| Summary: | In this study novel composites comprising poly(ethylene glycol) functionalised gold nanoparticles (PEG-AuNP) dispersed within a poy(DL-Iactic-co-glycolic) (PLGA) film were produced via a solvent-casting technique and their effect on the degradation of PLGA investigated. In addition to the release profile of AuNPs during degradation was studied. The production of PLGA films containing PEG-AuNPs is a first step proof-of-principle concept for the aim of producing a composite capable of both targeted and sustained drug delivery. PLGA films were produced via solvent-casting using a number of molecular weight 50:50 PLGA polymers and three commonly reported solvents, namely dichloromethane, chloroform and acetone. The effect of molecular weight and solvent choice was investigated in regard to drying time required and subsequent residual solvent levels. Analysis reported a drying time of 14 days at 40°C, 400 mbar, with dichloromethane displaying the lowest residual solvent content after drying, PLGA 3A (0.58 dL/g) was found to be the most robust sample in terms of ease of handing. The mould material is one of the most important features of solvent-casting in terms of removing the sample after drying, to this end it was demonstrated that glass petri dishes pre-coated with RainX proved ideal. PEG functionalisation of the AuNP surface allows for successful drying and re- dispersion in a range of media (PBS, H20, PBS-BSA, and DCM). A PEG capping density of 16.8 μg/mL was found from UV-Vis, TGA and DLS to be the most suitable for successful incorporation into PLGA films via solvent-casting. A range of weight percentages of PEG-AuNPs were successfully incorporated into PLGA films namely, 0.2, 0.4, 0.6, 0.8, 1 and 2 wt%. The AuNP release profile of PLGA containing 1 and 2 wt% PEG functionalised AuNPs was studied using ICP-MS during degradation. Unfunctionalised AuNPs could not be successfully incorporated in PLGA films due to irreversible aggregation after drying. The incorporation of PEG-AuNPs into PLGA films was found to aid in the drying process and resulted in reduced levels of residual solvent. The addition of 1 and 2 wt% PEG functionalised AuNPs was found to increase the PLGA degradation time from 39 to 58 days. Release of PEG-AuNPs from PLGA films during degradation was investigated using ICP-MS and appeared to follow a relatively sustained release profile for both 1 and 2 wt% PEG-AuNPs over the 58 day degradation timeframe.
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