Nanostructured Biodegradable Polymer Networks Using Lyotropic Liquid Crystalline Templates

Jason D Clapper; C Allan Guymon

In recent years, the use of nanotechnology in biomedical research has increased exponentially as scientists have seen numerous benefits ranging from highly efficacious drug nanocarriers to cell directing nanofibrous networks. 1 As nanostructured biomaterials begin to see greater use in biomedical applications, tissue engineering in particular is a field that will benefit greatly from the material implications of nanotechnology. Researchers have already shown increased cell attachment with the ability to create nanoscale topography on a polymer scaffold, as well as greater matching between the synthetic scaffold and actual tissue morphology with the incorporation of nanofibers within the scaffold matrix. 2 Nanostructured biomaterials also have the potential to enhance many of the physical properties and behavior of a synthetic gel, including water uptake, modulus, and degradation rate, that would not be possible with traditional fabrication methods. The use of self assembling media such as lyotropic liquid crystals (LLCs) has recently been identified as one of the more promising methods to create nanoscale structure in organic polymers. 3 LLCs are surfactant based aqueous solutions that exhibit a variety of nanostructured geometries directed by the concentration of surfactant in solution and the temperature of the system. Recent research has focused on the use of LLCs as polymerization templates, directing the structure of a forming polymer network into the highly ordered geometry of the parent liquid crystal. 4 In this study, non-degradable and biodegradable photopolymers were synthesized and templated with various LLC mesophases in an attempt to create ordered nanostructure within the network of these materials. By imposing specific nanostructure on the matrix of these gels through LLC templating, it is hypothesized that the physical properties that are tied to network structure can be manipulated through the morphology of the LLC template. The physical properties of templated non-degradable poly(ethylene glycol) diacrylate (PEGDA) and biodegradable PLA-PEG-PLA dimethacrylates were studied as a function of network morphology. Specifically, the network swelling, compressive modulus, diffusivity, and degradation rate were analyzed as a function of network morphology as the parent LLC template was altered in these materials. The ability to control the porosity, physical properties, and behavior of a hydrogel simply by imparting LLC network structure, without changing the chemistry or biocompatibility of the polymer, is highly advantageous in the design of synthetic biomaterials for medical applications.

Nanostructured Biodegradable Polymer Networks Using Lyotropic Liquid Crystalline Templates

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