Repairing a bone defect with a three-dimensional cellular construct composed of a multi-layered cell sheet on electrospun mesh

Abstract

In addition to providing maneuverability, electrospun nanofibrous meshes can make excellent supports for constructing flexible cell sheets to regulate cell behavior by nanofiber features. With the target of bone regeneration, herein composite nanofibers with two different fiber arrangements (nestlike, random) were electrospun from a blend solution containing poly(l-lactide) (PLLA) and gelatin (1:1 in weight ratio). Unlike the non-woven morphology in a random nanofibrous mesh, PLLA/gelatin composite nanofibers in the nestlike nanofibrous mesh displayed both non-woven and parallel morphologies. Both kinds of nanofibrous mesh were ∼50 μm thick as-prepared, and shrank to ∼30 μm after seeding with bone mesenchymal stromal cells (BMSCs). After 7 days of in vitro culture, cell sheets could form on both meshes (CSM) and on the culture plate. It was found that application of nanofibrous mesh promoted the osteogenic differentiation of BMSC sheets compared with the control. The nestlike mesh displayed slight superiority over the random mesh in enhancing osteogenic differentiation, but their different fiber arrangements did not cause much difference in cell proliferation. Three-dimensional multi-layered CSM constructs were built by stacking four mono-layered CSMs together. The CSM constructs (based on a nestlike or random nanofibrous mesh) were incubated in vitro for 3 days before being implanted into rat cranial defects. In comparison with the control group, there was significant formation of new calcified bone in both CSM construct-filled groups at 12 weeks' post-operation. The nestlike group showed slightly better bone healing (based on both qualitative and quantitative analysis) than the random group, while showing insignificant differences. We showed that the concept of using a three-dimensional multi-layered CSM construct in enhancing bone regeneration was feasible. Future studies should take more nanofiber features (e.g. bioactive components) into account to further enhance osteogenesis.

3D bioactive composite scaffolds for bone tissue engineering

“…In a different approach, Ren et al. recently electrospun a blend of PLLA and gelatin to create a nanofibrous mesh designed to aid bone defect repair [314] . The composite mesh was seeded with MSCs, with osteogenic differentiation occurring after 7 days of in vitro culture.…”

Natural and Synthetic Polymers for Bone Scaffolds Optimization

“…Considering the excellent in vitro results, the trial of this polymer reached the in vivo phase. For instance, Ren and colleagues showed that the nano-fibrous meshes increase the new calcified bone formation into rat cranial defects [135]. Other researchers, instead, tested PLA in combination with PCL.…”

“…Facilitate pore interconnectivity good porosity, cell infiltration, cell differentiation, angiogenesis and osteogenesis [69][70][71][72][73][74] Appropriate scaffold porosity, swelling, and drug release [75,76] Increased osteogenic potential [83] Increased compressive strenght of bone cement; increased prolifertion and osteogenic differantiation [87,88] [82] [128][129][130][131][132] Increased cellular attachment, angiogenesys, and osteogenesis [130,131] [ 126,127] PLA Good cell adhesion proliferation, and osteo-differentiation [134,136] Rapid and complete drug release, good cell viability, proliferation, and osteogenic differentiation [136] [ 133,135] PLGA Good porosity, osteogenic potential, and mineralization activity, higher cellular adhesion/proliferatio, and new bone formation [137][138][139][140][141][142]144,145][143] 1 Higher initial adhesion, increased proliferation, new bone formation, and suitable scaffold integration; controlled drug release. [144,147,148] Good cell viability, proliferation, and osteogenic differentiation [145] [146]…”

Tissue engineering of retina and Bruch’s membrane: a review of cells, materials and processes

“…Cell sheet engineering has become popular in retinal TE research recently 18. The principle is based on the cells secreting its own extracellular matrix (ECM) on reaching confluency, and it can be harvested without the use of any enzymatic methods 19.…”