Trifluoroethanol

Electrospinning was performed using an optimized protocol described previously [19 ]. The electrospinning solution for 100% PCL fibers was formed from a 10% (w/v) solution of PCL (MW: 70 kDa—90 kDa, Sigma, St. Louis, MO) in a 50:50 mixture of dichloromethane and dimethylformamide (Fisher Scientific, Pittsburg, PA). Electrospinning solutions used to form PCL+Gel fibers were made from polycaprolactone (PCL, Sigma, St. Louis, MO) and type A gelatin (Sigma) in a 90/10 (w/w) ratio dissolved in Trifluoroethanol (Fisher Scientific, Pittsburg, PA) with 1% acetic acid (Fisher Scientific) to improve miscibility [12 (link)]. The PCL+Gel concentration was 10% (w/v) in the electrospinning solution. Either polymer solution was loaded into a 10 mL syringe with a 25 Gauge needle and extruded at a rate of 0.5 mL/hr into a high voltage electric field. The applied static electric potential was +17kV relative to a grounded cylindrical collector 20 cm away. The collector was rotated at high RPMs to collect highly aligned fibers or at very low RPMs to produce randomly oriented fibers. After electrospinning, each sample was put in a vacuum desiccator overnight to remove any residual solvent.

The ammonium bicarbonate, acetonitrile, and Trifluoroethanol were purchased from Fisher Scientific, Pittsburgh, PA, iodoacetamide (IAA) was purchased from GE Healthcare Biosciences, Piscataway, NJ, formic acid from Sigma, St. Louis, MO, and β-mercaptoethanol was purchased from Amresco, Solon, OH. The Agilent Protein 80 chip kit was purchased from Agilent Technologies, Santa Clara, CA. The Proteomics Grade Plasma (PGPT) and Serum (PGST) tubes for collection of blood, protein digestion monitoring Kit (ProDM), and Total Protein Assay Reagent (ToPA) were supplied by ITSI-Biosciences, Johnstown, PA, and PicoFrit C18 nanospray column was purchased from New Objective, Woburn, MA.