A Highly Sensitive Label-free Aptasensor Based on Gold Nanourchins and Carbon Nanohorns for the Detection of Lipocalin-2 (LCN-2)

Abstract

A synergistic nanocomposite film composed of gold nanourchins (AuNU), oxidised carbon nanohorns (CNH), and chitosan functioned as an electrode modifier in the fabrication of the sensitive lipocalin-2 (LCN-2) aptasensor. The AuNUs/CNH/CS composite increased the surface area and thereby amplified the signal transduction. The amineterminated LCN-2 aptamer was immobilised through the amide bond formed between the carboxyl group of polyglutamic acid (PGA) and the amine group of aptamer. Interaction of LCN-2 with the aptamer caused conformational changes in the structure of the aptamer. This generated higher conductivity, resulting in increased DPV peak current. The DPV signal increased with increasing concentration of LCN-2, and the change in signal was used for quantitative detection. The proposed aptasensor was able to detect LCN-2 in the linear range of 0.1 – 100.0 pg mL−1, with a low detection limit of 10 fg mL−1. The aptasensor showed high sensitivity, selectivity, reproducibility, and was able to detect LCN-2 in serum samples.