ABSTRACT
A detection method based on an electrochemical aptasensor has been developed as an alternative fast, portable, simple, inexpensive, and high-accuracy detection method for detecting the SARS-CoV-2 Spike Receptor Binding Domain (spike RBD). The CeO2@NH2 functionalized Screen Printed Carbon Electrode (SPCE) was used to immobilize an aminated aptamer of spike RBD protein via glutaraldehyde as a linker. The aptamer's interaction with the SARS-CoV-2 Spike RBD was measured via the [Fe(CN)6]4-/3- redox system signal. Experimental conditions were optimized using a Box-Behnken experimental design and showed that the optimal conditions of the SARS-CoV-2 aptasensor were 1.5 ng mL-1 of aptamer, immobilization of aptamer for 60 minutes, and Spike RBD incubation for 10 minutes. The developed aptasensor was able to detect the standard SARS-CoV-2 Spike RBD with a detection limit of 0.017 ng mL-1 in the range of 0.001-100 ng mL-1. This aptasensor was used to detect salivary and oropharyngeal swab samples of normal individuals with the addition of Spike RBD, and the recoveries were 92.96% and 96.52%, respectively. The testing on nasopharyngeal swab samples of COVID-19 patients showed that the aptasensor results were comparable with the qRT-PCR results. Thus, the developed aptasensor has the potential to be applied as a SARS-CoV-2 rapid test method for clinical samples.
ABSTRACT
The development of the Coronavirus disease 2019 (COVID-19) vaccine is one of the most important efforts in controlling the pandemic. Serological tests are used to identify highly reactive human donors for convalescent plasma therapy, measuring vaccine efficacy and durability. This review article presents a review of serology tests and how antibody titers in response to vaccines have been developed. Some of the serological test methods discussed are Plaque Reduction Neutralization Test (PRNT), Enzyme-Linked Immunosorbent Assay (ELISA), Lateral flow immunoassay (LFIA), chemiluminescent immunoassay (CLIA), and Chemiluminescent Micro-particle Immunoassay (CMIA). This review can provide an understanding of the application of the body's immune response to vaccines to get some new strategies for vaccines.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/diagnosis , COVID-19/prevention & control , Clinical Laboratory Techniques/methods , Antibodies, Viral , Serologic Tests/methods , Enzyme-Linked Immunosorbent Assay/methods , Vaccination , Antibodies, Neutralizing , COVID-19 SerotherapyABSTRACT
WHO declared the outbreak of COVID-19, caused by SARS-CoV-2, a pandemic in March 2020. More than 223 million cases and approximately 4.6 million deaths have been confirmed. Early diagnosis and immediate treatment became a priority during this pandemic. However, COVID-19 diagnostic testing resources are limited, especially early in the pandemic. Apart from being limited, the COVID-19 diagnostic tests using reverse transcription polymerase chain reaction (RT-PCR) have encountered storage, transportation, and safety issues. These problems are mainly experienced by developing poor countries, countries in the equatorial region, and archipelagic countries. VITPAD® is a guanidine-based inactivation transport medium (ITM) formulated to maintain the RNA quality of SARS-CoV-2 during transportation without cold chains. This study, conducted from September 2020 to March 2021, performed clinical validation of VITPAD® by comparing its performance with a globally commercially available ITM from the NEST brand. Its stability at room temperature, safety, and resistance at high temperatures was also tested using RT-PCR analysis. VITPAD® can reduce the infectious nature of the specimen, preserve the SARS-CoV-2 for 18 days at an ambient temperature, and resist high temperatures (40°C for 3 hours). A guanidine-based transport medium, such as VITPAD®, is compatible and recommended for RT-PCR-based molecular diagnosis of COVID-19.