ABSTRACT
A single-chain variable fragment (scFv) is an antibody fragment composed of VH and VL linked by a hydrophilic linker that can be designed according to the shape of the target molecule and synthesized in prokaryotic or eukaryotic cells via biotechnology engineering. This study developed an electrochemical immunosensor that detects the RBD of SARS-CoV-2 using a screen-printed carbon electrode modified with gold nanoparticles, and scFv as a bioreceptor. Electrochemical impedance spectroscopy was employed to measure specific interactions of antigens with antibodies. The developed immunosensor had a limit of detection and a quantification limit of 4.86 ng mL(-1) and 16.20 ng mL(-1), respectively. The immunosensor was stable at room temperature for up to 30 days' storage. The immunosensor was assessed at biosafety level 3 using 33 nasopharyngeal swab specimens (clinical samples);the pieces of data were compared with quantitative Reverse Transcriptase-PCR. The agreement of the data, the low detection limit achieved, the rapid analysis (30 min), the miniaturization, and the portability of the instrument combined with the easiness to use has the potential to become Point of Care (POC) for diagnosing the COVID-19 disease.
ABSTRACT
The availability of a viral transport medium (VTM) is often an obstacle to COVID-19 testing, especially for countries that are not VTM producers, including Indonesia. Therefore, the Parasitology Laboratory of Medicinal Faculty, Universitas Padjadjaran, Indonesia, developed an inactivation transport medium called “VITPAD®” that uses a guanidium-based buffer solution. This study evaluated VITPAD® as a transport medium for swab samples and scaled-up production from 2,000 tubes per month to 60,000 per month to support COVID-19 testing in Indonesia. VITPAD® has good stability and sterility, with a lifespan of over 2 years, and it performs well as a transport medium for COVID-19 samples. The production capacity was successfully scaled-up by implementing scheduling and capacity management, with the first large-scale production of VITPAD® distributed to 26 teaching hospitals in Indonesia. © 2022. Shabarni Gaffar et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License
ABSTRACT
The world has been hit by coronavirus pandemic for around two years. Early detection of infection by SARS CoV-2 relies on the efficient detection using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) which require a viral genome extraction machine. An extraction machine for the nucleic acid has been designed and fabricated in this research. It utilizes magnetic rods and carousel driven by linear and rotary actuator as the main component to do each step of extraction procedure. It is equipped with a minicomputer and Liquid Crystal Display (LCD) touchscreen as an interface with user to make setting and running the machine. The machine has been tested to simulate each extraction process without viral genome sample comprises lysis, two times washing, holding and elution as designed. It was running well to rotate the carousel to the exact position for each extraction step, move the tip comb and magnetic rods appropriately to the sample plate holes, and move the tip comb up and down to mix the solution exactly on the sample plate for each extraction process. Next, the machine performance will be tested to do viral genome extraction in BSL Laboratory Class 2. © 2021 IEEE.
ABSTRACT
Introduction: Epidemics caused by outbreaks of the dengue virus (DENV) have been prevalent in Indonesia since it was first reported in 1968. Bandung, the capital city of West Java, Indonesia, is one of the regions where dengue is the most prevalent in Indonesia. Since late 2019;however, the coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has become a worldwide public health challenge. Concurrently, a peculiar pattern of DENV incidence has emerged beginning in early 2020. Based on data from the West Java Provincial Health Office, a significant decrease in DENV cases occurred from January to July 2020 compared with that in 2019. One possible cause could be the underdiagnosis of dengue due to the overlap of clinical features with COVID-19. Methodology: To test this hypothesis, we explored the possibility of under diagnosis or co-infection with COVID-19 and DENV by conducting multiplex real-time PCR of common arbovirus (DENV, Zika, Chikungunya) and SARS-Cov-2 on sera from patients with positive or negative COVID-19 swab test PCR results. Results: Of the 284 sera tested, 41 were positive for SARS-Cov-2, and one serum was positive for both SARS-Cov-2 and DENV, whereas the rest were negative for arbovirus (DENV) Conclusions: These results indicate that the co-infection of DENV and COVID-19 occurs only very rarely. We concluded that an underdiagnosis of DENV from January to July 2020 did not account for the significant decrease in cases in West Java, Indonesia.