Browsing by Author "Jayabalan, M"

Now showing 1 - 20 of 53
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    Bioactive, mechanically favorable and biodegradable copolymer nanocomposites for orthopedic applications
    (J. of Mater. Sci and Engg, 2014-06) Victor, SP; Jayabalan, M
    We report the synthesis of mechanically favorable, bioactive, and biodegradable copolymer nanocomposites for potential bone applications. The nanocomposites consist of in situ polymerized biodegradable copolyester with hydroxyapatite (HA). Biodegradable copolyesters comprise carboxy terminated poly(propylene fumarate) (CT-PPF) and poly(trimethylol propane fumarate co mannitol sebacate) (TF-Co-MS). Raman spectral imaging clearly reveals a uniform homogenous distribution of HA in the copolymer matrix. The mechanical studies reveal that improved mechanical properties formed when crosslinked with methyl methacrylate (MMA) when compared to N-vinyl pyrrolidone (NVP). The SEM micrographs of the copolymer nanocomposites reveal a serrated structure reflecting higher mechanical strength, good dispersion, and good interfacial bonding of HA in the polymer matrix. In vitro degradation of the copolymer crosslinked with MMA is relatively more than that of NVP and the degradation decreases with an increase in the amount of the HA filler. The mechanically favorable and degradable MMA based nanocomposites also have favorable bioactivity, blood compatibility, cytocompatibility and cell adhesion. The present nanocomposite is a more promising material for orthopedic applications.
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    Biological interactions: causes for risks and failures of biomaterials and devices.
    (Journal of biomaterials applications, 1993)
    Biomaterials and devices have been used in a variety of applications ranging from disposable extracorporeal devices and soft and hard tissue augmentation, to total artificial internal organs. However, there are risks and failures in each application which are a result of undesirable biological interactions. This article deals with various biological interactions in each category of implants and devices used in medical applications.
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    Capped oligomers of isocyanate of acrylic monomers as potential bioerodible tissue adhesives
    (JOURNAL OF POLYMER MATERIALS, 2000) Jayabalan, M; Lizymol, PP
    Tissue adhesives based on capped-oligomeric resin prepared from isocyanato ethyl methacrylate and acrylic acid monomers are found to bind beef muscle. The cured adhesive undergoes bioerosion. A potential soft tissue adhesive could be formulated from capped isocyanate based oligomer for optimised adhesive strength, bioerosion and shelf life.
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    Cucurbitural/Hydroxyapatite based nanoparticles for potential use in theranostic applications
    (CrystEngComm, 2014-05) Victor, SP; Paul, W; Jayabalan, M; Sharma, CP
    We present the engineering of cucurbituril/hydroxyapatite based theranostic nanoparticles with a high aspect ratio and a needle shaped morphology. These particles with varying sizes, surface charges and tunable degradation profiles manifested the advantages of the presence of cucurbituril with respect to drug loading, encapsulation efficacy and release kinetics. In vitro release profiles with two model drugs, Doxorubicin hydrochloride (Dox, hydrophilic) and Nile Red dye (NR, hydrophobic), were evaluated. It was ascertained that hydrophilic Dox was released at a faster rate compared to hydrophobic NR over similar time periods. The concomitant presence of samarium (Sm3+) and CB[7] confers theranostic potential to the synthesized nanoparticles. Cellular toxicity effects systematically assessed using MTT and live/dead assay protocols indicate inappreciable toxicity. The nanoparticles further reveal excellent blood compatibility and cellular internalization properties as visualized by fluorescence microscopy. Particles excited at 300 nm revealed Dox emission in the green channel (470 nm) as well as Sm3+ emission in the red channel (590 nm). These studies unravel the potential of these nanoparticles for effective theranostic applications.
