Journal Articles

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    Potential of Chitosan and its derivatives for controlled drug release applications – A review
    (Editions de Sante editions.de.sante@wanadoo.fr, 2019) Safdar, R.; Omar, A.A.; Arunagiri, A.; Iyyaswami, R.; Murugesan, M.
    Recent research on the drug delivery systems exhibited tremendous improvements for several short life drugs which disappear in few minutes in harsh conditions of the Gastrointestinal tract (GIT). After years of investigations, the current drug delivery system has been improved with new advanced materials with less toxicity and better therapeutic efficiency. In this regard, new formulations consisting of drugs encapsulated with natural biodegradable copolymer, Chitosan, in the form of nanoparticles have been studied, which in turn improved the release profile of drugs. In this review, the Chitosan and its physiochemical properties, nanoparticles and their drug release mechanism and effects of modification of various drugs (anti–cancer, anti–inflammatory, anti–diabetes, anti–infectious drugs etc) with Chitosan and co–materials on their release profiles are briefly reviewed. These biodegradable polymeric nanoparticles improved the in vitro release profile of drugs and provided a way forward for further improvement of the current and conventional drug delivery systems. © 2018 Elsevier B.V.
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    LiClO4-doped plasticized chitosan as biodegradable polymer gel electrolyte for supercapacitors
    (2009) Muthu, M.S.; Bhat, D.K.
    Studies on redox supercapacitors using electronically conducting polymers are of great importance for hybrid power sources and pulse power applications. In this study, electrochemical properties of a chitosan-based biodegradable polymer gel electrolyte (PGE) and a p/p polypyrrole supercapacitor fabricated using this electrolyte have been investigated. The variation of conductivity and dielectric properties of the electrolyte film with temperature has also been measured. The PGE film chosen for the study exhibited a specific conductivity of 5.5 × 10-3 S cm~. The electric modulus of the electrolyte film exhibits a long tail feature indicative of good capacitance. The fabricated supercapacitor showed a fairly good specific capacitance of 120 F g-1 and a time constant of 1 s. © 2009 Wiley Periodicals, Inc.
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    Electrical and magnetic properties of chitosan-magnetite nanocomposites
    (2010) Bhatt, A.S.; Bhat, D.K.; Santosh, M.S.
    Magnetite powders in nanometer size have been synthesized by the hydrothermal process. Various magnetic films of chitosan and the synthesized magnetite nanopowders containing different concentrations of the latter were prepared by ultrasonication route. The X-ray diffraction (XRD) studies and the transmission electron microscopy (TEM) images showed that the synthesized magnetite particles had 80 nm dimensions. The band gap of the composites was evaluated using the UV-visible Spectroscopy. The influence of magnetite content on the magnetic properties of the composite showed a decrease in the saturation magnetization with the decrease in the magnetic content. The effect of magnetite content on the dielectric properties of the polymer film at different frequencies from 0.01 to 105 Hz was studied using an electrochemical impedance spectroscopy. The possible mechanism for the observed electrical properties of the composite films was discussed. © 2010 Elsevier B.V. All rights reserved.
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    Electrochemical properties of chitosan-Co3O4 nanocomposite films
    (Elsevier B.V., 2011) Bhatt, A.S.; Bhat, D.K.; Santosh, M.S.
    Chitosan-Co3O4 composite films have been prepared by solution casting method. The obtained films have been characterised by XRD and FESEM. The electrical properties of the films are examined by impedance spectroscopy in the temperature range 303-343 K. The impedance plot of the films pronounces the role of temperature in charge-transfer resistance of the composite. Frequency as well as temperature dependencies of dielectric constant and dielectric loss exhibit the general trend followed by carrier dominated dielectrics. Electric modulus parameters give an insight on the ionic conductivity and relaxation phenomena of the composite films. The dielectric parameters along with modulus data have been exploited to discuss the conduction mechanism in the material. The minimum activation energy of 3.9 kJ mol -1 and maximum room temperature conductivity of 1.94 × 10 -2 S cm-1 were found for composite film with 8% Co 3O4 content. © 2011 Elsevier B.V. All rights reserved.
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    New polypropylene supported chitosan NF-membrane for desalination application
    (2011) Padaki, M.; Isloor, A.M.; Fernandes, J.; Prabhu, K.N.
    In the present study, a new NF membrane was prepared by coating chitosan on polypropylene fiber support, by the dissolution of chitosan in 2% acetic acid solution. The resulting membrane was characterized by thermo gravimetric analysis, water absorption, contact angle measurement and scanning electron microscopy. Prepared membrane showed two Tg peaks, one at ~90 °C that was due to chitosan and the other peak at ~170 °C that was corresponding to the supporting polypropylene membrane. The membrane showed a low swelling ratio at pH 7, 9, and 11 as compared with pH 5. The performance of the membrane was assessed out using dead end cell. Water flux was studied at different pressures. The salt rejection study was done using NaCl solution and the effect of pH on performance of the membrane was also examined. Newly prepared membrane showed improved water flux, and % of rejection is highest in acidic pH and lowest in basic pH. Hydrulic permeability coefficient and the dielectric constant confirms that the prepared membrane is nanofiltration membrane. © 2011 Elsevier B.V.
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    Miscibility studies of chitosan and starch blends in buffer solution
    (2012) Sudhakar, Y.N.; Holla, S.R.; Muthu, M.; Bhat, D.K.
    The miscibility of chitosan (CS) and starch in buffer solution (CH 3COOH and CH 3COONa) has been investigated by viscosity, density and refractive index methods at 303K, 313K, and 323K. Various interaction parameters such as polymer-polymer and blend-solvent interaction parameters and heat of mixing have been calculated using viscosity and density data. The results indicated the existence of positive interactions in the blend polymer solutions and that they are miscible below 40% of starch compositions. The study also revealed that variation of temperature does have significant effect on the miscibility of chitosan and starch blends. © 2012 Copyright Taylor and Francis Group, LLC.
