# A New Sensing Platform Based in CNF-TiO2NPs-Wax on Polyimide Substrate for Celiac Disease Diagnostic

## TL;DR

A new amperometric immunosensor is developed for detecting IgA anti-TGA antibodies in celiac disease diagnosis, using a novel CNF-TiO2NPs-wax structure on a polyimide substrate.

## Contribution

A novel CNF-TiO2NPs-wax ink on polyimide substrate is introduced for a sensitive and reliable immunosensor for celiac disease diagnosis.

## Key findings

- The CNF-TiO2NPs-wax ink significantly enhances electrode conductivity and active surface area.
- The immunosensor demonstrates high sensitivity, selectivity, and reproducibility for IgA anti-TGA detection.
- The device is a robust and reliable tool for precise serological diagnosis of celiac disease.

## Abstract

Celiac disease (CD), a human leukocyte antigen-associated disorder, is caused by gluten sensitivity and is characterized by mucosal alterations in the small intestine. Currently, its diagnosis involves the determination of serological markers. The traditional method for clinically determining these markers is the enzyme-linked immunosorbent assay. However, immunosensors offer sensitivity and facilitate the development of miniaturized and portable analytical systems. This work focuses on developing an amperometric immunosensor for the quantification of IgA antibodies against tissue transglutaminase (IgA anti-TGA) in human serum samples, providing information on a critical biomarker for CD diagnosis. The electrochemical device was designed on a polyimide substrate using a novel solid ink of wax and carbon nanofibers (CNFs). The working electrode microzone was defined by incorporating aminofunctionalized TiO2 nanoparticles (TiO2NPs). The interactions and morphology of CNFs/wax and TiO2NPs/CNFs/wax electrodes were assessed through different characterization techniques. Furthermore, the device was electrochemically characterized, demonstrating that the incorporation of CNFs into the wax matrix significantly enhanced its conductivity and increased the active surface area of the electrode, while TiO2NPs contributed to the immunoreaction area. The developed device exhibited remarkable sensitivity, selectivity, and reproducibility. These results indicate that the fabricated device is a robust and reliable tool for the precise serological diagnosis of CD.