Integrated optical and electrochemical detection of Cu2+ ions in water using a sandwich amino acid–gold nanoparticle-based nano-biosensor consisting of a transparent-conductive platform

摘要: In this paper, an optical-electrochemical nano-biosensor was introduced for measuring Cu2+ ion concentrations in water. A multi-step procedure used to fabricate the transparent-conductive biosensor platform consisting of L-cysteine–gold nanoparticle-based sandwich structure. First, colloidal gold nanoparticles (GNPs) were synthesized according Turkevich–Frens method with some modifications and then functionalized L-cysteine molecules (GNP/L-cys). Then, cyclic voltammetry preformed buffered solutions containing HAuCl4·3H2O nanoparticle electrodeposition on cleaned ITO glasses. The GNP-electrodeposited glasses (ITO/GNPs) thermally treated air atmosphere 1 hour at a temperature 300 °C. Following procedure, ITO/GNPs substrates prepare ITO/GNPs/L-cys substrates. Finally, sandwich-type ITO/GNPs/L-cys⋯Cu2+⋯L-cys/GNPs fabricated by accumulation ions using open circuit technique performed copper buffer presence previously produced GNP/L-cys nanoparticles. effective parameters including solution volume, pre-concentration pH time LSPR SWV responses investigated optimized. platforms successfully assessed as detection two different methods square wave (SWV) localized surface plasmon resonance (LSPR). As result, proposed showed high sensitivity, selectivity wide detectable concentration range ions. total linear limit (LOD) 10–100 000 nM (0.6–6354.6 ppb) below 5 (0.3 ppb), respectively. results demonstrated potential combining optical electrochemical quantitation single analyte same obtaining richer data. Also, these indicated that developed LSPR-SWV superior many other biosensors presented literature terms LOD. applied determination trace actual tap water samples.