Technics hummer 5 sputter coater

Electrospun fiber scaffolds were imaged via SEM to measure specimen thickness and ensure that fiber morphology was consistent among independently electrospun samples of each polymer. This was necessary since differences in fiber diameter, collection density, or alignment may confound TGA and mechanical testing results. Prior to SEM, all scaffolds were first coated with a 1-nm thick layer of gold-palladium using a Technics Hummer V sputter coater (Anatech Ltd., Denver, CO). Fibers were then imaged using a FEI Versa 3D DualBeam SEM (Hillsboro, OR) with a low accelerating voltage (2–4 kV) to avoid melting fibers while imaging.

Since drug release from electrospun fibers can be affected by fiber diameter, scanning electron microscopy (SEM) was performed on all fiber scaffolds to characterize fiber diameter. In preparation for SEM, all electrospun fiber scaffolds were sputter coated with a 5 Å thick layer of platinum using a Technics Hummer V sputter coater (Anatech Ltd., Denver, NC). SEM was conducted using a FEI Versa 3D DualBeam SEM (Hillsboro, OR). Low accelerating voltages (2 – 5 kV) were used during SEM to prevent melting the polymer fibers while imaging. Fiber SEM images were analyzed using NIH ImageJ software (Bethesda, MD). Briefly, fiber cross-sectional diameters were measured in ImageJ, and the pixel length of this diameter was compared to the pixel length of the accompanying image scale bar to obtain a fiber diameter value. Three independently fabricated electrospun fiber scaffolds were imaged for each fiber group and 100 fiber diameters were analyzed in each fiber scaffold. Thus, a total of 300 fiber diameters were measured for each fiber treatment group.