Detecting bacterial contaminants is critical for ensuring food safety and public health. Rapid and accurate identification of foodborne bacterial pathogens is essential to prevent illnesses and maintain the quality of food products. Traditional bacterial detection methods are often time-consuming, highlighting the need for innovative biosensors that offer faster and more efficient detection capabilities.
Schematic representation of the fabrication process for a flexible organic inverter-based biosensor. Image Credit: https://www.mdpi.com/2073-4360/16/11/1462
In this context, organic inverter-based biosensors have emerged as promising tools for detecting pathogenic bacteria due to their sensitivity, specificity, and potential advantages over conventional methods. A recent article published in the journal Polymers by researchers from Taiwan investigates the effectiveness of these biosensors in detecting bacterial contaminants, exploring their implications for food safety and microbiology.
Background
The field of biosensors has witnessed significant advancements in recent years, with a focus on integrating biological components with electronic detection systems to enable precise and rapid detection of target molecules. Biosensors play a crucial role in various applications, including medical diagnostics, environmental monitoring, and food safety. Particularly, biosensors offer the potential to revolutionize the way pathogenic bacteria are identified and quantified in food and environmental samples.
Organic inverter-based biosensors, which utilize organic field-effect transistors (OFETs) as sensing elements, have garnered attention for their ability to provide sensitive and specific detection of bacteria contaminants. By modulating the electrical characteristics of organic semiconductors based on the attachment of biological analytes, these biosensors offer a promising approach to rapid and accurate bacterial detection.
The Current Study
In this study, a blend of poly(4-vinylphenol) and poly(melamine-co-formaldehyde) was used to form a thin film acting as the dielectric layer in the organic inverter-based biosensors. The researchers deposited pentacene and N,N'-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C13) films as the active layers for p-type and n-type OFETs, respectively. The fabrication process involved spin-coating the organic semiconductor materials onto flexible polyimide substrates, followed by thermal annealing to enhance film quality.
The surface morphologies of the thin films were analyzed using atomic force microscopy (AFM) to assess the impact of bacterial exposure on film structure. The electrical properties of the OFETs were measured using a Keithley 4200 semiconductor characterization system inside a nitrogen-filled glove box to evaluate changes in device performance after exposure to bacteria and water.
Results and Discussion
The AFM analysis revealed that the surface structures of the films remained relatively unchanged following bacterial exposure, indicating that bacteria primarily adhered to the film surfaces without significantly altering their morphology. This observation suggests that the bacteria was unable to penetrate the film to induce structural changes, highlighting the importance of surface interactions in bacterial detection on organic semiconductor materials.
Furthermore, the electrical properties of the p-type OFETs, which use pentacene as the active layer, were evaluated to assess changes in device performance after exposure to bacteria. Interestingly, the electrical characteristics of the p-type OFETs did not show significant improvements following bacterial exposure. This suggests that the presence of bacteria had minimal impact on the performance of the p-type OFETs, indicating that the negative charges on bacterial surfaces did not significantly contribute to the accumulation of positive charges in the OFET channels. These results underscore the complex interplay between bacterial interactions and electrical properties in organic semiconductor devices.
In contrast, the n-type OFETs, which incorporate PTCDI-C13 as the active layer, exhibited distinct responses to bacterial exposure. Although the surface morphologies of the PTCDI-C13 films remained unchanged, the electrical properties of the n-type OFETs showed subtle variations after bacterial exposure. This suggests that the attachment of bacteria to the PTCDI-C13 films may have influenced the charge transport properties of the devices, leading to minor changes in their electrical characteristics. The differential responses of p-type and n-type OFETs to bacterial exposure highlight the importance of considering specific interactions between bacteria and organic semiconductor materials in biosensor design.
Conclusion
In conclusion, the research findings underscore the potential of organic inverter-based biosensors for detecting bacteria contaminants in food and environmental samples. While the study revealed minimal changes in the surface morphologies of organic semiconductor films after bacterial exposure, the electrical properties of the OFETs did not exhibit significant enhancements, indicating the need for further refinement in biosensor design.
Future research efforts should focus on optimizing the sensing mechanisms of organic inverter-based biosensors to improve detection sensitivity and specificity, ultimately advancing their application in food safety and microbiology. By harnessing the capabilities of organic semiconductor materials and innovative biosensor technologies, we can pave the way for more efficient and reliable methods of bacterial detection, contributing to enhanced food quality and public health.
Journal Reference
Fang, P.-H., Chang, H.-C., et al. (2024). Bacteria Contaminants Detected by Organic Inverter-Based Biosensors. Polymers, 16, 1462. https://doi.org/10.3390/polym16111462, https://www.mdpi.com/2073-4360/16/11/1462