Detection of natural rubber latex allergens using antibody conjugated with fluorescent dye-doped silica nanoparticles

Abstract

In this research, the tris (2,2’-bipyridyl dichlororuthenium (II) hexahydrate: Rubpy)-doped silica nanoparticles (DSNP) were synthesized by using a water-in-oil microemulsion method. The DSNP are shown to be uniform spherical shape with average diameter of 65 +- 5 nm. The surfaces of DSNP were modified and conjugated with antibody against skim latex protein antigen (31 and 39 kilodalton) and antibody against concentrated latex protein antigens (100 kilodalton). After conjugation with antibody, the DSNP were apparently uniform in size, 50+-2 and 51+-2 nm respectively. Utilization of the DSNP conjugated with antibody against skim latex proteins and concentrated latex protein antigens for the detection of protein antigens in natural rubber latex and rubber products indicated that this method is specific and showed very high sensitivity with detection limit at 0.01 ng/muL for both of skim latex antigen and concentrated latex antigen. On the contrary, the Enzyme-Linked ImmunoSorbent Assay (ELISA) exhibited signals at the detection limit only 1 ng/muL. This newly developed method using DSNP conjugated with antibody showed 100-fold higher specificity, and 4-time more rapid than ELISA. In addition, this method is practical and economic,because sample can be used with no need for concentration or purification, the trace amount of sample is enough to be determined by using DSNP conjugated with antibody as nanoprobe.