Synthesis, characterization, and antimicrobial activity of nano-hydroxyapatite-zinc for bone tissue engineering applications.

The bone implants used in tissue repair are susceptible to infections caused by staphylococci, specifically Staphylococcus aureus. Hence, the development of better biological materials that provide antimicrobial activity in bone tissue engineering is required. The nanoparticles of hydroxyapatite (nHAp) and nHAp dopped with Zn (nHAp-Zn) were prepared by the wet chemical method and the ion exchange method, respectively. They were characterized using SEM, AFM, FTIR and XRD. The antibacterial activity of nHAp and nHAp-Zn was determined with Gram-negative and Gram-positive bacterial strains. The results indicated that nHAp alone was acting as an inert matrix and when substituted with Zn, it showed better antibacterial activity. The nHAp-Zn was found to be non-toxic to osteoprogenitor cells. Thus, due to the antimicrobial property of nHAp-Zn nanoparticles, we suggest that they would have potential applications towards bone tissue engineering.

Metal doped calcium silicate biomaterial for skin tissue regeneration in vitro.

This study spots light on combined Wound healing process conjoining blood coagulation, inflammation reduction, proliferation and remodeling of the cells. The objective is to overcome the drawbacks of conventional clinically applied wound dressings such as poor rigidity, porosity, mechanical potency and bactericidal activity. As nosocomial infection is a very common condition at the wound site, bio-adhesive materials with intrinsic antibacterial properties are used in clinical applications. Considering the provenability of Wollastonite [Calcium silicate (CaSiO3)] to regenerate the soft tissues by inducing vascularization and regeneration of fibroblast cells And the antibacterial potentiality of zinc in clinical applications, the present study focuses on synthesis of Zn-Ws particles and evaluation of its antimicrobial and wound healing potentialities towards skin tissue engineering applications. The compositional characterization by EDAS and FT-IR spectral analysis have substantiated the presence of major elements and corresponding band stretching associated with the synthesized particles whereas the particles morphology by SEM images have shown the size of the Ws and Zn-Ws to be 370 nm and 530 nm respectively. From the in vitro studies, skin regenerative potential of Zn-Ws was determined on promoting fibroblast cell (NIH3T3) proliferation by providing better adhesiveness, biocompatibility and cytocompatibility. The antibacterial property of Zn-Ws evaluation by minimum inhibitory concentration (MIC) and zone of inhibition (ZOI) methods against clinical isolates of Gram +Ve and Gram -Ve bacterial strains have confirmed that the addition of Zn has diminished the bacterial growth and also helped in degrading the bacterial biofilms. Thus it is summed up that the process of wound healing is expected to occur with reduced risk of post-injury infections by the presence of zinc-doping on wollastonite for skin tissue application.

Preparation and characterization of chitosan/pectin/ZnO porous films for wound healing.

Three-dimensional (3D) porous films based on chitosan/pectin/ZnO nanoparticles (NPs) were prepared for wound healing by the freeze-drying method. The chemical nature, composition and morphology of these films were revealed by FTIR, XRD, EDX, SEM and BET analysis. SEM micrographs showed a decrease in the pore size and porosity of chitosan/pectin/ZnO films when increasing the content of ZnO NPs. The developed films presented the swelling degree and water retention ability in the range of 189-465 and 230-390%, respectively. Moreover, they showed an improved compression strength and controlled degradation in the lysozyme-containing medium in comparison with control. MTT assay demonstrated the biocompatibility of chitosan/pectin/ZnO films against the primary human dermal fibroblast cells (HFCs). Among the developed chitosan/pectin/ZnO films, CPZnO-2 films presented the increased rate of cell proliferation and migration. Also, they exhibited antimicrobial activity against the gram-positive and gram-negative bacteria and fungi. These results suggested that chitosan/pectin/ZnO films could be safe, convenient and effective for wound healing.

Regulation of Runx2 by post-translational modifications in osteoblast differentiation.

