Capacitive antibacterial susceptibility screening test with a simple renewable sensing surface

A simple renewable surface for a rapid antibacterial susceptibility test has been demonstrated. The 3-aminophenylboronic acid (3-APBA) modified electrode bind with cis-diol groups on the cell wall of both gram positive and gram negative bacteria. The detection of antibacterial susceptibility response by a capacitive system can be done within a short time, 2.5h for the whole process, with good repeatability of the electrode's preparation. An acid solution, could break the bonding between 3-APBA and the bacteria, which were then easily removed by the fluid flow, renewing the sensing surface for the next test. This modified electrode can be reused up to 35 times. This sensor is useful for testing the susceptibility of bacteria to antibacterial agents that affect their cell wall. Results from the capacitive sensor corresponded well with the antimicrobial information in the literature and to the morphology of the treated bacteria revealed by scanning electron microscopy. Antimicrobial susceptibility to natural products could also be easily tested.