Porous Silk Fibroin/Cellulose Hydrogels for Bone Tissue Engineering via a Novel Combined Process Based on Sequential Regeneration and Porogen Leaching

Abstract

Scaffolds used for bone tissue engineering need to have a variety of features to accommodate bone cells. The scaffold should mimic natural bone, it should have appropriate mechanical strength, support cell differentiation to the osteogenic lineage, and offer adequate porosity to allow vascularization and bone in-growth. In this work, we aim at developing a new process to fabricate such materials by creating a porous composite material made of silk fibroin and cellulose as a suitable scaffold of bone tissue engineering. Silk fibroin and cellulose are both dissolved together in N,N-dimethylacetamide/LiCl and molded to a porous structure using NaCl powder. The hydrogels are prepared by a sequential regeneration process: cellulose is solidified by water vapor treatment, while the remaining silk fibroin in the hydrogel is insolubilized by methanol, which leads to a cellulose framework structure embedded in a silk fibroin matrix. Finally, the hydrogels are soaked in water to dissolve the NaCl for making a porous structure. The cellulose composition results in improving the mechanical properties for the hydrogels in comparison to the silk fibroin control material. The pore size and porosity are estimated at around 350 µm and 70%, respectively. The hydrogels support the differentiation of MC3T3 cells to osteoblasts and are expected to be a good scaffold for bone tissue engineering.

Mechanosensitive Osteogenesis on Native Cellulose Scaffolds for Bone Tissue Engineering

“…After 1 week or 2 weeks of stimulation, scaffolds were assessed for change in Young's modulus (Figure 5). Although the measured mechanical properties of the scaffolds were consistent with previous studies (Aliabouzar et al, 2018;Burger et al, 2020;Contessi Negrini et al, 2020;Harris et al, 2021;Kim et al, 2018;Maharjan et al, 2021a;Osborn et al, 2019;Zaborowska et al, 2010;Zhou et al, 2016) we did not observe any statistically significant trends under the various culturing conditions. Data showed no significant changes between samples incubated in osteogenic media with applied hydrostatic pressure and without applied hydrostatic pressure after 1 week (16.1 ± 2.1 kPa and 17.2 ± 3.2 kPa, HP vs CTRL) or 2 weeks (13.9 ± 0.8 kPa and 18.7 ± 0.7 kPa, HP vs CTRL).…”

In Situ Viscoelasticity Behavior of Cellulose–Chitin Composite Hydrogels during Ultrasound Irradiation

“…They show superior properties which are favorable for such applications, especially in the form of hydrogels. By their nature, cellulose and chitin hydrogels have higher water retention [ 1 , 2 ] in a three-dimensional porous structure [ 3 , 4 ] formed by the cellulose or chitin network [ 5 , 6 ]. Moreover, the biocompatibility [ 7 ] and cytocompatibility [ 8 ] of such polysaccharide hydrogels are advantageous as tissue engineering scaffolds [ 8 ] and drug carriers [ 9 , 10 ].…”

Hydrogel-Forming Algae Polysaccharides: From Seaweed to Biomedical Applications

“… 227 Alternative noninvasive methods such as microcomputed tomography can analyze pores in micrometer and centimeter ranges and provide an image from which tortuosity and pore interconnectivity can be calculated. 228 , 229 …”

“… 294 Sophisticated structures showing inner porosity 295 or complex 3D structures can be obtained by sacrificial templating using sugar or salts, which can be removed without impacting the hydrogel stability or structure. 229 , 296 , 297 …”