Single-molecule AFM study of hyaluronic acid softening in electrolyte solutions

Evgeniy V Dubrovin; Nikolay A Barinov; Dmitry A Ivanov; Dmitry V Klinov

doi:10.1016/j.carbpol.2022.120472

Single-molecule AFM study of hyaluronic acid softening in electrolyte solutions

Carbohydr Polym. 2023 Mar 1:303:120472. doi: 10.1016/j.carbpol.2022.120472. Epub 2022 Dec 16.

Authors

Evgeniy V Dubrovin¹, Nikolay A Barinov², Dmitry A Ivanov³, Dmitry V Klinov⁴

Affiliations

¹ Sirius University of Science and Technology, 1 Olympic Ave, 354340 Sochi, Russian Federation; Moscow Institute of Physics and Technology, Institutskiy Per. 9, Dolgoprudny 141700, Russian Federation; Lomonosov Moscow State University, Leninskie Gory 1 bld. 2, 119991 Moscow, Russian Federation. Electronic address: dubrovin@polly.phys.msu.ru.
² Sirius University of Science and Technology, 1 Olympic Ave, 354340 Sochi, Russian Federation; Moscow Institute of Physics and Technology, Institutskiy Per. 9, Dolgoprudny 141700, Russian Federation. Electronic address: n.barinov@phystech.edu.
³ Sirius University of Science and Technology, 1 Olympic Ave, 354340 Sochi, Russian Federation; Institut de Sciences des Matériaux de Mulhouse - IS2M, CNRS UMR7361, 15 Jean Starcky, Mulhouse 68057, France. Electronic address: dimitri.ivanov.2014@gmail.com.
⁴ Sirius University of Science and Technology, 1 Olympic Ave, 354340 Sochi, Russian Federation; Moscow Institute of Physics and Technology, Institutskiy Per. 9, Dolgoprudny 141700, Russian Federation. Electronic address: klinov.dv@mipt.ru.

PMID: 36657830
DOI: 10.1016/j.carbpol.2022.120472

Abstract

Investigation of hyaluronic acid (HA) morphology and mechanical properties at a single-molecule level is important for the development of HA based biomaterials. We have developed the atomic force microscopy (AFM) based approach for quantitative characterization of conformation of HA molecules. HA molecules adsorbed on a modified graphitic surface form oriented linear segments. Conformation of HA molecules can be considered as two-dimensional quasi-projection of a three-dimensional conformation locally straightened by a substrate. The persistence length and Young's modulus of biomolecules estimated using wormlike chain model decrease from 15.7 to 9.9 nm, and from ∼21 to ∼13 GPa, respectively, when KCl concentration increases from 0 to 100 mM. The dependence of the persistence length on ionic strength supports the Odijk-Skolnick-Fixman model of polyelectrolyte stiffening in electrolyte solution. The obtained results represent a new insight into the conformation and mechanical characteristics of HA molecules and complement the characterization of this biopolymer by bulk methods.

Keywords: AFM; Adsorption; Hyaluronic acid; Persistence length; Wormlike chain model; Young's modulus.