@article { ISI:000238928100018, title = {Preparation and characterization of novel hybrid of chitosan-g-lactic acid and montmorillonite}, journal = {Journal of Biomedical Materials Research Part A}, volume = {78A}, number = {2}, year = {2006}, month = {AUG}, pages = {372-382}, publisher = {WILEY-LISS}, type = {Article}, address = {DIV JOHN WILEY \& SONS INC, 111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

The utilization of biopolymers and the development of organic-inorganic hybrids are ever increasing interest of material science researchers around the globe for various applications. The present attempt is intended to prepare nanocomposites of lactic acid grafted chitosan and layered silicates. Nanocomposites were prepared by dissolving chitosan and dispersing sodium montmorillonite in aqueous solution of L-lactic acid with subsequent heating and film casting. They were characterized by conventional techniques such as Fourier transform infrared spectroscopy, X-ray diffractometry, thermogravimetric analysis, energy dispersive X-ray spectroscopy, and elemental analysis. The results from polar optical and transmission electron microscopic measurements are also discussed. Sorption behavior of samples has been followed by measuring swelling degree and contact angle. The films have shown enhanced hydrophilicity when compared with polylactic acid (PLA). Issues on the interactions of polycationic chitosan with clay are also discussed. It is observed that nanocomposites are exhibiting better thermal and physical properties than neat chitosang-LA and PLA. (c) 2006 Wiley Periodicals, Inc.

}, keywords = {Chitosan, contact angle, graft copolymerization, Nanocomposites, polylactic acid, water absorption}, issn = {1549-3296}, doi = {10.1002/jbm.a.30738}, author = {Depan, Dilip and Kumar, Annamalai Pratheep and Singh, Raj Pal} } @article { ISI:000251068800001, title = {Metal complexes of crosslinked chitosans. part II. an investigation of their hydrolysis to chitooligosaccharides using chitosanase}, journal = {International Journal of Biological Macromolecules}, volume = {41}, number = {5}, year = {2007}, month = {DEC}, pages = {491-496}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

This paper investigates the behavior of crosslinked chitosans and metal-complexed crosslinked chitosans under similar hydrolytic conditions. Crosslinked chitosans with trimellitic anhydride, diisocyanatohexane, and dibromodecane as crosslinking agents under heterogenous reaction conditions were used as metal complexing agents by equilibrating them with metal salts such as ZnCl2, MnSO4, CuSO4, CdSO4, Pb(NO3)(2), and HgCl2. Crosslinked chitosan without metal complexation had the same hydrolytic behavior as uncrosslinked chitosan. However, when the crosslinked chitosans were complexed with metals, their rates of hydrolysis and extent of hydrolysis were significantly reduced. Thus, while for chitosan about 840 mu g/ml reducing sugar was produced in 4 h time, and 780 mu g/ml was produced for diisocyanatohexane crosslinked chitosan, only 400 mu g/ml and 320 [mu g/ml reducing sugars were produced for cadmium sulfate with crosslinked chitosan and diisocyanatohexane crosslinked chitosan, respectively. Similar results are obtained for other crosslinking agents. Studies on preincubation of the metal with the enzyme show that of the metals studied, Mn has no effect on preincubatioin with the enzyme, Hg, Cd, Pb, and Cu completely deactivates the enzyme, while Zn reduces the enzyme activity by about 43.3\%. Preincubation of the metal salts with the chitosan shows that Hg and Cu completely deactivate the molecule from enzyme hydrolysis, Cd and Zn inactivate it to the extent of 56.8\% and 43.3\%, respectively, while Mn has no effect. Availability of the amino functions seems to be a key feature for the chitosanase to hydrolyze the chitosan polymer. This was also proved by the significant increase in the extent of hydrolysis for chitosan samples with 88\% (final value 1120 mu g/ml reducing sugar) and 85\% deacetylation (final value 840 mu g/ml reducing sugar). HPIC studies of the products show that a variety of oligomers are produced in the chitosanase enzyme hydrolytic reaction. (C) 2007 Elsevier B.V. All rights reserved.

