TISSUE ENGINEERED MATRIX BASED ON SILK FIBROIN FOR CARDIOVASCULAR SURGERY

Highlights The article reports on the progress in the development of a method for producing porous nonwoven material based on silk fibroin, and the following study of its structural, physical, and mechanical properties. The findings indicate that the obtained material is similar in its characteristics to the native artery thus proving that silk fibroin has a high potential in vascular tissue engineering. Abstract Background . Natural polymer – silk fibroin, obtained from silkworm cocoons, is a promising biomaterial. Tissue engineering has allowed us to obtain 3D-scaffolds based on silk fibroin for cardiovascular surgery. Aim . To make a porous matrix based on regenerated silk fibroin (SF) and to study its characteristics in vitro . Methods . Silk was refined in an alkaline solution with further dissolution in LiBr, dialysis and freeze drying to obtain sponges. Matrices based on 15%, 18% and 20% SF in hexafluoroisopropanol were manufactured by electrospinning. By incubation in ethanol, methanol or isopropanol the β-sheet of SF was made water-insoluble. The structure of the matrix surface and the cross-section were studied by scanning electron microscopy. Physical and mechanical characteristics were evaluated using a universal bursting strength tester. Results . The optimal electrospinning parameters for 15% solution were as follows: needle 22 G; tip to collector 15 cm; voltage 20 kV; solution feed rate 1.0 mL/h; rotational speed of 200 rpm; humidity 65% and room temperature 23 °C. The obtained matrix had “flat fibers” with a width of 4.84 (4.20; 5.47) microns and a small number of shallow pores with a diameter of 8.65 (5.01; 11.13) microns. The walls of the matrix consisted of fibers with a diameter of 11.70 (10.04; 13.90) microns with a large number of pores with a diameter of 4.89 (4.46; 6.05) microns. Incubation of samples in 70% ethanol allowed us to form a non-water-soluble form of the SF matrix that has physical and mechanical characteristics comparable to sheep carotid arteries. Conclusion . We have developed a porous 3D matrix based on 15% silk fibroin with satisfactory structural, physical and mechanical characteristics. It is necessary to further conduct in vitro studies to fully understand the characteristics of the manufactured material for further testing on in vivo models.