Effect of coatings and surface modification on porous silicon nanoparticles for delivery of the anticancer drug tamoxifen

• Porous Si films were fabricated by electrochemical etching of n-type Si wafers.
• Thermal hydrosilylation and coatings were used to modify and stabilize pSi surface.
• Tamoxifen was used as a drug model to investigate the release time from the pSi.
• The modified pSi surface prolonged the tamoxifen release from hours to weeks.

Breast cancer is the most common cancer among women and the cancer that causes the most deaths after lung cancer. Tamoxifen has long been used for the treatment of breast cancer in different stages of the disease; however it presents several side effects. The use of delivery systems has been proposed to minimize its side effects, especially hepatotoxicity, and to improve its bioavailability, hence optimizing Tamoxifen therapy. Porous silicon (pSi) nanoparticles present excellent properties for applications in biomedical devices. In this study pSi nanoparticles were fabricated by electrochemical etching of n-type single crystalline Si wafers in order to be used as a carrier for the anticancer drug Tamoxifen. pSi surface was modified by thermal hydrosilylation with undecylenic acid and via coatings such as chitosan, silica-xerogel and a hybrid of these two. The effect of pSi surface modification on the release profile of the drug has been investigated. Tamoxifen completely released within 6 h when loaded into fresh pSi. When the bioactive polymer chitosan was used as a coating the drug release profile was observed to decrease by ~ 30%. However, silica xerogel coating appeared to have no effect on the release profile. In contrast, when using a mix of chitosan and silica xerogel as a coating the drug release was prolonged from 6 h to a week. In the case of the chemically modified pSi nanoparticles the drug release was prolonged to weeks with minimal to no burst effect. Hence, hydrosilylated pSi nanoparticles have the potential to be used as excellent Tamoxifen controlled release carriers for biomedical application in cancer therapies.

Graphical AbstractFE-SEM images of pSi (a) Top view of pSi etched with the optimum parameters (1:4 volume ratio of HF:ethanol solution and current density of 20 mA/cm2 for 30 min); (b) pSi nanoparticles after lift-off and fracture. (c) Tamoxifen release profiles. Percentage of TMX released in PBS (pH 7.4 and 37 °C) over a period of time with different surface and coating modifications methods. 278 nm UV absorption band was used for the measurements.Figure optionsDownload as PowerPoint slide