Osteogenesis is the process of new bone formation where transcription factors play an important role in controlling cell proliferation and differentiation. Runt-related transcription factor 2 (Runx2), a key transcription factor, regulates the differentiation of mesenchymal stem cells into osteoblasts, which further mature into osteocytes. Runx2 acts as a modulator such that it can either stimulate or inhibit the osteoblast differentiation. A defect/alteration in the expression/activity of this gene may lead to skeletal dysplasia. Runx2 thus serves as the best therapeutic model gene for studying bone and bone-related diseases. In this review, we briefly outline the regulation of Runx2 and its activity at the post-translational levels by the virtue of phosphorylation, acetylation, and ubiquitination in controlling the bone homeostasis.

5-Azacytidine incorporated polycaprolactone-gelatin nanoscaffold as a potential material for cardiomyocyte differentiation.

India has an alarming rate of growth of cardiovascular diseases (CVD). Similar to cancer there is a significant role for epigenetic factors in the increasing prevalence of CVD. Targeting the epigenetic mechanism, viz., the DNA methylation processes, histone modifications, and RNA based arrangements is today considered as a potential therapeutic approach to CVD management. 5-Azacytidine is an epigenetic treatment drug that is involved in the demethylation of DNA. 5-Azacytidine is an FDA approved drug for myelodysplastic syndrome. However, the usage of 5-Azacytidine for CVD has not been found acceptable because of its poor stability in neutral solutions and shorter half-live which makes it toxic to the cells. A significant breakthrough in the use of 5-azacytidine for cell therapy and tissue engineering for CVD treatment has been gained based on its ability to differentiate mesenchymal stem cells into cardiomyocytes. This work addresses the further need for a sustained release of this drug, to reduce its toxicity to the stem cells. Electrospun PCL-gelatin fibres that are well aligned to provide a mat-like structure with sufficient porosity for differentiated cells to move forward have been synthesized. The crystalline character, porosity, fibre width, thermal behavior hydrophilicity of these scaffolds are in tune with those reported in the literature as ideal for cell proliferation and adhesion. FTIR measurements confirm the entrapment of 5-azacytidine on to the scaffold. The adsorption of the drug did not alter the characteristic features of the scaffold. Primary results on cell viability and cell morphology, as well as cardiomyocyte differentiation, have shown that PCL-gelatin scaffolds carrying 5-azacytidine developed in this work could serve as an ideal platform for mesenchymal stem cell differentiation into cardiomyocytes.

Polymer coated mesoporous ceramic for drug delivery in bone tissue engineering.

Treatment strategy for various bone fracture and defects the researchers are focusing to develop a new carrier for delivering the drug into injured area with controlled and sustained manner using biomaterials with dynamic architecture orientation. Ceramic materials are resembled with bone compositional architecture and better bioactivity, degradability as well as antimicrobial activity made its enormous application in bone tissue engineering (BTE). Current focus in regenerative medicine were orchestration of biomaterials with the capacity of loading the drugs, growth factors, ionic components to promote better healing of bone tissue. Mesoporous type materials owed a great look towards the delivery of drugs, growth factors, etc in BTE because of its unique geometry. So the guest molecules loaded with geometrically organized ceramics would deliver onto the site of injury in controlled manner also the guiding and regulation of delivery of molecules have been controlled with the polymers response to different stimulation or biochemical factors as either scaffold or encapsulated particles for bone regeneration. Hence the review aims to describing the recent progress in bone tissue engineering using the ceramic based mesoporous materials encapsulated with polymers respond to different physiochemical stimulation for the efficient and controlled delivery of drug/growth factors for better bone healing.

Preparation and characterization of three-dimensional scaffolds based on hydroxypropyl chitosan-graft-graphene oxide.

