Real time detection of 3-nitrotyrosine using smartphone-based electrochemiluminescence

As an oxidase stress biomarker, 3-nitrotyrosine is closely associated with many cardiovascular diseases. Thus, early diagnosis and real time detection of 3-nitrotyrosine at bedside are highly important. Herein, we developed a handheld electrochemiluminescence (ECL) analysis device, which integrates printed circuit board (PCB) for electrical stimulation and smartphone for optical signals readout. Fast and accurate determination of 3-nitrotyrosine was achieved with Antibody/Ru(dcpy)₃²⁺@AuNPs/MoS₂ modified Au electrode (Ab/Ru@AuNPs/MoS₂) for ECL analysis. The linear range of 3-nitrotyrosine detection was from 10^-8 mol/L to 10^-6 mol/L with a detection limit of 8.4 × 10^-9 mol/L. In addition, an Android application was developed to realize real time analysis of ECL emissions and results readout for detection. To confirm the usage of the device, spiked serum with different concentrations was tested and the results indicated the practical reliability and stability of this device. The operating procedure for ECL analysis in this device is extremely easy and electrical stimulation was adjustable from 0 V to 5 V for general ECL systems. Thus, we believe this handheld device for ECL analysis has extensive prospects for application in Point-of-care testing and health caring.