Histological Evaluation of Bone Repair with Hydroxyapatite: A Systematic Review.

The aim of this study was to evaluate the morphological bone response in animal experiments by applying hydroxyapatite grafts in critical and non-critical size bone defects. Current report followed the guidelines established by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Animal experiments were selected by assessing repair of bone defects with hydroxyapatite as bone graft and with blood clot only as control. Eight articles were identified in specialized literature and included in the meta-analysis. Statistical analysis was carried out with a random-effect model (p = 0.05). Subgroup analyses were further performed to investigate bone repair in critical and non-critical bone defects. Comprehensive analysis of bone repair outcome showed a statistically significant difference between hydroxyapatite and blood clot control (p < 0.05). Subgroup analyses showed statistically significant difference for critical bone defects (p < 0.05). No statistically significant difference was reported in non-critical bone defects (p > 0.05). Although animal studies revealed a high risk of bias and results should be interpreted with caution, the literature suggests that non-critical bone defects may heal spontaneously and without the need of a bone graft. Conversely, when critical-size defects are present, the use of hydroxyapatite bone graft improves the bone repair process.

Highly transparent sustainable biogel electrolyte based on cellulose acetate for application in electrochemical devices.

In this study, an easy and low-cost production method for a cellulose acetate-based gel polymer containing lithium perchlorate and propylene carbonate is described, as well as the investigation of its properties for potential use as an electrolyte in electrochemical devices. Cellulose acetate, a biopolymer derived from natural matrix, is colourless and transparent, as confirmed by the UV-Vis spectroscopy, with 85 % transparency in visible spectrum. The gels were prepared and tested at different concentrations and proportions to optimise their properties. Thermogravimetry, XRD, and FTIR analyses revealed crucial characteristics, including a substantial 90 % mass loss between 150 and 250 °C, a semi-crystalline nature with complete salt dissociation within the polymer matrix, and a decrease in intensity at 1780 cm-1 with increasing Li+ ion concentration, suggesting an improvement in ionic conduction capacity. In terms of electrochemical performance, the gel containing 10 % by mass of cellulose acetate and 1.4 M of LiClO4 emerged as the most promising. It exhibited a conductivity of 2.3 × 10-4 S.cm-1 at 25 °C and 3.0 × 10-4 S.cm-1 at 80 °C. Additionally, it demonstrated an ideal shape of cyclic voltammetry curves and stability after 400 cycles, establishing its suitability as an electrolyte in electrochemical devices.

Fabrication of electrospun poly(lactic acid) nanoporous membrane loaded with niobium pentoxide nanoparticles as a potential scaffold for biomaterial applications.

Tissue engineering aims to regenerate and restore damaged human organs and tissues using scaffolds that can mimic the native tissues. The requirement for modern and efficient biomaterials that are capable of accelerating the healing process has been considerably increased. In this work, a novel electrospun poly(lactic acid) (PLA) nanoporous membrane incorporated with niobium pentoxide nanoparticles (Nb2 O5 ) for biomaterial applications was developed. Nb2 O5 nanoparticles were obtained by microwave-assisted hydrothermal synthesis, and different concentrations (0, 1, 3, and 5% wt/wt) were tested. Chemical, morphological, mechanical, and biological properties of membranes were evaluated. Cell viability results demonstrated that the membranes presented nontoxic effects. The incorporation of Nb2 O5 improved cell proliferation without impairing the wettability, porosity, and mechanical properties of membranes. Membranes containing Nb2 O5 nanoparticles presented biocompatible properties with suitable porosity, which facilitated cell attachment and proliferation while allowing diffusion of oxygen and nutrients. This study has demonstrated that Nb2 O5 nanoparticle-loaded electrospun PLA nanoporous membranes are potential candidates for drug delivery and wound dressing applications.