Browsing by Author "Prasad, T"

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    A Cytocompatible Poly(N-isopropylacrylamide-co-glycidylmethacrylate) Coated Surface as New Substrate for Corneal Tissue Engineering
    (JOURNAL OF BIOACTIVE AND COMPATIBLE POLYMERS, 2010) Joseph, N; Prasad, T; Raj, V; Kumar, PRA; Sreenivasan, K; Kumary, TV
    The conventional method of retrieving cells for tissue engineering to create three-dimensional functional tissues uses enzymes that may hamper cell viability and re-adhesion. Culturing cells on thermoresponsive surfaces of poly(N-isopropylacrylamide) (PNIPAAm) is a relatively new nondestructive method of creating in vitro tissues. In this study, PNIPAAm and glycidylmethacrylate (GMA)-based thermoresponsive copolymer N-isopropylacrylamide-co-glycidylmethacrylate (NGMA) were synthesized as a potential cell culture harvesting system for generating 3D synthetic tissues. The copolymer was characterized by differential scanning calorimetry, gel permeation chromatography, Fourier transform infrared spectroscopy, water contact angle, atomic force microscopy, and nuclear magnetic resonance spectroscopy. The NGMA-coated dishes were evaluated for cytotoxicity and cytocompatibility using L-929 cells. Primary rabbit corneal cultures established on NGMA surface were detached as an intact cell sheet with epithelial specific characteristics as well as maintenance of cell-cell and cell-extracellular matrix contact. The results confirmed the suitability of NGMA substrate for cell culture and temperature-induced cell sheet harvest. This is the first report on this copolymer formulation as a substrate for tissue engineering application. Hydrophobic GMA apart from modulating the lower critical solution temperature features the prospects of further modification, namely the incorporation of biomolecules through the epoxy groups.
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    A Novel Thermoresponsive Graft Copolymer Containing Phosphorylated HEMA for Generating Detachable Cell Layers
    (JOURNAL OF APPLIED POLYMER SCIENCE, 2010) Abraham, TN; Raj, V; Prasad, T; Kumar, PRA; Sreenivasan, K; Kumary, TV
    A novel polymeric formulation based on N-isopropylacrylamide (NIPAAm), methylmethacrylate (MMA), and phosphorylated hydroxylethyl methacrylate (Phosp-HEMA) was synthesized and characterized. NIPAAm was copolymerized with a known quantity of MMA to form a poly(NIPAAm-MMA) copolymer and was subsequently grafted with Phosp-HEMA by gamma irradiation to a total dose of 0.5 kGy. The thermoresponsive graft copolymer was characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, contact angle measurements, and energy dispersive X-ray analysis. The cytotoxicity of the graft copolymer analyzed using L-929 fibroblast cells showed noncytotoxic response. The cell adhesion on the graft copolymer was studied using rabbit corneal cells (SIRC) and human osteoblasts (HOS). The adhered cells were found to spread leading to the formation of cell layers. The cell layers with intact cell-cell and cell-extra cellular matrix contact were detached by lowering temperature below the lower critical solution temperature (29 degrees C) of the graft copolymer. The viability and morphology of the cells in detached cell sheets were assessed by live dead staining and environmental scanning electron microscopy, respectively. This interesting feature of cell adhesion to form cell layers and cell sheet retrieval is implicit to be due to the properties of phosphate moieties on thermoresponsive copolymer. To the authors knowledge there is no previous report on phosphate moiety containing thermo responsive polymeric formulations which can modulate cell adhesion and cell sheet retrieval. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 52-62, 2010
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    Characterization and in vitro evaluation of electrospun chitosan/polycaprolactone blend fibrous mat for skin tissue engineering
    (JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 2015) Prasad, T; Shabeena, EA; Vinod, D; Kumary, TV; Kumar, PRA
    The electrospinning technique allows engineering biomimetic scaffolds within micro to nanoscale range mimicking natural extracellular matrix (ECM). Chitosan (CS) and polycaprolactone (PCL) were dissolved in a modified solvent mixture consisting of formic acid and acetone (3:7) and mixed in different weight ratios to get chitosan-polycaprolactone [CS-PCL] blend solutions. The CS-PCL blend polymer was electrospun in the same solvent system and compared with PCL. The physicochemical characterization of the electrospun fibrous mats was done using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), tensile test, swelling properties, water contact angle (WCA) analysis, surface profilometry and thermo gravimetric analysis (TGA). The CS-PCL fibrous mat showed decreased hydrophobicity. The CS-PCL mats also showed improved swelling property, tensile strength, thermal stability and surface roughness. The cytocompatibility of the CS-PCL and PCL fibrous mats were examined using mouse fibroblast (L-929) cell line by direct contact and cellular activity with extract of materials confirmed non-cytotoxic nature. The potential of CS-PCL and PCL fibrous mats as skin tissue engineering scaffolds were assessed by cell adhesion, viability, proliferation and actin distribution using human keratinocytes (HaCaT) and L-929 cell lines. Results indicate that CSPCL is a better scaffold for attachment and proliferation of keratinocytes and is a potential material for skin tissue engineering.