}, keywords = {chitooligosaccharides, Chitosan, chitosanase hydrolysis, Crosslinked chitosan, metal-complexed crosslinked chitosan}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2007.06.009}, author = {Trimukhe, K. D. and Bachate, S. and Gokhale, D. V. and Varma, Anjanikumar} } @article { ISI:000251444400008, title = {Complexation of heavy metals by crosslinked chitin and its deacetylated derivatives}, journal = {Carbohydrate Polymers}, volume = {71}, number = {1}, year = {2008}, month = {JAN}, pages = {66-73}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Chitin was crosslinked using diisocyanatohexane (HDI), trimellitic anhydride (TMA), and dibromodecane (DBD), then deacetylated in strong aqueous alkali. This led to a product with amine functional groups on the exposed surface of the crosslinked chitin, which could be utilized for complexation with heavy metals. Thus, a key feature of the crosslinked derivatives prepared was that only the hydroxy Groups were utilized in the crosslinking reaction, and the acetylamino groups of chitin were hydrolyzed only after the crosslinking was accomplished. This ensured that all amino groups of the chitosans so produced would be available for metal complexation, and not partially used up in crosslinking. This proposed advantage was proved by the similar binding observed for heavy metals like Hg (348-372 mg/g), Cu (91-119 mg/g), Zn (71-92 mg/g), Mn (3-10 mg/g), Cd (121-160 mg/g), and Pb (32-86 mg/g) using these crosslinked polymers, whereas the control polymer (uncrosslinked chitosan powder) had complexation values for Hg (348-361 mg/g), Cu (100-106 mg/g), Zn (81-92 mg/g), Mn (4-7 mg/g), Cd (135 mg/g), and Pb (25-59 mg/g). Additionally, in a case where chitosan was crosslinked with HDI. the amino groups were consumed in the crosslinking reaction, and the metal complexation capacity has found to be decreased for Cu (91-109 mg/g), Cd (133 mg/g), and Zn (71-77 mg/g), while remaining nearly the same for Hg (362 mg/g). The literature value for Cu complexation is 59.67 mg/g for chitosan crosslinked with glutaraldehyde. The crosslinked derivatives have the added advantage of insolubility even in low pH aqueous media, making their repeated re-use possible. Further, these crosslinked derivatives could be used in powder form, and the additional step of preparing beads was found to be not necessary for ease of separation of the crosslinked powder by filtration. The binding capacity of various crosslinked chitin and deacetylated derivatives for Cu, Cd, Hg, Zn, Mn. and Pb was in the region of 100, 140, 360 88, 5, and 60 mg/g (rounded off values) of polymer, respectively, very close to the values obtained for uncrosslinked chitosan. The metal binding for crosslinked chitosan was slightly lower than that of crosslinked chitin and deacetylated derivatives, due to use of some amino groups in crosslinking. For Cu ions, the Langmuir equation was found to be the best fit for HDI crosslinked deacetylated chitin and TMA crosslinked deacetylated chitin. The morphological studies conducted using WAXRD are in close agreement with the metal complexation data, showing complete loss of original chitosan peaks for the heavily complexed derivatives, and minor changes for the weakly complexed metals. (c) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {Chitosan, Crosslinked chitosan, deacetylated chitin, metal complexation, Morphology}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2007.05.016}, author = {Trimukhe, K. D. and Varma, Anjanikumar} } @article { ISI:000261410200003, title = {Environment friendly crosslinked chitosan as a matrix for selective adsorption and purification of lipase of aspergillus niger}, journal = {International Journal of Biological Macromolecules}, volume = {43}, number = {5}, year = {2008}, month = {DEC}, pages = {422-425}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Chitosan and its derivatives have been used as affinity matrices for purification of lipase from Aspergillus niger NCIM 1207. Trimellitic anhydride (TMA)-crosslinked deacetylated chitin adsorbed lipase selectively, yielding approximately 5-fold purification of the crude lipase with 70\% yield. Further 9-fold purification occurred on eluting through Sephacryl-100. These results suggest that chitosan derivatives can be used as inexpensive biopolymer matrices for the purification of lipases for industrial applications. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {Adsorption, Chitosan, Lipase, Matrix, Purification}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2008.08.005}, author = {Trimukhe, K. D. and Mahadik, N. D. and Gokhale, D. V. and Varma, Anjanikumar} } @article { ISI:000253115600026, title = {Morphological study of heavy metal complexes of chitosan and crosslinked chitosans by SEM and WAXRD}, journal = {Carbohydrate Polymers}, volume = {71}, number = {4}, year = {2008}, month = {MAR}, pages = {698-702}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Metal complexes of salts of Hg, Cu, Cd, Pb, Zn, and Mn with chitosan and crosslinked chitosans were prepared, and their morphologies were studied using scanning electron microscopy and wide angle X-ray diffraction. The metal ions which were specifically and strongly complexed to the amino functions of chitosans, like Hg, showed smooth surface morphology inspite of large number of ions complexed (372 mg/g of chitosan). The presence of metal ions on the surface of the chitosans could be detected with decrease in metal ion binding, in the following sequence Hg \> Cu \> Cd \> Zn \> Pb \> Mn. Particularly in the case of Pb ions, the presence of these ions is clearly seen on the surface of the polymer by SEM. The number of ions of Mn complexed on the polymers was too few (5 mg/g of chitosan) to be visible. SEM of Hg and Cu complexes do not show the {\textquoteleft}{\textquoteleft}holes{\textquoteright}{\textquoteright} observed in the crosslinked polymers as they bind specifically to amino groups of chitosan, but for Cd, Zn, Mn, and Pb complexes, these {\textquoteleft}{\textquoteleft}holes{\textquoteright}{\textquoteright} are clearly visible. These results are also in agreement with the morphologies studied by WAXRD. The metal complexation data for each of these metal ions was also in the same sequence. (c) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {Chitosan, Crosslinked chitosan, metal complex, Morphology, SEM, WAXRD}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2007.07.010}, author = {Trimukhe, K. D. and Varma, Anjanikumar} } @article { ISI:000251802900022, title = {Preparation and characterization of novel hybrid of chitosan-g-PDMS and sodium montmorrilonite}, journal = {Journal of Biomedical Materials Research Part B-Applied Biomaterials}, volume = {84}, number = {1}, year = {2008}, month = {JAN}, pages = {184-190}, publisher = {WILEY-LISS}, address = {DIV JOHN WILEY \& SONS INC, 111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

