Researchers have developed a highly sensitive, portable electrochemical biosensor using biofunctionalized MXene nanosheets to detect vitamin D levels at the point of care.
Study: Antibody-functionalized MXene-based electrochemical biosensor for point-of-care detection of vitamin D deficiency. Image Credit: Natalya Bardushka/Shutterstock.com
Published in Communications Materials, the study introduces a promising alternative to traditional lab-based methods, aiming to address the global challenge of vitamin D deficiency with a more accessible diagnostic tool.
Background
Vitamin D deficiency is a global issue, affecting people across age groups and regions due to factors like limited sunlight exposure, poor nutrition, and certain chronic conditions. While the prevalence is particularly high in areas with less sunlight or older populations, even countries with abundant sun aren’t immune—modern indoor lifestyles and dietary gaps still contribute to significant deficiency rates.
Accurate diagnosis typically requires methods like high-performance liquid chromatography (HPLC) or radioimmunoassays. Although reliable, these techniques are expensive, labor-intensive, and require specialized lab infrastructure, making them impractical for widespread or remote testing. This has spurred efforts to develop compact, cost-effective biosensors that allow clinicians and patients to test vitamin D levels on-site, without sacrificing accuracy.
The Current Study
To build the biosensor, the researchers began by synthesizing MXene nanosheets through the etching of Ti3AlC2 MAX phase powder, yielding Ti3C2Tx sheets that were delaminated and dispersed in water for subsequent functionalization.
Next, they coated the nanosheets with polyethyleneimine (PEI), a polyamine polymer that introduces surface amine groups suitable for antibody attachment. Using glutaraldehyde as a crosslinker, anti-vitamin D antibodies were then stably bonded to the modified MXene surface.
Comprehensive surface analysis—including X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX)—confirmed successful antibody integration. These biofunctionalized nanosheets were deposited onto an electrode to create the biosensing interface.
The sensor's electrochemical behavior was characterized using cyclic voltammetry and differential pulse voltammetry (DPV). Calibration involved testing across a wide range of vitamin D concentrations, from as low as 1 pg/mL to 500 ng/mL, covering clinical ranges from deficiency to toxicity. The researchers also assessed key performance metrics, including sensitivity, linearity, reproducibility, and selectivity in both buffered and complex biological samples.
Results and Discussion
The biosensor showed excellent performance across all evaluation parameters. The functionalization process effectively attached antibodies to the MXene surface, while DPV measurements revealed strong signal responses even at extremely low vitamin D levels—down to 1 pg/mL.
A broad dynamic range (0.1 ng/mL to 500 ng/mL) and consistent linearity made the sensor suitable for both diagnostic screening and monitoring. Reproducibility was confirmed by low variance in repeated tests, and the device maintained high specificity when challenged with non-target biomolecules.
Tests with human serum also demonstrated robust detection, although signal intensity dropped slightly due to biofouling effects, which are common in biological environments. The team acknowledged this limitation and indicated that future work would focus on antifouling strategies.
Conclusion
This study presents a compelling solution for decentralized vitamin D testing through an antibody-functionalized MXene-based biosensor. It combines straightforward fabrication with strong analytical performance—ultra-low detection limits, wide clinical range coverage, and dependable selectivity.
Proven effective even in complex serum samples, the biosensor offers real potential for clinical and at-home vitamin D monitoring, particularly in settings where conventional lab access is limited.
Journal Reference
Barman S.C., Jin Y., et al. (2025). Antibody-functionalized MXene-based electrochemical biosensor for point-of-care detection of vitamin D deficiency. Communications Materials 6, 31. DOI: 10.1038/s43246-025-00756-9, https://www.nature.com/articles/s43246-025-00756-9