Hydroxypropyl chitosan (HPCH), a water soluble derivative of chitosan, is widely considered for tissue engineering and wound healing applications due to its biocompatibility and biodegradability. Graphene oxide (GO) is a carbon-based nanomaterial which is capable of imparting desired properties to the scaffolds. Hence, the integration of GO into HPCH could allow for the production of HPCH-based scaffolds with improved swelling character, mechanical strength, and stability aimed at being used in tissue engineering. In this study, hydroxypropyl chitosan-graft-graphene oxide (HPCH-g-GO) with varying GO content (0.5, 1, 3 and 4wt.%) was prepared using HPCH and GO as a tissue engineering scaffold material. The formation of HPCH-g-GO was confirmed by FTIR and XRD analysis. Using the HPCH-g-GO as a matrix material and glutaraldehyde as a crosslinking agent, the three dimensional (3D) porous scaffolds were fabricated by the freeze-drying method. The HPCH-g-GO scaffolds exhibited uniform porosity as observed in SEM analysis. The pore size and porosity reduced as the content of GO was increased. These scaffolds presented good swelling capacity, water retention ability, mechanical strength and in vitro degradation properties. The HPCH-g-GO scaffolds irrespective of their GO content demonstrated good cell viability when compared to control. Altogether, these results suggest that HPCH-g-GO scaffolds can be used as potential tissue engineering material.

Formulation and biological actions of nano-bioglass ceramic particles doped with Calcarea phosphorica for bone tissue engineering.

The improvisation of the treatment procedures for treating the various kind of bone defects such as, bone or dental trauma and for diseases such as osteoporosis, osteomyelitis etc., need the suitable and promising biomaterials with resemblance of bone components. Bioactive glass ceramic (BGC) has recently acquired great attention as the most promising biomaterials; hence it has been widely applied as a filler material for bone tissue regeneration. Because it elicts specific biological responses after implantation in addition more potential in formation of strong interface with both hard and soft tissues by dissolution of calcium and phosphate ions. Hence, the current focus in treating the bone defects by orchestrating the biomaterial in combination of alternative medicine such as homeopathic remedies with biomaterials to prevent the adverse effects at minimal concentrations. So the current study was focused on constructing the nano-bioglass ceramic particles (nBGC) doped with novel homeopathic remedy Calcarea phosphorica for dental and bone therapeutic implants. The nBGC particles were synthesized by sol-gel method and reinforced with commercially available Calcarea phosphorica. The synthesized particles were characterized by SEM, DLS, EDS, FT-IR, and XRD studies. The SEM and DLS were shown the size of the particles at nano scale, also the EDS, and FT-IR investigations indicated that the Calcarea phosphorica was integrated with nBGC particles and also the crystalline nature of particles was confirmed by XRD studies. Both nBGC and Calcarea phosphorica doped nBGC (CP-nBGC) were found to be non toxic to mouse mesenchymal stem cells at lower concentrations and also illustrated the better bone forming ability in vitro.

Antibacterial activity of agricultural waste derived wollastonite doped with copper for bone tissue engineering.

Bioactive ceramic materials with metal ions generation brought great attention in the class of biomaterials development and widely employed as a filler material for bone tissue regeneration. The present study aimed to fabricate calcium silicate based ceramic material doped with copper metal particles by sol-gel method. Rice straw of agricultural waste was utilized as a source material to synthesize wollastonite, then wollastonite was doped with copper to fabricate copper doped wollastonite (Cu-Ws) particles. The synthesized materials were subjected to physio-chemical characterization by TEM, DLS, FTIR, XRD and DSC analysis. It was found that the sizes of the WS particles was around 900nm, while adding copper the size was increased upto 1184nm and the addition of copper to the material sharpening the peak. The release of Cu ions was estimated by ICP analysis. The anti-bacterial potentiality of the particles suggested that better microbial growth inhibition against E. coli (Gram negative) and S. aureus (Gram positive) strains from ATCC, in which the growth inhibition was more significant against S. aureus. The biocompatibility in mouse Mesenchymal Stem cells (mMSC) showed the non-toxic effect up to 0.05mg/ml concentration while the increase in concentration was found to be toxic to the cells. So the particles may have better potential application with the challenging prevention of post implantation infection in the field of bone tissue engineering (BTE).

Effects of silica and calcium levels in nanobioglass ceramic particles on osteoblast proliferation.

