Biocompatible carboxymethyl chitosan-modified glass ionomer cement with enhanced mechanical and anti-bacterial properties.

Due to the potential adverse effects of conventional dental cements, the demand for biocompatible cements have grown tremendously in the field of dentistry. In this respect, Glass ionomer cements (GICs) are being developed by different researchers. However, low mechanical strength of GIC make them unsuitable for application in high-stress areas. Thus, numerous initiatives to improve mechanical performance have been attempted till date including incorporation of reinforcing fillers. Novelty of the study lies in using carboxymethyl chitosan (CMC) to develop a biocompatible dental cement (DC/CMC-m-GP), which would have enhanced mechanical strength due to greater interaction of CMC with the particles of GIC and better cyto-compatibility due to its cell-proliferation activity. The mechanical strength, acid erosion and fluoride release of DC/CMC-m-GP were studied and compared with control dental cement (DC/Control). DC/CMC-m-GP shows compressive strength of 157.45 M Pa and flexural strength of 18.76 M Pa which was higher as compared to DC/Control. The morphology of the GICs were studied through FESEM. Anti-microbial activity of DC/CMC-m-GP was studied by Agar disc-diffusion method and biofilm assay against S. mutans, which shows that DC/CMC-m-GP inhibits bacterial adhesion on its surface. MTT assay infers that DC/CMC-m-GP was non-cytotoxic and did not affect the cell viability significantly.

Effect of cellulose nanocrystals on chitosan/PVA/nano ß-TCP composite scaffold for bone tissue engineering application.

The need for an ideal tissue construct has lead to the search of a myriad of polymer composites with desirable properties. The nature, location and type of tissue to be regenerated determines the type of material to be used. A bone construct has its own requirements such as osteoconductivity, mineralization tendency, synchronized degradation rate, osteogenic differentiation potential etc, which results in search of new possible combination of materials aimed to improve tissue response. The present study involves fabrication of Chitosan/Polyvinyl alcohol (PVA)/ß-Tricalcium Phosphate (ß-TCP)/Cellulose nanocrystals (CNC) porous composite by freeze drying process to be used as bone tissue engineering matrix. CNCs were isolated by acid hydrolysis of cellulose derived from pistachio shells. The prepared scaffold samples were characterized by Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-RAY Diffraction analysis (XRD). The scaffolds exhibited refinement in pore morphology and increased mineralization tendency on increasing CNC concentration. Samples with 1% and 5% CNC concentration have deposited apatite crystals with Ca/P ratio of 1.61 and 1.66 which is very close to the stoichiometric ratio of natural bone apatite. Compressive modulus of CS/PVA/ß-TCP/CNC composite increased on increasing the CNC concentration to 5%. The highest cell viability was recorded in scaffolds with 5% CNC content. Though cell attachment tendency was observed in all samples but the samples with 5 and 10% CNC content demonstrated higher cell densities with significant calcium depositions when cultured for 72 h. Samples with 5% CNC concentration also possessed highest cell differentiation capabilities.

Effect of carbon based fillers on xylan/chitosan/nano-HAp composite matrix for bone tissue engineering application.

The objective of our present work is to analyze the effect of carbon derived fillers (GO/RGO) on microstructural, mechanical and osteoinductive potential of xylan/chitosan/HAp composite matrix for bone tissue engineering application. The composites were characterized by FTIR, XRD and SEM to evaluate the composition and morphological parameters. Change in microstructural and mechanical properties of scaffold was observed on tuning filler type (GO/RGO) and concentration. Composites with GO and RGO content demonstrated significant mineralization potential with dense apatite growth. A comparative evaluation of cell viability using MG-63 cell line revealed improved cell response in samples incorporated with carbon fillers than their native parent matrix. MTT Assay revealed highest cell viability in composite with 0.75% RGO content. Cell attachment was observed in all the scaffold samples cultured for 72 h. The filler incorporated X/C/HAp matrix demonstrated increase in ALP activity over a period of 7 and 14 days. Synergistic effect of these fillers in enhancing in vitro mineralization tendency and osteogenic differentiation capability make the composites a potential candidate for bone tissue engineering construct.

Surface coating of chitosan of different degree of acetylation on non surface sized writing and printing grade paper.

