Lyophilized Silk Sponges: A Versatile Biomaterial Platform for Soft Tissue Engineering

Abstract

We present a silk biomaterial platform with highly tunable mechanical and degradation properties for engineering and regeneration of soft tissues such as, skin, adipose, and neural tissue, with elasticity properties in the kilopascal range. Lyophilized silk sponges were prepared under different process conditions and the effect of silk molecular weight, concentration and crystallinity on 3D scaffold formation, structural integrity, morphology, mechanical and degradation properties, and cell interactions in vitro and in vivo were studied. Tuning the molecular weight distribution (via degumming time) of silk allowed the formation of stable, highly porous, 3D scaffolds that held form with silk concentrations as low as 0.5% wt/v. Mechanical properties were a function of silk concentration and scaffold degradation was driven by beta-sheet content. Lyophilized silk sponges supported the adhesion of mesenchymal stem cells throughout 3D scaffolds, cell proliferation in vitro, and cell infiltration and scaffold remodeling when implanted subcutaneously in vivo.

Elucidation of differential mineralisation on native and regenerated silk matrices

“…In braids, the percentage of â-sheet content was 61.5% with 24.6% â-turns ( Figure 3E). Significantly lower â-sheet content for lyophilised structures was observed which corresponded to 53.4% of â-sheet with about 31% of â-turns ( Figure 3D), as observed previously [33]. The fraction of â-sheet content within 2D fibroin films was the minimum (p<0.05), comprising of 17.9 % â-sheet (weak) and 58.4% random coils and 〈-helix ( Figure 3C).…”

Fabrication of functionalized citrus pectin/silk fibroin scaffolds for skin tissue engineering

“…Retaining PEC chains in 0.015 M borax containing scaffolds relatively increased the water uptake capacity of matrices. Besides that the biomechanical and structural stability of SF based structures have already been proved in in vivo and in vitro studies – . PEC is already known as water soluble polysaccharide and uncrosslinked chain release tendency has been shown on 3D scaffolds as 34% weight loss in PBS after 2 days of which 69% of material was PEC .…”

Design and characterization of microcapsules-integrated collagen matrixes as multifunctional three-dimensional scaffolds for soft tissue engineering

“…Soft tissue loss and damage associated with trauma and disease present a significant healthcare burden worldwide (Rnjak-Kovacina et al, 2015). Among soft tissues there is cartilage, a predominantly avascular and aneural tissue, composed by scattered chondrocytes, the only cell type, embedded within a dense extracellular matrix (ECM).…”

“…In the last years, tissue engineering (TE) approaches have emerged as potential alternative therapeutic strategies to treat severely injured patients with minimally invasive techniques (Lee and Shin, 2007). Biomaterials play a unique role in tissue regeneration and repair: they serve as tunable biophysical and biochemical environments that direct cellular behavior and functions thus promoting the replacement and regeneration of missing or injured tissues (Rnjak-Kovacina et al, 2015). Most TE approaches involve the use of 3D porous scaffolds, constructed from natural or synthetic materials, to modulate cell proliferation and differentiation (Bitar and Zakhem, 2014;Boix et al, 2005;Janik and Marzec, 2015;Lee et al, 2011;Nandakumar et al, 2013;Ribeiro et al, 2014;Smith and Grande, 2015;Tayalia and Mooney, 2009;Valonen et al, 2010;Vo et al, 2012).…”