Tapas Mitra

Potential use of curcumin loaded carboxymethylated guar gum grafted gelatin film for biomedical applications

Present study describes the synthesis of carboxylmethyl guar gum (CMGG) from the native guar gum (GG). Further, the prepared CMGG is grafted with gelatin to form CMGG-g-gelatin and then mixed with curcumin to prepare a biomaterial. The resultant biomaterial is subjected to the analysis of (1)H NMR, ATR-FTIR, TGA, SEM and XRD ensure the carboxymethylation and grafting. The results reveal that 45% of the amine groups of gelatin have been reacted with the--COOH group of CMGG and 90-95% of curcumin is released from CMGG-g-gelatin after 96h of incubation in the phosphate buffer at physiological pH. In vitro cell line studies reveal the biocompatibility of the biomaterial and the antimicrobial studies display the growth inhibition against gram +ve and gram -ve organisms at a considerable level. Overall, the study indicates that the incorporation of curcumin into CMGG-g-gelatin can improve the functional property of guar gum as well as gelatin.

Curcumin loaded nano graphene oxide reinforced fish scale collagen – a 3D scaffold biomaterial for wound healing applications

In recent years, graphene oxide (GO) has been functionalized to make GO a potential useful material in the biomedical field. GO is a one-atom thick planar sheet of sp2-bonded carbon atoms with functional groups containing oxygen attached to both the sides and surface area of the flake. Functionalized GO has attracted significant research interest based on its potential application in different fields including biomedicine. In the present work we prepare highly stabilized nano graphene oxide (NGO) in aqueous media. NGO is functionalized with type I collagen (2 : 1, NGO : collagen) to make a 3D scaffold as a novel platform for better tissue engineering research. The functionalization of NGO is achieved by a grafting process, an innovative method to modify the properties of NGO. The size of the prepared NGO is measured by dynamic light scattering, and the collagen functionalized NGO (CFNGO) is characterized by X-ray diffraction, attenuated total reflectance (ATR)-FTIR, ultraviolet visible (UV-vis), atomic force microscopy (AFM) and Raman spectroscopy. The surface property of the CFNGO is characterized by employing transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The mechanical stability of the CFNGO is three times greater than that of native collagen. An in vitro cell line study reveals no toxicity of CFNGO against NIH 3T3 fibroblast cell line. The antimicrobial study of curcumin loaded CFNGO shows Gram +ve and Gram −ve organism growth is reduced by a considerable amount, and in vivo wound healing studies showed faster wound healing efficiency of curcumin loaded CFNGO scaffold than that of collagen alone. These findings suggest that curcumin loaded CFNGO could serve as a better platform for wound healing applications.

Development of porous and antimicrobial CTS–PEG–HAP–ZnO nano-composites for bone tissue engineering

Herein, we have developed hybrid nanocomposites of chitosan, poly(ethylene glycol) and nano-hydroxyapatite–zinc oxide with interconnected macroporous structures for bone tissue engineering. These nanocomposites were characterized using different spectroscopic and analytical techniques. The percentage of porosity and the tensile strength of these materials were found to be similar to that of human cancellous bone. Moreover, these hybrid materials exhibited bio-degradability, a neutral pH (7.4) and erythrocyte compatibility. The addition of nano-hydroxyapatite–zinc oxide into the nanocomposites increased the antimicrobial activity and protein adsorption ability. The water uptake ability was found to increase with increasing the proportion of poly(ethylene glycol). Finally, osteoblast-like MG-63 cells were grown, attached and proliferated with these nanocomposites without them having any negative effect and the nanocomposites showed good cytocompatibility.