Preparation and properties of Chitosan (CS)-clay nanocomposites grafted with polydimethyl siloxane (PDMS) with different clay ratios are herein discussed. CS is intercalated into sodium montmorrilonite and PDMS is grafted onto CS under UV irradiation. Sample films of CS intercalated into clay and grafted with PDMS were prepared by solvent casting method with varying amount of nanoclay and PDMS. They were characterized by conventional techniques such as X-ray diffractometry, fourier transform infrared spectroscopy, C-13 NMR, thermo gravimetric analysis, and differential thermal analysis. Sorption behavior of samples has been followed by measuring swelling degree and issues on the interactions of biopolymers with clay are also discussed. The water absorption of composites films reduces with an increase in the amount of incorporated clay. This is due to the barrier formation in the form of cross-linking points, which prevents water permeation into CS. The amount of adsorbed water is more, when the amount of CS exceeds the amount of PDMS. This shows high water retention capacity of CS. (c) 2007 Wiley Periodicals, Inc.

}, keywords = {Chitosan, graft copolymerization, Nanocomposites, PDMS, water absorption}, issn = {1552-4973}, doi = {10.1002/jbm.b.30860}, author = {Depan, Dilip and Kumar, Bijandra and Singh, Raj Pal} } @article { ISI:000268795100001, title = {Acute and subacute toxicity studies of chitosan reduced gold nanoparticles: a novel carrier for therapeutic agents}, journal = {Journal of Biomedical Nanotechnology}, volume = {5}, number = {3}, year = {2009}, month = {JUN}, pages = {233-239}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

The objective of the present study was to evaluate the oral toxicity of chitosan reduced gold nanoparticles so as to demonstrate its applicability for drug delivery application. Acute oral toxicity studies in female rats documented no deaths or treatment related complications. The LD(50) value of gold nanoparticles was found to be greater than 2000 mg/kg. In case of sub-acute oral toxicity studies, gold nanoparticles were administered orally to male and female rats for a period of 28-days. At the end of study blood samples were collected for haematology and biochemical analysis. For histopathological analysis, organs of animals were weighed and processed for examination. All animals survived the duration of the study, with no significant changes in clinical signs, body weight, food consumption, hematological parameters, organ weights and histopathological findings. These studies establish that chitosan reduced gold nanoparticles produced no treatment related toxicity in rats following oral administration, thus can be exploited for potential therapeutic applications.

}, keywords = {Acute Toxicity, Chitosan, gold nanoparticles, Sub-Acute Toxicity, Wistar Rats}, issn = {1550-7033}, doi = {10.1166/jbn.2009.1027}, author = {Pokharkar, Varsha and Dhar, Sheetal and Bhumkar, Devika and Mali, Vishal and Bodhankar, Subhash L. and Bhagavatula L. V. Prasad} } @article { ISI:000261922400011, title = {Cell proliferation and controlled drug release studies of nanohybrids based on chitosan-g-lactic acid and montmorillonite}, journal = {Acta Biomaterialia}, volume = {5}, number = {1}, year = {2009}, month = {JAN}, pages = {93-100}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

The present paper reveals the potential uses of novel hybrids of chitosan-g-lactic acid and sodium montmorillonite (MMT) in controlled drug delivery and tissue engineering applications. The drug-loaded novel nanohybrid films and porous scaffolds have been prepared by solvent casting and freeze-drying of the grafted polymer solution, respectively. Sodium Ibuprofen was loaded into nanohybrids of chitosan-g-lactic acid/sodium montmorillonite (CS-g-LA/MMT). Grafting of lactic acid and the drug loading were characterized by Fourier transform infrared spectroscopy. Formation of intercalated nanocomposites was confirmed by X-ray diffraction. Mechanical properties measurements have shown improvement in modulus and strength with expense of elongation by MMT reinforcement. The nanohybrids were found to be stable regardless of pH of the medium. The cell proliferation profile also shows that prepared nanohybrids are biocompatible. MMT reinforcement was found to control the drug (Ibuprofen) release rate in phosphate buffer saline solution (pH 7.4). MMT clay is therefore a viable additive for formulating sustained drug delivery systems based on lactic acid grafted chitosan. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

}, keywords = {Chitosan, clay, Controlled release, drug delivery systems, Nanocomposites}, issn = {1742-7061}, doi = {10.1016/j.aetbio.2008.08.007}, author = {Depan, Dilip and Kumar, Annamalai Pratheep and Singh, Raj Pal} } @article { ISI:000260148600010, title = {Metal complexes of crosslinked chitosans: correlations between metal ion complexation values and thermal properties}, journal = {Carbohydrate Polymers}, volume = {75}, number = {1}, year = {2009}, month = {JAN}, pages = {63-70}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A series of heavy metal complexes of crosslinked chitosans were evaluated by thermogravimetric studies. The metal complexes with Cu, Cd and Hg ions exhibiting the highest complexing ability to chitosans (Hg 354-364, Cu 100-112, and Cd 121-160, in mg/g chitosan), had the lowest onset of degradation temperatures (range 194-210 degrees C) and the lowest final degradation temperatures (generally less than 294-304 degrees C for Hg, 296-338 degrees C for Cu, and 305-368 degrees C for Cd complexes). Mn ion, with the lowest binding to chitosans (Mn 5-7 mg/g), showed the reverse behavior, having onset (240-248 degrees C) and final degradation temperatures (range 300-368 degrees C). Zn (binding 74-87 mg/g) and Pb (binding 39-62 mg/g) ions have a binding ability intermediate to Cu/Cd/Hg and Mn extremes, and therefore the effects on onset and final degradation temperatures are intermediate to these values. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Chitosan, Crosslinked chitosan, Degradation temperature, Metal complexes, Thermal properties, Thermogravimetry}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2008.06.011}, author = {Trimukhe, K. D. and Varma, Anjanikumar} } @article { ISI:000264558200004, title = {Visible light induced photoreduction of methyl orange by N-doped mesoporous titania}, journal = {Applied Catalysis A-General}, volume = {357}, number = {1}, year = {2009}, month = {MAR}, pages = {26-33}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

