A dihydrolipoic acid-undecyl(ethylene glycol)-mannose-1,2mannose (DHLA-EG11-DiMan) multifunctional glycan ligand (see Fig. for chemical structure) was synthesized using previously reported procedures. A DHLA-tri(ethylene glycol) based ligand with a terminal di(ethylene glycol) group (denoted as DHLA-EG3-OH) was also synthesized and used as a negative control (see SI, Fig. for its chemical structure). Each glycan ligand contains three functional domains: a DHLA group for strong QD anchoring via chelative zinc-thiolate coordination; 33 a flexible EG11 linker for imposing high water solubility, excellent stability and resistance against nonspecific adsorption; 38-39 and a terminal DiMan group for specific DC-SIGN/R binding.