Natural polymers such as collagens, elastin, and fibrinogen make up much of the body’s native extracellular matrix (ECM). This ECM provides structure and mechanical integrity to tissues, as well as communicating with the cellular components it supports to help facilitate and regulate daily cellular processes and wound healing. An ideal tissue engineering scaffold would not only replicate the structure of this ECM, but would also replicate the many functions that the ECM performs. In the past decade, the process of electrospinning has proven effective in creating non-woven ECM analogue scaffolds of micro to nanoscale diameter fibers from an array of synthetic and natural polymers. The ability of this fabrication technique to utilize the aforementioned natural polymers to create tissue engineering scaffolds has yielded promising results, both in vitro and in vivo, due in part to the enhanced bioactivity afforded by materials normally found within the human body. This review will present the process of electrospinning and describe the use of natural polymers in the creation of bioactive ECM analogues in tissue engineering.

The purpose of this study was to perform a number of preliminary in vitro evaluations on an array of modified gelatin gel sponge scaffolds for use in a bone graft application. The gelatin gels were modified through the addition of a number of components which each possess unique properties conducive to the creation and regeneration of bone: a preparation rich in growth factors (PRGF, a bioactive, lyophilized form of platelet-rich plasma), hydroxyapatite, and chitin whiskers. Platelet-rich plasma therapy is an emerging practice that has proven effective in a number of clinical applications, including enhancing bone repair through improved deposition of new bony matrix and angiogenesis. As such, the inclusion of PRGF in our gelatin scaffolds was intended to significantly enhance scaffold bioactivity, while the addition of hydroxyapatite and chitin whiskers were anticipated to increase scaffold strength. Additionally, the gelatin sponges, which readily dissolve in aqueous solutions, were subjected to 1-Ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) cross-linking, either during or post-gelation, to control their rate of degradation. Scaffolds were evaluated in vitro with respect to compressive strength, mass loss/degradation, protein release, and cellular interaction, with results demonstrating the potential of the gelatin gel sponge scaffold for use in the regeneration of bone.