Sensitive and Portable Detection of Bacteria Using Exonuclease-III (Exo-III) Assisted Signal Amplification and Personal Glucose Meters.

Despite major advances in combating pathogenic bacteria caused infection, infectious diseases remain a major cause of death today. A variety of bacteria detection approaches have been established by exploiting the aptamer to specifically identify target. However, these methods require specific equipment or laboratory based instruments, which is expensive and not easily available to the public. To deal with this issue, we develop here a portable and sensitive pathogenic bacteria detection approach through integrating capture probe based recognition and Exo-III assisted signal amplification. In this method, a designed capture probe identifies the surface protein of target bacteria, leading to the release of blocker sequence. The released blocker sequence mediates Exo-III enzyme based signal amplification, generating a large amount of signal strand DNA (ssDNA) sequences. The obtained ssDNA works as a linker to conjugate streptavidin magnetic beads (SMBs) with DNA invertase. After magnet based enrichment and washing away of free DNA invertase, the SMBs-DNA invertase complex is used to catalyze the hydrolysis of sucrose into glucose for PGM readout. Based on this, the approach exhibits a 6 order of magnitudes in detecting Staphylococcus Aureus (S. aureus) with the limit of detection as low as 78 cfu/mL. In addition, the capability to specifically detect target bacteria and high repeatability (relative standard deviation, 4.44%) endows the method wider applicable scenes. In all, the established shows a promising prospect in the detection of bacteria pathogen and the early-diagnosis of bacterial infections.