Quantitative Estimation of Long-Range Interactions at the Nanoscale

Nano-bio interfaces attune nanoparticle-mediated biological responses. The nano-bio interface, like all interfacial interactions, is governed by non-covalent long-range interactions (LRIs). These LRIs include electrostatic, electrodynamic and acid-base interactions. There is a lack of understanding about the contribution of LRIs at the nano-bio interface for want of suitable methods for the estimation of dispersive, acidic, and basic components of the surface tension of nanoparticles. To address this, we developed an experimental and theoretical framework for the estimation of surface tension components of nanoparticles and biomacromolecules by partitioning them in a biphasic system. The work presented here is the first instance in the literature for estimating the surface tension components of nanoparticles and biomacromolecules suspended in aqueous suspensions. We also observed that LRIs have a deterministic role in biologically relevant phenomena such as salt-induced nanoparticle agglomeration and protein-nanoparticle interaction. Collectively, the results presented in this work provide a rapid and inexpensive framework for predicting the energetics of nanoparticle-nanoparticle and nanoparticle-protein interactions by estimating average ensemble surface characteristics like surface tension and surface charge density.