Development of an electrochemical nano-biosensor for rapid and sensitive diagnosis of bilharzia in Kenya

Bilharzia, also known as schistosomiasis, is still affecting more than 250 million people, killing about 200 000 annually and leaving millions of others debilitated. Current diagnostic tools have extremely low validity and are not readily applicable for rapid diagnosis in rural and remote areas. In low-grade infections, microscopy, the most commonly used method, may have low sensitivity. For example, in suspected cases, up to five real sample specimens are recommended for increased sensitivity. The rise of nanotechnology has created the potential to significantly improve the current diagnostic approaches. Conjugating antibodies with nanoparticles pools the distinctive properties of the nanoparticles with the specificity and selectivity of the antibodies in the recognition of the antigen. This in return leads to a very versatile and specific mixed product with improved analyticalsignal which is important for fast, sensitive and real-time point-of-care diagnosis. In this work, we report the use of nanotechnology to develop a simple and sensitive nano-biosensor which consisted of a nano-strip with immobilized gold nanoparticles conjugated with bilharzia antibody, and demonstrated its potential for diagnosis of bilharzia antigen. A detection range of 1.13 × 101 ng mL–1 to 2.3 × 103 ng mL–1 of bilharzia antigen in stool samples and with a limit of detection of 8.3887 × 10–2 ngmL–1 was attained, indicating the potential of the nano-biosensor to be used to detect bilharzia antigen in stool samples.Keywords: Bilharzia, nanobased-biosensor, nanostrips, nanokit

Spectro-electrochemical Characterization of Anti-Schistosoma-Gold Nanoparticle Conjugate for use in Immunoassays

A Journal Article by Dr. Naumih, a Lecturer in the School of Pharmacy at USIU -AfricaGold nanoparticles(AuNPs) have been used widely in biomedical diagnostic and imaging. Their high stability, ease of characterization and ability to bind with biological molecules are among the properties that promote their diverse applications. Of interest is the application as electrochemical markers especially in immuno histochemistry, biosensors and immunoassays. In order to serve that role, an antibody needs to be attached to the surface of the nanoparticle since proteins readily bind to AuNPs. However, this immobilization process might result in nanoparticle aggregation or the loss of the bioactivity of the conjugated antibodies. We hereby report the optimization of the covalent binding of anti-schistosome antibody to AuNPs via a carbodiimide cross-linker The characterization and functionality testing of the conjugation was done using UV/Vis spectrometry and electrochemically by cyclic voltammetry(CV). The conjugate was tested with varying concentrations of Soluble Egg Antigen (SEA) as the analyte. The signal response was directly proportional to the concentration of SEA. A plot of concentration of SEA against the change in current gave a limit of detection of 3.31×10-5ng/ml based on 3 times the standard deviation of the blank. These findings demonstrated the potential for development of a point-of-care immunosensor for rapid diagnosis of Schistosomiasis