A novel epinephrine biosensor based on gold nanoparticles coordinated polydopamine-functionalized acupuncture needle microelectrode

Epinephrine (EP) is an important neurotransmitter that plays a vital role in mammalian central nervous and hormone systems. So, the monitoring of EP is significant to evaluate human health. Until now, developing new methods for detecting EP has attracted increasing interest to avoid the previous disadvantages, such as high cost, long time-consuming, and professional operation. Acupuncture is a kind of traditional Chinese treatment. Herein, stainless steel needle, an acupuncture tool, was used as an electrochemical matrix and functionalized to be a simple, effective sensor for detecting EP. The acupuncture needle showed a typical electrochemical behavior. Gold nanoparticles coordinated polydopamine-modified acupuncture needle (AuNPs/PDA/AN) was fabricated via the green route of pure electron-transfer induced reaction of electrodepositing. The covered interface exhibited synergistic response performance to EP. The electron transfer of the phenolic hydroxyl group in EP molecular was enhanced via the superficial active site, showing the notable current peak. The generated current intensity can be used as an index to reflect the corresponding concentration. Under the optimized conditions, the fabricated biosensor expressed a wide and good linear relationship from 1 μM to 1000 μM, and a detection limit of 0.26 μM, which are competitive with former relative reports. In practical application, the fabricated sensor has been effectively used to analyze EP in real human serum, and also realized the real-time detection of EP secreted by PC12 cells irritated by salbutamol. The sensor was found to perform high selectivity, stability, and reproducibility, which is promising in the future given the advantages of electrochemical sensors, including low price, fast response, and simple operation.