Controlled drug delivery from composites of nanostructured porous silicon and poly(L-lactide)

Thumbnail Image
Date
2012-03-06
Authors
McInnes, Steven James
Irani, Yazad
Williams, Keryn Anne
Voelcker, Nicolas Hans
Journal Title
Journal ISSN
Volume Title
Publisher
Future Medicine
Abstract
Porous silicon (pSi) and poly(l-lactide) (PLLA) both display good biocompatibility and tunable degradation behavior, suggesting that composites of both materials are suitable candidates as biomaterials for localized drug delivery into the human body. The combination of a pliable and soft polymeric material with a hard inorganic porous material of high drug loading capacity may engender improved control over degradation and drug release profiles and be beneficial for the preparation of advanced drug delivery devices and biodegradable implants or scaffolds. Materials & methods: In this work, three different pSi and PLLA composite formats were prepared. The first format involved grafting PLLA from pSi films via surface-initiated ring-opening polymerization (pSi–PLLA [grafted]). The second format involved spin coating a PLLA solution onto oxidized pSi films (pSi–PLLA [spin-coated]) and the third format consisted of a melt-cast PLLA monolith containing dispersed pSi microparticles (pSi–PLLA [monoliths]). The surface characterization of these composites was performed via infrared spectroscopy, scanning electron microscopy, atomic force microscopy and water contact angle measurements. The composite materials were loaded with a model cytotoxic drug, camptothecin (CPT). Drug release from the composites was monitored via fluorimetry and the release profiles of CPT showed distinct characteristics for each of the composites studied. Results: In some cases, controlled CPT release was observed for more than 5 days. The PLLA spin coat on pSi and the PLLA monolith containing pSi microparticles both released a CPT payload in accordance with the Higuchi and Ritger–Peppas release models. Composite materials were also brought into contact with human lens epithelial cells to determine the extent of cytotoxicity. Conclusion: We observed that all the CPT containing materials were highly efficient at releasing bioactive CPT, based on the cytotoxicity data.
Description
Keywords
Opthalmology, Glaucoma
Citation
McInnes, S.J.P., Irani, Y., Williams, K.A. and Voelcker, N.H., 2012. Controlled drug delivery from composites of nanostructured porous silicon and poly(Llactide). Nanomedicine, 7(7), 995-1016.