Microfluidic device for 3-D electrokinetic manipulation of single fluorescent molecules Jason K. King, Brian K. Canfield, Lloyd M. Davis and William H. Hofmeister DC.00005 10/20/2011

Motivation

Nanochannel and ABEL trap 100 nm 400 nm Nanochannel ­ 20 nm sphere 8.90E04 5 nm ABEL ­ 20 nm sphere 5 nm 1.72E04

Theory – 3D trap V1 V4 V3 V1 = 3 V, V2 = V3 = V4 = 1 V Finite-volume time domain (FVTD) numerical simulations in ESI CFD-ACE+ Tetrahedral arrangement of electrodes on glass Uniform over laser focal volume Oriented by adjusting electrode potentials V1 V4 V3 V1 = 3 V, V2 = V3 = V4 = 1 V Electrode separation 200 µm V2 Davis et al, Proc. SPIE 6862 (2008)

Electrode-pair fabrication 1) Surface prep 2) Spin coat photoresist 3) Expose/Develop 5) Deposit Cr/Pt 6) Strip photoresist 4) Hard bake

Device assembly

Device assembly

Device assembly

Device assembly

Device assembly

Optical setup NI diffused light PCI - 7833R sample microscope objective lens iris mirror 660 notch 670 LP CCD cylindrical lens

Joystick Control X Y Z

XY Measurements 0.5V: 50 µm·s-1 1.0V: 80 µm·s-1 2.0V: 115 µm·s-1

Cycle XY

Cylindrical lens imaging X image focal plane Y Without Cylindrical Lens -5.0 +0.5 +1.5 +3.0 +5.0 -0.5 -1.5 -3.0 With Cylindrical Lens

Z Measurements 2.0V: 5 µm·s-1

Conclusion/Future Work Demonstrated control in three-axis Quantified motion Three-dimensional trapping of a single fluorescent particle in solution Automated tracking Increase data acquisition rate Further calibrate z-axis measurements Trapping algorithm Integrate z-motion into existing methods Optimize control for high speed operation

Thank you

Collision Simulations (Nanochannel) Rhodamine B: 360 µm s-1 20 nm bead: 21.8 µm s-1 7.06E06 10 nm 4.34E04 10 nm 1.47E06 5 nm 8.90E04 5 nm So why three dimensions? 2.40E05 2 nm 3.87E06 2 nm Time

Collision Simulations (ABEL trap) Rhodamine B: 360 µm s-1 20 nm bead: 21.8 µm s-1 1.47E05 10 nm 10 nm 1.09E04 3.52E05 5 nm 5 nm 1.72E04 So why three dimensions? 2 nm 2.12E04 1.65E05 2 nm Time