A novel L-cysteine regulated polydopamine nanoparticle-based electrochemiluminescence image application
In this work, a novel L-cysteine regulated polydopamine nanoparticle (PDAcp NPs) with extremely excellent electrochemiluminescence (ECL) behavior were synthesized. Because of the complex dopamine polymerization and the resulted disordered internal structure, the polydopamine nanoparticles (PDA NPs) suffered from the low luminous efficiency and poor optical performance. Therefore, we used L-cysteine to regulate the polymerization process and the interior structure of PDA NPs effectively. On the one hand, the thiol functional group of L-cysteine can react with dopamine oligomer underwent the Michael addition reaction. On the other hand, the amino group of the L-cysteine formed a Schiff base with the carbonyl group of the oligomer through nucleophilic addition. The surface of the obtained nanoparticles was further modified by polyethyleneimine (PEI). The prepared PDAcp NPs with ordered internal structure had 10 times ECL intensity than common PDA NPs. An internal filtering effect-based ECL aptasensing and image analysis were accomplished for the detection of adenosine triphosphate (ATP). The results showed that the proposed aptamer sensor can determine ATP with a detection limit of 3.79 fmol/L and a linear range from 10fmol/L to 100μmol/L. The ECL image of the PDAcp NPs can be recorded clear by the smartphone. The visual ECL analysis results indicated that PDAcp NPs had great potential in the ECL biosensor and clinical diagnosis.