(62g) Modeling Small Molecule Elution From a Hydrogel Using a Microfluidic Technique

Dye elution from hydrogels using a glass on glass microfluidic technique can be used to begin modeling drug release from a bio-contacting material. Photolithography is used to cure a poly(ethylene glycol) diacrylate (PEGDA), dye, and a photoinitiator solution inside a microfluidic device with a channel through the middle of the gel. Pumping water through the channel causes dye to diffuse out of the hydrogel and into the water stream based on a concentration gradient. Channel sizes within the devices range from 300-1000µm to simulate vessels within the body. Digital image analysis of the dye diffusion captured by a stereomicroscope is modeled to determine diffusion coefficients and the dye release profile with respect to time and position in the hydrogel. Analysis of the eluted fluid is performed through ultraviolet-visible spectroscopy to determine a short time diffusion coefficient. The properties of the hydrogel can characterized by the extent of PEGDA crosslinking, which is related to the UV exposure dosage, the initial water and dye content in the PEGDA solution, and the swelling ratio in the gel.