Silk fibroin knit scaffold for increased infiltration depth and improved elsticity in tissue engineering applications

3D scaffolds are in the center of attention for tissue engineering applications. So far, there has been continuous progress and competition in design and engineering of biomaterials as scaffold candidates for regenerative medicine[1]. Whilst biomaterials‐engineering approaches have mostly focused on a few mechanisms (mostly chemical), achieving suitable tissue biomechanical function remains an important challenge[2]. Besides, there are concerns that sustainable tissue engineering may not be achievable with current approaches[3]. This calls for further profound studies, emphasizing the need to imitate the structural and mechanical properties of the target tissue. Conventional 3D scaffolds suffer from limited depth of infiltration for cells due to their low porosity and/or not meeting the biomechanics of the target tissue, especially for regeneration of load‐bearing tissues. In this study, we have designed and fabricated a model of silk fibroin knit scaffold, which along with post‐fabrication degumming, results in a more bulky and less open structure compared with conventional knit fabrics. Our scaffold shows outstanding cell‐scaffold interaction including full 3D cell attachment, 360‐degree cell coverage around individual filaments, and full‐thickness cell infiltration depth. The optimized structure alleviates the need for the in‐advance filling of the pores and provides users with full depth access to the knit structure for increased cell adhesion and infiltration. From a mechanical viewpoint, the scaffold shows high elasticity and recovery upon unloading (up to around 90% strain), thanks to its intermeshed loops. Overall, our SF weft‐knitted construct represents appropriate characteristics for the regeneration of load bearing tissues

Production and properties of electrosprayed sericin nanopowder

Sericin is a proteinous substrate that envelops fibroin (silk) fiber, and its recovery provides significant economical and social benefits. Sericin is an antibacterial agent that resists oxidation and absorbs moisture and UV light. In powder form, sericin has a wide range of applications in food, cosmetics and drug delivery. Asides from other techniques of producing powder, such as precipitation and spray drying, electrospraying can yield solid nanoparticles, particularly in the submicron range. Here, we report the production of sericin nanopowder by electrospraying. Sericin sponge was recovered from Bombyx mori cocoons through a high-temperature, high-pressure process, followed by centrifugation and freeze drying of the sericin solution. The electrospraying solution was prepared by dissolving the sericin sponge in dimethyl sulfoxide. We demonstrate that electrospraying is capable of producing sericin nanopowder with an average particle size of 25 nm, which is by far smaller than the particles produced by other techniques. The electrosprayed sericin nanopowder consists of small crystallites and exhibits a high moisture absorbance

Emulsion Electrospinning as an Approach to Fabricate PLGA/Chitosan Nanofibers for Biomedical Applications

Novel nanofibers from blends of polylactic-co-glycolic acid (PLGA) and chitosan have been produced through an emulsion electrospinning process. The spinning solution employed polyvinyl alcohol (PVA) as the emulsifier. PVA was extracted from the electrospun nanofibers, resulting in a final scaffold consisting of a blend of PLGA and chitosan. The fraction of chitosan in the final electrospun mat was adjusted from 0 to 33%. Analyses by scanning and transmission electron microscopy show uniform nanofibers with homogenous distribution of PLGA and chitosan in their cross section. Infrared spectroscopy verifies that electrospun mats contain both PLGA and chitosan. Moreover, contact angle measurements show that the electrospun PLGA/chitosanmats are more hydrophilic than electrospun mats of pure PLGA. Tensile strengths of 4.94 MPa and 4.21 MPa for PLGA/chitosan in dry and wet conditions, respectively, illustrate that the polyblend mats of PLGA/chitosan are strong enough for many biomedical applications. Cell culture studies suggest that PLGA/chitosan nanofibers promote fibroblast attachment and proliferation compared to PLGA membranes. It can be assumed that the nanofibrous composite scaffold of PLGA/chitosan could be potentially used for skin tissue reconstruction

Emulsion Electrospinning as an Approach to Fabricate PLGA/Chitosan Nanofibers for Biomedical Applications

Novel nanofibers from blends of polylactic-co-glycolic acid (PLGA) and chitosan have been produced through an emulsion electrospinning process. The spinning solution employed polyvinyl alcohol (PVA) as the emulsifier. PVA was extracted from the electrospun nanofibers, resulting in a final scaffold consisting of a blend of PLGA and chitosan. The fraction of chitosan in the final electrospun mat was adjusted from 0 to 33%. Analyses by scanning and transmission electron microscopy show uniform nanofibers with homogenous distribution of PLGA and chitosan in their cross section. Infrared spectroscopy verifies that electrospun mats contain both PLGA and chitosan. Moreover, contact angle measurements show that the electrospun PLGA/chitosanmats are more hydrophilic than electrospun mats of pure PLGA. Tensile strengths of 4.94 MPa and 4.21 MPa for PLGA/chitosan in dry and wet conditions, respectively, illustrate that the polyblend mats of PLGA/chitosan are strong enough for many biomedical applications. Cell culture studies suggest that PLGA/chitosan nanofibers promote fibroblast attachment and proliferation compared to PLGA membranes. It can be assumed that the nanofibrous composite scaffold of PLGA/chitosan could be potentially used for skin tissue reconstruction