Abstract
Due to the large production of sorghum, the generation of associated agricultural residues, which contain high contents of silica, is inevitable. Also, these agricultural residues are not utilizing properly and it creates environmental pollution. Thus, we are utilizing the sorghum residues as a silica precursor to fabricating biogenic silica nanostructures using sequential processes. The physicochemical features of the synthesized BSNs, i.e., amorphous nature, surface functional groups, thermal stability, structure, and morphology, were analyzed using X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. The cytotoxic properties of the S. bicolor-derived BSNs were assessed using human colon carcinoma cells as an in vitro model and cell-based assays, including an 3-4,5-dimethylthiazol-2,5-diphenyltetrazolium bromide (MTT) assay, and acridine orange/ethidium bromide staining (AO/EB). The silica content of S. bicolor leaves was around 9.34%. We observed peaks at 1089 cm(-1) and 801 cm(-1) in the FTIR spectra of BSNs that corresponded to asymmetric, symmetric, and bending vibrations of O-Si-O. The BSNs had spherical morphology with diameters of 30-90 nm and an amorphous nature. The cytotoxic analysis suggested that BSNs do not induce cell death in colon carcinoma cells. Overall, the results suggested that BSNs exhibit good compatibility in colon cells, and may be applicable as an anti-caking agent in the food sector.