Characterization and evaluation of curcumin loaded guar gum/polyhydroxyalkanoates blend films for wound healing applications

The present paper explores the ‘in situ’ fabrication of guar gum/polyhydroxyalkanoates-curcumin blend (GPCC) films in view of their increasing applications as wound dressings and antibacterial materials. Curcumin is incorporated to assess its bactericidal activity and to enhance the production and accumulation of the extracellular matrix in the healing process. In order to characterize the nature of the polymer network in the blend, FTIR/ATR spectra analysis and TGA are performed. The results reveal that the rigidity of the guar gum/PHBV blend improves with the increase of PHBV content due to the formation of non-covalent interactions, especially H-bonds, between these molecules. Electron microscopy analyses reveal the homogenecity of the blends and surface roughness of the blended films, favoring cell attachment and cell proliferation compared with the film without curcumin. The anti-microbial study demonstrate that the bactericidal activity is more effective against Gram-positive strains than Gram-negative strains. Results of the in vivo wound healing study in an animal model demonstrates that the developed curcumin loaded guar gum/PHBV blend film shows markedly enhanced wound healing compared to the control one.

Chromium-assisted immobilization of N-isopropylacrylamide-based methacrylic acid copolymers on collagen and leather surfaces: thermo-responsive behaviour

In the present paper, we report the non-covalent immobilization of pH and temperature responsive poly(N-isopropylacrylamide)-co-methacrylic acid on a protein collagen (type I) and a leather surface. The polymer has N-isopropylacrylamide (NIPAM) functionality that is responsible for the thermo-responsive characteristics and carboxylic acid/carboxylate functionality that facilitates the pH-responsive behaviour. We were able to tune the clouding behaviour of the polymer in water from 15 to 40 °C by changing the pH from 4.5 to 5.7. The binding of the polymer to a native collagen protein (type I) or leather is facilitated by the carboxylate groups that form coordination complexes with chromium(III). The polymer was successfully used in the retanning and coating of leather. The polymer-coated leather as well as the polymer-grafted collagen clearly show thermo-responsive characteristics.

Development of bone-like zirconium oxide nanoceramic modified chitosan based porous nanocomposites for biomedical application.

Here, zirconium oxide nanoparticles (ZrO2 NPs) were incorporated for the first time in organic-inorganic hybrid composites containing chitosan, poly(ethylene glycol) and nano-hydroxypatite (CS-PEG-HA) to develop bone-like nanocomposites for bone tissue engineering application. These nanocomposites were characterized by FT-IR, XRD, TEM combined with SAED. SEM images and porosity measurements revealed highly porous structure having pore size of less than 1μm to 10μm. Enhanced water absorption capacity and mechanical strengths were obtained compared to previously reported CS-PEG-HA composite after addition of 0.1-0.3wt% of ZrO2 NPs into these nanocomposites. The mechanical strengths and porosities were similar to that of human spongy bone. Strong antimicrobial effects against gram-negative and gram-positive bacterial strains were also observed. Along with getting low alkalinity pH (7.4) values, similar to the pH of human plasma, hemocompatibility and cytocompatibility with osteoblastic MG-63 cells were also established for these nanocomposites. Addition of 15wt% HA-ZrO2 (having 0.3wt% ZrO2 NPs) into CS-PEG (55:30wt%) composite resulted in greatest mechanical strength, porosity, antimicrobial property and cytocompatibility along with suitable water absorption capacity and compatibility with human pH and blood. Thus, this nanocomposite could serve as a potential candidate to be used for bone tissue engineering.

Preparation of guar gum scaffold film grafted with ethylenediamine and fish scale collagen, cross-linked with ceftazidime for wound healing application.

