Electrical detection of pathogenic bacteria via immobilized antimicrobial peptides

Manu S. Mannoor, Siyan Zhang, A. James Link, Michael C. McAlpine

Research output: Contribution to journalArticlepeer-review

288 Scopus citations


The development of a robust and portable biosensor for the detection of pathogenic bacteria could impact areas ranging from waterquality monitoring to testing of pharmaceutical products for bacterial contamination. Of particular interest are detectors that combine the natural specificity of biological recognition with sensitive, label-free sensors providing electronic readout. Evolution has tailored antimicrobial peptides to exhibit broad-spectrum activity against pathogenic bacteria, while retaining a high degree of robustness. Here, we report selective and sensitive detection of infectious agents via electronic detection based on antimicrobial peptide-functionalized microcapacitive electrode arrays. The semiselective antimicrobial peptide magainin I-which occurs naturally on the skin of African clawed frogs-was immobilized on gold microelectrodes via a C-terminal cysteine residue. Significantly, exposing the sensor to various concentrations of pathogenic Escherichia coli revealed detection limits of approximately 1 bacterium?μL, a clinically useful detection range. The peptide-microcapacitive hybrid device was further able to demonstrate both Gram-selective detection as well as interbacterial strain differentiation, while maintaining recognition capabilities toward pathogenic strains of E. coli and Salmonella. Finally, we report a simulated "watersampling" chip, consisting of a microfluidic flow cell integrated onto the hybrid sensor, which demonstrates real-time on-chip monitoring of the interaction of E. coli cells with the antimicrobial peptides. The combination of robust, evolutionarily tailored peptides with electronic read-out monitoring electrodes may open exciting avenues in both fundamental studies of the interactions of bacteria with antimicrobial peptides, as well as the practical use of these devices as portable pathogen detectors.

Original languageEnglish (US)
Pages (from-to)19207-19212
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number45
StatePublished - Nov 9 2010
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


  • Bacterial sensing
  • Bioelectronic sensors
  • Biomimetic devices
  • Biorecognition
  • Water monitoring


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