Browsing by Author "Komeri, R"

Now showing 1 - 7 of 7
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    Covalently cross-linked hydroxyapatite-citric acid-based biomimetic polymeric composites for bone applications
    (JOURNAL OF BIOACTIVE AND COMPATIBLE POLYMERS, 2015) Victor, SP; Vineeth, VM; Komeri, R; Selvam, S; Muthu, J
    Composite materials based on bioceramics and polymers offer excellent opportunities in the quest for developing optimal bone grafts for bone tissue engineering. Herein, we have functionalized nano hydroxyapatite with citric acid and subsequently cross-linked with poly(propylene fumarate) and poly(ethylene glycol) to afford a composite with better interfacial bonding properties. This study involved two biomimetic composites, 3CP-VP and 5CP-VP, prepared by varying the concentration of hydroxyapatite. Uniform homogenous distribution of hydroxyapatite was identified through Raman spectral imaging in both the composite matrices. The compressive moduli of the biomimetic composites after 4-week immersion in phosphate-buffered saline ranged between 100 and 300MPa, which falls well within the accepted values reported for human trabecular bone. Moreover, biodegradation studies revealed only an average weight loss of 10%-17% during the 7-week time period. Furthermore, apatite mineralization was evaluated using scanning electron microscopy and energy dispersive X-ray analysis, and contact angle measurements revealed hydrophobic surfaces with preferential adsorption to albumin. More importantly, blood compatibility studies demonstrated no significant hemolysis and no visible red blood cell aggregation, while cytotoxicity evaluation via direct contact, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and live-dead assays on human osteoblast sarcoma cell line exhibited good biocompatibility with negligible cytotoxicity. In addition, in vitro drug release studies with gentamycin-loaded composites demonstrated a controlled and sustained release profile with about 35% of drug released over a period of 2weeks. These findings show that these composites could be developed into stand-alone bone substitutes for bone tissue engineering coupled with drug delivery applications.
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    Free radical scavenging injectable hydrogels for regenerative therapy
    (MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS, 2017) Komeri, R; Thankam, FG; Muthu, J
    Pathological free radicals generated from inflamed and infarcted cardiac tissues interferes natural tissue repair mechanisms. Hypoxic microenvironment at the injured zone of non-regenerating cardiac tissues hinders the therapeutic attempts including cell therapy. Here we report an injectable, cytocompatible, free radical scavenging synthetic hydrogel formulation for regenerative therapy. New hydrogel (PEAX-P) is prepared with D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer (PEAX) and PEGDiacrylate. PEAX-P hydrogel swells 4.9 times the initial weight and retains 100.07 kPa Young modulus at equilibrium swelling, which is suitable for cardiac applications. PEAX-P hydrogel retains elastic nature even at 60% compressive strain, which is favorable to fit with the dynamic and elastic natural tissue counterparts. PEAX-P hydrogel scavenges 51% DPPH radical, 40% hydroxyl radicals 41% nitrate radicals with 31% reducing power. The presence of hydrogel protects 62% cardiomyoblast cells treated with stress inducing media at LD 50 concentration. The free hydroxyl groups in sugar alcohols of the comacromer influence the free radical scavenging. Comparatively, PEAX-P hydrogel based on xylitol evinces slightly lower scavenging characteristics than with previously reported PEAM-P hydrogel containing mannitol having more hydroxyl groups. The possible free radical scavenging mechanism of the present hydrogel relies on the free IT electrons associated with uncrosslinked fumarate bonds, hydrogen atoms associated with sugar alcohols/PEG and radical dilution by free water in the matrix. Briefly, the present PEAX-P hydrogel is a potential injectable system for combined antioxidant and regenerative therapy. (C) 2016 Elsevier B.V. All rights reserved.
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    In situ crosslinkable elastomeric hydrogel for long-term cell encapsulation for cardiac applications
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, 2016) Komeri, R; Muthu, J
    The regenerative therapy of tissues relays on successful cell transplantation and engraftment. Soft hydrogel carriers are employed to protect transplanted cells from harmful microenvironment in soft tissue regeneration. Herein an injectable, porous, biodegradable, bioresorbable, and elastomeric hydrogel fabricated from poly(propylene fumarate-co-sebacate-co-ethylene glycol) crosslinked with PEGDA for cardiomyoblast encapsulation was reported. The hydrogel retains adequate mechanical property in the range of native myocardium even after 30 days of degradation (49 +/- 0.008 kPa). The hydrogel shows maximum extensibility without collapsing even under 60% compression. The hydrogel retains 70.58% equilibrium water content, wide internal porosity, and slow bulk degradation favorable for cell carriers. The cardiomyoblast cells encapsulated in hydrogel retains viability even after 30 days of culture. The long-term viability and proliferation studies of encapsulated cells in the hydrogel substantiate the suitability of hydrogel microenvironment for cell survival. The present hydrogel is a potential cell carrier with favorable physical and biological properties for cell encapsulation for cardiac applications. The candidate hydrogels perform better than the other reported elastomeric hydrogels fabricated for cell therapy. (c) 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2936-2944, 2016.
