Gold Nanoparticle Based DNA Sensor for Detection of Pathogen Causing Rheumatic Heart Disease

Human rheumatic heart disease (RHD) is defined as impairment or permanent damage to the heart valves due to multiple attacks of acute rheumatic fever (ARF). ARF is a autoimmune response of infection with group A [beta]-haemolytic Streptococci. RHD is the most significant abnormality of ARF caused by Streptococcus pyogenes. Biosensor can act as an efficient tool for early detection of RHD in human. The disease is initially started with throat infection and if it is not treated in time, it leads to RHD. The aim of the study was to develop nano-material based DNA sensor for quick, economical and early detection of RHD in human to prevent damage of mitral and aortic heart valves. Screen printed gold nanoparticle embedded carbon electrode, dendrimer, redox indicator, coupling agents, specific probe and buffer are required for electrochemical reactions. Carbon/gold nanoparticle/dendrimer/probe was fabricated for the early detection of S. pyogenes. The sof gene based biosensor was prepared by immobilization of 20 mer carboxyl labeled ssDNA probe on the composite electrode. The immobilized probe was hybridized with different concentrations of genomic DNA of S. pyogenes from throat swab samples. The electrochemical response was measured by cyclic voltammetry (CV) and differential pulse voltametry (DPV). The lower limit of detection of the sensor was found 1.2 pg from CV measurements. The sensitivity of the sensor was found to be 1299.20 [micro]A [cm.sup.-2] [ng.sup.-1]. The total time for diagnosis of the disease takes only 30 min. Specific sof gene based probe was immobilized on gold nanoparticle/dendrimer to enhance the sensitivity of the sensor. The usual methods of detection of pathogen are either complicated or time consuming. Therefore, we have fabricated sof gene based sensor for quick and early detection of pathogen to prevent damage of heart valves.