Silver nanoparticle based selective, sensitive and instantaneous electrochemical nanosensors for the analysis of riboflavin

Abstract

Silver nanoparticles (AgNPs) are versatile and utilised in numerous ways, for instance as catalysts, solar cells, fuels and hydrogen fuels in the evolution of energy solutions. Their versatile nature provides opportunities not only in optoelectronic areas, but also in human health and protection against antimicrobial, antifungal, anticancer and other toxic agents. There have been limited studies conducted on the ability of AgNPs to sense the vital biological molecule riboflavin (RF). Hence, the current work was undertaken to further examine AgNPs and their potential as RF sensing materials. We have synthesised AgNPs via the citrate method and determined a range of properties using various instruments and techniques. The AgNPs were then tested as a sensing material to determine the exposure of RF via an electrochemical process. For this, an AgNP slurry was transformed into an organic adhesive, pasted onto a glassy carbon electrode (GCE) and dried well to ensure the sensing efficiency in a three-electrode system. RF was prepared at a range of concentrations (0.976 × 10⁻⁶ μM, 1.953 × 10⁻⁶ μM, 3.906 × 10⁻⁶ μM, 7.812 × 10⁻⁶ μM, 15.625 × 10⁻⁶ μM and 31.25 × 10⁻⁶ μM) in phosphate-buffered saline (PBS). The current ranged from −1.5 to +1.5 V, and the electrode efficiency and effect of the potential (5, 10, 20, 50 and 100 mV/s) of the AgNP-based GCE (AgNPs/GCE) were determined in PBS. The ampherometric response over time was also analysed (0–600 s). The processed sensors’ cyclic response and electrochemical impedance (between 0.01 and 10 kHz) were also analysed. In addition to this, ion interference (Al³⁺, Ba²⁺, Ca²⁺, Co²⁺, Cu²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Sr²⁺, Zn²⁺ and PBS), and real samples collected from different places were examined with and without the analyte (RF) respectively. A probable mechanism has also been established based on the obtained results and is presented.