Metalon JG-125 Gold and JS-A191-S Silver Nanoparticle Inks Drive Sustainable, High-Resolution Printed Biosensors
The proliferation of pharmaceutical pollutants, particularly antibiotics, in aquatic ecosystems and food chains poses a significant and growing threat to both environmental health and human well-being. Traditional analytical methods for detecting these contaminants are often complex, costly, and ill-suited for rapid, on-site monitoring. This challenge underscores the urgent need for advanced, portable, and sustainable analytical tools.
A recently published study in the Microchemical Journal addresses this critical need by demonstrating a novel label-free electrochemical immunosensor for the precise determination of trimethoprim (TMP), a widely used antibiotic, in environmental water and fish samples. This groundbreaking work, led by researchers from REQUIMTE/LAQV, ISEP, Polytechnic of Porto, leverages the power of inkjet printing and high-performance conductive inks to create a robust, reproducible, and environmentally friendly diagnostic platform.
Why This Research Matters for Environmental and Food Safety
Trimethoprim is a frequently detected contaminant in aquatic environments, with reported concentrations ranging from nanograms to hundreds of micrograms per liter. Its presence in seafood, resulting from aquaculture applications, further highlights the need for effective monitoring. Current methods, such as chromatography, are often laboratory-bound, expensive, and time-consuming, making them impractical for widespread, decentralized monitoring.
The paper-based electrochemical immunosensor developed in this study offers a compelling alternative. By combining the advantages of miniaturization, portability, high sensitivity, and reduced material consumption, it provides a practical solution for detecting TMP at environmentally relevant levels. This approach is particularly significant because it enables rapid analysis without extensive sample pre-treatment, a key factor for real-world application in resource-constrained settings.
NovaCentrix Metalon Inks: The Foundation of High-Performance Sensing
At the heart of this innovative immunosensor are NovaCentrix’s advanced conductive inks. The researchers utilized Metalon JG-125 gold nanoparticle ink for the working electrode and Metalon JS-A191-S silver nanoparticle ink for the connector part. These inks were inkjet-printed onto a commercial waterproof paper-like substrate, demonstrating the versatility and precision of inkjet conductive inks for fabricating complex electrode geometries.
The fabrication process involved inkjet printing the gold and silver nanoparticles with a high resolution of 1693 dpi and a drop space of 15 µm. Following deposition, the electrodes were sintered at 175 °C for 10 minutes. This precise control over material deposition and post-processing is crucial for achieving the desired conductivity and surface characteristics required for sensitive electrochemical detection. The use of these specific NovaCentrix inks enabled:
- Direct, High-Resolution Printing: Facilitating mask-free operation and precise patterning of conductive elements on a flexible substrate.
- Robust and Reproducible Electrodes: The printed gold and silver layers formed a stable and repeatable transducer, essential for consistent analytical performance.
- Optimized Electrochemical Interface: The gold nanoparticles provided an ideal surface for antibody immobilization through a simple chemisorption process, crucial for the label-free immunosensing strategy.
- Scalability and Cost-Effectiveness: Inkjet printing with readily available inks and paper-like substrates offers a pathway to scalable manufacturing of low-cost diagnostic devices.
Exceptional Analytical Performance and Green Credentials
The optimized immunosensor demonstrated outstanding analytical performance for trimethoprim detection. It exhibited a linear response up to 2.43 µg/L (8.4 nM) and achieved remarkably low limits of detection (LOD) of 0.0093 µg/L (0.03 nM) and quantification (LOQ) of 0.028 µg/L (0.1 nM). These figures are sufficient to detect TMP concentrations well below the predicted no-effect concentration (PNEC) of 0.16 µg/L, highlighting its environmental relevance.
Beyond its sensitivity, the biosensor showed excellent reproducibility, with a coefficient of variation of 9.2% for three independently prepared devices. It also demonstrated high selectivity against common contaminants of emerging concern, with interferent signals consistently below 7.0%. Validation in real-world samples, including river water and gilthead seabream tissue, yielded excellent recoveries (99.3–111.5%) with minimal pre-treatment. Furthermore, the device maintained stable analytical performance for up to 14 days, supporting its applicability for routine monitoring.
A key aspect of this research is its commitment to sustainability. The method achieved an Analytical GREEnness Metric (AGREE) score of 0.77, indicating a high level of sustainability, with 10 out of 12 criteria fulfilling green analytical chemistry principles. The Green Analytical Procedure Index (GAPI) assessment further confirmed the favorable environmental profile of the method, reinforcing the potential for truly sustainable diagnostic solutions.
Advancing Sustainable Diagnostics with Printed Electronics
This study represents a significant step forward in the development of advanced analytical methods for environmental and food safety. By leveraging the unique properties of NovaCentrix Metalon gold and silver nanoparticle inks, researchers have created a label-free electrochemical immunosensor that is not only highly sensitive and selective but also sustainable and scalable. The ability to inkjet print robust and reproducible electrodes on flexible, paper-like substrates opens new avenues for creating compact, easy-to-use analytical devices for in situ analysis.
At NovaCentrix, we are proud to see our Metalon inks enabling such impactful research. This work exemplifies how high-performance conductive materials are crucial for transforming innovative concepts into practical solutions that address global challenges in environmental monitoring and public health. We look forward to continuing our support for the scientific community as printed electronics continues to push the boundaries of what’s possible in diagnostics.
Read the full paper: Torrinha, Á.; Silva, A.; Seguro, I.; Pacheco, J.; Delerue-Matos, C.; Morais, S.; Freitas, M. Gold-printed paper-like substrate immunosensor for label-free trimethoprim determination in water and fish. Microchemical Journal 228 (2026): 119121.