Controlled Drug Delivery From Composites of Nanostructured Porous Silicon and Poly( L -Lactide)

Abstract

Aims: 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. Original submitted 16 December 2010; Revised submitted 29 September 2011; Published online 6 March 2012

Targeted drug delivery using genetically engineered diatom biosilica

“…Indeed, the application of nanoporous silica materials for drug delivery is a cornerstone of the burgeoning field of nanomedicine 2 . The most intensively investigated silica materials for drug delivery are mesoporous silica and oxidized porous silicon 3 .…”

Controlled delivery of acyclovir from porous silicon micro- and nanoparticles

“…The Korsmeyer-Peppas model was chosen over other models, such as zero order, first order, Higuchi, and Hixson-Crowell, because it gave the best fittings for the drug release profiles obtained in this study. This model has been previously used to fit the drug release data from PSi to determine drug release kinetics [40,41]. In this model, the plot of log of percent cumulative drug released against log of time should be linear with the slope of plot equals to the exponent n. The accuracy of fit was evaluated by calculating correlation coefficient (R 2 ).…”

Silicon-Based Nanoagents for Cancer Therapy

“…Since the first report revealing porous silicon particles-induced enhancement of paracellular delivery of insulin [25], sufficient advancement in developing pSi-based effective drug delivery systems for various kinds of therapeutic agents (e.g., pharmaceutical drugs (indomethacin (IMC) [26,27], doxorubicin (DOX) [28][29][30][31][32], paclitaxel [33], mitoxantrone dihydrochloride (MTX) [34,35], camptothecin (CPT) [36][37][38][39], and emodin [40]), therapeutic proteins (insulin [25,41], bovine serum albumin (BSA) [41], peptide [26,[42][43][44][45][46] ), and genes (siRNA [33,[47][48][49][50]), etc.) has been achieved in recent decades.…”

“…The same authors also developed a kind of poly(L-lactide)-modified pSi as high-performance drug carriers, simultaneously possessing the excellent drug release properties of pSi and the favorable processability of poly(L-lactide) ( Fig. 5.2) [37]. As a result, the as-prepared pSibased drug carriers were favorable for improving drug stability and increasing the drug bioavailability at the tumor tissue.…”