Electrospinning polyaniline-contained gelatin nanofibers for tissue engineering applications

Polyaniline (PANi), a conductive polymer, was blended with a natural protein, gelatin, and co-electrospun into nanofibers to investigate the potential application of such a blend as conductive scaffold for tissue engineering purposes. Electrospun PANi-contained gelatin fibers were characterized using scanning electron microscopy (SEM), electrical conductivity measurement, mechanical tensile testing, and differential scanning calorimetry (DSC). SEM analysis of the blend fibers containing less than 3% PANi in total weight, revealed uniform fibers with no evidence for phase segregation, as also confirmed by DSC. Our data indicate that with increasing the amount of PANi (from 0 to approximately 5%w/w), the average fiber size was reduced from 803+/-121 nm to 61+/-13 nm (p<0.01) and the tensile modulus increased from 499+/-207 MPa to 1384+/-105 MPa (p<0.05). The results of the DSC study further strengthen our notion that the doping of gelatin with a few % PANi leads to an alteration of the physicochemical properties of gelatin. To test the usefulness of PANi-gelatin blends as a fibrous matrix for supporting cell growth, H9c2 rat cardiac myoblast cells were cultured on fiber-coated glass cover slips. Cell cultures were evaluated in terms of cell proliferation and morphology. Our results indicate that all PANi-gelatin blend fibers supported H9c2 cell attachment and proliferation to a similar degree as the control tissue culture-treated plastic (TCP) and smooth glass substrates. Depending on the concentrations of PANi, the cells initially displayed different morphologies on the fibrous substrates, but after 1 week all cultures reached confluence of similar densities and morphology. Taken together these results suggest that PANi-gelatin blend nanofibers might provide a novel conductive material well suited as biocompatible scaffolds for tissue engineering.