Label-Free Electrochemical-Based Biosensor for Gene-phosphatidylinositol mannosides Detection in Urine for the Determination of Multidrug-resistant Tuberculosis

Tuberculosis (TB) is a significant public health issue, and the existing diagnostic tests have shortcomings that cause delays in initiating treatment. In this study, we designed a<i>Gene-pimB</i>-based biosensor for the determination of TB and tested it using an electrochemical technique. The<i>Gene-pimB</i>has been reported to be upregulated in mannose-capped lipoarabinomannan (manLAM) in multidrug-resistant TB (MDR-TB). Due to its link with drug resistance,<i>Gene-pimB</i>holds promise as a biomarker for identifying MDR-TB strains. In this work, the biosensor is fabricated using graphite-zinc oxide nanofibers (GPH-ZnO NFs), which are generated using electrospinning and deposited on glassy carbon electrodes. The GPH-ZnO functionalized electrode were further functionalized with MSA/EDC/NHS protocol to provide efficient immobilization which enable the effective binding of pimB-sequences to the nanofibers on the electrodes. In addition, the<i>Gene-pimB</i>hybridization on biosensors immobilized with<i>Gene-pimB</i>probe sequences was quantified using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) techniques. The experimental tests revealed that the limit of detection (LoD) for CV is 0.1482 pM ml^-1, for DPV it is 0.196 pM ml^-1, and for EIS it is 0.302 pM ml^-1. Our findings suggest that<i>Gene-pimB</i>may prove to be a useful technique in the creation of novel tests for TB prognosis. The efficacy of the developed biosensor was confirmed by a hybridization sensing assay including targeted short oligonucleotide sequences (probe) and<i>Gene-pimB</i>(target) isolated from the urine sample. To assess its potential for clinical detection, urine samples were artificially spiked with the gene to simulate conditions encountered in clinical diagnostics. This approach allows for evaluating the feasibility of detecting<i>Gene-pimB</i>in a non-invasive manner, which could aid in the early identification of drug-resistant TB cases and improve diagnostic strategies for effective disease management.