A universal biosensor utilizing bacteria-initiated in situ growth of electroactive polymers for bacteria-related...

Here, an ultrasensitive and highly selective electrochemical biosensor is engineered by integrating bacteria-initiated click chemistry with in situ growth of electroactive polymers. Leveraging the unique copper-binding redox pathway of bacteria to reduce Cu^II to Cu^I, Cu^I-catalyzed click chemistry is initiated and high-density electroactive ferrocenyl polymers are subsequently generated and efficiently grafted on biosensing interface by potentiostatic electrochemical atom transfer radical polymerization that greatly enhances the sensitivity of electro-analytical performance. A good linearity between electrochemical signal and the logarithm of Staphylococcus aureus and Escherichia coli concentration over the range from 10² to 10⁷ CFU/mL is obtained with detection limits down to 4 and 6 CFU/mL, respectively. In order to further expand the applicability and universality of the sensor, bacterial magnetic separation section is supplemented into the system. With the help of aptamer-based magnetic preseparation section, selective detection of target bacteria with great anti-interference is achieved in complex real samples. Moreover, this biosensor can be applied in convenient antibiotics residue detection and rapid drug resistance analysis by merely substitution of recognition element or preincubation of bacteria with different anti-bacteria drugs. Thus, after further expansion of bacterial magnetic separation section or simple replacement of the originally identification element, a universal biosensor including bacteria analysis system and antibiotics detection system with excellent analytical performance is constructed. It provides new insight into the aspects of bacteria-related hazards detection that could not only reduce the detriment caused by bacterial contamination, but also guide antibiotic rational usage and help to control the emergence of multidrug-resistant bacteria.