N-doped mesoporous titania was synthesized using templating method. Biopolymer chitosan was used as a template and also as a nitrogen source along with ammonium hydroxide. Three different types of N-doped mesoporous titania were synthesized by varying composition of chitosan and titania precursor. These photocatalysts were characterized using XRD, BET-SA, FTIR, UV-DRS, SEM-EDX and XPS analysis. The photocatalytic activity of mesoporous titania was studied by methyl orange (MO) photoreduction reaction. From the experimental results it was observed that the N-doped mesoporous titania (1:2) gives the highest photocatalytic reduction of MO as compared to N-doped mesoporous titania prepared with (1:1) and (1:3) stoichiometry. This could be due to the optimal level of {\textquoteleft}N{\textquoteright} incorporation in the N-doped mesoporous titania (1:2). Photocatalysts reduce the MO dye into derivative of hydrazine. Photoactivity of N-doped mesoporous titania (1:2) is 1.0721 mg of MO reduced per g of TiO2 vis-a-vis 0.508 mg of MO reduced per g of TiO2 for Degussa P25 photocatalyst. The effect of various operating parameters like photocatalyst loading. initial concentration and intensity of light also has been studied. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {biopolymer, Chitosan, MO photoreduction, N-doped mesoporous titania, Visible active photocatalyst}, issn = {0926-860X}, doi = {10.1016/j.apcata.2008.12.030}, author = {Joshi, Meenal M. and Labhsetwar, Nitin K. and Mangrulkar, Priti A. and Tijare, Saumitra N. and Kamble, Sanjay P. and Rayalu, Sadhana S.} } @article { ISI:000282471100001, title = {Enhancement of thermal stability and phase relaxation behavior of chitosan dissolved in aqueous l-lactic acid: using {\textquoteleft}silver nanoparticles{\textquoteright} as nano filler}, journal = {Macromolecular Research}, volume = {18}, number = {8}, year = {2010}, month = {AUG}, pages = {713-720}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Chitosan films with various compositions of silver nanoparticles were prepared by solution casting with an aqueous solution of chitosan and l-lactic acid. The chitosan/Ag nanocomposites were characterized by wide angle Xray diffraction (WAXD) and UV-vis spectroscopy. An analysis of the surface topography and size of the Ag nanoparticles (\<= 100 nm) were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Thermogravimetric analysis (TGA/DTA) confirmed the increase in thermal stability with increasing Ag nanoparticle content in the nanocomposites. Dynamic thermal analysis (DMA) was used to examine the phase relaxation behavior of chitosan and its nanocomposites. The conductivity of chitosan/Ag nanocomposites was considered with respect to the frequency. Contact angle measurements were used to characterize the surface twistability, surface cleanliness, and hydrophilic/hydrophobic nature of the surface.

}, keywords = {Chitosan, conductivity, contact angle, relaxation, silver nanoparticles}, issn = {1598-5032}, doi = {10.1007/s13233-010-0801-9}, author = {Rana, V. K. and Pandey, Asutosh K. and Singh, Raj Pal and Kumar, B. and Mishra, Satyendra and Ha, Chang-Sik} } @article { ISI:000274069000060, title = {Preparation and characterization of novel hybrid of bio-assisted mineralized Zn-Al layered double hydroxides using chitosan as a template}, journal = {Journal of Applied Polymer Science}, volume = {115}, number = {6}, year = {2010}, month = {MAR}, pages = {3636-3644}, publisher = {JOHN WILEY \& SONS INC}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

The purpose of this study was to prepare and characterize a novel nanohybrid prepared from the template-assisted mineralization of Zn-Al Layered Double Hydroxide (LDH) onto the surface of Chitosan (CSI), with an emphasis on morphology, biocompatibitity, and its use as an efficient drug carrier agent. The as prepared LDH is highly crystalline, with platelet-like morphology and curved tactoids when nucleated onto the surface of CSI. Our results indicate that the -OH and -NH functional moieties on CSI can direct an ordered structure of LDH, due to the electrostatic interaction between biopolymer and inorganic lamellae. We have been successful to intercalate an anti-inflammatory drug, Sodium Ibuprofen (Ibu), into LDH, through conventional coprecipitation method. LDHs are endowed with great potential for delivery vector because their stacked layers lead to safe reservation of biofunctional molecules or genes, and their ion exchangeability and solubility in acidic media (pH \< 4) give rise to the controlled release of drug molecules. According to the cell-growth studies, LDHs are found as cell viable up to the concentration of 500 mu g/mL. This study reveals that LDH not only plays a role of a biocompatible-delivery matrix but also facilitates a significant increase in the delivery efficiency. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115:3636-3644,2010

