Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers
Holger Schulze,
Harry Wilson,
Ines Cara,
Steven Carter,
Edward N. Dyson,
Ravikrishnan Elangovan,
Stephen Rimmer,
Till T. Bachmann
Affiliations
Holger Schulze
Infection Medicine, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor’s Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
Harry Wilson
Infection Medicine, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor’s Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
Ines Cara
Infection Medicine, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor’s Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
Steven Carter
Polymer and Biomaterials Chemistry Laboratories, School of Chemistry and Biosciences, University of Bradford, Bradford BD7 1DP, UK
Edward N. Dyson
Polymer and Biomaterials Chemistry Laboratories, School of Chemistry and Biosciences, University of Bradford, Bradford BD7 1DP, UK
Ravikrishnan Elangovan
Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi 110016, India
Stephen Rimmer
Polymer and Biomaterials Chemistry Laboratories, School of Chemistry and Biosciences, University of Bradford, Bradford BD7 1DP, UK
Till T. Bachmann
Infection Medicine, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor’s Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
Rapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability.
