Novel Efficient Selenium-Based D-π-A NIR Polymer Dots Anodic Electrochemiluminescence Emitter and Its Application in Simultaneous Detection of Two Pneumonia Pathogens with CdS Quantum Dots.

Community-acquired pneumonia (CAP) is a major cause of death in children under 5 years old globally. With Streptococcus pneumoniae (S. pneumoniae) and Mycoplasma pneumoniae (M. pneumoniae) being the main pathogens linked to CAP that requires hospitalization, there is an urgent need for a straightforward, cost-efficient, and highly accurate diagnostic method for immediate and early detection of CAP. In this work, benzo[1,2-c;4,5-c']bis([1,2,5]thiadiazole) (BBT) as π-bridge spacer with the donor unit of poly(9,9-dioctylfluorene) (PF) and the acceptor unit of dithienylbenzoselenadiazole (DBS) has been successfully copolymerized to unprecedentedly prepare novel D-π-A selenium-based polymer dots with efficient NIR electrochemiluminescence (named as Se-Pdots in this work). Se-Pdots exclusively generated excellent anodic ECL in the two-component coreaction system comprising TPrA and K2S2O8. Moreover, a potential-resolved ECL biosensor to simultaneously detect S. pneumoniae and M. pneumoniae has also been successfully constructed based on this novel Se-based NIR Pdots as an anodic emitter with CdS QDs as a cathodic emitter. Under optimal conditions, the biosensor has a wide linear range for S. pneumoniae (10-15 to 10-9 M) and M. pneumoniae (10-15 to 10-9 M), with low detection limits for S. pneumoniae (0.56 fM) and M. pneumoniae (0.96 fM). The proposed ECL biosensor provides a simple, sensitive, and reliable method for the simultaneous detection of CAP pathogens in clinical applications.