Ultra-Sensitive Chemiluminescence Biosensor for Nuclease and Bacteria Determination Based on Hemin-Encapsulated Mesoporous Silica Nanoparticle

Bacterial determination, emerging as a critical step in the understanding of increasingly serious bacterial contaminations, remains a major challenge. Herein, a novel chemiluminescence biosensor was exploited for the ultrasensitive determination of nuclease activity and bacteria, in which, hemin, the chemiluminescent (CL) tag molecule was encapsulated into ordered mesopores of mesoporous silica nanoparticles with a specific DNA gate. The capped DNA could be specifically switched upon exposure to the DNA nuclease or bacterial lysate and allowed for an increased release of the encapsulated hemin, which therefore resulted in an obviously enhanced CL signal for the luminol–H2O2 system. Attributed to this unique behavior with the linear or sigmoidal relationship between CL intensity and DNA nuclease or bacterial concentration, the as-prepared CL biosensor could detect S1 nuclease activity in the concentration range 0.01–10.0 U with a detection limit of 0.1 mU, and Escherichia coli O157:H7 (E. coli) or Staphylo...