}, keywords = {bio-assisted mineralization, cell-growth studies, Chitosan, drug delivery systems, layered double hydroxides}, issn = {0021-8995}, doi = {10.1002/app.31463}, author = {Depan, Dilip and Singh, Raj Pal} } @article { ISI:000276061200012, title = {Ultrasound-triggered release of ibuprofen from a chitosan-mesoporous silica composite - a novel approach for controlled drug release}, journal = {Macromolecular Symposia}, volume = {287}, year = {2010}, note = {4th International Symposium on Macro-and Supramolecular Architectures and Materials, Dusseldorf, GERMANY, SEP 07-11, 2008}, month = {JAN}, pages = {80-88}, publisher = {Int Union Pure \& Appl Chem; German Res Fdn}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

In this work, an attempt was made to synthesize a novel Chitosan-Mesoporous silica (CS-MS) hybrid composite to design a drug delivery system based on ultrasound triggered stimuli-responsive smart release. The in-vitro drug release properties of both the Mesoporous Silica (MS) and Chitosan (CS) hybrids were investigated. Ibuprofen (Ibu) was used as a model drug. The results from powder X-Ray diffraction (XRD) patterns, and BET N(2) adsorption isotherms exhibited that MS can accommodate drug molecules into the lumen of the channels and pores. Drug release, stimulated by temperature and pH of the release media was also investigated. We studied the Ultrasound (US) triggered release of Ibu in a simulated body fluid (pH 7.4). The results exhibited that US can be used as a non-invasive technique for drug release from polymeric materials. The enhancing effect of ultrasound on drug release is due to the Cavitation effect, without causing any significant destruction on the polymer morphology.

}, keywords = {Chitosan, drug delivery systems, ibuprofen, Mesoporous silica, Ultrasound}, issn = {1022-1360}, doi = {10.1002/masy.201050111}, author = {Depan, Dilip and Saikia, Lakshi and Singh, Raj Pal} } @article { ISI:000287163600004, title = {Synthesis and drug-delivery behavior of chitosan-functionalized graphene oxide hybrid nanosheets}, journal = {Macromolecular Materials and Engineering}, volume = {296}, number = {2}, year = {2011}, month = {FEB}, pages = {131-140}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Chitosan-functionalized graphene oxides (FGOCs) were successfully synthesized. FGOCs were found to significantly improve the solubility of the GO in aqueous acidic media. The presence of organic groups was confirmed by means of XPS and TGA. Restoration of the sp(2) carbon network and exfoliation of graphene sheets were confirmed by Raman spectroscopy, UV-visible spectroscopy and WAXD. The SEM and AFM investigations of the resultant FGOCs showed that most of the graphene sheets were individual and few were layered. Controlled release behavior of Ibuprofen and 5-fluorouracil was then investigated. We found that FGOCs are a promising new material for biological and medical applications.

}, keywords = {Biocompatibility, Chitosan, drug delivery systems, functionalization of polymers, solution properties}, issn = {1438-7492}, doi = {10.1002/mame.201000307}, author = {Rana, Vijay Kumar and Choi, Myeon-Cheon and Kong, Jin-Yeon and Kim, Gwang Yeon and Kim, Mi Ju and Kim, Sun-Hee and Mishra, Satyendra and Singh, Raj Pal and Ha, Chang-Sik} } @article { ISI:000302664900061, title = {Glycolic acid-g-chitosan-gold nanoflower nanocomposite scaffolds for drug delivery and tissue engineering}, journal = {International Journal of Biological Macromolecules}, volume = {50}, number = {3}, year = {2012}, month = {APR}, pages = {878-883}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

This paper reports a simple novel method for the synthesis of flower like gold nanoparticle (three dimensional branched nanoparticle) with \>30 tips, under controlled temperature condition. Formation of flower like Au nanoparticle was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Next step of this paper reveals the potential use of novel hybrids of chitosan-g-glycolic acid and gold nanoflower (AuNF) in controlled drug delivery and tissue engineering applications. The drug loaded novel nanohybrid scaffold is prepared by freeze drying of grafted polymer solution. Grafting of glycolic acid to the chitosan and incorporation of drug were evaluated by Fourier transform infrared spectroscopy (FTIR). The nanohybrid scaffolds were found to be stable towards the pH of the medium. The cell viability study shows that prepared nanohybrid scaffolds are biocompatible. Gold nanoflowers were found to control the drug release rate in the buffer solution (pH 7.4). Therefore, for the glycolic acid grafted chitosan based system, gold nanoflowers are the viable additive for drug delivery. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {Chitosan, Drug delivery system, Glycolic acid grafting, Gold nanoflower, Nanocomposite}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2011.10.014}, author = {Kumari, Sangeeta and Singh, Raj Pal} } @article { ISI:000306038600011, title = {Glycolic acid-g-chitosan-Pt-Fe3O4 nanoparticles nanohybrid scaffold for tissue engineering and drug delivery}, journal = {International Journal of Biological Macromolecules}, volume = {51}, number = {1-2}, year = {2012}, month = {JUL}, pages = {76-82}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

