Facile synthesis of biomass silica-silver colloidal nanoparticles and its application as highly sensitive fluorescent biosensor

Abstract

Colloidal inorganic nanoparticles have a significant impact for biosensing due to its precise biomolecular interaction. Herein, we report on the efficiency of silica-silver colloidal nanoparticles towards optical biosensor application. Silica colloids was prepared by the sol-gel method using biomass of rice husk as a precursor and then composited with silver colloids. The size of silica and silver (SiO2-Ag) colloidal nanoparticles was found to be 80 nm and 75 nm, respectively. The SiO2-Ag colloidal nanoparticles have the unique fluorescence at 325 nm with an excitation of 260 nm, which is significant for the excitation of most biomolecules, organelle stains and fluorescent labelling. The biosensing properties were validated against biomolecules such as glucose, uric acid, paracetamol, ascorbic acid and dopamine through plasmon resonance energy transfer (PRET) process by fluorescence spectroscopic technique. The glucose molecules responded with good sensing efficacy and the detection limit was found to be 0.49 µM. The proof of efficient glucose sensing of the SiO2-Ag colloidal nanoparticles also validated on human urine and serum and it gives the maximum recovery of 99.3 % and 98.2 %, respectively. These results support the efficacy of SiO2-Ag colloidal nanoparticles for optical biosensing applications in future.