A novel chemiresistive biosensor utilizing green-synthesized AgNPs and MWCNT-ZnO nanofibers for rapid detection of tuberculosis Lipoarabinomannan (LAM) antigen

Background

Tuberculosis (TB) poses a major global health threat, especially in low- and middle-income countries with limited diagnostic infrastructure. Early and accurate detection is essential to control its spread and improve outcomes, but conventional methods like sputum microscopy and culture are slow, resource-intensive, and lack sensitivity for early or extrapulmonary cases. To address this, a cost-effective, disposable, paper-based interdigitated electrode (IDE) biosensor was developed, functionalized with green-synthesized silver nanoparticles (GSSNPs) and Multi-walled Carbon Nanotube - Zinc Oxide (MWCNT-ZnO) composite nanofibers. This innovative sensor combines affordability, portability, and high sensitivity, offering a practical and scalable solution for rapid TB diagnostics in resource-constrained settings.

Results

The developed paper-based interdigitated electrode (IDE) sensor demonstrates highly promising results for the early and accurate detection of tuberculosis (TB) antigens. The sensor achieved an exceptional lower limit of detection (LOD) of 25.79 fg/mL, enabling the detection of trace amounts of TB antigens. Furthermore, it exhibited a broad linear detection range from 10 pg/mL to 6 ng/mL, making it suitable for various clinical sample concentrations. This remarkable sensitivity and detection range highlight the unique capabilities of the functionalized MWCNT-ZnO composite nanofibers (NFs) and GSSNPs utilized in its design. The sensor's performance evaluation revealed high sensitivity, selectivity, and reproducibility, with minimal interference from non-specific interactions. Its disposable, scalable, and environmentally friendly design further enhances its suitability for point-of-care (PoC) applications in resource-limited settings, offering a rapid, cost-effective, and reliable diagnostic tool for managing TB, particularly in underserved regions.

Significance

This study concludes that the developed paper-based IDE sensor offers a highly sensitive, selective, and cost-effective solution for the early detection of TB antigens, with an impressive LOD of 25.79 fg/mL and a broad detection range. Its simple fabrication, disposable design, and environmentally friendly paper substrate make it ideal for point-of-care applications in resource-limited settings. This innovation is significant as it addresses critical diagnostic gaps, enabling early diagnosis and improved TB management, particularly in underserved regions where traditional methods fall short.