At nanoscale, bioglass ceramic (nBGC) particles containing calcium oxide (lime), silica and phosphorus pentoxide promote osteoblast proliferation. However, the role of varied amounts of calcium and silica present in nBGC particles on osteoblast proliferation is not yet completely known. Hence, the current work was aimed at synthesizing two different nBGC particles with varied amounts of calcium oxide and silica, nBGC-1: SiO2:CaO:P2O5; mol%~70:25:5 and nBGC-2: SiO2:CaO:P2O5; mol%~64:31:5, and investigating their role on osteoblast proliferation. The synthesized nBGC particles were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) studies. They exhibited their size at nanoscale and were non-toxic to human osteoblastic cells (MG-63). The nBGC-2 particles were found to have more effect on stimulation of osteoblast proliferation and promoted entering of more cells into G2/M cell cycle phase compared to nBGC-1 particles. There was a differential expression of cyclin proteins in MG-63 cells by nBGC-1 and nBGC-2 treatments, and the expression of cyclin B1 and E proteins was found to be more by nBGC-2 treatment. Thus, these results provide us a new insight in understanding the design of various nBGC particles by altering their ionic constituents with desirable biological properties thereby supporting bone augmentation.

Synthesis and characterization of diopside particles and their suitability along with chitosan matrix for bone tissue engineering in vitro and in vivo.

The scaffolds for bone tissue engineering should be porous to harbor the growth of new tissue ingrowths, biodegradable with no toxic end products, and biocompatible with no cytotoxicity. In this study we report that Diopside (CaMgSi2O6) (Dp) particles can be synthesized at a more economical route using the agricultural waste rice straw. Along with chitosan (CS) matrix, the CS/Dp scaffolds were synthesized and evaluated for their physico-chemical properties by SEM, EDS, XRD, FT-IR studies. Addition of Dp particles to chitosan matrix decreased water retention capacity but there was no change in their degradation properties. Dp particles in CS/Dp scaffolds exhibited good affinity for protein adsorption. Apatite forming ability of the CS/Dp scaffolds depicted their bioactivity. These scaffolds were found to be compatible with human osteoblastic cells (MG-63) and the cells were able to attach and proliferate with extended morphology on the CS/Dp membranes. The CS/Dp scaffolds supported up regulation of mRNA expression of osteoblast differentiation marker genes such alkaline phosphatase (ALP), type I collagen (COL-I) in the presence of osteogenic environment suggesting their osteo-conductive nature. In vivo rat model system identified that the CS/Dp scaffolds are biocompatible and may have the property of recruiting cells due to deposition of collagen. Hence, these studies suggest that the prepared CS/Dp scaffolds have potential applications towards bone tissue engineering.

Chitosan scaffolds containing chicken feather keratin nanoparticles for bone tissue engineering.

Chicken feathers are considered as major waste from poultry industry. They are mostly constituted by a protein called keratin. In this study, keratin was prepared from chicken feathers and from where keratin nanoparticles (nKer) were synthesized. Since chitosan has excellent properties like controlled biodegradation and biocompatibility, we used keratin nanoparticles along with chitosan matrix as scaffolds (CS/nKer) and they were characterized by SEM, FT-IR and XRD analyses. There was a porous architecture in the scaffolds in the range to support cell infiltration and tissue ingrowth. The keratin nanoparticles had interaction with chitosan matrix and did not alter the semi crystalline nature of chitosan scaffolds. The biodegradation and protein adsorption of the scaffolds were significantly increased upon addition of keratin nanoparticles. The scaffolds were also found to be non-cytotoxic to human osteoblastic cells. Thus, CS/nKer scaffolds could serve as a potential biomimetic substrate for bone tissue engineering applications.

Expression of microRNA-30c and its target genes in human osteoblastic cells by nano-bioglass ceramic-treatment.

Osteoblast differentiation is tightly regulated by post transcriptional regulators such as microRNAs (miRNAs). Several bioactive materials including nano-bioglass ceramic particles (nBGC) influence differentiation of the osteoblasts, but the molecular mechanisms of nBGC-stimulation of osteoblast differentiation via miRNAs are not yet determined. In this study, we identified that nBGC-treatment stimulated miR-30c expression in human osteoblastic cells (MG63). The bioinformatics tools identified its regulatory network, molecular function, biological processes and its target genes involved in negative regulation of osteoblast differentiation. TGIF2 and HDAC4 were found to be its putative target genes and their expression was down regulated by nBGC-treatment in MG63 cells. Thus, this study advances our understanding of nBGC action on bone cells and supports utilization of nBGC in bone tissue engineering.

