Silk fibroin aerogels: potential scaffolds for tissue engineering applications

Abstract

Silk fibroin (SF) is a natural protein, which is derived from the Bombyx mori silkworm. SF based porous materials are extensively investigated for biomedical applications, due to their biocompatibility and biodegradability. In this work, CO2 assisted acidification is used to synthesize SF hydrogels that are subsequently converted to SF aerogels. The aqueous silk fibroin concentration is used to tune the morphology and textural properties of the SF aerogels. As the aqueous fibroin concentration increases from 2 to 6 wt%, the surface area of the resultant SF aerogels increases from 260 to 308 m(2) g(-1) and the compressive modulus of the SF aerogels increases from 19.5 to 174 kPa. To elucidate the effect of the freezing rate on the morphological and textural properties, SF cryogels are synthesized in this study. The surface area of the SF aerogels obtained from supercritical CO2 drying is approximately five times larger than the surface area of SF cryogels. SF aerogels exhibit distinct pore morphology compared to the SF cryogels. In vitro cell culture studies with human foreskin fibroblast cells demonstrate the cytocompatibility of the silk fibroin aerogel scaffolds and presence of cells within the aerogel scaffolds. The SF aerogels scaffolds created in this study with tailorable properties have potential for applications in tissue engineering.

Synthesis and biomedical applications of aerogels: Possibilities and challenges

“…Protein-based aerogels such as gelatin [1], whey protein [30], soy [162], egg white [29] or silk fibroin [163] were also added to this category with encouraging life science and biomedical applications. Polysaccharide-based aerogels are new and sustainable materials, with a great deal of biocompatibility and abundance, that can be a suitable alternative to silica aerogels for some biomedical applications (i.e.…”

“…Sustainable protein based aerogels and cryogels from whey protein precursors have been reported with the prospect of being used as drug carriers and other healthcare applications [30]. More recently, Mallepally et al [163] fabricated promising protein based aerogels from silk fibroin (SF) sources, which are produced by B. Mori silkworm, with the potential to be applied as a scaffold in the field of tissue engineering. The sol-gel reaction by CO 2 -assisted acidification has been employed to prepare the SF hydrogels, which have subsequently been processed in aerogels with improved mechanical and textural properties (high specific area, high pore volume, and interconnected porous network), featuring them for cytocompatibility, cell attachments, and migrations.…”

“…In general, aerogels from natural polymers are usually preferred for tissue engineering since they are usually biodegradable, have a composition similar to components encountered in the extracellular matrices (ECM) of tissues and show good cytocompatibility [163,233,234]. Use of admixtures like bioceramics or lignin with aerogels has been reported to confer improved mechanical properties, osteoconductivity or increased cell adhesion to the resulting scaffolds [232,235].…”

Chapter 14. Cellulose and Protein Aerogels for Oil Spill Cleaning, Life Science and Food Engineering Applications

“…Recently, natural protein-based aerogels have attracted increasing research interest due to their biocompatibility and biodegradability for food engineering and life science applications. A few proteins such as whey protein, [43][44][45] silk fibroin, 46,47 egg white protein, 48 and soy protein [49][50][51][52] have been exploited for the formation of aerogels. This section introduces the fabrication methods and the multi-properties of the different types of proteinbased aerogels and their potential applications.…”

“…In recent years, the production of natural protein-based aerogels has become a highly attractive subject in materials chemistry due to the requirement of biodegradability and biocompatibility for pharmaceutical, medical and food applications. 42 Several types of proteins, including whey protein, [43][44][45] silk fibroin, 46,47 egg white protein 48 and soy protein, [49][50][51][52] have been exploited for the formation of aerogels. The effects of various synthesis conditions, such as drying methods, 43 pH values, 48 ionic strengths 48 and precursor concentrations 47 have been investigated for optimizing the porous structure and multi-properties of the resultant aerogels.…”