Browsing by Author "Sudip Malik"

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Layered double hydroxide induced advancement in joint prosthesis using bone cement: 0054he effect of metal substitution
(Royal Society of Chemistry, 2013) Govinda Kapusetti; Raghvendra Raman Mishra; Swati Srivastava; Nira Misra; Vakil Singh; Partha Roy; Santosh Kumar Singh; Chanchal Chakraborty; Sudip Malik; Pralay Maiti
Poly(methyl methacrylate) based bone cement and its nanocomposites with layered double hydroxide (LDH) have been developed with greater mechanical strength and biocompatibility as a grouting material for total joint arthroplasty. Bivalent magnesium has been replaced with trivalent aluminium with various mole ratios, keeping the layered pattern of the LDH intact, to cater for the effect of varying substitution on the property enhancement of the nanocomposites. The intercalation of polymer inside the LDH layers makes them disordered and mechanically stiffer and tougher by more than 100%. The thermal stability of bone cement has increased by more than 30 °C in the presence of 1 wt% of nanoLDH, homogenously distributed in the bone cement matrix by creating an inorganic thermal barrier out of the LDH dispersion. The improvement in the properties of the nanocomposites has been explained in terms of the strong interaction between nanoLDH and polymer. The superior bioactivity and biocompatibility of the nanocomposites, as compared to pure bone cement, has been established through hemolysis assay, cell adhesion, MTT assay and cell proliferation using fluorescence imaging. The developed nanocomposites have been used as a grouting material and significant improvements have been achieved in fatigue behaviour with gradual increment of Al substitution in the Mg:Al mole ratio in nanoLDH, demonstrating the real use of the material in the biomedical area. In vivo experiments on rabbits clearly revealed the superior efficacy of bone cement nanocomposites, over pure bone cement and a blank. © The Royal Society of Chemistry.
Nanoparticle-induced controlled biodegradation and its mechanism in poly(ε-caprolactone)
(2010) Narendra K. Singh; Biswapratim Das Purkayastha; Jagat K. Roy; Rathindra M. Banik; Madhu Yashpal; Gajendra Singh; Sudip Malik; Pralay Maiti
Poly(ε-caprolactone) (PCL)/layered silicate nanocomposites have been prepared via solution route. Two different organically modified nanoclays were used to compare the variation in properties based on organic modifications. The nanostructures, as observed from wide-angle X-ray diffraction and transmission electron microscopy, indicate intercalated and partially exfoliated hybrids depending on the nature of organic modification in nanoclay. The nanohybrids exhibit significant improvement in thermal and mechanical properties of the matrix as compared to neat polymer. The nanoclays act as nucleating agent for the crystallization of PCL. The biodegradability of pure PCL and its nanocomposites have been studied under controlled conditions in enzyme, pure microorganism (fungi), compost, Ganges water, and alkaline buffer solution. The rate of biodegradation of PCL has enhanced dramatically in nanohybrids and depends strongly on the media used. Scanning confocal, electron, and atomic force microscopes have used to demarcate the nature of biodegradation of pristine PCL and its nanocomposites. The change in biodegradation is rationalized in terms of the crystallization behavior and organic modification in nanoclays of the nanohybrids vis-a-vis the neat polymer. The extent of compatibility was measured quantitatively through the interaction parameter for two different nanoclays to compare and establish the reason for variation in their properties in nanohybrids. A biodegradation mechanism has been revealed for PCL and its nanocomposites through enzyme activity in varying pH environment. © 2010 American Chemical Society.
Polyurethane-grafted chitosan as new biomaterials for controlled drug delivery
(American Chemical Society, 2015) Arun Kumar Mahanta; Vikas Mittal; Nitesh Singh; Debabrata Dash; Sudip Malik; Mohan Kumar; Pralay Maiti
The present investigation focuses on the grafting of chitosan (CHT) with diisocyanate terminated polyurethane. Solid state 13C NMR spectroscopy confirms the grafting reaction and the degree of substitution (DS) was calculated from the deconvoluted area of the corresponding NMR peak. Solubility studies, swelling behavior and contact angle measurements support the hydrophobic chemical modification on CHT molecules and higher DS leads to the cross-linking of CHT molecules having polyurethane bridges resulting insolubility and regulated swelling in the graft copolymer. Molecular relaxations phenomena due to the constraint associated with the grafting have been revealed using spin-lattice relaxation tine (T1) and shifting of peak position in tan δ curve toward lower temperature in dynamic mechanical measurement at constant frequency indicating flexible nature of graft copolymers as compared to pure CHT. The sustained drug delivery has been achieved using graft copolymers vis-à-vis pure CHT following the Fickian diffusion behavior (n ≤ 0.45) and the release rate can be tuned by altering the DS. In depth biocompatibility studies through platelet aggregation, platelet adhesion, reactive oxygen species of the developed graft copolymers, and in vitro hemolysis assay and cell viability have been performed to understand its potential use in biomedical applications and compared the improved properties with respect to pure CHT. Hence, bio- and hemocompatible CHT graft copolymers have been developed with the capability of controlled and sustained drug release. © 2015 American Chemical Society.
Simple synthesis of end functionalized regioregular poly(3-hexyl thiophene) by catalytic-initiated Kumada catalyst transfer polymerization
(John Wiley and Sons Inc., 2019) Koomkoom Khawas; Soumili Daripa; Pallavi Kumari; Manas K. Bera; Sudip Malik; Biplab K. Kuila
[No abstract available]