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    Cucurbituril/hydroxyapatite based nanoparticles for potential use in theranostic applications
    (CRYSTENGCOMM, 2014) Victor, SP; Paul, W; Jayabalan, M; Sharma, CP
    We present the engineering of cucurbituril/hydroxyapatite based theranostic nanoparticles with a high aspect ratio and a needle shaped morphology. These particles with varying sizes, surface charges and tunable degradation profiles manifested the advantages of the presence of cucurbituril with respect to drug loading, encapsulation efficacy and release kinetics. In vitro release profiles with two model drugs, Doxorubicin hydrochloride (Dox, hydrophilic) and Nile Red dye (NR, hydrophobic), were evaluated. It was ascertained that hydrophilic Dox was released at a faster rate compared to hydrophobic NR over similar time periods. The concomitant presence of samarium (Sm3+) and CB[7] confers theranostic potential to the synthesized nanoparticles. Cellular toxicity effects systematically assessed using MTT and live/dead assay protocols indicate inappreciable toxicity. The nanoparticles further reveal excellent blood compatibility and cellular internalization properties as visualized by fluorescence microscopy. Particles excited at 300 nm revealed Dox emission in the green channel (470 nm) as well as Sm3+ emission in the red channel (590 nm). These studies unravel the potential of these nanoparticles for effective theranostic applications.
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    Design, preparation and characterization of pH-responsive prodrug micelles with hydrolyzable anhydride linkages for controlled drug delivery
    (Journal of Colloid and Interface Science, 2017-01) Girija, S; Adarsh, R; Vineeth, MV; Jayabalan, M; Shivaram, S
    We report a new prodrug micelle-based approach in which a model hydrophobic non-steroidal antiinflammatory drug (NSAID), ibuprofen (Ibu), is tethered to amphiphilic methoxy polyethylene glycolpolypropylene fumarate (mPEG-PPF) diblock copolymer via hydrolytic anhydride linkages for potential controlled release applications of NSAIDs. Synthesized mPEG-PPF-Ibu polymer drug conjugates (PDCs) demonstrated high drug conjugation efficiency ( 90%) and self-assembled to form micellar nanostructures in aqueous medium with critical micelle concentrations ranging between 16 and 30 lg/mL. The entrapment efficiency of Ibu in prepared PDC micelles was as high as 18% (w/w). Crosslinking of prodrug micelles with N,N0-dimethylaminoethyl methacrylate conferred pH-responsive characteristics. pH-responsive PDC micelles averaged 100 nm in size at pH 7.4 and exhibited concomitant changes in size upon incubation in physiologically relevant mildly acidic conditions. Ibu release was observed to increase with increasing acidic conditions and could be controlled by varying the amount of crosslinker used. Furthermore, the prepared mPEG-PPF-based micelles demonstrated excellent cytocompatibility and cellular internalization in vitro. More importantly, PDC micelles exerted anti-inflammatory effects by significantly decreasing monosodium urate crystal-induced prostaglandin E2 levels in rabbit synoviocyte cultures in vitro. Cumulatively, our results indicate that this new prodrug micelle approach is promising for NSAID-based therapies in the treatment of arthritis and cancer.
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    Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility
    (BIOMEDICAL MATERIALS, 2011) Dawlee, S; Jayabalan, M
    Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.
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    Diethylene glycol acrylate-n-vinyl pyrrolidone copolymer resins for bone cement applications
    (INDIAN JOURNAL OF ENGINEERING AND MATERIALS SCIENCES, 2000) Celin, D; Thomas, V; Jayabalan, M
    Biodegradable and injectable monomer diethylene glycol acrylate (DGA) and diethylene glycol acrylate-n-vinyl pyrrolidone (DGA-VP) blends have been prepared and evaluated their suitability for bone cement applications. Studies on the setting of the monomer DGA and the blend DGA-VP have been carried out using a free radical initiator. Lower setting time is observed with the monomer in comparison with that of the blend. The degradation of cured PDGA and P(DGA-VP) polymeric materials has been evaluated in simulated physiological fluids. Studies on degradation in hydrolytic and oxidative media reveal faster degradation during initial period of aging followed by slower and steady state degradation. br vitro degradation studies show more hydrolytic degradation in PDGA while both hydrolytic and oxidative degradation in P(DGA-VP) in comparison to that of PDGA. Also, the biocompatible comonomer (VP) enhances biodegradation of aliphatic polyester PDGA.
