Bone regeneration of multichannel biphasic calcium phosphate granules supplemented with hyaluronic acid.

The present work is to investigate the efficiency of hyaluronic acid (HyA) supplemented biphasic calcium phosphate (BCP) injectable granule to promote the bone regeneration. The effect of adding HyA to the multichannel BCP granule (MCG-HyA) was studied in terms of morphology, chemical structure, porosity, in-vitro and in-vivo biocompatibility, RT-PCR, western blot and compared with MCG. The addition of HyA to MCG successfully made the granules injectable type. In-vivo studies in rabbit model showed an enhancement in bone formation after 4 weeks of implantation and better handling characteristics for MCG-HyA than MCG. RT-PCR and Western Blotting studies revealed that MCG-HyA significantly unregulated the osteogenic gene and protein expressions respectively. Our results indicated that MCG-HyA could be used as a promising injectable bone substitute in clinical applications.

Enhancement of hemostatic property of plant derived oxidized nanocellulose-silk fibroin based scaffolds by thrombin loading.

To combat post-surgical and traumatic bleeding conditions effective hemostasis is of great importance. The study was designed to investigate the effect of thrombin (Th) loading on hemostatic performance of TEMPO-oxidized cellulose nanofiber (TOCN)-silk fibroin (SF) scaffolds. Addition of SF with TOCN significantly (***P < 0.001) increased blood absorption capacity and improved biocompatibility of TOCN. Thrombin loading potentiated platelet activation and hemostatic property of scaffolds (TOCN-SF-Th) compared to samples without thrombin (TOCN-SF). The hemostatic time of TOCN-SF5-Th in rabbit ear artery bleeding model was reduced (*** P < 0.001) to 114 s from 220 s of TOCN-SF5. Reduction in bleeding time and blood loss of TOCN-SF5-Th in rat tail amputation and liver avulsion model was comparable to commercial hemostat (Floseal). Surface morphology (SEM) of samples applied on bleeding site showed that RBCs and fibrin fiber could strongly interact with TOCN-SF and TOCN-SF-Th scaffolds. The result suggests that TOCN-SF-Th can be a promising candidate for designing hemostatic agents.

Investigation of efficiency of a novel, zinc oxide loaded TEMPO-oxidized cellulose nanofiber based hemostat for topical bleeding.

Lethal bleeding due to street accidents, natural calamities, orthopedic/dental surgeries, organ transplantation and household injuries, is the leading cause of morbidity and mortality. In the current study, zinc oxide (ZnO) was incorporated in TEMPO-oxidized cellulose nanofiber (TOCN) and polyethylene glycol (PEG) polymer system for hemorrhage control by freeze drying method. SEM and XRD data showed the presence of ZnO in the porous structure. FT-IR analysis showed that, successful conjugation occurs among the TOCN and PEG. The results revealed that, the incorporation of ZnO and higher concentrations of PEG increased the degradability but decreased swelling of the scaffolds. The increase in PEG content and ZnO incorporation significantly decreased the bleeding time in rabbit ear arterial bleeding model. Further, the incorporation of ZnO enhanced the antibacterial property of TOCN-PEG. The results suggested that excellent hemostatic and mechanical properties of the TOCN-5% PEG-ZnO might contribute in controlling bleeding and reducing post traumatic dermal bacterial infection.

Bone regeneration strategy by different sized multichanneled biphasic calcium phosphate granules: In vivo evaluation in rabbit model.

A variety of synthetic materials are currently in use as bone substitutes, among them a new calcium phosphate-based multichannel, cylindrical, granular bone substitute that is showing satisfactory biocompatibility and osteoconductivity in clinical applications. These cylindrical granules differ in their mechanical and morphological characteristics such as size, diameter, surface area, pore size, and porosity. The aim of this study is to investigate whether the sizes of these synthetic granules and the resultant inter-granular spaces formed by their filling critical-sized bone defects affect new bone formation characteristics and to determine the best formulations from these individual types by combining the granules in different proportions to optimize the bone tissue regeneration. We evaluated two types of multichanneled cylindrical granules, 1 mm and 3 mm in diameter, combined the granules in two different proportions (wt%), and compared their different mechanical, morphological, and in vitro and in vivo biocompatibility characteristics. We assessed in vitro biocompatibility and cytotoxicity using MC3T3-E1 osteoblast-like cells using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and confocal imaging. In vivo investigation in a rabbit model indicated that all four samples formed significantly better bone than the control after four weeks and eight weeks of implantation. Micro-computed tomography analysis showed more bone formation by the 1 mm cylindrical granules with 160 ± 10 µm channeled pore and 50% porosity than the other three samples ( p<.05), which we confirmed by histological analysis.

Effects of platelet-rich plasma on biological activity and bone regeneration of brushite-based calcium phosphate cement.

In this study, we focused on identifying the effects of platelet-rich plasma (PRP) on bioactivity and bone ingrowths incorporated into brushite cement. We introduced PRP as a series of substitutions with an aqueous citrate-ion solution, and the optimized cement with PRP showed no disintegration of the paste consistency. Incorporating PRP showed that the setting time decreased with the increasing of PRP ratios, although the compressive strength was not significantly changed. We evaluated in vitro degradation and bioactivity with the simulated body fluid test, and the result showed that adding PRP accelerated the carbonated apatite nucleation and markedly improved the surface reactivity of the cement. The in vitro studies demonstrated that incorporating PRP into the brushite cement improved cell adhesion and proliferation. The in vivo effects of PRP were faster degradation, improved tissue response in the early stage, and bone ingrowths. We demonstrated based on our results of this study, incorporation of PRP into brushite cement could be helpful for improving biological activity of the cement as well as bone regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2316-2326, 2018.