CPMV-induced synthesis of hollow mesoporous SiO2 nanocapsules with excellent performance in drug delivery

Abstract

Hollow mesoporous-SiO₂ nanocapsules have been synthesized at room temperature using unmodified cowpea Mosaic Virus (CPMV) as a template, and without using any catalyst or surfactant during the synthesis. The average size of the capsules synthesized was ∼200–250 nm with a 60–100 nm hollow core. The resulting nanocapsules were characterized using high resolution transmission electron microscopy (HRTEM). The biocompatibility of the hollow mesoporous SiO₂ nanocapsules was investigated with an MTT assay using the RAW 264.7 cells, HepG2 cells (human liver carcinoma cells), and Hek293 cells (human embryonic kidney cells). The nanocapsules were loaded with fluorescent molecules (rhodamine 6G), doxorubicin (DOX) – an anticancer drug, and chloroquine diphosphate (CQDP) – an antimalarial drug, and their release was studied using a UV-Vis spectrometer. The development of surfactant free, bio-safe, hollow and mesoporous SiO₂ nanocapsules with CPMV provides a route for the synthesis of porous nanocapsules for drug loading and the sustained delivery of drugs. The synthesis method for hollow mesoporous SiO₂ nanocapsules using CPMV is novel, straightforward, and further demonstrates that, in general, nanoformulated capsules can be used for various drug-delivery-based therapeutic applications. To check the in vitro efficacy in medical biotechnology, Hek293 and HepG2 cell lines were used to study the cell viability of DOX-loaded hollow silica nanocapsules. The results show that the bio SiO₂ nanocapsules synthesized with CPMV present an effective cargo and are suitable for nanoformulating with DOX, with the resultant nanoformulation showing good promise for killing cancer specific cells.