Visual Detection of Human Antibodies Using Sugar Chain-Immobilized Fluorescent Nanoparticles: Application as a Point of Care Diagnostic Tool for Guillain-Barré Syndrome

Abstract

Sugar chain binding antibodies have gained substantial attention as biomarkers due to their crucial roles in various disorders. In this study, we developed simple and quick detection method of anti-sugar chain antibodies in sera using our previously developed sugar chain-immobilized fluorescent nanoparticles (SFNPs) for the point-of-care diagnostics. Sugar chain structure on SFNPs was modified with the sugar moieties of the GM1 ganglioside via our original linker molecule to detect anti-GM1 antibodies. The structures and densities of the sugar moieties immobilized on the nanoparticles were evaluated in detail using lectins and sera containing anti-GM1 antibodies from patients with Guillain-Barré syndrome, a neurological disorder, as an example of disease involving anti-sugar chain antibodies. When optimized SFNPs were added to sera from patients with Guillain-Barré syndrome, fluorescent aggregates were able to visually detect under UV light in three hours. The sensitivity of the detection method was equivalent to that of the current ELISA method used for the diagnosis of Guillain-Barré syndrome. These results suggest that our method using SFNPs is suitable for the point-of-care diagnostics of diseases involving anti-sugar chain antibodies.

Sensitive dipstick assays for lectin detection, based on glycan–BSA conjugate immobilisation on gold nanoparticles

“…It has been noted before that glycan density on the surface of nanoparticles is a key parameter to tune when designing a glyconanoparticle-based sensing system and that more sugar does not necessarily equate with greater assay sensitivity. 76…”

“…It has been noted before that glycan density on the surface of nanoparticles is a key parameter to tune when designing a glyconanoparticle-based sensing system and that more sugar does not necessarily equate with greater assay sensitivity. 76 Prompted by the performance of the BSA-glyconanoparticles, a new Gal-BSA glycoconjugate was synthesised, Gal 14 -BSA (8a), containing 14 glycan units instead of 3, as for Gal 3 -BSA (8). The glyconanoparticles functionalised with the new glycoconjugate (Gal 14 -BSA-AuNPs, 15a) were applied to the dipstick assay, giving rise to a lower limit of detection (5 ng of RCA 120 ).…”