Table . Summary of key parameters of Gx-psDiMan conjugates under different glycan densities. Dh = hydrodynamic diameter (mean ± ½ FWHM); N = glycan valency per GNP (assuming identical GNP binding properties for LA-EG4-psDiMan and LA-EG2-EG2-OH); X = average inter-glycan distance. Apparent Kd and n values were obtained from fitting the QE -concentration plots by equation 2 with fixed QEmax% = 100 (R 2 > 0.995 for all fits); "-" indicates binding curves not fitted, due to binding being too weak; multivalent binding enhancement factor, β = Kd mono /Kd, where Kd mono = 1.1 mM, obtained from ITC (see SI, Fig. ). The successful preparation of Gx-psDiMan conjugates was supported by a small increase of the hydrodynamic diameters (Dhs) compared to the parent, citrate stabilized Gxs and the formation of monodispersed particles in water with narrow size distributions of hydrodynamic diameters (Dhs, see Table and SI, Fig. ). The resulting Gx-psDiMan conjugates were found to be highly stable, no visible changes of solution color or precipitation were observed after storage for > 6 months. No changes in UV-vis absorption spectra after dispersion to a standard DC-SIGN binding buffer (20 mM HEPES, 100 mM NaCl, 10 mM CaCl2, pH7.8). The concentrations of Gx-psDiMan were estimated from their maximal absorbance at ~515 (for G5) and ~520 nm (for G13) using an extinction coefficient of 6.3 ×10 6 (for G5) and 2.32 × 10 8 M -1 cm -1 (for G13), respectively. The glycan valency on Gx surface was estimated from the difference in glycan ligand amount between that added and that remained unbound in the post-incubation supernatant via a phenol-sulfuric acid carbohydrate quantifying method as described previously (SI, Fig. ), and the results were summarized in Table . By using the hydrodynamic diameter and glycan valency of Gx-psDiMan conjugates under different glycan content, the average glycan footprint, deflection angle, and inter-glycan distance were estimated via the method reported by the Mirkin group, and summarized in Table and SI, Table . A systematically increasing glycan footprint, deflection angle, and inter-glycan distance were obtained with the decreasing glycan content on the Gx surface. Interestingly, the average inter-glycan distances for G5-psDiMan100% (~1.05 nm) and G13-psDiMan (50-100%, ~0.8-1.2 nm) are comparable to the majority of inter-glycan sequon distances (~0.7-1.3 nm) found on gp160, the HIV surface heavily glycosylated trimeric glycoprotein, which mediates specific DC-SIGN binding and viral infection.