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Functional regeneration of bone defects, especially critical-sized, in the craniofacial region remains a major clinical challenge that needs intervention. To address this, the present work focuses on the development of an injectable chitin–PLGA hydrogel (CG) containing bioglass nanoparticles (nBG) or whitlockite nanoparticles (nWH) with FGF-18, and compares the osteogenic and neo-bone formation potential against commercially available hydroxyapatite nanoparticles (nHAP) with FGF-18 fortified CG hydrogel in the critical-sized defect region. The developed CG was injectable and the incorporation of bio-ceramics didn't affect the injectability. Sustained release of FGF-18 was achieved in bio-ceramic containing CG hydrogel systems, while CG hydrogel alone displayed rapid release. In addition, the nBG or nWH containing CG hydrogel groups showed in vitroangiogenic potential. Furthermore, ALP activity, BMP-2 quantification and osteogenic gene expression assays were conducted to ascertain the osteogenic differentiation potential of the hydrogels. In the combination groups, CGnWHF (nWH + FGF-18 containing CG) showed highest osteogenic potential with a synergistic effect, compared to all other groups studied. In vivobone regeneration studies displayed near-complete bone regeneration for CGnWHF, where its BV/TV% was the highest (synergistic effect) compared to CGnBGF (nBG + FGF-18 in CG) and nHAP with FGF-18 (additive effect) after 8 weeks of implantation. Thus, the use of CGnWHF in irregular craniofacial bone defects could be an attractive option.

A braided multiscale fibrous scaffold consisting of aligned PCL micro/collagen-bFGFnano fibers was fabricated (mPCL-nCol-bFGF) to mimic native tendon tissue architecture which was further coated with alginate to aid in prevention of peritendinous adhesion. The bFGF release kinetics showed a sustained release of growth factors for a period of 20 days. Further, in vitrocell viability, attachment, and proliferation were performed using rabbit tenocytes under static and dynamic conditions. mPCL-nCol-bFGF showed a higher cell proliferation and enhanced expression of tenogenic markers compared to mPCL-nCol (braided scaffold without bFGF). When subjected to dynamic stimulation in a bioreactor, mPCL-nCol-bFGF-DS (braided scaffold with bFGF after dynamic stimulation) showed enhanced cellular proliferation and tenogenic marker expression, compared to mPCL-nCol-bFGF. The in vivostudies of the cell seeded scaffold after dynamic stimulation in Achilles tendon defect model showed tendon tissue regeneration with aligned collagen morphology within 12 weeks of implantation.

Background: Therapeutic angiogenesis is a clinical intervention for controlled stimulation and augmentation of neovascularisation in ischemic tissues. Conventional therapeutic techniques involve proangiogenic factor based induction of host tissue angiogenesis. In this review, we provide a holistic idea about therapeutic angiogenesis while specifically highlighting the role of proangiogenic factors as growth factors, peptides, small molecules and polysaccharides in tissue neovascularisation. Methods: A detailed search of peer-reviewed literature was carried out with prime focus on therapeutic angiogenesis and proangiogenic factors. The content of each literature reviewed in this paper was qualitatively analysed for particulars and relevance to the subject of study. This work has been distributed under four broad titles, namely, proangiogenic growth factors, peptides, small molecules and polysaccharides. Also, recent developments pertaining to proangiogenic factors for therapeutic angiogenesis have been detailed. Results: A total of 244 literatures have been reviewed from the bibliographic database to present a conceptual understanding about the importance of proangiogenic factors in revascularisation of ischemic tissues. Conclusion: This review focuses on importance of various proangiogenic factors, with reference to therapeutic angiogenesis. Thorough analysis of clinical data reveals the dearth of a defined system for proangiogenic growth factor delivery. Designing of a biomaterial based paradigm for growth factor therapy, might help in enhancing clinical translation of therapeutic angiogenesis.

Poly(caprolactone) (PCL) has been frequently considered for bone tissue engineering because of its excellent biocompatibility. A drawback, however, of PCL is its inadequate mechanical strength for bone tissue engineering and its inadequate bioactivity to promote bone tissue regeneration from mesenchymal stem cells. To correct this deficiency, this work investigates the addition of nanoparticles of silica (nSiO2) to the scaffold to take advantage of the known bioactivity of silica as an osteogenic material and also to improve the mechanical properties through nanoscale reinforcement of the PCL fibers. The nanocomposite scaffolds and the pristine PCL scaffolds were evaluated physicochemically, mechanically, and biologically in the presence of human mesenchymal stem cells (hMSCs). The results indicated that, when the nanoparticles of size approximately 10 nm (concentrations of 0.5% and 1% w/v) were embedded within, or attached to, the PCL nanofibers, there was a substantial increase in scaffold strength, protein adsorption, and osteogenic differentiation of hMSCs. These nSiO2nanoparticles, when directly added to the cells evidently pointed to ingestion of these particles by the cells followed by cell death. The polymer nanofibers appeared to protect the cells by preventing ingestion of the silica nanoparticles, while at the same time adequately exposing them on fiber surfaces for their desired bioactivity.

