Electron beam treatment of bioresorbable polymers for the enhanced release of incorporated bioactives

• Main Author: Simpson, Mark Derek Wilson
• Published: Queen's University Belfast 2016
• Subjects: 610
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709820

Bioresorbable polymers are being increasingly utilised in a range of biomedical applications. These polymers degrade in-vivo with their degradation by-products being metabolisable. This ability to degrade in-vivo makes them an excellent choice for many implants as the requirement for invasive surgery for implant removal is rendered unnecessary. However, the mode in which these polymers typically degrade can prove problematic. One such issue is the sudden “burst” of incorporated additives. This can be problematic when controlled release is required, such as osteoconductive or antimicrobial additives for bone repair and microbial inhibition respectively. This project investigated the use of low energy electron beam (e-beam) irradiation to surface modify bioactive (beta tri-calcium phosphate (β-TCP) & silver nano-particle (SNP)) loaded bioresorbable polymers (poly(lactic-co-glycolic) (PLGA)), with a view to achieving earlier commencement of bioactive release. Furthermore, it was investigated whether this treatment would improve the antimicrobial efficacy of antimicrobial (SNP) loaded PLGA. The work outlined has shown that low energy e-beam treatment of bioactive loaded bioresorbable polymers enhanced bioactive release by achieving earlier commencement of release. It was also shown that irradiated SNP loaded PLGA exhibited microbial inhibition when compared to irradiated non-SNP loaded PLGA. However, irradiated non-SNP loaded PLGA showed increased microbial attachment when compared to non-irradiated PLGA with the same SNP loading. The results indicated that low energy e-beam treatment of bioresorbable polymers can actually aid microbial attachment. However, the use of an antimicrobial in conjunction with irradiation treatment can null the enhanced microbial efficacy brought about by e-beam treatment. The work outlined has potential benefits for orthopaedic applications where earlier commencement of osteoconductive additives would aid bone repair in its crucial early stages. This work has potential benefits for applications where antimicrobial efficacy is not the primary function, rather to offset the favourable microbial attachment conditions caused by irradiation treatment.