New sensor uses natural germ-fighting compounds for rapid bacterial detection

Jenn Hoskins
23rd November, 2025

New sensor uses natural germ-fighting compounds for rapid bacterial detection

This figure from the study illustrates the fabrication of electrochemical biosensors via gold nanoparticle electrodeposition, antimicrobial peptide immobilization, and subsequent detection of pathogenic microorganisms through changes in electrical signal.

Image adapted from: Ropero-Vega et al. / CC BY (Source)

Key Findings

  • Researchers developed new biosensors to quickly detect E. coli, Staphylococcus aureus, and Pseudomonas aeruginosa bacteria, addressing the need for faster pathogen identification
  • These biosensors utilize antimicrobial peptides to recognize bacteria and measure changes in electrical signals, achieving detection of as few as 0.8 to 1.4 bacterial cells per milliliter
  • Adding carbon nanotubes to the sensors improved their performance, particularly for E. coli and S. aureus detection, enhancing sensitivity and lowering detection limits
Detecting harmful bacteria in water, food, and clinical samples is crucial for protecting public health. Traditional methods can take days to yield results, delaying necessary interventions. Faster, more sensitive detection methods are therefore highly sought after. Researchers from Universidad de Santander, Universidad del Magdalena, and Islamic Azad University have developed a new type of biosensor capable of rapidly detecting several dangerous bacteria[1]. The study focused on creating sensors that can identify Escherichia coli O157:H7, Pseudomonas aeruginosa, and Staphylococcus aureus. These bacteria are all significant threats: E. coli O157:H7 causes severe food poisoning, P. aeruginosa can lead to infections in hospitals and vulnerable individuals, and S. aureus, including its antibiotic-resistant form MRSA, causes skin infections and more serious illnesses. The new biosensor aims to detect these pathogens quickly and at very low concentrations. The core of the biosensor lies in its ability to recognize specific bacteria. This is achieved using antimicrobial peptides – naturally occurring molecules that bacteria are susceptible to. The researchers used two specific peptides, Ib-M1 and Ib-M6, and attached them to a specially prepared surface. This surface consists of a screen-printed electrode modified with gold nanoparticles, arranged in a self-assembled monolayer. This arrangement maximizes the surface area for the peptides to bind to, and therefore increases the sensor’s sensitivity. Detection is performed using a technique called electrochemical impedance spectroscopy (EIS). EIS measures the electrical resistance of the sensor surface. When bacteria bind to the antimicrobial peptides, it changes the electrical properties of the surface, which the sensor detects. The biosensor developed in this study is remarkably sensitive, capable of detecting as few as 0.8 to 1.4 bacterial cells per milliliter of liquid – a level that would be difficult to detect with many existing methods. The sensors also work within a limited, but useful, range of bacterial concentrations, from 0 to 100 cells per milliliter for E. coli and S. aureus, and 0 to 75 cells per milliliter for P. aeruginosa. The researchers found that adding carbon nanotubes to the sensor further improved its performance, particularly for detecting E. coli O157:H7 and S. aureus. Carbon nanotubes are known for their excellent electrical conductivity and ability to enhance the signal in electrochemical sensors. This research builds upon previous work in developing electrochemical sensors for bacterial detection. For example, studies have demonstrated the effectiveness of using antibodies to detect E. coli O157:H7 with a limit of detection as low as 2 CFU/mL[2]. The current study improves upon this by utilizing antimicrobial peptides instead of antibodies, potentially offering advantages in terms of stability and cost. Furthermore, the use of gold nanoparticle-modified electrodes and carbon nanotubes represents a significant advancement in sensor design, leading to even greater sensitivity. Another study highlighted the use of Bayesian decision theory alongside impedance spectroscopy for Salmonella typhimurium detection, achieving results in approximately 6 minutes[3]. The new biosensor aims for similar speed and portability, offering a potential alternative for rapid on-site testing. The potential applications of this technology are broad. The biosensors could be used to monitor drinking water for contamination, ensure food safety in processing plants, and rapidly diagnose infections in clinical settings. The ability to detect multiple pathogens with a single sensor is also a significant advantage. The research also echoes earlier work using electrochemical biosensors for E. coli O157:H7 detection, utilizing nanomaterials like carbon dots and iron oxide to enhance sensitivity and allow for sample recovery[4]. The current study’s use of antimicrobial peptides and gold nanoparticles offers a different, potentially more efficient approach. Interestingly, the need for rapid detection is underscored by research showing that humans shed bacteria like Staphylococcus aureus into recreational waters[5], highlighting the importance of monitoring these environments for potential pathogens. The biosensor developed in this study could be a valuable tool for such monitoring efforts.

MedicineBiotechBiochem

References

Main Study

1) Advanced electrochemical biosensing of pathogens: Harnessing the antimicrobial properties of Ib-M peptides for highly sensitive bacterial detection

Published 21st November, 2025

https://doi.org/10.1371/journal.pone.0337227

Related Studies

2) Highly sensitive detection of pathogen Escherichia coli O157:H7 by electrochemical impedance spectroscopy.

https://doi.org/10.1016/j.bios.2013.01.009

3) A methodology for rapid detection of Salmonella typhimurium using label-free electrochemical impedance spectroscopy.

https://doi.org/10.1016/j.bios.2008.06.036

4) Electrochemical Biosensing Interface Based on Carbon Dots-Fe3O4 Nanomaterial for the Determination of Escherichia coli O157:H7.

https://doi.org/10.3389/fchem.2021.769648

5) Shedding of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus from adult and pediatric bathers in marine waters.

https://doi.org/10.1186/1471-2180-11-5


Related Articles

An unhandled error has occurred. Reload 🗙