50 likes | 159 Views
Formation of Microparticles using a Heat Sensitive Gel in a Microfluidic Device. Gordon Christopher and Shelley L. Anna Department of Mechanical Engineering Carnegie Mellon University, Pittsburgh, PA 15213. 77 th Annual Meeting of The Society of Rheology Vancouver, British Columbia, Canada
E N D
Formation of Microparticles using a Heat Sensitive Gel in a Microfluidic Device Gordon Christopher and Shelley L. Anna Department of Mechanical Engineering Carnegie Mellon University, Pittsburgh, PA 15213 77th Annual Meeting of The Society of Rheology Vancouver, British Columbia, Canada October 16 - 20, 2005
Droplet Formation in Microfluidic T-Junctions Dispersed Phase Continuous Phase • Shearing leads to drops • Ease of fabrication/operation • Droplet size monodisperse and controllable
Possible Applications for Microscale Particles Drug Delivery Collect • Drugs composed of protein susceptible to: • Enzymes • Acid in Stomach • Solution encapsulate (Patil et al., Journal of Polymer Science,1999) Monodispersed drop size Controlled Dosage and Diffusion Dispersed Phase withDrug Drug Diffuses controlled by drop sizes Microfluidic Probe of Fast Gel Kinetics? • Thermoreversible gelation processes: • Phase separation • Crosslinking • Conformation Change • Rates affect final gel morphology (Manno et al., Phys. Rev. E., 1999) • Morphology domains order of 10-15μm (Bansil and Lal, Poly., 1992) Make microscale drops Heat in microfluidic device Confinement and Quench Rates impossible in Macroscale Rheometers
Strongly Shear Thinning • Gels with thermal hysteresis • Agarose • Carrageenan: κ,λ,ι • Water soluble • i-Car: soluble with Ca2+ (Hossain, Biomacro.,2001) • Applications: biotechnology and consumer products… i-Car Repeat Unit (Patil et al., Journal of Polymer Science,1999) Drop size dependent on Constant Effective Viscosity (Pa•sec) Drop Size Shear Rate
Measuring Gel Particle Properties i-Car, Qd=40 PDMS, Qc=400 i-Car, Qd=60 PDMS, Qc=600 Agarose Particles • Packing • Non-Spherical Shapes