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    Effect of autoclaving sterilization on the stability of polyurethane potting compounds based on caprolactone polyol
    (JOURNAL OF POLYMER MATERIALS, 1997) Jayabalan, M; Lizymol, PP
    Stability of polyurethane potting compounds based on caprolactone polyol and cycloaliphatic diisocyanate in repeated autoclaving and methanol treatment was studied. While methanol treatment alone induces degradation of polyurethane and leaching of fragments, the single cycle autoclaving do not induce degradation. However, the increased cycles of autoclaving and exposure to more hydrophilic reagents like methanol enhances the degradation and leaching of low molecular weight components. There was no evidence of formation of cycloaliphatic diamine product.
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    Effect of dehydrochlorination of PVC on miscibility and phase separation of binary and ternary blends of poly(vinyl chloride), poly(ethylene-co-vinyl acetate) and poly(styrene-co-acrylonitrile)
    (POLYMER INTERNATIONAL, 1997) Lizymol, PP; Thomas, S; Jayabalan, M
    The enhancement of miscibility at the lower critical solution temperature (LOST) of the blends poly(vinyl chloride)/poly(ethylene-co-vinyl acetate) (PVC/EVA), poly(vinyl chloride)/poly(styrene-co-acrylonitrile) (PVC/SAN) and poly(vinyl chloride)/poly(ethylene-co-vinyl acetate)/poly(styrene-co-acrylonitrile) (PVC/EVA/SAN) was observed at the micron level. Such miscibility is attributed to the dehydrochlorination and formation of hydrogen bonds between blend components. However, macrolevel immiscibility of these blends heated to the LCST was observed. Such microdomain compatibility of these blends gives a synergistic character. Brittle-type failure observed for LCST samples testifies to the synergism in treated blends.
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    Effect of gamma-radiation sterilization on the stability of polyurethane potting compounds based on castor oil SMDI and caprolactone polyol SMDI, used for hollow fibre haemodialyzer
    (BULLETIN OF MATERIALS SCIENCE, 1997) Jayabalan, M; Lizymol, PP
    Stability of polyurethane potting compounds based on castor oil/SMDI and caprolactone polyol/SMDI in repeated gamma radiation sterilization was studied. Radiation-induced degradation and leaching of low molecular weight fragments are higher in castor oil based polyurethane than in caprolactone polyol based polyurethane. For castor oil and caprolactone polyol based polyurethanes degradation increases up to 5 Mrad dose of sterilization. Further increase of dose of sterilization decreases leaching in caprolactone polyol based polyurethane which has resulted from secondary reactions leading to crosslinking. In the case of castor oil based polyurethane such crosslinks undergo cleavage at 10 Mrad dose of sterilization.
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    Effects of biostability and morphology on host response of polyurethane-based soft tissue implants.
    (Clinical materials, 1992)
    Polyurethane has been found to be one of the most successful polymers for soft tissue applications. We have investigated the effect of material biostability and morphology on the host response of polyurethane-based soft tissue implants in rabbits. The polyurethane containing allophanate linkage was prepared by using hexamethylene diisocyanate, polypropylene glycol (400) and 1,4-butane diol. Biuret-based biostable polyurethanes were prepared by using hexamethylene diisocyanate, polytetramethylene glycol and trimethylol propane and water. Samples of circular button and rectangular specimens were implanted subcutaneously in rabbits in the paravertebral region for a post-implantation period of 9 months. Relatively larger polyurethane samples with different morphology elicit a varied tissue response with our candidate polyurethane materials. A favorable tissue response was observed with rectangularly shaped thin polyurethane. Giant cell reaction, absence of fibrous tissue encapsulation and degradation were noticed for the rectangular smooth samples at the end of post-implantation period of 9 months. No malignant changes were noticed in any of these samples.
