Functionalized hollow mesoporous silica for detection of Staphylococcus aureus and sterilization

Abstract

A dual-functional smart material for both bacterial detection and sterilization was prepared through the electrostatic interaction between Rhodamine B-loaded amino-modified hollow mesoporous silica spheres (RAHMSN) and Staphylococcus aureus (S. aureus)-specific aptamer-modified gold nanorods (AGNR). The internal RAHMSN portion was used for detection of S. aureus, while the external AGNR was used for photothermal sterilization. In the presence of S. aureus, it would specifically bind to the aptamer that modified on AGNR, resulting in the removal of AGNR from RAHMSN. Subsequently, Rhodamine B could be released from the AHMSN for the fluorescent detection of S. aureus. Then, upon near-infrared (NIR) light irradiation, the photothermal effect of AGNR was utilized to kill the specifically bound S. aureus, exerting the function of photothermal sterilization. When the ratio of RAHMSN to AGNR is 8 and the concentration of Rhodamine B is 11 μg/mL, the dual-functions of the composite material are harmoniously combined. The assay exhibited a wide detection range from 6.5 × 102 CFU/mL to 6.5 × 107 CFU/mL with the limit of detection of 51 CFU/mL, as well as good specificity. In terms of sterilization, 100% sterilization can be achieved after 5 min of irradiation. Based on these excellent properties, the dual-functional material will be very helpful to save resources and avoid the abuse of antibiotics in the potential applications in environmental sterilization and testing.