This work presents the potential use of novel nanohybrid based on chitosan-g-glycolic acid and Pt-Fe3O4 composite nanoparticles in drug delivery and tissue engineering applications. The Pt-Fe3O4 hybrid nanoparticles are prepared by thermal decomposition of H2PtCl6 center dot 6H(2)O at high temperature. The prepared nanoparticles were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and physical property measurement system (PPMS). Next step of this paper reveals the potential use of novel hybrids of chitosan-g-glycolic acid and Pt-Fe3O4 hybrid nanoparticles in controlled drug delivery applications. The drug loaded nanohybrid scaffold is prepared by freeze drying of grafted polymer solution. Drug loading and grafting of chitosan was characterized by Fourier transform infrared spectroscopy (FTIR). The cell proliferation also shows that the prepared nanohybrids are biocompatible. The nanohybrid was found to be stable regardless of pH of the medium. Therefore, Pt-Fe3O4 hybrid nanoparticles are viable additive for sustained drug delivery and it could be applied in the field of biomedical. (c) 2012 Elsevier B.V. All rights reserved.

}, keywords = {Cell viability, Chitosan, drug delivery, Glycolic acid grafting, Pt-Fe3O4 hybrid nanoparticle}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2012.01.040}, author = {Kumari, Sangeeta and Singh, Raj Pal} } @article { ISI:000331624700039, title = {Chitosan and chitosan-co-poly(epsilon-caprolactone) grafted multiwalled carbon nanotube transducers for vapor sensing}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {14}, number = {3}, year = {2014}, month = {MAR}, pages = {2425-2435}, publisher = {AMER SCIENTIFIC PUBLISHERS}, type = {Article}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

Vapor sensitive transducer films consisting of chitosan grafted (CNT-CS) and chitosan-co-polycaprolactone grafted (CNT-CS-PCL) multiwalled carbon nanotubes were prepared using a spray layer-by-layer technique. The synthesized materials (CNT-CS and CNT-CS-PCL) were characterized by Fourier transform infrared spectroscopy, C-13 CP/MAS solid state nuclear magnetic resonance spectroscopy and thermogravimetric analysis. Both CNT-CS and CNT-CS-PCL transducers were analyzed for the response of volatile organic compounds and toluene vapors. The ranking of the relative resistance (A(r)) for both chitosan based transducers were as follows: toluene \< chloroform \< ethanol \< methanol. The CNT transducer (CNT-CS) was correlated selectively with an exponential law to the inverse of Flory-Huggins interaction parameters, chi(12). Dosing the films on the interdigitated electrodes with methanol, ethanol, chloroform and toluene vapors increased the film resistance of CNT-CS but decreased the resistance of CNT-CS-PCL compared to that of the reported transducers.

}, keywords = {Biocompatibility, Chitosan, MWCNTs, Poly(epsilon-caprolactone), Vapour Sensing}, issn = {1533-4880}, doi = {10.1166/jnn.2014.8498}, author = {Rana, Vijay Kumar and Akhtar, Shamim and Chatterjee, Sudipta and Mishra, Satyendra and Singh, Raj Pal and Ha, Chang-Sik} } @article { ISI:000339692700028, title = {Defluoridation using biomimetically synthesized nano zirconium chitosan composite: kinetic and equilibrium studies}, journal = {Journal of Hazardous Materials}, volume = {276}, year = {2014}, month = {JUL}, pages = {232-240}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

{The present study reports a novel approach for synthesis of Zr nanoparticles using aqueous extract of Aloe vera. Resulting nanoparticles were embedded into chitosan biopolymer and termed as CNZr composite. The composite was subjected to detailed adsorption studies for removal of fluoride from aqueous solution. The synthesized Zr nanoparticles showed UV-vis absorption peak at 420 nm. TEM result showed the formation of polydispersed, nanoparticles ranging from 18 nm to 42 nm. SAED and XRD analysis suggested an fcc (face centered cubic) Zr crystallites. EDAX analysis suggested that Zr was an integral component of synthesized nanoparticles. FT-IR study indicated that functional group like -NH

