Elmer Keiser Bolton
When Wallace Carothers arrived at DuPont in 1928 one of the tasks his group took on was the development of new synthetic fibers for textiles. At that time a number of natural polymers such as latex and cellulose were in common use, rayon as a semisynthetic from nitrated cellulose had recently been improved and begun upending the textile industries, and some fully synthetic polymers such as bakelite were also known and being used for certain applications, but the existing fully synthetic polymers could not be drawn into fibers and spun into thread, so great opportunity existed to manufacture thread and yarn from synthetic polymers to join or replace the existing fibers in the market (natural fibers such as cotton, wool, linen, and silk and artificial fiber in the various recently emerged types of rayon).
Nanofiber
However, cellular recognition of natural polymers can easily initiate an immune response. Consequently, synthetic polymers such as poly(lactic acid) (PLA), polycaprolactone (PCL), polyurethane (PU), poly(lactic-co-glycolic acid) (PLGA), poly(L-lactide) (PLLA), and poly(ethylene-co-vinylacetate) (PEVA) have been developed as alternatives for integration into scaffolds. Being biodegradable and biocompatible, these synthetic polymers can be used to form matrices with a fiber diameter within the nanometer range. Out of these synthetic polymers, PCL has generated considerable enthusiasm among researchers. PCL is a type of biodegradable polyester that can be prepared via ring-opening polymerization of ε-caprolactone using catalysts. It shows low toxicity, low cost and slow degradation. PCL can be combined with other materials such as gelatin, collagen, chitosan, and calcium phosphate to improve the differentiation and proliferation capacity (2, 17). PLLA is another popular synthetic polymer. PLLA is well known for its superior mechanical properties, biodegradability and biocompatibility. It shows efficient cell migration ability due to its high spatial interconnectivity, high porosity and controlled alignment. A blend of PLLA and PLGA scaffold matrix has shown proper biomimetic structure, good mechanical strength and favorable bioactivity.