Coaggregation Strengthened Nanozymes for the Identification of Oral Cariogenic Bacteria

Dental caries, caused by oral cariogenic bacteria, underscore the critical importance of early diagnosis for effective prevention and treatment. The identification of oral cariogenic bacteria depends on the development of the recognition elements. In this work, coaggregation between bacteria has been subtly mined for exploration of the recognition elements, which has been further used to construct a colorimetric sensor array for the identification of nine oral cariogenic bacteria. Three fermentative bacteria (Kocuria sp. RXG-8, Bacillus sp. 7578-18, and Bacillus sp. LTZ-12) can coaggregate with the cariogenic bacteria to varying degrees, and they are covalently conjugated with single-atom nanozymes. Compared with free fermentative bacteria, nanozymes modified by fermentative bacteria show significantly enhanced coaggregation stability with cariogenic bacteria. Coaggregation recognition obviously adjusts the oxidase-like activities of nanozymes, which serves for the identification of cariogenic bacteria. Subsequently, fermentative bacterium-modified nanozymes have been further exploited to construct a colorimetric sensor array, and linear discriminant analysis is employed to create unique fingerprints for each cariogenic bacterium. The constructed colorimetric sensor array can be successfully applied not only for the identification of nine oral cariogenic bacteria but also for the discrimination of saliva samples from healthy and caries-affected children. This work offers an alternative strategy to develop recognition elements and a potential tool for the early diagnosis and prevention of dental caries.