Successive detection of glucose and bio-copper in human serum based on a multiplex biosensor of gold nanorods

Abstract

In this paper, a promising combined assay for the successive detection of blood glucose and sera copper levels based on etching of gold nanorods (GNRs) was developed. A hydroxyl radical-enhanced GNR oxidation under ultraviolet irradiation facilitates the establishment of a plasmonic biosensor that may quickly detect blood glucose. A linear relationship between the change of the plasmonic wavelength and the glucose concentration was found (Δλ = 4.2284 + 132.0c) in the range of 0.23 to 0.928 mM and the LOD was 0.45 μM. The determination of blood glucose using this proposed method was satisfactory and closely comparable to the results given by the local hospital. On the other hand, a blue-shift of the longitudinal plasmon wavelength induced by various forms of copper in the presence of Na₂S₂O₃ provides a sensitive approach to detect the total copper level in a biological sample. The copper levels of human sera were measured and corroborated by flame atomic absorption spectrometry, which confirms that this approach might be applicable for bio-copper analysis with high accuracy. A combined assay for the successive detection of the blood glucose level and serum copper was subsequently developed. Compared to other related biosensors requiring a modified design, bio-molecular modification or/and sophisticated instruments, the dual glucose and copper sensor is very simple, cost-effective and easy to use for detection, suggesting great potential applications for successively monitoring blood glucose and copper concentrations and their changes during the progression of diabetes.