Biocomposite scaffolds containing chitosan/alginate/nano-silica for bone tissue engineering.

Bone tissue engineering is a promising alternative method for treating bone loss by a combination of biomaterials and cells. In this study, we fabricated biocomposite scaffolds by blending chitosan (CS), alginate (Alg) and nano-silica (nSiO2), followed by freeze drying. The prepared scaffolds (CS/Alg, CS/Alg/nSiO2) were characterized by SEM, FT-IR and XRD analyses. In vitro studies such as swelling, biodegradation, biomineralization, protein adsorption and cytotoxicity were also carried out. The scaffolds possessed a well-defined porous architecture with pore sizes varying from 20 to 100 µm suitable for cell infiltration. The presence of nSiO2 in the scaffolds facilitated increased protein adsorption and controlled swelling ability. The scaffolds were biodegradable and the addition of nSiO2 improved apatite deposition on these scaffolds. There was no significant cytotoxicity effect of these CS/Alg/nSiO2 scaffolds towards osteolineage cells. Thus, these results indicate that CS/Alg/nSiO2 scaffolds may have potential applications for bone tissue engineering.

Enhanced osteoblast adhesion on polymeric nano-scaffolds for bone tissue engineering.

Bone tissue engineering is an interdisciplinary field which is emerged for the development of viable substitutes that restore and maintain the function of human bone tissues. The success of bone tissue engineering depends on designing of the scaffolds. The polymer-based composite scaffolds containing micro- and nano-structures could provide a platform influencing osteoblastic cell adhesion, spreading, proliferation, and differentiation. Osteoblasts may adhere strongly to the nano-structures than micro-structures in the scaffolds due to the large surface area, better osteo-integrative property and mechanical reliability etc. In this review we are focusing the factors such as pore size, surface topography and roughness, protein adsorption and wettability of nano-structures and their interaction with cell surface integrins molecules. A better understanding of the interactions of nano-structures with osteoblastic cells will have potential applications in the regeneration of bone.

Chitosan and its derivatives for gene delivery.

Gene delivery can particularly be used for the treatment of diseases by the insertion of genetic materials (DNA and RNA) into mammalian cells either to express new proteins or to prevent the expression of existing proteins. Chitosan, a natural polymer is nontoxic, biocompatible, and biodegradable and it is used as a support material for gene delivery. However, practical use of chitosan has been mainly limited to its unmodified forms, and thus modified chitosans can be used for the wide range of biomedical applications including the interaction and intracellular delivery of genetic materials. In this context, this review paper provides the recent development on chitosan derivatives available for gene delivery.

Synthesis and characterization of nanoscale-hydroxyapatite-copper for antimicrobial activity towards bone tissue engineering applications.

The bacterial infection is one of the major problems associated with implant and reconstructive surgery of bone. Hence, the aim of this study was to develop biomaterials having antibacterial activity for bone tissue engineering. The hydroxyapatite nanoparticles (nHAp) improve the mechanical properties and incorporate nanotopographic features that mimic the nanostructure of natural bone. We report here for the first time the synthesis and characterization of nHAp and nHAp soaked with copper (nHAp-Cu) using SEM, AFM, FTIR and XRD. The antibacterial activity of nHAp and nHAp-Cu was determined using Gram-positive and Gram-negative bacterial strains. To have accelerated antibacterial activity, polyethylene glycol 400 (PEG 400), a synthetic biodegradable polymer was also added along with nHAp-Cu. The nHAp-Cu/PEG 400 had increased antibacterial activity towards Gram-positive than Gram-negative bacterial strains. The cytotoxicity of nHAp-Cu/PEG 400 was determined using MTT assay with rat primary osteoprogenitor cells and these biomaterials were found to be non-toxic. Hence, based on these results we suggest that the biomaterials containing nHAp-Cu/PEG 400 can be used as antibacterial materials in bone implant and bone regenerative medicine.