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    Hybrid alginate-polyester bimodal network hydrogel for tissue engineering - Influence of structured water on long-term cellular growth
    (COLLOIDS AND SURFACES B-BIOINTERFACES, 2015) Finosh, GT; Jayabalan, M; Vandana, S; Raghu, KG
    The development of biodegradable scaffolds (which promote cell-binding, proliferation, long-term cell viability and required biomechanical stability) for cardiac tissue engineering is a challenge. In this study, biosynthetic amphiphilic hybrid hydrogels were prepared using a graft comacromer of natural polysaccharide alginate and synthetic polyester polypropylene fumarate (PPF). Monomodal network hydrogel (HPAS-NO) and bimodal network hydrogel (HPAS-AA) were prepared. Between the two hydrogels, HPAS-AA hydrogel excels over the HPAS-NO hydrogel. HPAS-AA hydrogel is mechanically more stable in the culture medium and undergoes gradual degradation in vitro in PBS (phosphate buffered saline). HPAS-AA contains nano-porous structure and acquires structured water (non-freezing-bound water) (53.457%) along with free water (11.773%). It absorbs more plasma proteins and prevents platelet adsorption and hemolysis when contacted with blood. HPAS-AA hydrogel is cytocompatible and promote 3D cell growth (approximate to 170%) of L929 fibroblast even after 18 days and H9C2 cardiomyoblasts. The enhanced and long-term cellular growth of HPAS-AA hydrogel is attributed to the cell responsive features of structured water. HPAS-AA hydrogel can be a better candidate for cardiac tissue engineering applications. (c) 2015 Elsevier B.V. All rights reserved.
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    Hybrid amphiphilic bimodal hydrogels having mechanical and biological recognition characteristics for cardiac tissue engineering
    (RSC ADVANCES, 2015) Finosh, GT; Jayabalan, M
    Tissue engineering strategies rely on the favourable microniche scaffolds for 3D cell growth. For cardiac tissue engineering, a biodegradable hydrogel has to meet the essential requirements viz. adequate strength, compatibility of degradation products to the host tissue, maintenance of cellular viability and differentiation, favouring cell integration, controlled degradation of scaffold commensurate with the contractile function under ischemic conditions of the injured heart. In this work, an attempt is made to explore some of these stringent and diagonally opposite requirements. Hybrid amphiphilic bimodal hydrogels having mechanical and biological recognition characteristics were developed using graft comacromer of alginate-poly(mannitol fumarate-co-sebacate). Alginate was graft copolymerized with poly(mannitol fumarate-co-sebacate) macromer (HT-MFS). The resultant comacromer was crosslinked with PEGDA and DEGDMA to form two bimodal hydrogel scaffolds. Both hydrogels exhibited better physiochemical and mechanical properties and supported long-term cell viability under static and dynamic conditions. Laser scanning confocal microscopy Z-stacking evaluations showed infiltration of FDA-stained L929 fibroblasts in the interstices of the hydrogels with appreciable depth. The hydrogel based on PEGDA promoted cell growth to an extent of 98 mm when compared to that of DEGDMA based hydrogel with 52 mm. These hydrogels supported the co-culture of fibroblasts and cardiomyoblasts and provided a better microniche for the cells as evident by the viability and cell cycle progression analyses. The favourable cellular responses of these hydrogels are attributed to the inherent biological recognition characteristics. On comparing the two hydrogels, the PEGDA-based hydrogel was superior to its DEGDMA counterpart due to the higher hydrophilicity of the former. The PEGDA-based hydrogel is a promising candidate for cardiac tissue engineering.
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    In vitro studies on the effect of physical cross-linking on the biological performance of aliphatic poly(urethane urea) for blood contact applications
    (BIOMACROMOLECULES, 2001)
    The effect of physical cross-Linking in candidate cycloaliphatic and hydrophobic poly(urethane urea) (4,4'-methylenebis(cyclohexylisocyanate), H12MDI/hydroxy-terminated polybutadiene, HTPBD/hexamethylene-diamine, HDA) and poly(ether urethane urea)s (H12MDI/HTPBD-PTMG/HDA) on the in vitro calcification and blood-material interaction was studied. All the candidate poly(urethane urea)s and poly(ether urethane urea)s elicit acceptable hemolytic activity, cytocompatibility, calcification, and blood compatibility in vitro. The studies on blood-material interaction reveal that the present poly(urethane urea)s are superior to polystyrene microtiter plates which were used for the studies on blood-material interaction. The present investigation reveals the influence of physical cross-link density on biological interaction differently with poly(urethane urea) and poly(ether urethane urea)s. The higher the physical cross-link density in the poly(urethane urea)s, the higher the calcification and consumption of WBC in whole blood. On the other hand, the higher the physical cross-link density in the poly(ether urethane urea)s, the lesser the calcification and consumption of WBC in whole blood. However a reverse of the above trend has been observed with the platelet consumption in the poly(urethane urea)s and poly(ether urethane urea)s.
