ABSTRACT
Background: Aptamers are single-stranded nucleic acids, so-called ‘artificial antibodies’, identified from the randomized combinatorial library against the target by the process called ‘SELEX’ (Systematic Evolution of Ligands by EXponential enrichment). Target can have any sizes from small molecules to the whole cell, attests the versatility of aptamers to bind a wide range of targets. Aptamers have several advantages over antibodies, such as they are easy to prepare, cheaper, have no batch variations, are easy to modify, stable and most importantly, non-immunogenic. Because of these positive characteristics, aptamers are incorporated in different fields, and most attractive in the applications involving therapeutics and diagnoses (theranostics). With either aptamers alone or complementing with antibodies, several high sensitive, portable sensors have been demonstrated for use in ‘bedside analysis’. Moreover, aptamers are more amenable to chemical modifications, making them capable of utilization with the most developed aptasensors (aptamerbased sensors). Significance: The development of more sensitive aptasensors could be useful and important for medical diagnosis, identification of pathogens for the quality control of consumable items, and surveillance of emerging diseases. In fact, aptasensors have already shown their efficacy in the detection of life threatening diseases caused by early stage of viral infections. In this review, role of aptasensors in detecting pathogenic viruses are overviewed. Keywords: Anti-virus; aptamer; aptasensor; bedside analysis; SELEX
ABSTRACT
Objectives: The aim of this study is to compare the use of biotin-streptavidin and gold nanoparticle [GNP] technologies in enzyme linked immunosorbent assay [ELISA] techniques to improve its sensitivity and accuracy
Methods: We evaluated two ELISA methods to improve the sensitivity and accuracy. Biotin-streptavidin technology was selected to enhance the ELISA limit of detection due to the high binding affinity of biotin-streptavidin. GNP-conjugated biomolecules were selected to improve detection by ELISA. To evaluate these two methods, the early secreted antigenic target-6 [ESAT-6] from Mycobacterium tuberculosis and the anti-ESAT-6 antibody were used
Results: The detection limit of ESAT-6 was the same with and without GNP due to the saturation of biotin and streptavidin binding. However, higher absorbance was noticed using GNP only
Conclusion: The proposed modified ELISA can be used to screen different types of common diseases. Additionally, this study showed how several new techniques can improve the detection and accuracy of ELISA