Aggregation-induced emission silence-mediated pathogen detection using a rapidly degradable nanographene-embedded polymersome.

Typical pathogen detection processes are time-consuming and require expensive equipment and professional operators, limiting their practical applicability. Developing a rapid and easy-to-read method of accurately sensing pathogenic bacteria is critical for reducing the spread and risk of infection in high-risk areas. Herein, the synthesis of nanographene (nanoG) that exhibits aggregation-induced emission (AIE) is described. The nanoG was embedded into a hydrophobic shell of poly(lactic--glycolic acid) (PLGA) polymersome in a double-emulsion process, significantly enhancing the nanoG luminescence under irradiation at 330 nm due to the enrichment of nanoG between the inner and outer PLGA shells. Both Gram-positive and Gram-negative bacteria can rapidly degrade the PLGA vesicular structure, leading to dispersal of the nanoG inside the shell and silencing the AIE effect. A linear relationship between the bacterial concentration and emissivity was established, and the detection limit was identified. Moreover, the polymersome has excellent selectivity for methicillin-resistant (MRSA) detection after a screening pretreatment of a bacterial mixture with suitable antibiotics. The AIE silencing could be observed with the naked eye in an MRSA-infected wound treated with the polymersome after 1 h of incubation, demonstrating a high potential for clinical rapid screening applications.