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    Preparation and characterization of sulfonated polysulfone and N-phthloyl chitosan blend composite cation-exchange membrane for desalination
    (2012) Padaki, M.; Isloor, A.M.; Wanichapichart, P.; A.F., A.F.
    Sulfonated polysulfone (sPSf) was prepared and used as a polymer matrix for cation-exchange membranes (CEM). The sulfonation reaction was carried out at room temperature and the degree of sulfonation was calculated by titration method. Blend composite membranes were prepared using different ratios of sPSf and modified chitosan (CS). Membrane properties were studied in terms of water flux, water swelling ratio, molecular weight cut off (MWCO), ion-exchange capacity (IEC) and contact angle measurement. Charge on the membrane was confirmed by ionic diffusion potential (DP). It was observed that, DP increased with the increase in the concentration of sPSf. The membrane sPSf:CS 60:40 showed 1000Da MWCO, 14.6mV diffusion potential (DP) and 0.083mM/g of IEC. Similarly sPSf:CS 90:10 showed 10,000Da MWCO, 71.7mV diffusion potential (DP) and 0.176mM/g of IEC. Moreover, membrane sPSf:CS 60:40 showed 93%, 89% and 69% for MgSO 4, Na 2SO 4 and NaCl rejection respectively. © 2012 Elsevier B.V.
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    LiClO4-doped plasticized chitosan and poly(ethylene glycol) blend as biodegradable polymer electrolyte for supercapacitors
    (Institute for Ionics, 2013) Sudhakar, Y.N.; Muthu, M.; Bhat, D.K.
    Biodegradable polymer electrolyte comprising the blend of chitosan (CS) and poly(ethylene glycol) (PEG) plasticized with ethylene carbonate and propylene carbonate, as host polymer, and lithium perchlorate (LiClO4), as a dopant, was prepared by solution casting technique. The ionic conductivity has been calculated using the bulk impedance obtained through impedance spectroscopy. The variation of conductivity and dielectric properties has been investigated as a function of polymer blend ratio, plasticizer content and LiClO4 concentration at temperature range of 298-343 K. The DSC thermograms show two broad peaks for CS/PEG blend and increased with increase in the LiClO4 content. The maximum conductivity has been found to be 1. 1 × 10-4 S cm-1 at room temperature for 70:30 (CS/PEG) concentration. The electric modulus of the electrolyte film exhibits a long tail feature indicative of good capacitance. The activation energy of all samples was calculated using the Arrhenius plot, and it has been found to be 0. 12 to 0. 38 eV. A carbon-carbon supercapacitor has been fabricated using this electrolyte, and its electrochemical characteristics and performance have been studied. The supercapacitor showed a fairly good specific capacitance of 47 F g-1. © 2012 Springer-Verlag.
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    Permeation, Antifouling and desalination performance of TiO2 nanotube incorporated PSf/CS blend membranes
    (2013) Kumar, R.; Isloor, A.M.; A.F., A.F.; Abdul Rashid, S.A.; Ahmed, A.A.
    Polysulfone (PSf) and chitosan (CS) blend membranes were prepared by incorporating titanium dioxide nanotubes (TiO2NT) in different compositions. The proper blending of PSf and CS in the PSf/CS/TiO2 membranes was confirmed by ATR-IR spectroscopy. The influence of nanotubes on morphology of membranes was investigated by Field Emission Scanning Electron Microscopy (FESEM). The effect of nanotubes on hydrophilicity of the membranes was studied by water swelling and contact angle measurements. The distribution of TiO2NT on the membrane surface was determined by Transmission Electron Microscope (TEM) analysis. The permeation property of PSf/CS/TiO2NT membranes was carried out by measuring the time dependent pure water flux (PWF). Bovine serum albumin (BSA) protein rejection studies were performed to know the antifouling properties. The rheological percolation threshold of PSf/CS/TiO2NT solutions was measured by viscosity studies. The nanotubes incorporated PSf/CS membranes showed enhanced permeation and antifouling properties compared to PSf/CS and nascent PSf ultrafiltration membranes. Membranes prepared well above rheological percolation threshold showed drastic reduction in pore size and acted as nanofiltration (NF) membranes. © 2013 Elsevier B.V.
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    Preparation and characterization of PPEES/chitosan composite nanofiltration membrane
    (2013) Shenvi, S.S.; Abdul Rashid, S.A.; A.F., A.F.; Kassim, M.A.; Isloor, A.M.
    Composite membrane having chitosan (CH) as the active layer supported on Poly(1,4-phenylene ether ether sulfone) (PPEES) membrane was synthesized in the current study. The chitosan layer was crosslinked by glutaraldehyde in two different concentrations. The scanning electron microscopic images and hydraulic permeability coefficient revealed the ultrafiltration (UF) nature of the neat PPEES membrane. This was used as a new support material for the casting of chitosan layer in order to get composite membranes. The composite nature of the PPEES/CH membranes was confirmed by FESEM and DSC analysis. The Infrared spectroscopy results confirmed the crosslinking of the chitosan surface by glutaraldehyde (GA). The changes in the hydrophobic nature of the PPEES membrane surface due to deposition of chitosan active layer followed by crosslinking were studied by their contact angle measurement and water flux study. From our studies, PPEES has proved to be a good support membrane for preparation of composite membranes. Increase in GA concentration increased the salt rejection of the membrane up to 34% for NaCl and 53% for MgSO4 on one hand with a simultaneous decrease in the flux values. The hydraulic permeability coefficient values confirmed that the prepared membranes are in nanofiltration range. © 2012 Elsevier B.V.