N.A. Chumakova, E.N. Golubeva, T.A. Ivanova, N.N. Vorobieva, P.S. Timashev, V.N. Bagratashvili
EPR Diagnostics of Porous Matrixes on the Basis of D,L-Polylactide, Generated in the Medium of Supercritical CO2
The spin probe technique as a version of the electron paramagnetic resonance (EPR)
spectroscopy was used to reveal the regularities of the formation of porous matrixes
based on D,L-polylactide in a supercritical CO2 medium with the simultaneous
impregnation by paramagnetic biologically active test molecule 4-Hydroxy-2,2,6,6-tetramethylpiperidine
1-oxyl (TEMPOL). The dependences of the average and local dopant
concentration on impregnation conditions were estimated. It was concluded that EPR
spectroscopy is a promising method for studying porous polymeric materials formed
in supercritical conditions. Impregnation of the polymer with a paramagnetic compound
allows one to estimate the uniformity of the dopant distribution in a sample on both
macroscopic and microscopic levels, and also to judge the structure of the polymer
matrix. The data obtained by EPR and optical spectroscopy showed that the resulting
matrixes meet the important requirements for porous materials for tissue engineering.
Key words: impregnation, supercritical carbon dioxide, EPR, spin probe method, matrixes for tissue engineering.