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 K 2 S 2 O 8 . 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.