Researchers have developed a low-cost, quantum dot-enhanced biosensor that can rapidly and reliably detect vitamin B6 (pyridoxine), offering a promising alternative to conventional methods that are often time-consuming or expensive.
Study: Development of low cost ZnO based chemi resistive biosensor for the detection of vitamin B6 mediated by quantum dots. Image Credit: Mosiahina Yulia/Shutterstock.com
The sensor, detailed in a recent article in Scientific Reports, integrates cadmium telluride (CdTe) quantum dots with zinc oxide (ZnO) thin films to enhance performance. Given vitamin B6’s essential role in numerous biological functions, this work presents an important step toward more accessible and efficient diagnostic tools for both clinical and pharmaceutical applications.
Why Vitamin B6 Detection Matters
Vitamin B6 is essential for a range of biological functions, including enzymatic activity and energy metabolism, especially during periods of physical exertion and recovery. As humans cannot produce it endogenously, it must be obtained through diet, making accurate detection important for both clinical diagnostics and nutritional studies.
However, conventional methods for vitamin analysis often involve complex protocols or costly materials, limiting their use in real-world or resource-limited settings. This study addresses that challenge by introducing a more accessible and efficient approach, building on prior research into the biosensing capabilities of metal oxide thin films and quantum dots.
The Current Study: Sensor Design and Fabrication
To develop the sensing platform, the team employed a spin-coating sol-gel technique to fabricate ZnO thin films. These films were then annealed at 500 °C to enhance their structural integrity and electrical conductivity. The integration of CdTe quantum dots played a pivotal role in boosting the sensor’s electrochemical sensitivity—essential for detecting low concentrations of vitamin B6.
The device operates via amperometric current-voltage (I–V) measurements conducted at a low working voltage (under 2 V). It was tested across a clinically relevant concentration range of 2 to 10 μM. In parallel, electrochemical impedance spectroscopy (EIS) was used to analyze charge transfer dynamics within the sensing platform, providing complementary insights to the I–V data.
Results and Discussion
Performance testing revealed a sensitivity of 7.56 ± 0.92 nA/μM, with a detection limit of 0.906 μM, confirmed through five independent measurements. As vitamin B6 concentrations increased, the sensor exhibited a clear, linear decline in current—indicating reliable and predictable detection behavior.
The underlying mechanism centers on electrostatic interactions between vitamin B6 and the ZnO surface, facilitated by the CdTe quantum dots. This interaction improves charge transfer efficiency, enabling the sensor to generate a measurable electrical response even at low analyte concentrations. EIS results aligned closely with I–V data, reinforcing the consistency of the sensing mechanism.
To assess selectivity, the sensor was challenged with various biological interferents—including ascorbic acid, bovine serum albumin (BSA), cysteine, and glucose—at concentrations much higher than that of vitamin B6. Despite these potential interferences, the sensor maintained a strong and specific response to vitamin B6.
Further validation involved human serum samples, where the sensor achieved recovery rates of 106.4 % with relative standard deviations below 5 %, underscoring its potential utility in clinical diagnostics.
Beyond performance metrics, the study also explored the physicochemical interactions underlying the sensor’s function. Adsorption of vitamin B6 onto the ZnO surface significantly enhanced electron transfer, an effect amplified by the presence of CdTe quantum dots. This synergy between materials resulted in improved current responses and greater detection accuracy.
While the sensor showed strong initial stability and responsiveness, the researchers also acknowledged the need for further investigation into long-term durability and performance under real-world conditions, particularly in complex biological matrices.
Conclusion
This study presents a ZnO thin-film-based biosensor enhanced with CdTe quantum dots as a sensitive, cost-effective tool for detecting vitamin B6. With its low detection limit, reliable linear response, and proven performance in human serum, the sensor offers a compelling alternative to traditional analytical methods.
Its advantages—simple fabrication, low voltage operation, and minimal sample requirements—make it well-suited for applications in pharmaceutical quality control, point-of-care diagnostics, and broader biomedical analysis. Future work will focus on optimizing long-term stability and expanding applicability across a wider range of biological samples.
Journal Reference
Anchan B., Kamath U S., et al. (2025). Development of low cost ZnO based chemi resistive biosensor for the detection of vitamin B6 mediated by quantum dots. Scientific Reports 15, 11219. DOI: 10.1038/s41598-025-95892-0, https://www.nature.com/articles/s41598-025-95892-0