Feasibility of Electrospinning the Globular Proteins Hemoglobin and Myoglobin

Various concentrations of the globular protein hemoglobin were successfully electrospun to create micro-fibrous mats of varying physical and mechanical characteristics. The electrospinning parameters are reported. One concentration of myoglobin was electrospun into a mat for comparison to the hemoglobin mats. Scanning electron microscopy revealed ribbon-like morphologies for the hemoglobin and myoglobin structures. Mean fiber width and thickness for each mat electrospun from a different hemoglobin concentration increased from 2.68 ± 0.83 to 3.55 ± 1.49 μm and from 0.49 ± 0.08 to 0.99 ± 0.41 μm, respectively, for increasing hemoglobin solution concentrations (from 150 to 225 mg/mL). For calculations of surface area to volume ratio for the four different electrospun hemoglobin concentrations, there was a negative correlation (r = −0.84) with concentration; the surface area to volume ratio ranged between 0.50 ± 0.16 and 1.53 ± 0.24 m ² /cm ³ . Also, there appears to be a positive correlation between electrospun hemoglobin concentration and porosity, which increased with increasing concentration from 69.5 to 83.3 %. Following cross-linking with glutaraldehyde, the mechanical properties of two constructs were evaluated via uniaxial tensile testing to demonstrate handling capability. Results indicated that increased cross-linking time produced stiffer structures, as peak stress and modulus increased while strain at break decreased when the mats were cross-linked for 30 minutes with glutaraldehyde versus the 20 minute cross-linking time.