COVALENT CONJUGATION OF ANTIBODY AND GOLD NANOPARTICLE FOR DEVELOPMENT OF LATERAL FLOW IMMUNOASSAY TEST STRIP

Abstract

Nanotechnology is one of the fastest growing technologies in this era. Gold nanoparticle (AuNP) based immunoassays have been performed on the basis of antigen-antibody interaction using AuNP antibody conjugates. Lateral flow immunoassays(LFA) which are also based on AuNP antibody conjugates are useful innovation in nanotechnology and widely applied in medicine and research fields. However, there are some limitations of the present LFA kits such as sensitivity and stability. In the study, we showed the result of covalent conjugation of anti-rotavirus antibody and AuNP for generating a lateral flow immunoassay strip to detect rotavirus in fecal samples. The suitable conditions for coating polyethylene glycol (PEG) on the surface of AuNP were 10.0 mM PEG for 3 hours at room temperature (25 oC). Optimized conditions for covalent conjugation of antibody and AuNP were pH 4.0, 0.1 mg antibody/conjugate, 0.01 mM reactant EDC/NHS [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/(N-hydroxy sulfosuccinimide]. The coupling reaction was carried out at room temperature for 90 min. The conjugate pad, antibody immobilized nitrocellulose membrane strip were created with investigated conditions for generating an LFA test strip. The limit of detection of LFA test strip was determined by 1.6 × 105 virus particles/ml, three times lower than that of Rotaclone kit (UK). The generated strip could be used to detect rotavirus in fecal sample of patient.