A No‐washing Point‐of‐Care Electrochemical Biosensor Based on CuS Nanoparticles for Rapid and Sensitive Detection of Neuron‐specific Enolase

Abstract

AbstractElectrochemical biosensors have made outstanding achievements in recent years. However, the single pursuit of sensitivity and accuracy sometimes cannot meet the detection requirements and achieve high‐efficiency measurements. Therefore, no‐washing biosensors have more practical advantages. In this work, a disposable point‐of‐care (POC) electrochemical biosensor was designed for the sensitive and fast detection of neuron‐specific enolase (NSE). Fe3O4 and CuS nanoparticles were used as the substrate material for capturing Ab1 and the signal probe for labeling Ab2 respectively. The disposable syringe filter was introduced into the determination procedure for simple sample separation, which easily realized no‐washing detection. Due to the syringe filters with 200 nm pore diameter could only allow the small nanoparticles of CuS−Ab2 pass through, the large‐sized immunocomplex of Fe3O4−Ab1/NSE/CuS−Ab2 were blocked on the membrane. The uncombined CuS−Ab2 particles were pushed out from the syringe and would occur electron transfer between Cu2+ and Cu+ to generate a current signal detected by the Au electrode. Under optimal conditions, the no‐washing biosensor shows a wide linear concentration range (100 fg mL−1∼50 ng mL−1) with the limit of detection of 33 fg mL−1 (S/N=3). Additionally, the biosensor exhibited excellent selectivity, storage stability and reproducibility. The outstanding advantages of the no‐washing biosensor make it more suitable for POC testing.