Highly luminescent quantum dots functionalized and their conjugation with IgG.

A sol-gel approach including partially removing capping agents, depositing SiO(2) monomers, and growing a SiO(2) shell was developed to generate a bio-compatible functionalization on CdTe quantum dots (QDs). The QDs retained their high photoluminescence (PL) efficiency after coating with a SiO(2) shell (22.5%) by controlling the surface state of the QDs to decrease PL degradation during a sol-gel preparation. Furthermore, the CdTe QDs with a SiO(2) shell were conjugated with IgG using 3-sulfo-N-hydroxysuccinimide or streptavidin-maleimide as linkers. The biotin-streptavidin linker resulted in a high PL efficiency retained (only ~23% lower than the initial value of the QDs), which is crucial for bio-applications.