Nonequilibrium uptake kinetics of molecular cargo into hollow hydrogels tuned by electrosteric interactions
File(s)ACS_absorption_nanogels.pdf (1.97 MB)
Accepted version
Author(s)
Moncho-Jordá, Arturo
Germán-Bellod, Alicia
Angioletti-Uberti, Stefano
Adroher-Benítez, Irene
Dzubiella, Joachim
Type
Journal Article
Abstract
Hollow hydrogels represent excellent nano- and microcarriers due to their ability to encapsulate and release large amounts of cargo molecules (cosolutes) such as reactants, drugs, and proteins. In this work, we use a combination of a phenomenological effective cosolute–hydrogel interaction potential and dynamic density functional theory to investigate the full nonequilibrium encapsulation kinetics of charged and dipolar cosolutes by an isolated charged hollow hydrogel immersed in a 1:1 electrolyte aqueous solution. Our analysis covers a broad spectrum of cosolute valences (zc) and electric dipole moments (μc), as well as hydrogel swelling states and hydrogel charge densities. Our calculations show that, close to the collapsed state, the polar cosolutes are predominantly precluded and the encapsulation process is strongly hindered by the excluded-volume interaction exerted by the polymer network. Different equilibrium and kinetic sorption regimes (interface versus interior) are found depending on the value and sign of zc and the value of μc. For cosolutes of the same sign of charge as the gel, the superposition of steric and electrostatic repulsion leads to an “interaction-controlled” encapsulation process, in which the characteristic time to fill the empty core of the hydrogel grows exponentially with zc. On the other hand, for cosolutes oppositely charged to the gel, we find a “diffusion-controlled” kinetic regime, where cosolutes tend to rapidly absorb into the hydrogel membrane and the encapsulation rate depends only on the cosolute diffusion time across the membrane. Finally, we find that increasing μc promotes the appearance of metastable and stable surface adsorption states. For large enough μc, the kinetics enters an “adsorption-hindered diffusion”, where the enhanced surface adsorption imposes a barrier and slows down the uptake. Our study represents the first attempt to systematically describe how the swelling state of the hydrogel and other leading physical interaction parameters determine the encapsulation kinetics and the final equilibrium distribution of polar molecular cargo.
Date Issued
2019-02-26
Date Acceptance
2019-01-16
Citation
ACS Nano, 2019, 13 (2), pp.1603-1616
ISSN
1936-0851
Publisher
American Chemical Society (ACS)
Start Page
1603
End Page
1616
Journal / Book Title
ACS Nano
Volume
13
Issue
2
Copyright Statement
© 2019 American Chemical Society
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Multidisciplinary
Chemistry, Physical
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Chemistry
Science & Technology - Other Topics
Materials Science
hollow hydrogels
cargo encapsulation
dynamic density functional theory
partitioning
kinetics
steric interaction
DENSITY-FUNCTIONAL THEORY
SWELLABLE POLYMER MATRIX
COMPUTER-SIMULATION
SOLUTE RELEASE
DIFFUSION
NANOPARTICLES
MICROGELS
NANOGELS
ADSORPTION
SEPARATION
MD Multidisciplinary
Publication Status
Published
Article Number
acsnano.8b07609
Date Publish Online
2019-01-16