Investigation of micro- and nanostructure of biocompatible scaffolds from regenerated fibroin of Bombix mori by scanning probe nanotomography

This paper presents a study of three-dimensional micro- and nanosctuctures of porous biocompatible matrices from regenerated fibroin and a quantitative analysis of their microporosity parameters. An analysis of the three-dimensional structure of matrices has been carried out by scanning probe nanotomography with the use of an experimental setup combining an ultramicrotome and scanning probe microscope. The formation of a three-dimensional network of interconnected pores with characteristic dimensions ranging from 1.7 to 6.0 μm is observed in the bulk volume of studied matrices. The measured mean pore diameter is 3.54 ± 1.23 μm; the mean pore wall thickness is 672 ± 282 nm. The volume porosity of macropore walls is 65.7%, while the volume fraction of pores interconnected in large pore clusters is more than 80% of the whole pore volume. Quantitative characteristics of porous micro- and nanostructures of matrices obtained as a result of the study show a significant degree of porosity and percolation of micropores, which correlates with the reported high efficiency of tissue regeneration on such matrices. The use of scanning probe nanotomography to analyze three-dimensional morphology characteristics and the topology of micro- and nanopore systems enables us to improve the efficiency of developing new biomaterials.