Molecular dynamics study of chitosan adsorption at a silica surface

Hudek, Magdalena and Johnston, Karen and Kubiak-Ossowska, Karina and Ferro, Valerie A. and Mulheran, Paul A. (2024) Molecular dynamics study of chitosan adsorption at a silica surface. The Journal of Physical Chemistry C. ISSN 1932-7455 (In Press) (https://doi.org/10.1021/acs.jpcc.4c05821)

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Abstract

Chitosan is a non-toxic biopolymer with many potential biomedical and material applications due to its biodegradability, biocompatibility and antimicrobial properties. Here, fully atomistic molecular dynamics simulations and enhanced sampling methods have been used to study the adsorption mechanism of chitosan oligomers on a silica surface from aqueous solution. The free energy of adsorption of chitosan on a silica surface was calculated to be 0.6 kcal mol−1 per monomer in 0.15 mol L−1 aqueous solution, which is comparable to kBT at room temperature. The loading capacity of chitosan on the silica surface was found to be 0.094 mg m−2, and is dominated by charge compensation. Furthermore, the hydrogen bonding between chitosan and silica was analysed. The nitrogen and hydroxyl group oxygen chitosan atoms were found to be the main contributors to the hydrogen bonding between chitosan and silica. These findings have the potential to guide the experimental design of chitosan-coated silica nanoparticles for applications such as drug delivery or additives for biopolymer food packaging.

ORCID iDs

Hudek, Magdalena ORCID logoORCID: https://orcid.org/0000-0003-2087-1498, Johnston, Karen ORCID logoORCID: https://orcid.org/0000-0002-5817-3479, Kubiak-Ossowska, Karina, Ferro, Valerie A. ORCID logoORCID: https://orcid.org/0000-0003-1967-3603 and Mulheran, Paul A. ORCID logoORCID: https://orcid.org/0000-0002-9469-8010;
CORE (COnnecting REpositories)