Chitin is a polysaccharide found in the outer skeleton of insects, crabs, shrimps, and lobsters and in the internal structures of other invertebrates. Sulfated chitin was prepared by reacting carboxymethyl chitin (CM‐chitin) with 2‐aminoethane sulfonic acid by using 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) catalyst. The prepared sulfated chitin was characterized by FTIR, elemental analysis, thermogravimetric analysis (TGA) and X‐ray diffraction (XRD). The degree of substitution was found to be 0.98 by elemental analysis. The TGA studies showed that sulfated chitin was less thermal stability than carboxymethyl chitin. This is due to the grafting reaction. The sulfated chitin membranes were prepared from sulfated chitin and then crosslink with glutaradehyde. The biodegradation process was performed in PBS (pH 7.4) containing lysozyme (10 µg/ml) at 37 °C in an incubator. Experimental results from weight loss throughout the study showed that the biospecific degradation occur on the membrane by lysozyme.

Chitin, a natural abundant polysaccharide, have been investigated as prospected biochemical material due to its several biological advantages. It is insoluble in the most of the organic solvents due to its rigid crystalline structure. However, chitin regenerated hydrogel (RG) has been prepared by using the saturated calcium solvent system under mild conditions. And also, swelling hydrogel (SG) was prepared by using water. In this study, we prepared the suspension of chitinous hydrogel, and applied to fabricated the chitinous compound/gelatin composite sheets. Additionally, N‐acetyl D‐(+)‐glucosamine was added into some composite sheets. We investigated the mechanical properties and growth of NIH/3T3 fibroblast cell for the prepared composite sheet.

N-Carboxymethyl chitosan (NCMC) is a water soluble derivative of chitosan. The NCMC beads were prepared by using ionotropic gelation process with the counter polyanion tripolyphoshate at pH 4.0 and characterized by scanning electron microscopy. The swelling behavior of the beads at different time intervals was monitored at different pH conditions. The in vitro drug release behavior in various pH solutions was studied using indomethacin as a model drug with two different concentrations (0.3 and 0.6% w/w). The release percent of indomethacin from NCMC beads was found to increase with increasing of pH in phosphate buffer solution medium due to the ionization of carboxymethyl group and high solubility of indomethacin in alkaline medium. These results indicated that the NCMC beads are useful for controlled drug delivery systems through oral administration by avoiding the drug release in the highly acidic gastric fluid region of the stomach.

Phosphorylated chitosan (P-chitosan) was synthesized by means of graft copolymerization technique. The conjugate membranes were prepared from oxidised starch and Pchitosan using reductive alkylation crosslinking. The synthesized membranes were characterised by FT-IR. In order to characterize degradation behaviour of this conjugated system, the membranes were incubated in enzyme solutions of alpha-amylase and lysozyme as well as a physiological saline solution (PBS) used as control solution. In PBS, low starch containing membranes (0.16-0.38 weight (starch)/weight (P-chitosan), (ws/wc)) and control membranes have not showed significant change in their weight during two months of incubation. High starch containing membranes (0.73-1.04 ws/wc) indicated less than 20 % weight loss after this period. After α-amylase incubation, a distinct degradation behaviour was observed from starch-P-chitosan membranes. The degradation of the conjugate membranes was found to be fast with increasing starch content. Weight losses between 20 to 55 % were detected for the lowest (0.16 ws/wc) starch and highest (1.04 ws/wc) starch containing membranes, respectively. In the lysozyme degradation study, the conjugate membranes were not degraded by enzymatic activity and the weights of membranes were seen to be increased about 20 % because of swelling. The control membranes showed gradual weight loss in enzyme solutions. These results indicated the lysozyme degradation of starch-free P-chitosan membranes and inhibition of degradation P-chitosan by highly conjugated starch molecules.

Zinc-containing poly(urethane-ether)s (PUEs) were synthesized by the reaction of hexamethylene diisocyanate (HMDI) or toluylene 2,4-diisocyanate (TDI) with a mixture of zinc salt of mono(hydroxyethoxyethyl)phthalate [Zn(HEEP)2] and poly(ethylene glycol) (PEG300or PEG400) by using di-n-butyltin dilaurate as a catalyst. Blank PUEs without [Zn(HEEP)2] were also prepared by reaction of PEG300or PEG400with HMDI or TDI. Thus prepared PUEs were characterized by FT-IR, 1H and 13C NMR, solid-state 13C-CP-MAS NMR, viscosity, solubility, and X-Ray diffraction studies. Thermal properties of the polymers were studied by using thermogravimetric analysis and differential scanning calorimetry.