No abstract

We report development of poly(vinyl alcohol) (PVA)‐based novel injectable hydrogel nanocomposite scaffolds. Nanocellulose (NC), synthesized from agricultural biomass, was used as reinforcement within PVA matrix. The hydrogels were formed using physical crosslinking process involving multiple freeze–thaw cycles. A range of bio‐nanocomposite hydrogels were prepared with varying concentrations of NC. With increasing loading of NC, crystallinity was found to be increased, which could be attributed to nucleating effect and crystalline nature of nanofibrillar cellulose. Investigation of microstructural surface topology indicated reduced surface perturbations upon incorporation of NC. Fourier transform infrared spectroscopy studies further indicated presence of characteristic functional groups and possible interactions between PVA and NC. Enhanced structural integrity and dynamic stability of the bio‐nanocomposite hydrogels were also confirmed by carrying out rheological investigations at different frequency, amplitude, temperature, and time sweeps. Further, the bio‐nanocomposite hydrogels demonstrated excellent injectability and self‐standing behavior, establishing the promising potential as injectable scaffolds. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48789.

There has been significant interest in the recent past to develop injectable hydrogel scaffolds that follow minimally invasive implantation procedures towards efficient healing and regeneration of defective bone tissues. Such scaffolds offer several advantages, as they can be injected into the irregularly shaped defect and can act as a low‐density aqueous reservoir, incorporating necessary components for bone tissue repair and augmentation. Considering that bone is a biocomposite of natural biopolymer and bioapatite nanofiller, there has been a growing trend to develop nanocomposite scaffolds by combining biopolymers and inorganic nanofillers to biomimic the hierarchical nanostructure and composition of natural bone. Furthermore, the nanocomposite scaffolds can be tailored to have patient‐specific bone properties, which can lead to better biological responses. The present article begins with the introduction, followed by an overview of polymer matrices, property requirements, and crosslinking techniques employed for injectable hydrogels. Various strategies to develop injectable composites, with emphasis on nanocomposite hydrogels incorporating bioinert and bioactive nanofillers have been discussed. The fundamental challenges related to the development of injectable hydrogel nanocomposite scaffolds and the research efforts directed towards solving these problems have also been reviewed. Finally, future trends and conclusions on new generation injectable hydrogel nanocomposite bone scaffolds have been discussed in this article.