Present study describes the synthesis of carboxymethyl guar gum (CMGG) from the native guar gum (GG) and the prepared CMGG is grafted with ethylenediamine (EDA) to form aminated CMGG. Then, fish scale collagen and aminated CMGG are cross-linked by ceftazidime drug through non- covalent ionic interaction. The resultant cross-linked film is subjected to the analysis of (1)HNMR, ATR-FTIR, TGA, SEM and XRD. The TNBS results revealed that 45% of interaction between EDA and CMGG and 90-95% of Ceftazidime is released from aminated CMGG-Ceftazidime-Collagen (ACCC) film after 96h of incubation at physiological pH. In vitro cell line studies reveal the biocompatibility of the cross-linked film and the antimicrobial studies display the growth inhibition against Staphylococcus aureus and Pseudomonas aeruginosa organisms. Overall, the study indicates that the incorporation of Ceftazidime into collagen and aminated CMGG can improve the functional property of aminated CMGG as well as collagen, leading to its biomedical applications.

Development of biomimetic nanocomposites as bone extracellular matrix for human osteoblastic cells.

Here, we have developed biomimetic nanocomposites containing chitosan, poly(vinyl alcohol) and nano-hydroxyapatite-zinc oxide as bone extracellular matrix for human osteoblastic cells and characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction. Scanning electron microscopy images revealed interconnected macroporous structures. Moreover, in this study, the problem related to fabricating a porous composite with good mechanical strength has been resolved by incorporating 5wt% of nano-hydroxyapatite-zinc oxide into chitosan-poly(vinyl alcohol) matrix; the present composite showed high tensile strength (20.25MPa) while maintaining appreciable porosity (65.25%). These values are similar to human cancellous bone. These nanocomposites also showed superior water uptake, antimicrobial and biodegradable properties than the previously reported results. Compatibility with human blood and pH was observed, indicating nontoxicity of these materials to the human body. Moreover, proliferation of osteoblastic MG-63 cells onto the nanocomposites was also observed without having any negative effect.

Organically modified clay supported chitosan/hydroxyapatite-zinc oxide nanocomposites with enhanced mechanical and biological properties for the application in bone tissue engineering

The objective of this study is to design biomimetic organically modified montmorillonite clay (OMMT) supported chitosan/hydroxyapatite-zinc oxide (CTS/HAP-ZnO) nanocomposites (ZnCMH I-III) with improved mechanical and biological properties compared to previously reported CTS/OMMT/HAP composite. Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to analyze the composition and surface morphology of the prepared nanocomposites. Strong antibacterial properties against both Gram-positive and Gram-negative bacterial strains were established for ZnCMH I-III. pH and blood compatibility study revealed that ZnCMH I-III should be nontoxic to the human body. Cytocompatibility of these nanocomposites with human osteoblastic MG-63 cells was also established. Experimental findings suggest that addition of 5wt% of OMMT into CTS/HAP-ZnO (ZnCMH I) gives the best mechanical strength and water absorption capacity. Addition of 0.1wt% of ZnO nanoparticles into CTS-OMMT-HAP significantly enhanced the tensile strengths of ZnCMH I-III compared to previously reported CTS-OMMT-HAP composite. In absence of OMMT, control sample (ZnCH) also showed reduced tensile strength, antibacterial effect and cytocompatibility with osteoblastic cell compared to ZnCMH I. Considering all of the above-mentioned studies, it can be proposed that ZnCMH I nanocomposite has a great potential to be applied in bone tissue engineering.

Fabrication of porous magnetic nanocomposites for bone tissue engineering

Here, the fabrication and characterization of porous magnetic nanocomposites was carried out via the blending of chitosan, polyethylene glycol and nano-hydroxyapatite–Fe3O4. Scanning electron microscope images revealed a highly interconnected macro- and micro-porous structure. These nanocomposites showed good water uptake abilities and have good antimicrobial properties. The tensile strengths of these nanocomposites were enhanced significantly compared to previously reported results, after the addition of nano-Fe3O4. Moreover, these nanocomposites could be applied for magnetic therapy as this material exhibited superparamagnetic properties. Finally, these nanocomposites were good supports for human osteoblast-like MG-63 cells’ growth, attachment and proliferation and they showed good cytocompatibility. No negative effect on the MG-63 cells was observed, suggesting that these nanocomposites have great potential to be applied for bone regeneration.