Rheological characterization of human fibrin and fibrin-agarose oral mucosa substitutes generated by tissue engineering

Abstract

In regenerative medicine, the generation of biocompatible substitutes of tissues by in vitro tissue engineering must fulfil certain requirements. In the case of human oral mucosa, the rheological properties of tissues deserve special attention because of their influence in the acoustics and biomechanics of voice production. This work is devoted to the rheological characterization of substitutes of the connective tissue of the human oral mucosa. Two substitutes, composed of fibrin and fibrin-agarose, were prepared in cell culture for periods in the range 1-21 days. The time evolution of the rheological properties of both substitutes was studied by two different experimental procedures: steady-state and oscillatory measurements. The former allows the plastic behaviour of the substitutes to be characterized by estimating their yield stress; the latter is employed to quantify their viscoelastic responses by obtaining the elastic (G') and viscous (G'') moduli. The results demonstrate that both substitutes are characterized by a predominant elastic response, in which G' (order 100 Pa) is roughly one order of magnitude larger than G'' (order 10 Pa). But the most relevant insight is the stability, throughout the 21 days of culture time, of the rheological quantities in the case of fibrin-agarose, whereas the fibrin substitute shows a significant hardening. This result provides evidence that the addition to fibrin of a small amount of agarose allows the rheological stability of the oral mucosa substitute to be maintained. This feature, together with its viscoelastic similitude with native tissues, makes this biomaterial appropriate for potential use as a scaffold in regenerative therapies of human oral mucosa.

Effect of the hydration on the biomechanical properties in a fibrin‐agarose tissue‐like model

“…Nevertheless, potentiality for precise applications will depend on the biomechanical properties of the native tissue to be replaced, which should be matched by those of the artificial hydrogels. Previous works demonstrated that the values of the viscoelastic moduli of nanostructured and non‐nanostructured FA hydrogels at 0.1% of agarose are comparable to the ones of porcine cornea and human vocal fold mucosa, respectively . Our present study demonstrates that it is possible to adjust the biomechanical properties of fibrin and FA hydrogels within a broad range, by changing the agarose content and the hydration grade—the Young's Modulus ranges between 5 and 460 kPa, the compression elastic modulus between 1 and 75 kPa, G between 4 and 3100 Pa, G ′ between 15 and 4750 Pa and G ″ between 2 and 600 Pa.…”

“…Previous works demonstrated that the values of the viscoelastic moduli of nanostructured and non-nanostructured FA hydrogels at 0.1% of agarose are comparable to the ones of porcine cornea and human vocal fold mucosa, respectively. 9,14 Our present study demonstrates that it is possible to adjust the biomechanical properties of fibrin and FA hydrogels within a broad range, by changing the agarose content and the hydration gradethe Young's Modulus ranges between 5 and 460 kPa, the compression elastic modulus between 1 and 75 kPa, G between 4 and 3100 Pa, G 0 between 15 and 4750 Pa and G 00 between 2 and 600 Pa. The adjustability of their biomechanical properties makes fibrin and FA hydrogels potential candidates for a good number of applications in tissue engineering ( Figs.…”

“…FA hydrogels have been successfully used for the preparation of different bioengineered tissues, including cornea, skin, oral mucosa, and peripheral nerve . Dehydration by plastic compression proved to be an efficient way to improve the mechanical properties of FA hydrogels at 0.1% of agarose concentration .…”

“…9 FA hydrogels have been successfully used for the preparation of different bioengineered tissues, including cornea, skin, oral mucosa, and peripheral nerve. 8,[11][12][13][14] Dehydration by plastic compression proved to be an efficient way to improve the mechanical properties of FA hydrogels at 0.1% of agarose concentration. 9 Nevertheless, there is not any reported study that thoroughly analyzes the main variables of the preparation protocol of this kind of hydrogels, that is, the agarose concentration and the water content.…”

Sequential keratinocytic differentiation and maturation in a three‐dimensional model of human artificial oral mucosa

“…In our work, we employed a fibrin-agarose scaffold that overcomes the drawbacks of both the animal-derived and the synthetic biomaterials used in other studies, such as the biocompatibility, biodegradability, fibroblastic infiltration capacity, morphologic and mechanical stability, and feasibility of an autologous source (17). Moreover, in comparison with other fibrin-based scaffolds previously reported (2,3,20), the fibrin-agarose improves the rheological stability while maintaining the viscoelastic properties of the native tissue (21). The construction of a human oral mucosa substitute intended for clinical application should ideally employ cells and biomaterials derived from the patient to avoid immunological concerns.…”