}, keywords = {Aloe vera, Chitosan, FT-IR spectroscopy, Sorption, Zirconium nanoparticles}, issn = {0304-3894}, doi = {10.1016/j.jhazmat.2014.05.038}, author = {Prasad, Kumar Suranjit and Amin, Yesha and Selvaraj, Kaliaperumal} } @article { ISI:000353754000021, title = {Preparation and characterization of self-photostabilizing UV-durable bionanocomposite membranes for outdoor applications}, journal = {Carbohydrate Polymers}, volume = {123}, year = {2015}, month = {JUN}, pages = {164-173}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Here, we report a durable and ultraviolet (UV) resistant nanocomposite membrane of chitosan (CS) with effective photostabilization ascribed to Zinc oxide (ZnO) nanoparticles. Zinc oxide nanoparticles were successfully dispersed in the solution of chitosan polymer. The nanocomposite films with the homogenous dispersion of ZnO nanoparticles in the chitosan matrix were obtained by solution casting method and the influence of ZnO nanoparticles as a photostabilizer was studied. The nanocomposite membranes were photoirradiated by polychromatic radiations with lambda \> 300 nm using mercury vapour lamps in SEPAP instrument. The resulting nanocomposite material exhibited excellent UV-resistance in very low percentages of ZnO nanoparticles. The chitosan membranes showed fast degradation attributes than the nanocomposite membranes. ZnO nanoparticles effectively absorbed UV radiations, thus protecting polymer from radiation degradation. The neat and irradiated nanocomposites of chitosan and ZnO nanoparticles (CS/ZnO) were characterized by Fourier Transform Infrared Spectroscopy (FT-IR) spectroscopy for the chemical changes/degradation taking place. Chitosan nanocomposites were further characterized for tensile properties, contact angle measurements and surface morphology. (C) 2015 Elsevier Ltd. All rights reserved.

}, keywords = {Bionanocomposite membrane, Chitosan, Contact angle measurement, Fourier transform infrared spectroscopy, Photostabilization, Zinc oxide nanoparticles}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2014.12.062}, author = {Kushwaha, Omkar S. and Avadhani, C. V. and Singh, R. P.} } @article { ISI:000380943900048, title = {Proton play in the formation of low molecular weight chitosan (LWCS) by hydrolyzing chitosan with a carbon based solid acid}, journal = {Carbohydrate Polymers}, volume = {151}, year = {2016}, month = {OCT}, pages = {417-425}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

Low molecular weight chitosan (LWCS) constitute a special class of value added chemicals that are primarily obtained from crustacean shells, which are the main water pollutants from crabs and shrimp processing centers. Unlike chitin and chitosan, LWCS possess improved solubility in water and aqueous solutions, making them widely applicable in numerous fields ranging from drug delivery to waste water treatment. Among the methods employed for their production, chemical breakdown by strong liquid acids has yielded good success. However, this method is met with severe concerns arising from the harsh nature of liquid acids, which may corrode the reactors for commercial synthesis, and their limited reusability. The physical methods like ultrasound and microwave are energy intensive in nature, while the enzymatic methods are expensive and offers limited scope for reuse. We have attempted to overcome these problems by employing carbon based solid acid (CSA) for hydrolyzing chitosan to LWCS. CSA can be easily produced using activated carbon, a cost-effective and easily available raw material. Reactions were carried out between chitosan and CSA in a hydrothermal glass reactor and the products, separated by cold centrifugation, were purified and dried. The dried products were characterized for their molecular weight and solubility. Results indicated more than ten-fold decrease in the molecular weight of chitosan and the product exhibited water solubility. The CSA could be used upto four times, without regeneration, to give a consistent quality product. The aqueous solution of resulting LWCS exhibited a pH of 6.03 +/- 0.11, as against the acidic pH range of solutions of commercially available LWCS, indicating its suitability for biomedical applications. Our investigation facilitates a {\textquoteleft}green approach{\textquoteright} that may be employed for commercial production of value added chemicals from waste products of marine industry. (C) 2016 Elsevier Ltd. All rights reserved.

}, keywords = {Carbon based solid acid, Chitosan, green synthesis, Hydrolysis, Low molecular weight chitosan}, issn = {0144-8617}, doi = {10.1016/j.carbpol.2016.05.082}, author = {Krishnan, R. Akhil and Deshmukh, Pranjal and Agarwal, Siddharth and Purohit, Poorvi and Dhoble, Deepa Arun and Waske, Prashant and Khandekar, Dileep and Jain, Ratnesh and Dandekar, Prajakta} } @article {44529, title = {Surface colonized silver nano particles over chitosan poly-electrolyte micro-spheres and their multi-functional behavior}, journal = {Materials Research Express}, volume = {5}, year = {2018}, month = {FEB }, pages = { 025032}, type = {Journal Article}, abstract = {hitosan/tripolyphosphate polyelectrolyte (TPP) microspheres, decorated and surface functionalized with silver nanoparticles (NPs) of average diameter of 15 nm, were synthesized following a simple two-step procedure. These Ag NP-functionalized polyelectrolyte microspheres (Ag-CSPMs) are found to be biocompatible and enhancing the reactive oxygen species in curcumin with excellent anti-bacterial activity for selected Gram-positive and negative bacterial strains, making them much attractive relative to bare surface counterparts; the well-stabilized silver NPs do not form any agglomerations on the surface of the chitosan microspheres. They also show excellent cytotoxic behavior towards MCF7 cell lines, showing a half-maximal inhibitory concentration (IC50) of 32 μg ml-1. Therefore, Ag-CSPMs exhibit multi-functional ability having potential towards theranostics applications.}, keywords = {antibacterial properties, Chitosan, Cytotoxicity, reactive oxygen species, silver nanoparticles, theranostics}, issn = {20531591}, doi = { 10.1088/2053-1591/aaa3c6}, author = {Prakash, B.}, editor = {Asha, S.} } @article {46857, title = {Removal of fluoride from aqueous solution by mesoporous silica nanoparticles functionalized with chitosan derived from mushroom}, journal = {Journal of Macromolecular Science Part A-Pure and Applied Chemistry}, volume = {57}, year = {2020}, month = {SEP }, pages = {619-627}, type = {Article}, abstract = {

