Polycaprolactone nanofiber interspersed collagen type-I scaffold for bone regeneration: a unique injectable osteogenic scaffold

Abstract

There is an increasing demand for an injectable cell coupled three-dimensional (3D) scaffold to be used as bone fracture augmentation material. To address this demand, a novel injectable osteogenic scaffold called PN-COL was developed using cells, a natural polymer (collagen type-I), and a synthetic polymer (polycaprolactone (PCL)). The injectable nanofibrous PN-COL is created by interspersing PCL nanofibers within pre-osteoblast cell embedded collagen type-I. This simple yet novel and powerful approach provides a great benefit as an injectable bone scaffold over other non-living bone fracture stabilization polymers, such as polymethylmethacrylate and calcium content resin-based materials. The advantages of injectability and the biomimicry of collagen was coupled with the structural support of PCL nanofibers, to create cell encapsulated injectable 3D bone scaffolds with intricate porous internal architecture and high osteoconductivity. The effects of PCL nanofiber inclusion within the cell encapsulated collagen matrix has been evaluated for scaffold size retention and osteocompatibility, as well as for MC3T3-E1 cells osteogenic activity. The structural analysis of novel bioactive material proved that the material is chemically stable enough in an aqueous solution for an extended period of time without using crosslinking reagents, but it is also viscous enough to be injected through a syringe needle. Data from long-term in vitro proliferation and differentiation data suggests that novel PN-COL scaffolds promote the osteoblast proliferation, phenotype expression, and formation of mineralized matrix. This study demonstrates for the first time the feasibility of creating a structurally competent, injectable, cell embedded bone tissue scaffold. Furthermore, the results demonstrate the advantages of mimicking the hierarchical architecture of native bone with nano- and micro-size formation through introducing PCL nanofibers within macron-size collagen fibers and in promoting osteoblast phenotype progression for bone regeneration.

Bone regenerative medicine: classic options, novel strategies, and future directions

“…At structural analysis, this novel bioactive material was chemically stable enough in an aqueous solution for extended periods without using crosslinking reagents, but it is also viscous enough to be injected through a syringe needle. Data from long-term in vitro proliferation and differentiation suggests that PN-COL scaffolds promote osteoblast proliferation, phenotype expression, and formation of mineralized matrix [96]. A novel dicalcium phosphate anhydrate/poly(lactic acid) (DCPA/PLA) composite nanofiber, which mimics the mineralized collagen fibrils via biomimetic in situ synthesis and electrospinning for hard tissue regenerative medicine, has been produced.…”

Modified poly(caprolactone trifumarate) with embedded gelatin microparticles as a functional scaffold for bone tissue engineering

“…The numbers of live and dead cells were then counted based on each grid square for the whole image. The live and dead cell counts were summed and the viability percentage was calculated as the ratio of live cells to total cells …”

Biomaterials for Craniofacial Bone Regeneration

“…Recent advances in scaffolds for bone regeneration involve the use of hybrid natural and synthetic biomaterials in order to take advantage of the benefits of each. Inclusion of PCL or PCL-PEG-PCL copolymer nanofibers in collagen [82, 83] or chitosan [84] serves to combine the biomimicry and stimulatory effects of natural polymers with the structural and mechanical stability of synthetic polymers, thus offering viable scaffold options with superior osteogenic potential.…”