A Novel Model System for Design of Biomaterials Based on Recombinant Analogs of Spider Silk Proteins

Abstract

Spider dragline silk possesses impressive mechanical and biochemical properties. It is synthesized by a couple of major ampullate glands in spiders and comprises of two major structural proteins--spidroins 1 and 2. The relationship between structure and mechanical properties of spider silk is not well understood. Here, we modeled the complete process of the spider silk assembly using two new recombinant analogs of spidroins 1 and 2. The artificial genes sequence of the hydrophobic core regions of spidroin 1 and 2 have been designed using computer analysis of existing databases and mathematical modeling. Both proteins were expressed in Pichia pastoris and purified using a cation exchange chromatography. Despite the absence of hydrophilic N- and C-termini, both purified proteins spontaneously formed the nanofibrils and round micelles of about 1 microm in aqueous solutions. The electron microscopy study has revealed the helical structure of a nanofibril with a repeating motif of 40 nm. Using the electrospinning, the thin films with an antiparallel beta-sheet structure were produced. In summary, we were able to obtain artificial structures with characteristics that are perspective for further biomedical applications, such as producing three-dimensional matrices for tissue engineering and drug delivery.

Stem cell differentiation to epidermal lineages on electrospun nanofibrous substrates for skin tissue engineering

“…The diameter of the electrospun Coll/PLLCL nanofibers ranged from 183 to 235 nm, which mimics the nanoscale dimensions of native ECM. It was reported that cells attach to and organize well around fibers with diameters smaller than the diameter of the cells [28]. Furthermore, fibrillar structure was found to promote cell attachment, proliferation and colony-forming capacity of stem cells in vitro in comparison with (non-fibrillar) tropocollagen layers [12].…”

Cytocompatibility of electrospun nanofiber tubular scaffolds for small diameter tissue engineering blood vessels

“…Spider silk has come to focus as its extraordinary mechanical and biochemical properties [19] in materials cloning and expression, as well as mimicking these properties in polymeric systems [20]. Recombinant spider silk protein has been successfully applied for such biomedical materials as scaffolds for tissue engineering [21][22][23].…”

Spider silk proteins: recent advances in recombinant production, structure–function relationships and biomedical applications

“…This is not surprising as not even the respinning of dissolved native spider silk results in fibres that match native silk [94,95]. For recombinant spidroins that do not self-assemble spontaneously, different methods to convert them into fibres have been used, such as wet spinning [9,53,62,70,79,86,96,97], hand drawing [82,96], spinning though microfluidic devices [83] and electrospinning [56,59,66,86,98]. A few recombinant spidroins that generate fibres stable and long enough to allow mechanical testing have been reported [11,70,86,92,93,96].…”