Hou, Yaping (2009-12). Photocurable Inorganic-Organic Hydrogels for Biomedical Applications. Doctoral Dissertation. Thesis uri icon

abstract

  • There are two primary objectives of this dissertation research. The first objective was to prepare a library of inorganic-organic hydrogels from methacrylated star polydimethylsiloxane (PDMSstar-MA) and diacrylated poly(ethylene oxide) (PEO-DA) with tunable chemical and physical properties for use as tissue engineering scaffolds. These inorganic-organic hydrogels provide a useful platform to study the effect of scaffold properties on cell behavior in tissue culture. Twenty compositionally unique hydrogels were prepared by photo-crosslinking varing molecular weights (Mn) of PEO-DA (Mn = 3.4k and 6k g/mol) and PDMSstar-MA (Mn = 1.8k, 5k and 7k g/mol) at varying weight ratios (up to 20 wt% PDMSstar-MA). Introduction of PDMSstar-MA caused formation of discrete PDMS-enriched "microparticles" dispersed within the PEO hydrogel matrix. The swelling ratio, mechanical properties in tension and compression, non-specific protein adhesion and cytotoxicity of hydrogels were studied. The second objective was to prepare thermoresponsive nanocomposite hydrogels, which are mechanically robust and can remove adhered cells via thermal modulation. Such hydrogels may be useful as "self-cleaning" membranes for implanted biosensors to extend their lifetime and efficiency. These hydrogels are comprised of a poly(Nisopropylacrylamide) (PNIPAAm) hydrogel matrix and polysiloxane colloidal nanoparticles (~220 nm and 50 nm ave. diameter). Due to the low preparation temperature, the nanocomposite hydrogels exhibited a homogeneous morphology by SEM analysis. The volume phase transition temperature (VPTT, ~33 degrees C) of the nanocomposite hydrogels was not altered versus the pure PNIPAAm hydrogel, which is near body temperature. Generally, nanoparticles led to improve mechanical properties versus pure PNIPAAm hydrogels. When these nanocomposite hydrogels are heated above the VPTT, they become more hydrophobic. When they are reversibly switched from a water-swollen to a deswollen state, the change in surface properties, as well as swelling-deswelling, was effective upon the removal of adhered cells.
  • There are two primary objectives of this dissertation research. The first objective
    was to prepare a library of inorganic-organic hydrogels from methacrylated star
    polydimethylsiloxane (PDMSstar-MA) and diacrylated poly(ethylene oxide) (PEO-DA)
    with tunable chemical and physical properties for use as tissue engineering scaffolds.
    These inorganic-organic hydrogels provide a useful platform to study the effect of
    scaffold properties on cell behavior in tissue culture.
    Twenty compositionally unique hydrogels were prepared by photo-crosslinking
    varing molecular weights (Mn) of PEO-DA (Mn = 3.4k and 6k g/mol) and PDMSstar-MA
    (Mn = 1.8k, 5k and 7k g/mol) at varying weight ratios (up to 20 wt% PDMSstar-MA).
    Introduction of PDMSstar-MA caused formation of discrete PDMS-enriched "microparticles"
    dispersed within the PEO hydrogel matrix. The swelling ratio, mechanical
    properties in tension and compression, non-specific protein adhesion and cytotoxicity of
    hydrogels were studied.
    The second objective was to prepare thermoresponsive nanocomposite hydrogels,
    which are mechanically robust and can remove adhered cells via thermal modulation. Such hydrogels may be useful as "self-cleaning" membranes for implanted biosensors to
    extend their lifetime and efficiency. These hydrogels are comprised of a poly(Nisopropylacrylamide)
    (PNIPAAm) hydrogel matrix and polysiloxane colloidal
    nanoparticles (~220 nm and 50 nm ave. diameter). Due to the low preparation
    temperature, the nanocomposite hydrogels exhibited a homogeneous morphology by
    SEM analysis. The volume phase transition temperature (VPTT, ~33 degrees C) of the
    nanocomposite hydrogels was not altered versus the pure PNIPAAm hydrogel, which is
    near body temperature. Generally, nanoparticles led to improve mechanical properties
    versus pure PNIPAAm hydrogels. When these nanocomposite hydrogels are heated
    above the VPTT, they become more hydrophobic. When they are reversibly switched
    from a water-swollen to a deswollen state, the change in surface properties, as well as
    swelling-deswelling, was effective upon the removal of adhered cells.

publication date

  • December 2009