Chitosan is a renewable biopolymer which can be applied on the surface of writing and printing (W&P) grade paper to enhance its different properties. A variety of chitosan is available based on degree of acetylation (DA), molecular weight, viscosity, etc. DA has a profound effect on the performance of chitosan in many applications. Present study compared the performance of different DA chitosan for surface application of W&P grade paper. Chitosan samples of 23 %, 16 % and 6% DA were studied for their impact on various physical and surface properties of W&P grade paper. Surface coating of chitosan was done at 1.6 ± 0.2 g/m2 (lower dose) and 2.3 ± 0.3 g/m2 (higher dose) on W&P grade paper. Some properties including air permeance, TEA, showed considerable effect of DA in which high DA chitosan outperformed the low DA. Broadly, chitosan with different DA had varied impact on individual properties of paper.

Redox-sensitive nanoparticles based on xylan-lipoic acid conjugate for tumor targeted drug delivery of niclosamide in cancer therapy.

In this study, novel redox-sensitive nanoparticles based on xylan-lipoic acid (Xyl-LA) conjugate were developed for tumor targeted delivery of niclosamide (Nic) in cancer therapy. The niclosamide loaded xylan-lipoic acid conjugate nanoparticles (Xyl-LA/Nic NPs) showed redox responsive behaviour in presence of reductive glutathione (GSH), which indicate their suitability for intracellular drug release. The obtained Xyl-LA/Nic NPs exhibited uniform particle size (196 ± 1.64 nm), high loading capacity (~28.6 wt %) and excellent blood compatibility. The anticancer activity of the Niclosamide and the Xyl-LA/Nic NPs against the colon carcinoma cell lines (HCT-15, Colo-320) were evaluated by MTT assay and the overall results indicate that the Xyl-LA/Nic NPs significantly enhanced the therapeutic efficiency of niclosamide in cancer therapy.

Nanoporous Sodium Carboxymethyl Cellulose-g-poly (Sodium Acrylate)/FeCl3 Hydrogel Beads: Synthesis and Characterization.

Novel sodium carboxymethyl cellulose-g-poly (sodium acrylate)/Ferric chloride (CMC-g-PNaA/FeCl3) nanoporous hydrogel beads were prepared based on the ionic cross-linking between CMC-g-PNaA and FeCl3. The structure of CMC and CMC-g-PNaA were elucidated by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, and the elemental composition was analyzed by energy dispersive X-ray analysis (EDX). The physicochemical properties of the CMC-g-PNaA/FeCl3 hydrogel beads were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). The swelling percentage of hydrogel beads was studied at different time periods. The obtained CMC-g-PNaA/FeCl3 hydrogel beads exhibited a higher nanoporous morphology than those of CMC-g-PNaA and CMC beads. Furthermore, an AFM image of the CMC-g-PNaA/FeCl3 beads shows granule type topology. Compared to the CMC-g-PNaA (189 °C), CMC-g-PNaA/FeCl3 hydrogel beads exhibited improvement in thermal stability (199 °C). Furthermore, CMC-g-PNaA/FeCl3 hydrogel beads depicted a higher swelling percentage capacity of around 1452%, as compared to CMC-g-PNaA (1096%). Moreover, this strategy with preliminary results could be useful for the development of polysaccharide-based hybrid hydrogel beads for various potential applications.

Harnessing pongamia shell hydrolysate for triacylglycerol agglomeration by novel oleaginous yeast Rhodotorula pacifica INDKK.

BACKGROUND: To meet the present transportation demands and solve food versus fuel issue, microbial lipid-derived biofuels are gaining attention worldwide. This study is focussed on high-throughput screening of oleaginous yeast by microwave-aided Nile red spectrofluorimetry and exploring pongamia shell hydrolysate (PSH) as a feedstock for lipid production using novel oleaginous yeast Rhodotorula pacifica INDKK. RESULTS: A new oleaginous yeast R. pacifica INDKK was identified and selected for microbial lipid production. R. pacifica INDKK produced maximum 12.8 ± 0.66 g/L of dry cell weight and 6.78 ± 0.4 g/L of lipid titre after 120 h of growth, showed high tolerance to pre-treatment-derived inhibitors such as 5-hydroxymethyl furfural (5-HMF), (2 g/L), furfural (0.5 g/L) and acetic acid (0.5 g/L), and ability to assimilate C3, C5 and C6 sugars. Interestingly, R. pacifica INDKK showed higher lipid accumulation when grown in alkali-treated saccharified PSH (AS-PSH) (0.058 ± 0.006 g/L/h) as compared to acid-treated detoxified PSH (AD-PSH) (0.037 ± 0.006 g/L/h) and YNB medium (0.055 ± 0.003 g/L/h). The major fatty acid constituents are oleic, palmitic, linoleic and linolenic acids with an estimated cetane number (CN) of about 56.7, indicating the good quality of fuel. CONCLUSION: These results suggested that PSH and R. pacifica INDKK could be considered as potential feedstock for sustainable biodiesel production.

