Development of SPQC Biosensor for Streptococcus pneumoniae Detection Based on IscB Nuclease Recognition

Streptococcus pneumoniae is a major pathogen responsible for a wide range of infectious diseases in humans and is also the bacterium that causes the most deaths in children. Consequently, the rapid and accurate detection of S. pneumoniae is crucial for public health management. The IscB protein of the OMEGA (obligate mobile element-guided activity) system, as a programmable RNA-guided DNA endonuclease, shows high application potential for detecting single-nucleotide mismatches. This study developed a novel series piezoelectric quartz crystal (SPQC) sensor for S. pneumoniae detection based on specific recognition of IscB, combined with rolling circle amplification and urease-catalyzed urea hydrolysis. The biosensor demonstrates rapid detection of S. pneumoniae nucleic acids across 10³-10⁸ CFU/mL within 3 h, exhibiting a detection limit of 550 CFU/mL. This sensor has excellent selectivity, and common bacteria do not interfere with the detection of S. pneumoniae. This biosensing platform demonstrates significant potential for clinical diagnostic applications.