Charge Regulation Mediated Interaction of Amphoteric Nanoparticle Surfaces
Abstract
Charge regulation refers to the ability of ionizable biomolecules and their counterparts to adjust their ionization state in response to external perturbations, including changes in pH, ionic strength, or electrostatic interactions with neighboring charged species. Here, we use explicit-ion molecular dynamics / charge-regulation Monte Carlo simulations to compute the interaction force between two spherical, charge-regulated nanoparticles as a function of separation, and compare symmetric (chemically identical) and asymmetric (chemically complementary) surface configurations against the constant charge approximation. We find that charge regulation produces up to an order-of-magnitude stronger short-range attraction than constant charge for asymmetric nanoparticle pairs, particularly at low electrolyte concentration, and that charge regulation qualitatively alters the interaction between symmetric, chemically identical nanoparticles, driving a crossover from net repulsion to net weak-attraction as ionic strength decreases. This transition is not observed under the constant charge assumption which shows that charge regulation is not a minor correction but can change both the strength and the sign of nanoscale electrostatic interactions, with implications for the assembly and stability of charge-regulated colloidal systems
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BibTeX
@misc{tyagi2026charge,
title = {{Charge Regulation Mediated Interaction of Amphoteric Nanoparticle Surfaces}},
author = {Saurav Tyagi and Kamal Tripathi and Saikat Chakraborty and Sunita Kumari},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.33793},
eprint = {2609.33793},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.33793},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Charge Regulation Mediated Interaction of Amphoteric Nanoparticle Surfaces
AU - Saurav Tyagi
AU - Kamal Tripathi
AU - Saikat Chakraborty
AU - Sunita Kumari
PY - 2026
DA - 2026/09/27
PB - arXiv
DO - 10.48550/arxiv.2609.33793
UR - https://arxiv.org/abs/2609.33793
AB - Charge regulation refers to the ability of ionizable biomolecules and their counterparts to adjust their ionization state in response to external perturbations, including changes in pH, ionic strength, or electrostatic interactions with neighboring charged species. Here, we use explicit-ion molecular dynamics / charge-regulation Monte Carlo simulations to compute the interaction force between two spherical, charge-regulated nanoparticles as a function of separation, and compare symmetric (chemically identical) and asymmetric (chemically complementary) surface configurations against the constant charge approximation. We find that charge regulation produces up to an order-of-magnitude stronger short-range attraction than constant charge for asymmetric nanoparticle pairs, particularly at low electrolyte concentration, and that charge regulation qualitatively alters the interaction between symmetric, chemically identical nanoparticles, driving a crossover from net repulsion to net weak-attraction as ionic strength decreases. This transition is not observed under the constant charge assumption which shows that charge regulation is not a minor correction but can change both the strength and the sign of nanoscale electrostatic interactions, with implications for the assembly and stability of charge-regulated colloidal systems
ER -