In the present study, chitosan functionalized mesoporous silica nanoparticles have been synthesized. Chitosan derived from an edible mushroom, Agaricus bisporus was used during synthesis of chitosan functionalized silica nanoparticles. The functionalized silica nanoparticles were subjected to fluoride sorption using a batch method which subsequently showed removal efficiency of 95\% with maximum sorption capacity, 58.8 mg/g. The characterization of nanoparticles was carried out by SEM, EDAX, XRD and FTIR analysis respectively. EDAX analysis suggested that oxygen, 51.83\% and silica 37.24\% was main constituent of the functionalized nanomaterials. XRD yielded characteristic diffraction pattern corresponding to the lattice planes (100), (110), (112), (120), (200) and (220) respectively. Sorption data was used to study equilibrium isotherm namely Langmuir and Freundlich model. The adsorption capacity increased with temperature while kinetics studies revealed that the adsorption process followed a pseudo-second-order rate equation. The enthalpy change (Delta H) and entropy change (Delta S) was found to be -31.36 kJmol(-1) and -7.75 Jmol(-1) K-1, showing endothermic and spontaneous nature of the fluoride adsorption. Data suggested that the nature of adsorption belonged to chemisorptions. The overall results suggested that the synthesized nanoparticles showed strong and specific affinity for fluoride and could be excellent adsorbents for defluoridation.

}, keywords = {Adsorption, Chitosan, EDAX, Fluoride, SEM}, issn = {1060-1325}, doi = {10.1080/10601325.2020.1738896, Early Access Date = MAY 2020}, author = {Srivastava, Anushree and Kumari, Madhu and Ramanathan, Alagappan and Selvaraj, Kaliaperumal and Prasad, Bablu and Prasad, Kumar Suranjit} } @article {47369, title = {Characterization of a novel nanocomposite film based on functionalized chitosan-Pt-Fe3O4 hybrid nanoparticles}, journal = {Nanomaterials}, volume = {11}, year = {2021}, month = {MAY}, pages = {1275}, type = {Article}, abstract = {

The development of organic-inorganic hybrids or nanocomposite films is increasingly becoming attractive in light of their emerging applications. This research focuses on the formation of a unique nanocomposite film with enhanced elasticity suitable for many biomedical applications. The physical property measurement system and transmission electron microscopy were used to analyze Pt-Fe3O4 hybrid nanoparticles. These nanohybrids exhibited magnetic effects. They were further exploited to prepare the nanocomposite films in conjunction with a chitosan-g-glycolic acid organic fraction. The nanocomposite films were then examined using standard techniques: thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, and atomic force microscopy. Tensile strength testing demonstrated a significantly greater elastic strength of these nanocomposite films than pure chitosan films. The water absorption behavior of the nanocomposites was evaluated by measuring swelling degree. These nanocomposites were observed to have substantially improved physical properties. Such novel nanocomposites can be extended to various biomedical applications, which include drug delivery and tissue engineering.

}, keywords = {Chitosan, nanocomposite films, Pt-Fe3O4 hybrid nanoparticles, tensile strength testing, Thermogravimetric analysis}, doi = {10.3390/nano11051275}, author = {Kumari, Sangeeta and Singh, Raj Pal and Chavan, Nayaku N. and Sahi, Shivendra V. and Sharma, Nilesh} } @article {49719, title = {Sustainable UV absorbing bio-plastic films by valorisation of humins and chitosan}, journal = {International Journal of Biological Macromolecules}, volume = {311}, year = {2025}, month = {JUN}, pages = {143710}, type = {Article}, abstract = {

Humins, an inevitable bio-refinery waste by-product of sugar dehydration have been efficiently utilized for the first time for developing biodegradable thin films for UV shielding. The films were prepared from chitosan, and humins, a novel combination, aiming towards simultaneous utilization of marine and bio-refinery waste, rendering simple, effective, robust UV absorbing films. The structure-activity relationship of these films were elucidated with the help of different analytical techniques like X-ray diffraction, Fourier transform infrared spectroscopy, Thermogravimetric analysis, UV-vis spectroscopy, Atomic force microscopy, Scanning electron microscopy, Tensile testing, Contact angle measurements and water absorption studies. Intrinsic biodegradability was studied using fungi i.e. Aspergillus niger. Different feedstocks (corncob, rice husk, glucose and xylose) were explored for generating humins. Amongst them, humins derived from xylose were utilized for the preparation of the bio-plastic films of chitosan. The results revealed that, addition of 5.0 \% humins was observed to be an optimum concentration yielding films with excellent UV absorption, mechanical properties, and biodegradability. The current work is in perfect alignment with sustainability and green chemistry as it ameliorates waste valorization (lignocellulosic and marine altogether). Further, its innovation stems from the first-hand use of humins for UV absorption, novel combination of biopolymers, use of green raw materials.

}, keywords = {biodegradable, Chitosan, Humins, Thin films, UV absorption, Waste valorization}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2025.143710}, author = {Lucas, Nishita and Tambe, Snehal S. and Parate, Roopa and Hengne, Amol and Rode, C. V. and Athawale, Anjali A.} }