Water-stable Three-dimensional Ultrafine Fibrous Scaffolds From Proteins Via Electrospinning

In this research, water stability of scaffolds with ultrafine protein fibers oriented randomlyand evenly in three dimensions could be remarkably enhanced via crosslinking with a new type ofbiological crosslinking agent, without affecting their biocompatibility. Proteins have beenintensively investigated for tissue engineering due to the structural similarity to the majorcomponent in native extracellular matrices (ECMs). Proteins are generally biocompatible andbiodegradable. Their degradation products are oligopeptides and amino acids, which could bebuilding blocks of native ECMs. Some proteins might contain unique tripeptides, Arg-Gly-Asp(RGD) and Leu-Asp-Val (LDV), in their molecules to promote cell binding. The3D ultrafinefibrous scaffolds, which have been electrospun via regulation of the conductivity of spinningdopes, are one of the few scaffolds that could mimic the authentic architectures of3D structures ofnative ECMs.Generally speaking, most protein biomaterials quickly lost their physical forms andmechanical robustness in physiological environments. The hydrogen bonding that stabilizedproteins could be easily broken by water and the polypeptides were prone to be attachedenzymatically. Larger surface area made protein biomaterials disintegrate and degrade faster.Larger surface area exacerbated the problem. Comparing to films, two-dimensional (2D) fibrousmats, three-dimensional (3D) non-fibrous sponges,3D ultrafine fibrous proteins had even poorerdimensional stability and mechanical properties due to the enlarged surface area. Crosslinking wasa feasible approach to solve this problem. However, most crosslinkers currently used were either toxic or with low efficiency. An effective and safe crosslinking method should be developed.In this research, oxidized sucrose, a new type of biological crosslinking agent, was agroup of polar polyaldehydes produced by oxidation of sucrose using sodium periodate. Waterstability of scaffolds with ultrafine protein fibers oriented randomly and evenly in threedimensions could be remarkably enhanced via crosslinking without affecting theirbiocompatibility. Comparing to potent glutaraldehyde crosslinked ultrafine zein fibers, theoxidized sucrose crosslinked ones showed similarly long-term water stability but provided bettersupport for attachment and proliferation of preosteoblasts in vitro study. Comparing to non-toxiccitric acid crosslinked ultrafine zein fibers, the oxidized sucrose crosslinked ones showed similarsupporting effects on growth of preosteoblasts, but with much better water stability. In summary,oxidized sucrose could be a safe and potent crosslinker to improve water stability of protein-basedmaterials for medical and industrial applications.