Ultrasensitive and label-free detection of creatine based on CdO nanoparticles: a real sample approach
Low-dimensional cadmium oxide nanoparticles (CdO NPs) were prepared by a facile wet-chemical method in an alkaline medium with reactant precursors and urea surfactants. The optical, morphological, and structural properties of CdO NPs were characterized in detail using FT-IR, UV-Vis, FESEM, XEDS, XPS, TEM and XRD techniques. A glassy carbon electrode (GCE, surface area = 0.0316 cm2) was fabricated with a thin-layer of CdO NPs using a conducting binder, nafion, for the development of selective and sensitive label-free creatine (Ctr) sensors. Electrochemical investigation along with determination of the sensitivity, limit of detection (LOD), linear dynamic range (LDR) and long-term stability towards Ctr was performed by an electrochemical approach. The calibration curve was found to be linear in a wide range of Crt concentrations (0.1 nM–0.1 M). The sensitivity (1.90 μA μM−1 cm−2) and LDR were calculated from the calibration curve and were also found to be linear (R2 = 0.9297). The signal to noise ratio was ∼3, and the LOD was calculated and found to be 50.0 ± 0.1 pM. It is an enzyme-free organized route for the development of sensors based on low-dimensional CdO NP embedded GCE using electrochemical oxidation phenomena. To the best of our knowledge, this is the first report on the detection of highly sensitive Ctr using a CdO NP/GCE by an I–V method. A pioneering development of Ctr sensitive sensors using CdO NPs by a facile and reliable I–V method is suggested for important sensor applications of less useful materials in biological systems.