Porous silicon (pSi) microparticles with pore diameter 15 to 20 nm were fabricated by electrochemical etching of single-crystalline silicon (Si) wafers (n-type) to be used as delivery systems for the anticancer drug mitomycin C (MMC). The in vitro toxicity of the mitomycin-loaded pSi carrier was investigated on human prostate carcinoma (DU145) cells. The cells showed a decrease in viability of ~80% over a 6 hours period, when using mitomycin. Meanwhile, a ~55% decrease in cell viability was observed, when using the pSi carrier to deliver the drug. The drug-loaded carrier showed a sustained release throughout 24 hours, with an 80% decrease in cell viability after 16 hours. This observed controlled release of mitomycin from the pSi carrier suggests a superior therapeutic effect than the direct administration of mitomycin, as it potentially minimizes the drug side effects. Results showed that the strong cytotoxic effect towards the prostate cancer cells was due to the drug and not the carrier since the mitomycin-loaded pSi carrier affected cell viability, but the pSi carrier showed no toxicity. Furthermore, it was observed that with a higher amount of drug-loaded carriers, the toxicity effect was higher, thus, allowing further control of the therapeutic effect of the carrier.
Tissue distribution and therapeutic effect of intravenous free or encapsulated liposomal doxorubicin on human prostate carcinoma xenografts