Browsing by Author "Nair, BP"

Now showing 1 - 6 of 6
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    Fabrication of a microvesicles-incorporated fibrous membrane for controlled delivery applications in tissue engineering
    (BIOFABRICATION, 2014) Nair, BP; Vaikkath, D; Mohan, DS; Nair, PD
    A scaffold, which can provide mechanical support for tissue regeneration and simultaneously release functionally active biomolecules are highly desirable for tissue engineering applications. Herein, we report the fabrication of a fibrous mesh of polycaprolactone (PCL) incorporating PCL-pluronic (F127) microvesicles through electrospinning, by exploiting the slow dissolution of PCL in glacial acetic acid (g-AA). Micro-vesicles 1-10 mu m in diameter were fabricated through a non-solubility driven spontaneous self-assembly and stabilization of F127 with low molecular weight PCL in tetrahydrofuran-water mixture. Time-dependent stability of the vesicles in g-AA was confirmed prior to the electrospinning. The electrospun membrane was found to be comprised of microvesicles entangled in a fibrous mesh of PCL with a fiber diameter ranging from 50-300 nm. Significant reduction in the release rate of rhodamine-B, an indicator dye from the electrospun membrane, when compared to that from the vesicle alone, evidences the surface coating of the vesicles with high molecular weight PCL during electrospinning. The vesicle incorporated membrane exhibited increased hydrophilicity when compared to the control PCL membrane, possibly due to surface unevenness and the hydrophilic F127. This enhanced surface hydrophilicity led to an increased cell viability of L929 cells on the membrane.
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    Fabrication of a microvesicles-incorporated fibrous membrane for controlled delivery applications in tissue engineering.
    (Biofabrication., 2014-10) Nair, BP; Vaikkath, D; Mohan, DS; Nair, PD
    A scaffold, which can provide mechanical support for tissue regeneration and simultaneously release functionally active biomolecules are highly desirable for tissue engineering applications. Herein, we report the fabrication of a fibrous mesh of polycaprolactone (PCL) incorporating PCL-pluronic (F127) microvesicles through electrospinning, by exploiting the slow dissolution of PCL in glacial acetic acid (g-AA). Micro-vesicles 1-10 μm in diameter were fabricated through a non-solubility driven spontaneous self-assembly and stabilization of F127 with low molecular weight PCL in tetrahydrofuran-water mixture. Time-dependent stability of the vesicles in g-AA was confirmed prior to the electrospinning. The electrospun membrane was found to be comprised of microvesicles entangled in a fibrous mesh of PCL with a fiber diameter ranging from 50-300 nm. Significant reduction in the release rate of rhodamine-B, an indicator dye from the electrospun membrane, when compared to that from the vesicle alone, evidences the surface coating of the vesicles with high molecular weight PCL during electrospinning. The vesicle incorporated membrane exhibited increased hydrophilicity when compared to the control PCL membrane, possibly due to surface unevenness and the hydrophilic F127. This enhanced surface hydrophilicity led to an increased cell viability of L929 cells on the membrane.
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    Hybrid scaffold bearing polymer-siloxane Schiff base linkage for bone tissue engineering
    (MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS, 2015) Nair, BP; Gangadharan, D; Mohan, N; Sumathi, B; Nair, PD
    Scaffolds that can provide the requisite biological cues for the fast regeneration of bone are highly relevant to the advances in tissue engineering and regenerative medicine. In the present article, we report the fabrication of a chitosan-gelatin-siloxane scaffold bearing interpolymer-siloxane Schiff base linkage, through a single-step dialdehyde cross-linking and freeze-drying method using 3-aminopropyltriethoxysilane as the siloxane precursor. Swelling of the scaffolds in phosphate buffered saline indicates enhancement with increase in siloxane concentration, whereas compressive moduli of the wet scaffolds reveal inverse dependence, owing to the presence of siloxane, rich in silanol groups. It is suggested that through the strategy of dialdehyde cross-linking, a limiting siloxane loading of 20 wt.% into a chitosan -gelatin matrix should be considered ideal for bone tissue engineering, because the scaffold made with 30 wt.% siloxane loading degrades by 48 wt.%, in 21 days. The hybrid scaffolds bearing Schiff base linkage between the polymer and siloxane, unlike the stable linkages in earlier reports, are expected to give a faster release of siloxanes and enhancement in osteogenesis. This is verified by the in vitro evaluation of the hybrid scaffolds using rabbit adipose mesenchymal stem cells, which revealed osteogenic cell-clusters on a polymer-siloxane scaffold, enhanced alkaline phosphatase activity and the expression of bone-specific genes, whereas the control scaffold without siloxane supported more of cell-proliferation than differentiation. A siloxane concentration dependent enhancement in osteogenic differentiation is also observed. (C) 2015 Elsevier B.V. All rights reserved.
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    Polycaprolactone-laponite composite scaffold releasing strontium ranelate for bone tissue engineering applications
    (COLLOIDS AND SURFACES B-BIOINTERFACES, 2016) Nair, BP; Sindhu, M; Nair, PD
    We report polycaprolactone-laponite composite scaffold for the controlled release of strontium ranelate (SRA), a drug for osteoporosis. Laponite-SRA complex with electrostatic interaction between the drug and laponite was obtained through an aqueous phase reaction. Structural evaluation verified complexation of the bulky SRA molecules with the negatively charged laponite tactoid surfaces, leading to extended ordering of the tactoids, leaving behind the interlayer spacing of the laponite unchanged. The laponite-SRA complex was solution blended with polycaprolactone to obtain composite scaffolds. The strategy was found improving the dispersibility of laponite in PCL due to partial organomodification imparted through interaction with the SRA. The composite scaffolds with varying laponite-SRA complex content of 3-12 wt% were evaluated in vitro using human osteosarcoma cells. It was confirmed that an optimum composition of the scaffold with 3 wt% laponite-SRA complex loading would be ideal for obtaining enhanced ALP activity, by maintaining cell viability. (C) 2016 Elsevier B.V. All rights reserved.
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    Polyhedral Oligomeric Silsesquioxane-F68 Hybrid Vesicles for Folate Receptor Targeted Anti-Cancer Drug Delivery
    (LANGMUIR, 2014) Nair, BP; Vaikkath, D; Nair, PD
    Polyhedral Oligomeric Silsesquioxane (POSS)-F68 hybrid vesicles with an average diameter of 700 nm are produced using a stable solution of heterofunctional POSS having 3-aminopropyl and vinyl groups and pluronic F68 in ethanol-water mixture. Thermogram and zeta potential values evidence the spontaneous self-assembly of POSS into bilayers through H-bonding interaction between the aminopropyl groups, and the effective stabilization of the POSS-bilayers by amphiphilic F68 during solvent-evaporation to form the vesicles. The vesicles are noncytotoxic and dispersible in aqueous solvents through steric stabilization provided by the hydrophilic F68. A highly facile coinclusion method has been used for making doxorubicin and folic acid loaded vesicles. Doxorubicin loaded in the vesicles exhibits a controlled release profile in phosphate buffered saline. Confocal microscopic and flow cytometric studies on the endocytosis of the vesicles by HeLa and HOS cells prove that a noncovalent entrapment of excess folic acid in the vesicles through H-bonding is sufficient to enhance the uptake significantly. POSS-F68 vesicles in combination with folic acid and a chemotherapeutic can have potential for targeted intracellular anti-cancer drug delivery.