Researchers have developed a fast and highly sensitive biosensor that uses dielectrophoresis—an electric field-based technique—to detect foodborne viruses in real time, offering a promising tool for on-site safety testing.
Study: Flow-Based Dielectrophoretic Biosensor for Detection of Bacteriophage MS2 as a Foodborne Virus Surrogate. Image Credit: Natali _ Mis/Shutterstock.com
Background
Biosensors are gaining traction as effective tools for virus detection. These devices combine biological recognition elements, such as antibodies or nucleic acids, with electronic components that convert biological interactions into electrical signals. Electrochemical biosensors, in particular, offer high sensitivity and fast response times, making them well-suited for identifying virus particles, proteins, or genetic material.
Advances in nanotechnology have further improved biosensor performance. Materials like graphene, carbon nanotubes, and metallic nanoparticles boost signal transduction, expand surface area for molecular binding, and enhance virus capture. Despite these innovations, detecting intact viruses remains a challenge due to their small size and similarity in electrical properties to other particles in complex samples.
To tackle this, researchers have turned to dielectrophoresis (DEP)—a technique that uses non-uniform electric fields to move particles based on their dielectric properties.
The Current Study
The biosensor developed in this study features two main components: a concentration unit and a detection unit. The concentration unit uses interdigitated electrode arrays to generate the DEP forces needed to guide viral particles—specifically MS2—toward the sensor surface, concentrating them from dilute solutions.
The detection unit is built around a silver electrode coated with anti-MS2 IgG antibodies. These antibodies enable specific recognition and binding of the virus particles concentrated via DEP.
To prepare the electrode, researchers used a covalent bonding method involving carbodiimide chemistry (EDC/NHS) to firmly attach antibodies to the surface. They confirmed successful modification and virus binding using electrochemical techniques like cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). All testing took place inside a microfluidic channel, where serial dilutions of MS2 were injected to simulate realistic flow conditions.
The team monitored current responses at the sensor electrode, applying a 10 V peak-to-peak voltage at 1 MHz to generate DEP effects. By comparing current levels before and after virus binding, they measured the sensor’s response, quantified as the change in current (ΔI).
To validate their results, the researchers conducted repeated experiments with various virus concentrations. Statistical methods, including analysis of variance (ANOVA) and t-tests, were used to assess the sensor’s sensitivity and reliability.
Results and Discussion
The biosensor was able to detect MS2 across a wide concentration range—from 102 to 108 plaque-forming units per milliliter (PFU/mL)—with clear, measurable changes in current. Virus binding led to a decrease in current, signaling successful capture by the antibodies. The response was both consistent and rapid: detection took just 15 minutes, and the sensor showed strong linearity (R2 = 0.98) across tested concentrations.
Electrochemical methods, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), confirmed successful antibody coating and virus detection. The use of DEP significantly enhanced virus concentration at the sensing surface, resulting in more reliable signals, which is especially important when working with low viral loads or complex fluids like food samples.
Why It’s a Big Deal
This biosensor not only shortens detection time but also increases accuracy by actively drawing viral particles to the sensing surface. That’s a big improvement over passive sensors, which can miss low concentrations or get overwhelmed by background noise. The use of nanomaterials, like single-walled carbon nanotubes (SWCNTs), further boosts sensitivity by enhancing signal transfer.
Together, these features make the device especially promising for field use in food safety, where quick, reliable detection of pathogens is critical.
What’s Next
Looking ahead, the research team plans to refine the system’s performance, expand detection capabilities to include other viruses, and evaluate long-term stability. They also aim to explore strategies for regenerating the sensor surface for repeated use and begin field testing in real-world environments.
Journal Reference
Lee I., So H., et al. (2025). Flow-Based Dielectrophoretic Biosensor for Detection of Bacteriophage MS2 as a Foodborne Virus Surrogate. Biosensors. 15(6):353. DOI: 10.3390/bios15060353, https://www.mdpi.com/2079-6374/15/6/353