Investigation of potential injectable polymeric biomaterials for bone regeneration

Abstract

This article reviews the potential injectable polymeric biomaterial scaffolds currently being investigated for application in bone tissue regeneration. Two types of injectable biomaterial scaffolds are focused in this review, including injectable microspheres and injectable gels. The injectable microspheres section covers several polymeric materials, including poly(l-lactide-co-glycolide)-PLGA, poly (propylene fumarate), and chitosan. The injectable gel section covers alginate gels, hyaluronan hydrogels, poly(ethylene-glycol)-PEG hydrogels, and PEG-PLGA copolymer hydrogels. This review focuses on the effect of cellular behaviorin vitro andin vivo in terms of material properties of polymers, such as biodegradation, biocompatibility, porosity, microsphere size, and cross-linking nature. Injectable polymeric biomaterials offer a major advantage for orthopedic applications by allowing the ability to use noninvasive or minimally invasive treatment methods. Therefore, combining injectable polymeric biomaterial scaffolds with cells have a significant potential to treat orthopedic bone defects, including spine fusion, and craniofacial and periodontal defects.

Nanofibrous yet injectable polycaprolactone-collagen bone tissue scaffold with osteoprogenitor cells and controlled release of bone morphogenetic protein-2

“…Based on in vitro and in vivo studies, a low dose of BMP2 with a sustained release profile has been found optimal for osteogenesis [18][19][20]. Thus, there is a great need for a BMP2-encapsulated bone scaffold that is able to both retain the growth factor and preserve its bioactivity Materials Science and Engineering C 51 (2015) [16][17][18][19][20][21][22][23][24][25][26][27] for the duration necessary to attain conductive environment for osteogenesis.…”

“…HA nanoparticles encapsulated with BMP2 within the chitosan hydrogels [23] and PLGA/HA composite scaffolds [24] also enhanced the osteoinductivity of the respective materials. Despite promising results, the limitations noticed with such encapsulation techniques are initial burst release and decreased bioactivity of encapsulated proteins due to the organic solvents used in microsphere and nanoparticle fabrication [25,26]. Thus, growth factors subjected to harsh organic solvents during microsphere/scaffold synthesis were blended with bovine serum albumin (BSA) prior to encapsulation in order to provide a protective shell around the protein and subsequently preserving its bioactivity [17,27].…”

Effect of lactoferrin-impregnated porous poly(lactide-co-glycolide) (PLGA) microspheres on osteogenic differentiation of rabbit adipose-derived stem cells (rADSCs)

“…The main advantage of injectable scaffolds compared to 3D porous scaffolds for orthopedic procedures is that they can be administered using 10-16-gauge needles at the bone defect site [17]. In addition, injectable scaffolds loaded with osteoinductive agents or therapeutic drugs minimize patient discomfort, scarring, operation time, and risk of infections from bone regeneration as a clinical treatment [18].…”

Dentin regeneration by stem cells of apical papilla on injectable nanofibrous microspheres and stimulated by controlled BMP-2 release

“…Biodegradable polymer microspheres as tissue engineering scaffolds have received increasing attention for their potential to regenerate and repair irregularly-shaped tissue defects due to their injectability, controllable biodegradability, and capacity of drug incorporation and release, making possible a clinical protocol that features minimal invasion and short-term manipulation in comparison to traditional surgical procedures [4, 5]. Biodegradable microspheres can be advantageous in repairing small irregularly-shaped dentin defects and allows for easier treatment of traditionally hard-to-reach dental defects.…”