Redox responsive xylan-SS-curcumin prodrug nanoparticles for dual drug delivery in cancer therapy.

Chemotherapeutic agents with different anticancer mechanisms could enhance therapeutic effect in cancer therapy by their combined application. In this study, redox-sensitive prodrug nanoparticles based on Xyl-SS-Cur conjugate were developed for co-delivery of curcumin and 5-FU in cancer therapy. The Xyl-SS-Cur conjugate was synthesized via covalent conjugation of curcumin to xylan through a disulphide (-S-S-) linkage. The Xyl-SS-Cur conjugate could self-assemble in aqueous medium into nanoparticles and the lipophilic 5-fluorouracil-stearic acid (5-FUSA) prodrug was encapsulated into the hydrophobic core of Xyl-SS-Cur NPs through dialysis membrane method. The obtained Xyl-SS-Cur/5-FUSA NPs had an appropriate size (∼217 ±â€¯2.52 nm), high drug loading of curcumin (∼ 31.4 wt%) and 5-FUSA (∼ 11.8 wt%) and high stability. The interaction of Xyl-SS-Cur/5-FUSA NPs with blood components was investigated by hemolysis study. The cytotoxicity study demonstrated that Xyl-SS-Cur/5-FUSA NPs induced higher cytotoxicity than free drugs against the Human colorectal cancer cells (HT-29, HCT-15). These results indicate that Xyl-SS-Cur/5-FUSA NPs can serve as a promising drug delivery system in cancer therapy.

Effect of incorporation of montmorillonite on Xylan/Chitosan conjugate scaffold.

The present study reports the fabrication of Xylan/Chitosan/Montmorillonite (MMT) composite scaffold by freeze drying process with the aim of achieving improved properties for bone tissue engineering applications. The scaffolds were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and mechanical testing. The fabricated scaffolds were found to be highly porous with variations in pore size (102 µm-290 µm) on varying the filler concentration. XRD study revealed complete exfoliation of MMT incorporated in polymer conjugates (Xylan/Chitosan) prepared by Maillard reaction. In-vitro bio-mineralization study revealed significant apatite deposition on polymer matrix. Scaffolds with 5% MMT concentration exhibited needle like morphology of deposited apatite which can further provide synergistic response in increasing the mechanical properties of scaffolds when placed in contact with body fluid. The average length and thickness of apatite needles were calculated to be 140 µm and 1.2 µm respectively. The deposited apatite crystals on scaffold with 2% MMT content demonstrated Ca/P ratio of 1.67, resembling that of natural bone apatite. Swelling and biodegradation behavior of scaffold were also studied with regard to hydrophilic and barrier effect of MMT on composites. MTT assay revealed non-cytotoxic nature of scaffold with good cell viability.

Lipophilic 5-fluorouracil prodrug encapsulated xylan-stearic acid conjugates nanoparticles for colon cancer therapy.

In this study, self-assembled nanoparticles based on amphiphilic xylan-stearic acid (Xyl-SA) conjugates have been developed for the efficient delivery of 5-fluorouracil (5-FU) in cancer therapy. The self-assembled behavior of Xyl-SA conjugates in aqueous medium was investigated using pyrene as fluorescent probe. To enhance the loading efficacy of 5-FU, the lipophilic 5-fluorouracil-stearic acid (5-FUSA) prodrug was synthesized and subsequently encapsulated into the hydrophobic core of Xyl-SA NPs. The obtained Xyl-SA/5-FUSA NPs had an appropriate size (~278 nm), high drug loading of 5-FUSA (~14.6 wt%) and high physiological stability. The interaction of the Xyl-SA/5-FUSA NPs with blood components was investigated by hemolysis study. The cell cytotoxic studies demonstrated that Xyl-SA/5-FUSA NPs induced higher cytotoxicity than free drugs against the Human colorectal cancer cells (HT-29, HCT-15). These results indicate that Xyl-SA/5-FUSA NPs can serve as a promising drug delivery system for the efficient delivery of 5-FU in cancer therapy.

Chitosan film incorporated with citric acid and glycerol as an active packaging material for extension of green chilli shelf life.

