Benchaporn Lertanantawong

Human papillomavirus type 16 (HPV‐16) is a key driver in the development of cervical carcinoma, with the integration of its genome into the host DNA marking a critical step in disease progression. Monitoring the physical state of HPV‐16, particularly the transition from episomal to integrated forms, is essential for evaluating the risk of malignancy development in cervix. This study presents the development of a duplex electrochemical biosensor for the simultaneous detection of the E2 and E6 genes of HPV‐16. Using a one‐step sandwich hybridization assay, the biosensor was able to detect HPV‐16 E2 and E6 genes with a sensitivity of 8 copies/mL and 12 copies/mL respectively and distinguish between the episomal and integrated forms based on the E2/E6 ratio (cut‐off 0.77, 100% sensitivity/specificity). The sensor was validated with 30 clinical cervical tissue samples, providing results comparable to qPCR method. This novel biosensor offers a rapid and efficient platform for the detection and monitoring of HPV‐16, with potential applications in cervical cancer screening and prognosis.

Liquid metal electrodes based on Ga are an emerging area of interest given their fluid properties which can have significant impact on electrochemical processes. Here we study metal electrodeposition, namely lead electrodeposition on the liquid metal electrodes, gallium (Ga) and galinstan (GaInSn), which was performed in two different Pb2+ electrolytes (PbCl2 and Pb(NO3)2) to investigate any differences in the nature of the electrodeposit. Cyclic voltammetry and chronoamperometry were used to study the characteristics, kinetics, and nucleation and growth mechanisms of the electrodeposition process. Analysis of this electrochemical data, such as current density-time transients and diffusion coefficients under different potentials, revealed distinct behaviors for Pb deposition at each liquid metal and electrolyte, influencing the final morphology of the lead deposit. It was also found that the electrolyte concentration and deposition time were found to impact the morphology of the electrodeposited Pb. Scanning electron microscopy and energy dispersive X-ray spectroscopy revealed various types of Pb microstructures, including wire, branch-like, and flake-like formations, highlighting the differences in lead structural development when deposited on liquid gallium and Galinstan electrodes.

Hepatitis C virus (HCV) is a common blood-borne infection that can lead to long-term illnesses such as hepatocellular cancer and liver cirrhosis. Early diagnosis is crucial for effective management, as no vaccine is available for preventing HCV infection. However, the high cost and complexity of current molecular diagnostic tools hinder efforts to achieve early diagnosis and prevent transmission, particularly in resource-limited settings. We developed a novel electrochemical biosensor for point-of-care testing (POCT) of HCV RNA. The sensor utilizes a strand displacement method, where the target RNA displaces a gold nanoparticle-labeled reporter probe (AuRP) from a pre-hybridized duplex with a magnetic nanoparticle (MNP)-labeled capture probe. The amount of displaced AuRP, detected using differential pulse anodic stripping voltammetry (DPASV), is directly proportional to the target RNA concentration. The biosensor exhibited excellent analytical performance, with a detection limit of 4 fM for synthetic targets and 43 ng/µL for RT-PCR products. Importantly, it successfully detected HCV RNA directly in clinical plasma samples without the need for RNA extraction or amplification. The sensor was used to analyze 30 RNA samples from HCV-positive patients, 20 cDNA samples from viral RNA, 30 HCV-positive plasma samples, and 22 HCV-negative plasma samples. The sensor results show good concordance with the RT-PCR results, demonstrating the sensor’s potential for detecting HCV in clinical samples.

Electron transfer flavoprotein subunit beta (ETFB) of Leptospira interrogans is a biomarker for diagnosing leptospiral infection.

An essential biomarker for the early detection of cardiovascular diseases is serum homocysteine (Hcy). In this study, a molecularly imprinted polymer (MIP) and nanocomposite were used to create a label-free electrochemical biosensor for reliable Hcy detection. A novel Hcy-specific MIP (Hcy-MIP) was synthesized using methacrylic acid (MAA) in the presence of trimethylolpropane trimethacrylate (TRIM). The Hcy-MIP biosensor was fabricated by overlaying the mixture of Hcy-MIP and the carbon nanotube/chitosan/ionic liquid compound (CNT/CS/IL) nanocomposite on the surface of a screen-printed carbon electrode (SPCE). It showed high sensitivity, with a linear response of 5.0 to 150 µM (R² of 0.9753) and with a limit of detection (LOD) at 1.2 µM. It demonstrated low cross-reactivity with ascorbic acid, cysteine, and methionine. Recoveries of 91.10–95.83% were achieved when the Hcy-MIP biosensor was used for Hcy at 50–150 µM concentrations. The repeatability and reproducibility of the biosensor at the Hcy concentrations of 5.0 and 150 µM were very good, with coefficients of variation at 2.27–3.50% and 3.42–4.22%, respectively. This novel biosensor offers a new and effective method for Hcy assay compared with the chemiluminescent microparticle immunoassay at the correlation coefficient (R²) of 0.9946.

Since the declaration of COVID-19 as a pandemic in early 2020, multiple variants of the severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) have been detected. The emergence of multiple variants has raised concerns due to their impact on public health. Therefore, it is crucial to distinguish between different viral variants. Here, we developed a machine learning web-based application for SARS-CoV-2 variant identification via duplex real-time polymerase chain reaction (PCR) coupled with high-resolution melt (qPCR-HRM) analysis. As a proof-of-concept, we investigated the platform's ability to identify the Alpha, Delta, and wild-type strains using two sets of primers. The duplex qPCR-HRM could identify the two variants reliably in as low as 100 copies/μL. Finally, the platform was validated with 167 nasopharyngeal swab samples, which gave a sensitivity of 95.2%. This work demonstrates the potential for use as automated, cost-effective, and large-scale viral variant surveillance.

We report a simple and rapid method for the synthesis of fluorescent gallium oxyhydroxide (GaOOH) nanoparticles from liquid Ga by a probe sonication method in the presence of H ₂ O ₂ as an oxidant for potential biomedical applications.