Wavelength-Resolved Magnetic Multiplex Biosensor for Simultaneous and Ultrasensitive Detection of Pneumonia Pathogens via Catalytic Hairpin Assembly Strategy with Luminescent Iridium Complexes

Pneumonia is a prevalent acute respiratory infection and a major cause of mortality and hospitalization, and the urgent demand for a rapid, direct, and highly accurate diagnostic method capable of detecting both <i>Streptococcus pneumoniae</i> (<i>S. pneumoniae</i>) and <i>Klebsiella pneumoniae</i> (<i>K. pneumoniae</i>) arises from their prominent roles as the primary pathogens responsible for pneumonia. Herein, two luminescent iridium complexes with nonoverlapping photoluminescence spectra, iridium(III)-bis [4,6-(difluorophenyl)-pyridinato-N,C²'] picolinate (abbreviated as Ir-B) and bis (2-(3,5- dimethylphenyl) quinoline-C2,N') (acetylacetonato) iridium(III)) (abbreviated as Ir-R), were unprecedently proposed to construct a novel wavelength-resolved magnetic multiplex biosensor for simultaneous detection of <i>S. pneumoniae</i> and <i>K. pneumoniae</i> based on catalytic hairpin assembly (CHA) signal amplification strategy combined with dye-doped silica nanoparticles. Notably, the proposed wavelength-resolved multiplex biosensor not only exhibits a broad linear range from 50 pM to 10 nM but also demonstrates excellent recovery rates for <i>S. pneumoniae</i> (96.1-99.3%) and <i>K. pneumoniae</i> (94.8-101.5%) in real clinical samples, with corresponding relative standard deviation (RSD) values ranging from 2.57 to 3.15% for <i>S. pneumoniae</i> and 1.45 to 3.17% for <i>K. pneumoniae</i>. These favorable experimental outcomes undoubtedly offer a promising approach for the simultaneous detection of multiple pathogens in the future.