Fabrication of porous bovine pericardium scaffolds incorporated with bFGF for tissue engineering applications

Abstract

Background The design and fabrication of porous scaffolds are important issues for tissue engineering applications. In this study, we attempted to fabricate porous scaffolds using bovine pericardium (BP) and examined whether these scaffolds were beneficial for cell ingrowth and bioactive factors delivery. Methods A vacuum‐freeze‐thawing‐Triton X‐100 (VFTT) protocol was used to fabricate porous BP scaffolds. The porous and mechanical properties were assessed using histology, scanning electron microscopy, and mechanical assay. The fabricated scaffolds were seeded with mesenchymal stem cells (MSCs), and cell ingrowth was evaluated. Basic fibroblast growth factor (bFGF) was subsequently incorporated into the fabricated scaffolds. The bioactive factor delivery capacity was evaluated using loading and release studies. The bioactivity of released bFGF was assessed using a rat subcutaneous model. Results The BP scaffolds fabricated by the VFTT protocol displayed interconnected porous structures with porosity of 6.82 ± 1.36%.There were no significant differences in thickness, ultimate load, Young's modulus, and ultimate tensile strength between the fabricated porous BP scaffolds and native BPs (all P > .05). However, the water content of BPs was slightly reduced after VFTT treatment (P < .05). Cell ingrowth analysis showed that the seeded MSCs penetrated into the porous BP scaffolds with time of culture, while MSCs were limited to the surface layers of native BPs. Furthermore, bFGF was observed to be effectively loaded onto and released from the porous BP scaffolds. The released bFGF increased the phosphorylation levels of Akt, ERK 1/2, and MEK1/2, promoted host MSC recruitment, and inhibited myofibroblast differentiation in vivo. Conclusions The porous BP scaffolds fabricated using a VFTT protocol were promising natural scaffolds for tissue engineering applications, since they had considerable mechanical properties as native BPs, supplied porous channels for cell ingrowth, and possessed bioactive factors delivery capability.

Xenotransplantation literature update, January/February 2020

“…Basic fibroblast growth factor impacts many cells involved in regeneration and specifically recruits and maintains stem cell qualities of mesenchymal stem cells . The VFTT protocol did not alter the scaffold strength compared to unmodified pericardium, but slightly decreased the water content . After subcutaneous implantation into rats, the adjoining pores in VFTT scaffolds allowed better mesenchymal stem cell ingrowth compared to staying on the surface on unaltered pericardium.…”

“…However, decellularization with chemicals such as collagenase and acetic acid can alter the structure of the scaffold and strip away essential growth factors . Liu et al aimed to avoid this by using the VFTT protocol using Triton X‐100 and sodium deoxycholate detergent solution, creating porous bovine pericardial scaffolds, which were then recellularized with mesenchymal stem cells and supplemented with basic fibroblast growth factor. Basic fibroblast growth factor impacts many cells involved in regeneration and specifically recruits and maintains stem cell qualities of mesenchymal stem cells .…”

Decellularized pericardial extracellular matrix: The preferred porous scaffold for regenerative medicine

“…Different fabrication methods have been used simultaneously with sterilization and freeze‐drying steps to obtain porous scaffolds. In a recent issue of Xenotransplantation , Liu et al fabricated porous bovine pericardial scaffolds using a decellularization method that combines a detergent solution (1% Triton X‐100 and 0.5% sodium deoxycolate) and vacuum freeze‐thawing cycles. This protocol successfully creates porous scaffolds with interconnected pore channels and well‐preserved mechanical properties.…”

“…In the referred report, Liu et al evaluated the capability of porous bovine pericardial scaffolds to load and release basic fibroblast growth factor (bFGF), a potent mitogen that regulates the migration, differentiation, and growth of different cell types and plays an important role in tissue repair and regeneration. They showed that bFGF is easily absorbed, penetrates the porous scaffolds and was effectively released in vitro in a concentration‐dependent manner . Furthermore, when these scaffolds were subcutaneously implanted in the rat model, they promoted MSC recruitment and inhibited myofibroblast differentiation, indicating that the released bFGF preserved its bioactivity in vivo …”

“…They showed that bFGF is easily absorbed, penetrates the porous scaffolds and was effectively released in vitro in a concentration‐dependent manner . Furthermore, when these scaffolds were subcutaneously implanted in the rat model, they promoted MSC recruitment and inhibited myofibroblast differentiation, indicating that the released bFGF preserved its bioactivity in vivo …”