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    Influence of matrix and bulk behaviour of an injectable hydrogel on the survival of encapsulated cardiac cells
    (RSC ADVANCES, 2015) Komeri, R; Thankam, FG; Muthu, J
    Cytocompatibility, suitable porosity, higher equilibrium water content and tissue like elasticity are the demanding criteria required to design a hydrogel for cell encapsulation and delivery. Here a mechanically stable cell supporting synthetic hydrogel was fabricated from poly(propylene fumarate-co-ethylene glycol)/PEGDA by redox initiating polymerisation for cell encapsulation. A hydrogel prepared with 93.5% poly(propylene fumarate-co-ethylene glycol) and 6.5% PEGDA acquired matrix and bulk characteristics of equilibrium water content (EWC) 84.45 + 0.80%, freezable water content 67.93%, Young modulus 212.2 +/- 0.02 kPa and pore diameter 88.64 +/- 18.96 mu m. This hydrogel with higher free water content, favourable pore dimensions and mechanical strength was used to encapsulate cardiomyoblasts. The encapsulated cardiomyoblasts were showing increasing viability from 3-30 days with viable green fluorescence. The matrix and bulk characteristics of the hydrogel are favourable and elicited uniform, green fluorescing, live cardiomyoblasts (H9c2) inside with 150% cell viability (MTT assay) and uniform ECM protein distribution after 30 days. The slow in vitro degradation of the hydrogel in physiological-like conditions is favourable for the delivery and retention of the encapsulated cells at the injection site.
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    Neodymium doped hydroxyapatite theranostic nanoplatforms for colon specific drug delivery applications
    (COLLOIDS AND SURFACES B-BIOINTERFACES, 2016) Victor, SP; Paul, W; Vineeth, VM; Komeri, R; Jayabalan, M; Sharma, CP
    Theranostic nanoplatforms integrate therapeutic payloads with diagnostic agents, and help monitor therapeutic response. In this regard, stimuli responsive nanoplatforms further favour combinatorial therapeutic approach that can considerably improve efficacy and specificity of treatment. Herein, we present the engineering of a smart theranostic nanoplatform based on neodymium doped hydroxyapatite (HAN). The presence of neodymium endows the HAN nanoplatforms with near-infrared fluorescence capability. These HAN nanoparticles were then subsequently modified with alginic acid (HANA) to confer pH responsiveness to the synthesized nanoplatforms delivering them to the colon after oral administration. These nanoplatforms possessing optimum size, needle shaped morphology and negative zeta potential, are conducive to cellular internalization. On excitation at 410 nm they exhibit near infrared emission at 670 nm unraveling their theranostic capabilities. Cytotoxic effects systematically assessed using MIT and live dead assays reveal excellent viability. Raman microscopic imaging technique used to visualize uptake in HeLa cells demonstrate increased uptake from 4 to 16 h, with growing cluster size and localization in the cytoplasm. Moreover the concomitant presence of alginic acid manifested advantages of augmented loading and pH dependent release profiles of the model drug, 4 acetyl salicylic acid (4ASA). We could thus establish a theranostic system for early tumour detection, targeted tumour therapy and monitoring of colon cancer that can be administered via the oral route. (C) 2016 Elsevier B.V. All rights reserved.
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    Photoluminescent PEG based comacromers as excitation dependent fluorophores for biomedical applications
    (COLLOIDS AND SURFACES B-BIOINTERFACES, 2015) Vijayan, VM; Komeri, R; Victor, SP; Muthu, J
    We report a novel multi-modal biodegradable photoluminescent comacromer [poly(propylene fumarate)-PEG-glycine] (PLM) having excitation-dependent fluorescence (EDF) for biomedical applications. The photoluminescence of the synthesized PLM in aqueous and solid state condition, fluorescence life time and photo stability were evaluated. Hydrogels and nanogels were prepared from the PLM by cross linking with acrylic acid. Nanogels exhibited spherical morphology with a particle size of 100 nm as evaluated by transmission electron microscopy (TEM). In vitro cytotoxic and hemolytic studies revealed cytocompatibility. Furthermore, cellular imaging of nanogels on L929 fibroblast and Hela cell lines revealed EDF characteristics. We hypothesize that the EDF characteristics of the synthesized PLM may be attributed to the presence of n-pi* interactions of the hydroxyl oxygen atoms of PEG with carbonyl groups of the ester linkages. Taken together, our results indicate that the synthesized PEG-based comacromer can serve as biocompatible fluorophores for various biomedical applications. More importantly, the facile way of synthesizing fluorescent polymers based on PEG with EDF characteristics demonstrated in this work can pave the way for developing more novel biocompatible fluorophores with wide range of biomedical applications. (C) 2015 Elsevier B.V. All rights reserved.
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    Photoluminescent PEG based comacromers as excitation dependent fluorophores for biomedical applications.
    (Colloids and Surfaces B: Biointerfaces, 2015-09) Vijayan, VM; Komeri, R; Victor, SP; Muthu, J
    We report a novel multi-modal biodegradable photoluminescent comacromer [poly(propylene fumarate)-PEG-glycine] (PLM) having excitation-dependent fluorescence (EDF) for biomedical applications. The photoluminescence of the synthesized PLM in aqueous and solid state condition, fluorescence life time and photo stability were evaluated. Hydrogels and nanogels were prepared from the PLM by cross linking with acrylic acid. Nanogels exhibited spherical morphology with a particle size of 100 nm as evaluated by transmission electron microscopy (TEM). In vitro cytotoxic and hemolytic studies revealed cytocompatibility. Furthermore, cellular imaging of nanogels on L929 fibroblast and Hela cell lines revealed EDF characteristics. We hypothesize that the EDF characteristics of the synthesized PLM may be attributed to the presence of n–π* interactions of the hydroxyl oxygen atoms of PEG with carbonyl groups of the ester linkages. Taken together, our results indicate that the synthesized PEG-based comacromer can serve as biocompatible fluorophores for various biomedical applications. More importantly, the facile way of synthesizing fluorescent polymers based on PEG with EDF characteristics demonstrated in this work can pave the way for developing more novel biocompatible fluorophores with wide range of biomedical applications.