Detection of Lectins by Saccharide-gold Nanoparticle Conjugates

A general functionalization strategy was reported, which enables one to conjugate saccharide(SA) on gold nanoparticle(GNP) surface without affecting SA properties. First, disulfide phenylboronic acid(Bor) functionalized GNPs(Bor@GNPs) were synthesized by the reaction of citrate stabilized GNPs of 13 nm in diameter with the mixture of Bor and pentapeptide(Cys-Ala-Leu-Asn-Asn, CALNN). Subsequently, the SA-GNP conjugates(SA@GNPs) were prepared by coupling SA to the GNP surface via the reaction of phenylboronic acid(PBA) with the cis-diol configuration in SA. The interactions of three SA@GNPs with three lectins have been analyzed by UV-visible spectroscopic and transmission electronic microscopic(TEM) techniques, respectively. The experimental results demonstrate that SA@GNPs can efficiently bind to lectins and show a great promise as optical probes for monitoring specific affinities of lectins for SA, and detecting lectins with high sensitivity.