Binding of HIF-1α on COOH-N-MWCNTs: Effect of Local Curvature

Abstract

The efficiency of carbon nanotubes as biomolecule carriers is determined by the strength of surface binding and the kinetics of subsequent release. One of the factors capable of influencing these parameters is the local curvature of the graphene layer of nanotubes. In this study, the effect of local surface curvature of carboxyl-functionalized nitrogen-doped multi-walled carbon nanotubes (COOH-N-MWCNTs) on HIF-1α protein binding was investigated.
TEM analysis revealed regions with positive (convex) and negative (concave) curvature, with local curvature radii ranging from 0.7 to 5 nm. Based on experimental data, atomistic models of local surface fragments (~200 atoms) containing carboxyl groups (4 at.% O), substitution nitrogen atoms, carbonyl oxygen, and Stone–Wales defects were constructed. The formation of models with different curvatures, optimization of the atomic structure, and modeling of the interaction between the HIF-1α protein and the nanotube surface were performed using the SCC DFTB method. Binding energies and activation barriers for protein attachment were calculated.
The binding energies were similar for positive and negative curvature regions over the studied range, varying from –0.47 to –0.35 eV. In contrast, the activation barrier strongly depended on both the sign and magnitude of curvature. For concave regions, it was ~0.05–0.15 eV, whereas for convex regions it reached ~0.2–0.35 eV. Thus, despite comparable binding energies, HIF-1α attachment is energetically more favorable on concave COOH-N-MWCNT regions due to the substantially lower activation barrier.
This work was supported by the Russian Science Foundation (project No. 25-22-00377, https://rscf.ru/project/25-22-00377/).

Speaker

Tatyana Sapezhinskaya
Institute of Strength Physics and Materials Science of SB RAS
Russia

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