Design of Silver Nanoprobe to Construct Sandwich Immunosensor for Early Diagnosis of Dengue Biomarker

Abstract

Dengue, a viral disease caused by a Flavivirus belonging to family Flaviviridae, is a serious threat to human health in tropical and subtropical regions worldwide. Life-threatening diseases can be caused in human by these parasites and viruses. According to an estimation, Mosquitos transmit diseases to more than seven hundred million people per year. There has been many efforts to control mosquito borne diseases but these disease are still being flourished and are a major concern around the world. For example, Malaria, stays a major reason for deaths particularly amongst infants and children. According to a report, about 1 million deaths and 300-500 million cases of infection are due to malaria. Herein, an antibody functionalized silver-nanoparticle (Ab-Ag NPs) is designed as trace tag for simple, fast, highly sensitive and selective detection of dengue biomarker NS1 using a sandwich type immunosensor. After interacting with capture antibodies modified pencil graphite electrode in the presence of NS1, AbAgNPs can be immobilized on electrode surface via hydrogen-bonding interactions between NS1 and antibody. Well defined and sharp electrochemical signal by the oxidation of Ag NPs present on the detection dengue NS1 antibody is translated into specific detection of NS1. A proportional increase in the faradic current for the oxidation of silver is observed by increasing concentration of analyte NS1. A wide linear range of 3-300 ng/mL with limit of detection 0.5 ng/mL is achieved. The specificity studies evaluating possible interference with analog analytes have been carried out. The NS1 detection experiments are also extended to human serum samples. The designed sandwich type immunosensor strategy with extra-ordinary selectivity and sensitivity may find potential in clinical applications in rapid and early detection of dengue virus. After the formation of samples, different characterization techniques have been used to study their morphological, electrical and structural properties. The detailed information about structure and surface morphology of samples was determined using X-ray fraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM) and by doing xi electrochemical analysis such as electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV).