Figure 2. Isothermal titration calorimetry (ITC) study of protein binding on NPs.

The dynamic topographical structure of PEG shell reduces the affinity of protein binding on NPs. (a-d) Representative ITC data. Graphs show integrated heat of each titration (■) with a corresponding fitted curve based on the one-site binding model for (a) PLGA-NPs, (b) PLGA-PEG-NPs, (c) PLGA-TPEG-NP-20, and (d) PLGA-TPEG-NP-100. (e,f), Calculated stoichiometry (Na) and binding affinity (Ka) for the indicated samples. Values indicate mean ± SD (n = 3). ***, P < 0.001.