Materials selection and residual solvent retention in biodegradable electrospun fibers

Electrospun tissue engineering scaffolds provide mechanical support to seeded cells that populate the structure while depositing specific extracellular matrix components. The potent sterilizing agent 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) is often used in electrospinning investigations involving biologically‐derived polymers. Surprisingly, there has been no study of solvent retention versus composition even though materials selection should influence organic solvent content. We developed a method quantifying HFIP retention following electrospinning of gelatin, polycaprolactone (PCL), and PCL‐gelatin blends using electro‐spray mass spectroscopy. The acetone content of acetone‐spun PCL was also established. Pure gelatin fiber contained as much as 1600 ppm of HFIP. In contrast, little acetone or HFIP was detected in 100% PCL. Gelatin clearly has a greater affinity for HFIP than PCL and materials selection has a strong influence on the amount of retained solvent. Vacuum + heat treatment at 37 and 45ºC reduced [HFIP] to 10 and 5.6 ppm, respectively, levels having no demonstrated effects on mammalian cell viability.