Concurrent application of conductive biopolymeric chitosan/polyvinyl alcohol/MWCNTs nanofibers, intracellular signaling manipulating molecules and electrical stimulation for more effective cardiac tissue engineering

Fabrication of appropriate electro-conductive scaffold, application of small molecules (SMs), electrical stimulation (ES), and stem cells are steps forward in cardiac tissue engineering. Herein, for the first time, all mentioned factors have been taken into account concurrently regarding the differentiation of unrestricted somatic stem cells (USSCs) into cardiac cells. To accomplish this goal, electrospun composite scaffolds made of chitosan (CS) and polyvinyl alcohol (PVA) with multi-wall carbon nanotubes (MWCNTs; ranged from 0 to 2.5% w/w) were fabricated. After analyzing mechanical, electrical, and biological properties, the best MWCNTs portion was selected. Of note, the addition of 2%w/w MWCNTs to the CS/PVA samples reduced average fiber diameter from 225 to 110 nm, increasing electrical conductivity from 8 x 10(-5) S/m to 9 x 10(-3) S/m and trebling tensile strength. Then, by using a 10-day differentiation protocol (including CHIR99021, IWP2, SB431542, and pur-morphamine SMs) and ES, USSCs were induced into cardiomyocytes. Overexpression of some cardiac-associated genes, including troponin I, CX43, and beta-MHC, along with proper phenotypic alteration, were observed. (Scaf-fold + SM + ES) show a significant increase in the expression of these genes, 172, 5.3, and 64-times as normalized to undifferentiated cells, respectively. Our findings confirmed the importance of the simultaneous implementation of different factors for the developing functionality of the cardiac tissue. Altogether, it is rec-ommended to deploy all mentioned features to obtain effective cardiac tissue engineering.