Highly reliable label-free detection of urea/glucose and sensing mechanism using SiO2 and CdSe-ZnS nanoparticles in electrolyte-insulator-semiconductor structure
Journal
Journal of the Electrochemical Society
Journal Volume
163
Journal Issue
13
Date Issued
2016
Author(s)
Kumar, P.
Maikap, S.
Singh, K.
Chatterjee, S.
Chen, Y.-Y.
Cheng, H.-M.
Mahapatra, R.
Qiu, J.-T.
Yang, J.-R.
Abstract
A simple, label-free and cost effective sensor have been studied for reliable urea/glucose sensing, and common serum analyte detection comparable with market available urea "Assay Kit" is also performed by using SiO2 and CdSe-ZnS nanoparticles in electrolyte-insulator-semiconductor structure for the first time. Thermally grown SiO2 membrane has shown lower pH detection limit (0.081) and lowest drift rate (2.9 mV/hr) than those of the sputtering and E-beam deposited SiO2 membranes. The urea detection at physiological buffer pH 7.4 with sensitivity of ��1.6 mV/mg.dl?1 at linear range of 6 to 36 mg/dl is shown. The pH detection limit is further reduced (0.074) by using chaperonin protein mediated CdSe-ZnS nanoparticles assembly over SiO2 surface owing to high pH sensitivity of 55 mV/pH. The sensing mechanism is due to the SiOx content decreased with increasing pH value. This suggests the lower H+ ions absorption on the sensing membrane surface, which is observed by X-ray photo-electron spectroscopy. The glucose concentration is detected by using the core-shell CdSe-ZnS nanoparticles through H2O2 sensing because of reduction/oxidation (redox) properties of Zn as well as Zn2+ ions generation. Due to the high catalytic activity for H2O2 sensitivity, low detection limit of 1 �gM is obtained, which will help to detect glucose using this bio-chip in future.
SDGs
Type
journal article