LASER STRUCTURING OF THE CARBON NANOTUBES ENSEMBLE INTENDED TO FORM BIOCOMPATIBLE ORDERED COMPOSITE MATERIALS

Abstract

The article presents the results of the creation of composite materials. Laser irradiation in the near infrared region (970 nm) of water-albumin dispersion of single-layer carbon nanotubes (SLCNT) is characterised by an intensive absorption of radiation, which is accompanied by nanotube heating. Significant warming occurs at the ends of nanotubes and in the areas of localised defects where the thermal conductivity is significantly reduced. In terms of chemical reaction, the open ends of nanotubes and areas with defects appear to be most active, thus, the idea of splicing SLCNT in the defective areas was taken as the basis. Numerical simulation showed that the process of nanotube matching in the frame starts when the laser heats to a temperature of 80–100 ºC. This process occurs within a few nanoseconds. The graphs of enthalpy allow us to conclude that the process of SLCNT frame forming with four defects in the form 1V (single carbon atom vacancies) present in the region of the tube junctions results in the greatest energetic advantage.

In composite materials, the bonding of SLCNT with albumin molecules occurs though the Glu and Asp amino acid residues. The interaction energy between the nanotube frame and the albumin matrix is up to 580 kJ/mol.

Molecular dynamic simulations show that an increase in the number of oxygen atoms leads to a decrease in the interaction energy between SLCNT and albumin. The attachment of the oxygen atoms to the SLCNT leads to the distortion of nanotubes, which increases with the increase in the number of oxygen atoms. The change of the attachment points of the oxygen atom to the nanotube oxygen atoms allows configuring the desired shape of the nanotube frame in the albumin matrix.

Composite materials based on SLCNT water-albumin dispersion have a developed surface with periodic peaks and troughs. This can be seen from the atomic force microscopy images and is associated with the carbon nanotube framework which is formed under laser radiation. The pore size ranges between 30-120 nm.

Composite materials can provide superior adhesion of cells planted on their surface.  It can be used as a tissue-engineered matrix to restore three-dimensional structure of bone and connective tissue.

The author is grateful to the professor, Dr. Sc. (Phys.-Math.) Podgaetsky V. M. and the scientific team of the Department of Biomedical Systems MIET for assistance in carrying out experimental work and discussing the results, as well as the scientific team of the professor, Dr. Sc. (Phys.-Math.) Glukhova O.E. for assistance in conducting theoretical studies, including using the software product KVAZAR (www.nanokvazar.ru).

This work was supported by the grant of the President of the Russian Federation dated 22 February, 2017 (grant no 14.Y30.17.1328-МК).