Source optimization, characterization, assessing biocompatibility and drug loading efficiency of biogenic silica particles from agro wastes

Abstract

Biogenic Silica Nanoparticles (BSN) were manufactured from different agro-wastes and their physico-chemical characterization and suitability as a drug carrier were tested. All the starting materials yielded high purity BSN, but the percentage of yield differed, with Indian goose grass and rice husk giving the highest percentage yield. Different conditions adopted in the manufacture were found to affect the amorphous nature of BSN produced. The BSN remained amorphous and porous at temperatures below 700°C. BSN at 500°C was found to have the best surface area and zeta potential which was found favorable in drug surface modifications and drug loading. BSN was not toxic to cells up to 200µg/mL and slightly improved the antioxidant response.  Rice husk is a viable by-product of rice milling industry which can be used as a precursor for biogenic silica. Acid treatment followed by calcination at 500°C yielded high-quality BSN. Different physical characterization using SEM, TEM, BET, XRD, XRF etc revealed that the particles are spherical with 50-100 nm diameters and surface area 232m²/g. The prepared BSN were highly pure (>99%). The cell viability study revealed the excellent biocompatibility of BSN. Propidium Iodide staining had shown that there were no significant changes in the nuclear morphology of the cells treated with BSN. Curcumin loaded BSN showed a slightly better ameliorating effect on the oxidative stress response caused by cypermethrin treatment than free curcumin alone. Surface modification of BSN with PEG and chitin was found to improve the antioxidant power of BSN and its drug loading efficiency. All these in vitro observations suggest the possibility of harnessing BSN isolated from rice husk as an effective drug carrier, or for other biomedical applications.