Facile preparation of multifunctional hollow silica nanoparticles and their cancer specific targeting effect

Efficient delivery of therapeutics to tumor cells is one of the key issues in cancer therapy. In the present work, we have established a facile and unique chemical strategy for fabrication of highly biocompatible and water-dispersible multifunctional hollow silica nanoparticles (HSNPs). These mesoporous silica nanoparticles, having ring-like morphology, were fabricated by the sol-gel method followed by selective etching of the inner inorganic core. Further, to accomplish cancer-specific targeting properties, folic acid was tethered to the surface of HSNPs through amide bond formation using the EDC/NHS coupling method. Thereafter, rhodamine B isothiocyanate (RITC) was conjugated to the HSNPs to endow the fluorescent property to the nanoparticles required for biological imaging applications. The successful formation of multifunctional HSNPs was confirmed by XRD, FTIR, zeta potential, TEM, FESEM, and BET surface area measurements. The average particle size of HSNPs was found to be 50 nm to 70 nm from TEM analysis, which is the desired size-range for drug-delivery vehicles. These HSNPs showed good mesoporous behavior and were found to be an excellent candidate for loading and releasing the anticancer drug doxorubicin (DOX). The bioactivity of the HSNPs was verified by biological assay including cell cytotoxicity by MTT assay, intracellular uptake by fluorescence microscopy, cell cycle analysis by fluorescence-activated cell sorting (FACS), and apoptosis study. Besides, the effect of salt concentration on the drug release performance was evaluated. An in vitro biological study revealed that these DOX-loaded folate-targeted HSNPs achieved excellent efficacy for simultaneously targeting and destroying cancer cells.