Abstract
Development of rapid diagnostic tests are a fundamental component for an effective public health system. At present, the availability of rapid diagnostic test and equipment quality in Thailand still insufficient. In this study, we aimed to develop the smartphone-controlled electrochemical sensor operated via Near Field Communication (NFC) as portable devices for screening test. This study used the electrochemical gas sensor to detect blood alcohol concentration from breath sample. For hepatitis B detection kit, the operating system was composed of a card-sized electrochemical NFC tag sensor integrated with a smartphone and antibody-modified electrode with gold nanoparticles to provide high sensitivity and β-cyclodextrin (β-CD). The modification and immobilization processes were verified by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrochemical immunosensor was then used to quantify Hepatitis B surface antigen (HBsAg) by measuring the current-time response obtained from amperometric detection. The current from the Fe(CN)63-/4- redox couple was measured before and after addition of HBsAg. A resistance-based lateral flow immunosensor diagnosis device (R-LFI) that integrated NFC with portable smartphone for L. interrogans detection in clinical samples. The performance of R-LFI sensor was evaluated using recombinant LipL32 (rLipL32), L. interrogans, and clinical samples. The results showed that the performance of the smartphone-based breath alcohol sensor was acceptable (SD ≤ 1.4mg%). Under optimal conditions, a linear calibration curve and a limit of detection for HBsAg were found to be 10-200 μg/mL and 0.17 μg/mL, respectively. The R-LFI device exhibited linear responses toward rLipL32 protein in phosphate buffer and L. interrogans spiked in healthy human serum samples within concentration ranging from 1 to 100 ng (limit of detection, LOD: 0.16 ng). This platform is sensitive, specific, simple, label-free, and requires small sample volume. These desirable features make it particularly suitable for resource-poor settings. However, these device improvement needs to be studied for commercial use in the future.
