A Review of Injectable Polymeric Hydrogel Systems for Application in Bone Tissue Engineering

Abstract

Biodegradable, stimuli-responsive polymers are essential platforms in the field of drug delivery and injectable biomaterials for application of bone tissue engineering. Various thermo-responsive hydrogels display water-based homogenous properties to encapsulate, manipulate and transfer its contents to the surrounding tissue, in the least invasive manner. The success of bioengineered injectable tissue modified delivery systems depends significantly on their chemical, physical and biological properties. Irrespective of shape and defect geometry, injectable therapy has an unparalleled advantage in which intricate therapy sites can be effortlessly targeted with minimally invasive procedures. Using material testing, it was found that properties of stimuli-responsive hydrogel systems enhance cellular responses and cell distribution at any site prior to the transitional phase leading to gelation. The substantially hydrated nature allows significant simulation of the extracellular matrix (ECM), due to its similar structural properties. Significant current research strategies have been identified and reported to date by various institutions, with particular attention to thermo-responsive hydrogel delivery systems, and their pertinent focus for bone tissue engineering. Research on future perspective studies which have been proposed for evaluation, have also been reported in this review, directing considerable attention to the modification of delivering natural and synthetic polymers, to improve their biocompatibility and mechanical properties.

Colloidally stable polypeptide‐based nanogel: Study of enzyme‐mediated nanogelation in inverse miniemulsion

“…This behavior was also observed for hydrogel systems based on poly(glutamic acid). 10,34 The inhibition of enzymatic nanogelation was supported by cryo-TEM measurements [ Figure 1(e,f)] documenting the presence of only a few particles. Therefore, D n , D w , and Ð were not evaluated from the cryo-TEM images.…”

“…The course of the measurement indicated the oxidative and gradual inactivation of HRP by excessive H 2 O 2 concentrations. This behavior was also observed for hydrogel systems based on poly(glutamic acid) . The inhibition of enzymatic nanogelation was supported by cryo‐TEM measurements [Figure (e,f)] documenting the presence of only a few particles.…”

Bioactive glass ions for in vitro osteogenesis and microvascularization in gellan gum‐collagen hydrogels

“…Indeed, according to reports, collagen type I (COL) and polysaccharide gellan gum (GG) are besides biocompatible and bioresorbable hydrophilic natural polymer hydrogels, also suited to bone and vascularization applications (Gantar et al, ; Koivisto et al, ; Manda et al, ; Marelli et al, ; Oliveira, Custodio, Gasperini, Reis, & Mano, ). Also, injectable hydrogel biomaterials facilitate minimally invasive procedures thus avoiding risks of adverse complications (Kondiah et al, ). Additionally, bioactive glasses (BaGs) have been shown besides fitting for medical bone implants (Jones, ), also to induce bone tissue vascular network formation (Bi et al, ).…”

Promising biocompatible hydrogels of crosslinked polyelectrolytes for biomedical applications

“…Hydrogels functionalised for drug delivery have a broad spectrum of application overarching drug eluting stent technology [1] and drug-coated balloons [2] for cardiovascular therapy but also injectable biomaterials [3] for ophthalmologic therapies [4], bone tissue engineering [5] and local cancer therapy [6].…”