Spatially Controlled Surface Modification of Porous Silicon for Sustained Drug Delivery Applications

Abstract

A new and facile approach to selectively functionalize the internal and external surfaces of porous silicon (pSi) for drug delivery applications is reported. To provide a surface that is suitable for sustained drug release of the hydrophobic cancer chemotherapy drug camptothecin (CPT), the internal surfaces of pSi films were first modified with 1-dodecene. To further modify the external surface of the pSi samples, an interlayer was applied by silanization with (3-aminopropyl)triethoxysilane (APTES) following air plasma treatment. In addition, copolymers of N-(2-hydroxypropyl) acrylamide (HPAm) and N-benzophenone acrylamide (BPAm) were grafted onto the external pSi surfaces by spin-coating and UV crosslinking. Each modification step was verified using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, water contact angle (WCA) measurements, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In order to confirm that the air plasma treatment and silanization step only occurred on the top surface of pSi samples, confocal microscopy was employed after fluorescein isothiocyanate (FITC) conjugation. Drug release studies carried out over 17 h in PBS demonstrated that the modified pSi reservoirs released CPT continuously, while showing excellent stability. Furthermore, protein adsorption and cell attachment studies demonstrated the ability of the graft polymer layer to reduce both significantly. In combination with the biocompatible pSi substrate material, the facile modification strategy described in this study provides access to new multifunctional drug delivery systems (DDS) for applications in cancer therapy.

Crystallisation Behaviour of Pharmaceutical Compounds Confined within Mesoporous Silicon

“…Pharmaceutics 2020, 12, x 13 of 24 additional layer of polymer was attached to the loaded pSi surface to further control the release of the drug. Modification of the pSi doubled the drug-loading concentration, and the external polymer coat improved the drug release profile with a slower, steadier release than the control ( Figure 6) [114]. Reproduced with permission from [114].…”

Fabrication of Non‐enzymatic Electrochemical Glucose Sensor Based on Pd−Mn Alloy Nanoparticles Supported on Reduced Graphene Oxide

“…Generally, nanostructured materials are promising candidates in the field of diagnosis and medical treatment . In view of literature, the noble metals nano‐architectures have been approved as promising tools to design the non‐enzymatic electrochemical sensors owing to their excellent features including abundant electro‐active sites, fast electron transport ability, good stability and higher electrochemical efficacy . To date, numerous tailor‐made noble metals and metal oxide nanostructures such as Au , Ag , Pt , Ru , Rh , and Pd have been reported to show excellent electro‐catalytic sensing properties toward glucose and other analytes.…”

“…To fabricate the efficient electrochemical sensor, the selection of appropriate electrode material is very important to control its performance . Generally, nanostructured materials are promising candidates in the field of diagnosis and medical treatment . In view of literature, the noble metals nano‐architectures have been approved as promising tools to design the non‐enzymatic electrochemical sensors owing to their excellent features including abundant electro‐active sites, fast electron transport ability, good stability and higher electrochemical efficacy .…”

Acetylcholinesterase Modified Porous Silicon for Electrochemical Measurement of Total Active Immobilized Enzyme Amount and Effective Malathion Detection

“…Porous silicon (PSi) material has been used as highperformance solid substrate due to their large surface to volume ratio which allowed the attachment of a large number of molecules over a large surface in a small volume [15,16]. In addition, PSi is easily prepared either in powder [17] or wafer [18], it has an excellent biocompatibility [19] and has flexibility in controlling the surface chemistry [20,21] which make this material ideal for the immobilization of enzymes [22]. However, PSi amperometric biosensors didn't get much attention most likely due its low conductivity and weak stability [23].…”