Fabrication and Mechanical Characterization of Hydrogel Infused Network Silk Scaffolds

Abstract

Development and characterization of porous scaffolds for tissue engineering and regenerative medicine is of great importance. In recent times, silk scaffolds were developed and successfully tested in tissue engineering and drug release applications. We developed a novel composite scaffold by mechanical infusion of silk hydrogel matrix into a highly porous network silk scaffold. The mechanical behaviour of these scaffolds was thoroughly examined for their possible use in load bearing applications. Firstly, unconfined compression experiments show that the denser composite scaffolds displayed significant enhancement in the elastic modulus as compared to either of the components. This effect was examined and further explained with the help of foam mechanics principles. Secondly, results from confined compression experiments that resemble loading of cartilage in confinement, showed nonlinear material responses for all scaffolds. Finally, the confined creep experiments were performed to calculate the hydraulic permeability of the scaffolds using soil mechanics principles. Our results show that composite scaffolds with some modifications can be a potential candidate for use of cartilage like applications. We hope such approaches help in developing novel scaffolds for tissue engineering by providing an understanding of the mechanics and can further be used to develop graded scaffolds by targeted infusion in specific regions.

Hydrogel scaffolds based on blood plasma cryoprecipitate and collagen derived from various sources: Structural, mechanical and biological characteristics

“…Thus, the identified differences can be explained by the peculiarities of the internal architecture of the scaffolds formed with the collagen derived from different sources. We know of works that indicate that the density of scaffold structures can determine their module of elasticity to a great extent [76]. F. You et al [77] also demostrated that the mechanical properties of hydrogel scaffolds depend on their porosity and other structural characteristics.…”

Influence of the Mechanical Environment on the Regeneration of Osteochondral Defects

“…While unconfined and confined compression require the cartilage sample or the scaffold to be tested within a chamber, indentation allows the test to be performed on a whole osteochondral specimen (Griffin et al, 2016 ; Tozzi et al, 2020 ). Compression tests can be performed by applying a strain at a constant rate (ramp), by applying a strain to a target level and holding the strain constant (stress-relaxation) or applying a cyclic strain (dynamic) (Scholten et al, 2011 ; Vikingsson et al, 2015 ; Coluccino et al, 2016 ; Kundanati et al, 2016 ). Compression tests can be also load-controlled, applying a rapid load that is then kept constant, measuring sample strain over time (Oyen, 2014 ; Patel et al, 2019 ).…”

Emerging therapies for cartilage regeneration in currently excluded ‘red knee’ populations

“…For example, Valonen and colleagues developed a 3D-woven poly(ε-caprolactone) (PCL) scaffold with an aggregate modulus of 550 kPa, well within the range of native articular cartilage. 86 Other groups have created fiber-reinforced hydrogels, and achieved stiffness values greater than 400 kPa, 80,87 resulting in replacement scaffolds for defects that require greater mechanical support. An important consideration is balancing the mechanics of these scaffolds with their resorption and ability to form new cartilage tissue.…”