Nilkamal Pramanik

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.

Novel magnetic antimicrobial nanocomposites for bone tissue engineering applications

In the present study, we demonstrate the fabrication of novel bone-like magnetic nanocomposites by the blending of chitosan, polymethylmethacrylate-co-2-hydroxyethylmethacrylate, and nano-hydroxyapatite–Fe3O4. The hybrid nanomaterials were thoroughly characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction and field emission scanning electron microscopy. The magnetic nanocomposites exhibited excellent mechanical properties (e.g. tensile strength, Youngs modulus and stiffness) and antimicrobial activities. Hemolysis assays indicated that blood compatibility of the polymer sample is significant. Water uptake ability of the nanocomposite materials was found to increase with increasing the proportion of PMMA-co-PHEMA. In addition, the superparamagnetic nature of the nanocomposite was observed which makes these materials suitable for magnetic therapy.

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.

Fabrication of magnetite nanoparticle doped reduced graphene oxide grafted polyhydroxyalkanoate nanocomposites for tissue engineering application

In tissue engineering, magnetic nanoparticle based polymeric nanocomposites are attractive due to some superior properties that are demonstrated in monitoring the nature of cell proliferation, differentiation and the activation of cell construction in the tissue regeneration phase. Herein, we have developed a non-toxic, antimicrobial, biocompatible and biodegradable magnetic Fe3O4/RGO-g-PHBV composite based porous 3D scaffold. The facile and cost-effective green pathways were chosen to reduce the exfoliated graphite oxide using a new microbial strain, Lysinibacillus fusiformis at room temperature. The reduction of exfoliated graphite oxide and the fabrication of iron nanoparticle embedded Fe3O4/RGO-g-PHBV nanocomposite were confirmed by X-ray powder diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The analysis of the stretching vibrations by Raman spectroscopy indicated that both the graphite oxide and reduced graphene oxide exhibit frequencies at nearly 1560 cm−1 (G-band) and 1307 cm−1 (D-band). Field Emission Scanning Electron Microscopy (FESEM) and high-resolution transmission electron microscopic studies demonstrated the exfoliated nano sheets of the graphite oxide and the uniform distribution of the deposited ferrite nanoparticles. The inclusion of magnetite nanoparticles and reduced graphene oxide in the network of the PHBV matrix revealed the improvement of the mechanical strength of the nanocomposite, in comparison to the pure PHBV copolymer. The magnetic properties measured by vibrating sample magnetometer (VSM) and magnetic imaging resonance (MRI) confirmed the super-paramagnetic behavior of the nanocomposite, evidenced by the saturation magnetization having low coercive field and dark contrast images in the presence of applied magnetic fields. The confocal and scanning electron microscopy analyses demonstrated the excellent fibroblast cell infiltration, adhesion and proliferation into the micro-porous 3D scaffold, indicating the biocompatibility of the Fe3O4/RGO-g-PHBV nanocomposite based supporting biomaterials.

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.

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.

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.

Mechanical and biological investigations of chitosan–polyvinyl alcohol based ZrO2 doped porous hybrid composites for bone tissue engineering applications

ZrO2 nanoparticle (NP) doped CTS–PVA–HAP composites (ZrCPH I–III) were developed and characterized by FT-IR and XRD studies to mimic human bone for bone tissue engineering applications. Interconnected porous structures of these composites were observed via SEM and the porosities were in the range of human cancellous bone. These composites also have good swelling abilities both in aqueous and SBF media. The addition of ZrO2 NPs into the CTS–PVA–HAP composites improved the tensile strength of ZrCPH I–III compared with previously reported CTS–PVA–HAP composites, and the maximum tensile strength was obtained with ZrCPH III (CTS : PVA : HAP-ZrO2 = 55 : 30 : 15 wt%), which had the highest ZrO2 content (0.3 wt%). The strongest antimicrobial effect was also observed for ZrCPH III, which had the maximum amount of nano-HAP-ZrO2. Cytocompatibility with human osteoblastic MG-63 cells was also established and the highest cell proliferation was observed with ZrCPH III. Thus, ZrCPH III should have the potential to be applied as a bone tissue engineering material.

Spectroscopic characterization and microbial degradation of engineered bio-elastomers from linseed oil

Abstract The microbial degradation of elastomers synthesized through the cationic polymerization reaction of linseed oil, styrene, and divinylbenzene was investigated by using the Alkaliphilus oremlandii OhILAs strain. In Fourier transform infrared (FTIR) analysis, the bound oil content in the elastomers was found to vary from 29.63 to 45.5 wt%, whereas the percentage of unreacted oil in the elastomers were in the range of 12.9–38 wt%. In 1H nuclear magnetic resonance spectrum analysis, the unreacted oil and unreacted aromatic components in the elastomers were obtained in the ranges of 13.2–39 wt% and 6.8–16 wt%, respectively. The amount of unreacted oil in the elastomers enhanced the percentage of biodegradation, which varied from 26 to 51 wt%. The biodegradation of elastomers was also confirmed by FTIR and scanning electron micrograph analyses.