating that the type and distribution of free radicals generated by gamma-irradiation are similar to those generated by beta-irradiation. The radicals were identified by EPR simulations as the chain scission species -(CHO-(approximately 27% abundance),-C(CH(3))O- ( approximately 23% abundance) and the terminal-C(CH(3))-OR fragment (approximately 50% abundance), and these assignments were supported by the ENDOR analysis. The latter two radical species were demonstrated to originate from the lactide component of the PLGA polymer. Overall systematically higher radical concentrations were found as the lactide content of the PLGA raw polymer and microspheres increases (ie., 75:25 > 65:35 > 50:50) for both gamma- and beta-irradiation. However, while the relative concentrations of free radicals was similar in the raw polymer samples after exposure to gamma- or beta-irradiation, a substantial difference was found for the microsphere samples; an approximate doubling of the radical content was found in the gamma-irradiated PLGA microspheres compared to the identical beta-irradiated microspheres.
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Claybourn M, Gray H, Murphy DM, Purnell IJ, Rowlands CC. Electron magnetic resonance study of gamma-irradiated poly(lactide-co-glycolide) microspheres. J Control Release 2003; 91:431-8. [PMID: 12932720 DOI: 10.1016/s0168-3659(03)00269-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A series of poly(lactide-co-glycolide) samples of compositions ranging from (75:25) to (65:35) to (50% (65:35):50% (50:50)) were gamma-irradiated under ambient conditions in air. The irradiation doses used were 15, 20, 25, and 30 kGy. The generation of radicals resulting from the gamma-irradiation was confirmed using EPR. Two major radical species were observed and identified as centered at alkyl and alkyl peroxy groups. The indication from the X-band (9 GHz) frequencies showed that alkyl radicals gave rise to a quartet hyperfine pattern. However, measurements performed at higher W-band frequencies (90 GHz) showed that the X-band spectra are actually a composite profile arising from a series of overlapping individual resonances. Using combined EPR and ENDOR (Electron-Nuclear DOuble Resonance) measurements, an alkyl peroxy radical was identified. For increasing glycolide concentration from 75:25 to the 50:50 blend, there was a factor of 7 increase in the concentration of radicals A and B. Furthermore, both radical species were found to be stable for several weeks after storage at ambient temperature conditions. At elevated temperatures and humidities, radical stability decreased--the decay rate was estimated at approximately 3x10(-8) mol K(-1). The stability characteristics of the radicals under different conditions are attributed to changes in the morphology of the polymer.
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Affiliation(s)
- Mike Claybourn
- AstraZeneca, Silk Road Business Park, Charterway, Macclesfield, Cheshire SK10 2NA, UK.
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Södergård A, Stolt M. Properties of lactic acid based polymers and their correlation with composition. Prog Polym Sci 2002. [DOI: 10.1016/s0079-6700(02)00012-6] [Citation(s) in RCA: 1077] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sakai W, Sadakane T, Nishimoto W, Nagata M, Tsutsumi N. Photosensitized degradation and crosslinking of linear aliphatic polyesters studied by GPC and ESR. POLYMER 2002. [DOI: 10.1016/s0032-3861(02)00443-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Hill DJ, Choi BK, Ahn HK, Choi EJ. An ESR study of the gamma radiolysis of aromatic polyesters containing isomeric naphthalene links. Radiat Phys Chem Oxf Engl 1993 2001. [DOI: 10.1016/s0969-806x(01)00438-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sakai W, Kinoshita M, Nagata M, Tsutsumi N. ESR studies of photosensitized degradation of poly(L-lactic acid) via photoionization of dopant. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/1099-0518(20010301)39:5<706::aid-pola1042>3.0.co;2-p] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hill DJ, Choi BK, Ahn HK, Choi EJ. Synthesis, characterization and ESR study of the γ-radiolysis of aromatic polyesters containing isomeric naphthalene links. POLYM INT 1999. [DOI: 10.1002/(sici)1097-0126(199910)48:10<956::aid-pi254>3.0.co;2-n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Wollersheim O, Hormes J, Hünerbein FJ, Fußhöller G, Bargon J. In situ ESR investigations of synchrotron radiation-induced degradations of polymers. Radiat Phys Chem Oxf Engl 1993 1999. [DOI: 10.1016/s0969-806x(98)00285-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Babanalbandi A, Hill D, Whittaker A. Volatile products and new polymer structures formed on 60Co γ-radiolysis of poly(lactic acid) and poly(glycolic acid). Polym Degrad Stab 1997. [DOI: 10.1016/s0141-3910(97)00050-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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