Chitosan films with cross linker and plasticizer were prepared using solvent casting method for food packaging application. Citric acid was used as the cross linker which enhances the stability of the films. Glycerol was used as plasticizer which imparts flexibility. Successful cross linking was confirmed by Fourier Transform-Infra Red (FT-IR) spectra and incorporation of glycerol was seen clearly in the Field Emission Scanning Electron Microscope (FE-SEM) images. The modified films show an improved water resistance and transparency. An improved moisture barrier was also observed with a 5.5% and 29% reduction in water vapor transmission and water vapor permeability, respectively. Modified films showed drastic 12 times increase in the elongation percentage value, hence enhanced flexibility. However, the tensile strength and Young's modulus decreased substantially by 82% and 98%, respectively. The films also showed better thermal and antioxidant properties as compared to neat chitosan films and were found to enhance green chilli shelf life.

pH-responsive prodrug nanoparticles based on xylan-curcumin conjugate for the efficient delivery of curcumin in cancer therapy.

In the present study, novel pH-responsive prodrug nanoparticles based on xylan-curcumin (xyl-cur) conjugate were developed to enhance the therapeutic efficacy of curcumin in cancer therapy. The synthesis of xyl-cur conjugate (prodrug) was confirmed by FT-IR, 1H NMR, UV-vis and fluorescence spectroscopy. The xyl-cur prodrug was subsequently self-assembled in to nanoparticles (xyl-cur prodrug NPs) in an aqueous medium with the average particle size 253 nm and the zeta potential of -18.76 mV. The xyl-cur prodrug NPs were highly pH-sensitive in nature and most of the drug was released at lower pH. The interaction of the xyl-cur prodrug NPs with blood components was tested by hemolysis study. The cytotoxic activity of the xyl-cur prodrug NPs against human colon cancer cells (HT-29, HCT-15) demonstrated that the prodrug NPs exhibits greater cytotoxic effect than curcumin. Therefore, these results reveal that xyl-cur prodrug NPs could be a promising candidate for improving the intracellular delivery of curcumin in cancer therapy.

Water absorption and viscosity behaviour of thermally stable novel graft copolymer of carboxymethyl cellulose and poly(sodium 1-hydroxy acrylate).

A novel thermally stable hydrolysed carboxymethyl cellulose-g-poly(sodium 1-hydroxy acrylate) i.e. CMC-g-PNaHA graft copolymer was synthesized from the CMC and vinyl monomer 5-methylene-2-isopropyl-1,3-dioxolan-4-one (MD) in an aqueous medium using an initiator followed by transformation of resulting CMC-g-PMD via alkaline hydrolysis. The graft copolymerization is confirmed by the Fourier transform infrared spectroscopy (FT-IR), Nuclear magnetic resonance spectroscopy (NMR) and X-ray diffractometer (XRD). The influence of the CMC and PNaHA content on the properties of the resulting hydrolysed CMC-g-PNaHA graft copolymer was investigated. In comparison with the PNaHA polymer, the resulted hydrolysed CMC-g-PNaHA grafted copolymer has improved thermal stability, water absorption properties, viscosity and weight-average molecular weight.

Studies on cellulose nanocrystals isolated from groundnut shells.

Today, various renewable biomass resources are accepted as waste material and are mostly burnt or used as cattle feed. The commercial value of these wastes can be increased by utilising them in production of nanomaterials. So, the present work was conducted for isolation of cellulose nanocrystals (CNCs) from groundnut shells which are produced annually as waste in large quantity (∼7 million tons). The structural, thermal, morphological & elemental analyses were assessed through corresponding techniques. Light Scattering studies were performed to analyse more likely weight average molecular weight (Mw) & radius of radius (Rg). The high Mw ∼105g/mol obtained for CNCs in lithium chloride (LiCl)/N,N-dimethylacetamide (DMAc) system, was an interesting feature which gets affected by LiCl and polymer concentrations. Solution with high polymer and low LiCl concentration was found to show higher values of Mw & Rg.

Synthesis and bio-evaluation of xylan-5-fluorouracil-1-acetic acid conjugates as prodrugs for colon cancer treatment.

In the present study, xylan-5-fluorouracil-1-acetic acid (Xyl-5-FUAC) conjugates as colon specific prodrugs were synthesized and evaluated by in-vitro release study. The chemical stability of the conjugates was performed in acidic (pH 1.2) and basic buffers (pH 7.4), which showed their stability in upper gastrointestinal tract. The in-vitro drug release profiles of the conjugates were studied in the presence of rat's gastrointestinal contents. The results showed that the low amounts of drug 3-4% and 5-7% were released in gastric and small intestine contents respectively, while 53-61% of the drug was released in cecum and colonic contents. The cytotoxicity studies of the conjugates were also evaluated on human colorectal cancer cell line (HTC-15 and HT-29), which showed that the conjugates are more cytotoxic than the free drug. Therefore the results reveal that Xyl-5-FUAC conjugates are potential candidates for colon specific drug delivery in the treatment of colonic cancer with minimal undesirable side effects.