Simultaneous structuring and mineralization of silk fibroin scaffolds

Abstract

Silk fibroin is commonly used as scaffold material for tissue engineering applications. In combination with a mineralization with different calcium phosphate phases, it can also be applied as material for bone regeneration. Here, we present a study which was performed to produce mineralized silk fibroin scaffolds with controlled macroporosity. In contrast to former studies, our approach focused on a simultaneous gelation and mineralization of silk fibroin by immersion of frozen silk fibroin monoliths in acidic calcium phosphate solutions. This was achieved by thawing frozen silk fibroin monoliths in acidic calcium phosphate solution, leading to the precipitation of monocalcium phosphate within the silk fibroin matrix. In the second approach, a conversion of incorporated β-tricalcium phosphate particles into brushite was successfully achieved. Furthermore, a controlled cryostructuring process of silk fibroin scaffolds was carried out leading to the formation of parallel-oriented pores with diameters of 30–50 µm.

Gradient Biomineralized Silk Fibroin Nanofibrous Scaffold with Osteochondral Inductivity for Integration of Tendon to Bone

“…As reported in the literature of Roedel et al, at the same time of mineralization, a sol-to-gel transition was also induced because of the pH of the solution (resulting from the presence of Ca ions). This was accompanied by a more stable β-sheet form inside the nanofiber, which resulted in higher mechanical properties . In addition, the interfacial bonding between SF nanofiber and mineral coating could lead to a more potent stiffening effect, which is also directly positively correlated with the amount of mineral …”

Ice Templating Soft Matter: Fundamental Principles and Fabrication Approaches to Tailor Pore Structure and Morphology and Their Biomedical Applications

“…Unidirectionally frozen using a dry ice/ethanol slurry and freeze-dried Anisotropic Investigating novel materials relevant for cardiac tissue engineering; study improved tissue infiltration and cellular proliferation by incorporating ECM material into processed solution [16] Silk fibroin cryogel Unidirectionally frozen between two differently cooled tempered Peltier elements; cross-linked by thawing in acidic calcium phosphate solution Anisotropic Developing protocols for the fabrication of mineralized silk; experimental conditions yielded scaffolds with uniformly aligned pores and inlet diameters ranging from 30 to 50 µm [34] Silk fibroin sponge Silk fibroin solution of different concentrations and molecular weights frozen at − 20 °C and then freeze-dried Isotropic Using silk fibroin as a representative polymer to investigate the effect polymer concentration and molecular weight have on sponge pore morphology and mechanical properties [12] Collagen-nanohydroxyapatite (nanoHA) cryogel Gelled in − 18 °C and thawed at room temperature; washed scaffolds were then freeze-dried; scaffolds had varying compositions of collagen and nanoHA Isotropic Investigated as novel biomaterial for bone tissue engineering; study demonstrated different compositions of collagen:nanoHA affected tissue infiltration and cell proliferation, with a 30:70 composition, functioning best compared to 100:0 and 50:50 compositions [35] Silk fibroin sponges with microchannels Silk fibroin solution cast around linear wire arrays (508 µm ϕ and 1 mm gap) and frozen at − 20 °C and then freeze-dried Isotropic Augmenting standard silk fibroin sponges with a set of microchannels to demonstrate that microchannels improve mass transfer across scaffold and tissue infiltration [36] Chitosan scaffolds Gelled chitosan solution frozen at − 80 °C and freezedried; dried scaffolds were cut to size and then loaded with plasmid DNA encoding perlecan domain I and VEGF189…”

Suitability of Chitosan Scaffolds with Carbon Nanotubes for Bone Defects Treated with Photobiomodulation

“…The mineralization of scaffolds can further potentiate the osteogenesis process [ 65 ], however, contradictory results were demonstrated by Munhoz et al (2018), who reported that the mineralization of collagen and chitosan sponges did not stimulate bone neoformation sufficiently for tissue repair [ 66 ]. However, it must be considered that the experimental procedure was performed on the calvaria of rats, which is not subject to biomechanical load by muscle action.…”