Study of polylactide matrices using x-ray microtomography

Abstract

Three-dimensional matrices of biodegradable polymers are promising materials for regenerative medicine. They are widely used in restoring the integrity and functions of tissues and organs using bio-artificial tissue engineering structures. We present the results of studying the structure of porous bioresorbable polymer matrices for tissue engineering using X-ray microtomography. Samples were obtained by supercritical fluid plasticization of D,L-polylactide with subsequent foaming in cylindrical molds. The tomographic method makes it possible to construct a three-dimensional voxel model of the object under study and gain apart from the estimate on the integral matrix porosity (characteristic data obtained by traditional sorption procedures) additional information about the size and spatial distribution of pores thus providing a possibility of optimization of the process parameters for production of polylactide matrices required for specific biomedical applications of architectonics, as well as forecasting the processes of their bioresorption in enzymatic media. The experiments were carried out on a laboratory microtomograph (Mo anode, the scan time of the sample is 120 min, the detector pixel size is 9 μm). Tomographic reconstruction was performed by algebraic method. The binarization procedure required for calculation of the structural characteristics of studied matrices was implemented by the method with the choice of a global threshold. Calculations of the porosity and homogeneity of the porosity distribution in the bulk, as well as estimation of the specific surface area of pores revealed the isotropy of the spatial structure of polylactide matrices.