title: Rapid, electrical impedance detection of bacterial pathogens using immobilized antimicrobial peptides.
abstract: The detection of bacterial pathogens plays an important role in many biomedical applications, including clinical diagnostics, food and water safety, and biosecurity. Most current bacterial detection technologies, however, are unsuitable for use in resource-limited settings where the highest disease burdens often exist. Thus, there is an urgent need to develop portable, user-friendly biosensors capable of rapid detection of multiple pathogens in situ. We report a microfluidic chip for multiplexed detection of bacterial cells that uses antimicrobial peptides (AMPs) with species-specific targeting and binding capabilities. The AMPs are immobilized onto an electrical impedance microsensor array and serve as biorecognition elements for bacterial cell detection. Characterization of peptide immobilization on the sensors revealed robust surface binding via cysteine-gold interactions and vertical alignment relative to the sensor surface. Samples containing Streptococcus mutans and Pseudomonas aeruginosa were loaded in the chip, and both microorganisms were detected at minimum concentrations of 10⁵ cfu/mL within 25 min. Measurements performed in a variety of solutions revealed that high-conductivity solutions produced the largest impedance values. By integrating a highly specific bacterial cell capture scheme with rapid electrical detection, this device demonstrates great potential as a next-generation, point-of-care diagnostic platform for the detection of disease-causing pathogenic agents.
authors.affiliation: 1Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Lillehoj
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Kaplan
authors.forename: Jian
authors.initials: J
authors.lastname: He
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Shi
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Ho
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000378:metabolism*; D001431:Bacteriological Techniques / Q000379:methods*; D015374:Biosensing Techniques / Q000379:methods*; D017097:Electric Impedance; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013295:Streptococcus mutans / Q000187:drug effects / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D023181:Antimicrobial Cationic Peptides; D055767:Immobilized Proteins
keywords: antimicrobial peptides; bacterial detection; impedance biosensor; microfluidics