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    Injectable in situ forming xylitol-PEG-based hydrogels for cell encapsulation and delivery.
    (Colloids and Surfaces B: Biointerfaces., 2015-01) Selvam, S; Pithapuram, VM; Victor, PS; Jayabalan, M
    Injectable in situ crosslinking hydrogels offer unique advantages over conventional prefabricated hydrogel methodologies. Herein, we synthesize poly(xylitol-co-maleate-co-PEG) (pXMP) macromers and evaluate their performance as injectable cell carriers for tissue engineering applications. The designed pXMP elastomers were non-toxic and water-soluble with viscosity values permissible for subcutaneous injectable systems. pXMP-based hydrogels prepared via free radical polymerization with acrylic acid as crosslinker possessed high crosslink density and exhibited a broad range of compressive moduli that could match the natural mechanical environment of various native tissues. The hydrogels displayed controlled degradability and exhibited gradual increase in matrix porosity upon degradation. The hydrophobic hydrogel surfaces preferentially adsorbed albumin and promoted cell adhesion and growth in vitro. Actin staining on cells cultured on thin hydrogel films revealed subconfluent cell monolayers composed of strong, adherent cells. Furthermore, fabricated 3D pXMP cell-hydrogel constructs promoted cell survival and proliferation in vitro. Cumulatively, our results demonstrate that injectable xylitol-PEG-based hydrogels possess excellent physical characteristics and exhibit exceptional cytocompatibility in vitro. Consequently, they show great promise as injectable hydrogel systems for in situ tissue repair and regeneration.
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    Intrinsically radiopaque polyurethanes with chain extender 4,4 '-isopropylidenebis [2-( 2,6-diiodophenoxy)ethanol] for biomedical applications
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 2015) Dawlee, S; Jayabalan, M
    Radiopaque polyurethanes are used for medical applications as it allows post-operative assessment of the biomaterial devices using X-ray. Inherently, radiopaque polyurethanes based on polytetramethylene glycol (PTMG), polypropylene glycol, 4,4-methylenebis(phenyl isocyanate), and a new iodinated chain extender 4,4-isopropylidenebis[2-(2,6-diiodophenoxy)ethanol] with flexible spacers were synthesized and characterized. The iodinated polyurethanes were clear, optically transparent, and had high molecular weights. The polyurethanes also possessed excellent radiopacity and high thermal stability. The biocompatibility of the most promising iodinated polyurethane was evaluated both in vitro (cytotoxicity evaluation by direct contact and MTT assay, using L929 mouse fibroblast cells) and in vivo (toxicology studies in rabbits and subcutaneous implantation in rats). The material was nontoxic and well tolerated by the animals. Thus, these radiopaque and transparent polyurethanes are expected to have potential for various biomedical applications.
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    Iodinated glycidyl methacrylate copolymer as a radiopaque material for biomedical applications
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 2013) Dawlee, S; Jayabalan, M
    Polymeric biomaterial was synthesized by copolymerizing 50:50 mol% of monomers, glycidyl methacrylate and methyl methacrylate. Iodine atoms were then grafted to the epoxide groups of glycidyl methacrylate units, rendering the copolymer radiopaque. The percentage weight of iodine in the present copolymer was found to be as high as 23%. The iodinated copolymer showed higher glass transition temperature and thermal stability in comparison with unmodified polymer. Radiographic analysis showed that the copolymer possessed excellent radiopacity. The iodinated copolymer was cytocompatible to L929 mouse fibroblast cells. The in vivo toxicological evaluation by intracutaneous reactivity test of the copolymer extracts has revealed that the material was nontoxic. Subcutaneous implantation of iodinated copolymer in rats has shown that the material was well tolerated. Upon explantation and histological examination, no hemorrhage, infection or necrosis was observed. The samples were found to be surrounded by a vascularized capsule consisting of connective tissue cells. The results indicate that the iodinated copolymer is biocompatible and may have suitable applications as implantable materials.
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    Materials for Biomedical Applications Symposium - IUMRS-ICAM 2007 - Preface
    (JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 2009) Jayabalan, M