Droplet Gradient Array For Parallel Experimentation via Microfluidic Device Lindsay Pickett Faculty Mentor: Abraham P. Lee Graduate Mentor: Rob Lin IM-SURE 2006 Lindsay Pickett Faculty Mentor: Abraham P. Lee Graduate Mentor: Rob Lin IM-SURE 2006

Outline of Discussion Introduction Goals Process Results Issues Solutions Future Direction Introduction Goals Process Results Issues Solutions Future Direction

Introduction Microfluidic Devices Widely applicable- engineering, biology, chemistry –Research tools –Commercial applications Advantages: –microscale fluid physics –less reagent & shorter Rxn time –parallel operations –lab space conservation, –easy/cheap fabrication Widely applicable- engineering, biology, chemistry –Research tools –Commercial applications Advantages: –microscale fluid physics –less reagent & shorter Rxn time –parallel operations –lab space conservation, –easy/cheap fabrication

Project Goal Droplet Gradient Array Ismagilov Laboratory –Thorough characterization –Control over droplet properties Droplet volume Gradient steps –Versatility of device for multiple applications Droplet Gradient Array Ismagilov Laboratory –Thorough characterization –Control over droplet properties Droplet volume Gradient steps –Versatility of device for multiple applications

Project Outline Process: Device design Fabrication Testing External valve system Computer-mediated step gradient Characterization Process: Device design Fabrication Testing External valve system Computer-mediated step gradient Characterization

Device Design Outlet reservoir Reagent Inlets Oil Inlet Shearing Junction Array Observation Region

Process: Device design 12 µm 7.5 µm 70/30 µm50/50 µm12/7.5 µm

Process : Experimental Setup

Results:Testing Top Aq. Inlet: DI (variable rate) Bottom Aq. Inlet: DI + dye (const. rate) Oil inlet: Silicon oil (const. rate 2µL/min) *Droplet content control* Top Aq. Inlet: DI (variable rate) Bottom Aq. Inlet: DI + dye (const. rate) Oil inlet: Silicon oil (const. rate 2µL/min) *Droplet content control* 0.80 vs 0.70 µL/min 0.95 vs 0.70 µL/min 1.25 vs 0.70 µL/min

Results: Array Capture (Colorcam) Array image capture  external valves work Not pictured  instability introduced by valves –Initializing system: backflow, fluctuation of flow rate –Over 20 min observation period: chaotic, random instability Array image capture  external valves work Not pictured  instability introduced by valves –Initializing system: backflow, fluctuation of flow rate –Over 20 min observation period: chaotic, random instability

Solutions… VALVES Contacted vendor… –no suitable suggestions –different fluid route (Dr. Lee) Different External Valves Quake pressure-actuation Valves 2-D valve for sufficient freeze VALVES Contacted vendor… –no suitable suggestions –different fluid route (Dr. Lee) Different External Valves Quake pressure-actuation Valves 2-D valve for sufficient freeze

Other Solutions… *Fluid re-routing…*new filtration design… *input tips

Future Direction Valves/new designs Computer-mediated step gradient (Hyperterminal) Characterization via GFP and ImageJ Step gradient Droplet volume Valves/new designs Computer-mediated step gradient (Hyperterminal) Characterization via GFP and ImageJ Step gradient Droplet volume

Acknowledgements NSF and the IMSURE program Abraham P. Lee (faculty mentor) Rob Lin (grad. student mentor) Lee laboratory team Eckerd College Biochemistry Dept. NSF and the IMSURE program Abraham P. Lee (faculty mentor) Rob Lin (grad. student mentor) Lee laboratory team Eckerd College Biochemistry Dept.