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Optical Biosensors
Joel Kindt
Lauren Netherton
Acknowledgements
Dr. Kevin Lear
Dr. Dave Kisker
Weina Wang
Hailey Cutler
1
Lauren Netherton
• Motivation and Introduction
• Prior Research
• How Optical Biosensors Work
2
3Courtesy of Kian Behbakht of UC Denver
Prior Research
Senior Design Team 2007-2008
4
Pipe Organ Analogy
• Place fruit in organ pipe
• Changes pitch based on:– Size– Shape
http://lib.colostate.edu/archives/phelps/
5
6
Optical Detection & RF Switch
Circuit Spectrometer
HealthyCancerous!
Courtesy of Weina Wang
Trapping Requirements
• Lower voltages– Trap at
slower velocity
• Higher voltages– Trap at
higher velocity
7
Dielectrophoretic Force
• Use of electromagnetics• Non-uniform electric field
– Polarizes molecules within cell– Induces DEP force to hold cell in trap
Electric field
8
December 2007 Senior Design Presentation
3 22 Re[ ]DEP mF r K E
Polarization factor (K factor):* *
* *2p m
p m
K
* j
Complex permittivity of particle/suspending medium:
Dielectrophoretic Force
9Courtesy of Weina Wang
Joel Kindt
• Electrostatic Modeling
• Experimental Data
• Budget
• Conclusions and Future Work
10
Electrodes on Chip
11
Electrostatic Modeling
12
3 22 Re[ ]DEP mF r K E
DEP ForceE-Field
13
Positive and Negative DEP
• Mammalian white blood cell
• σm = 0.1 S/m (~ water)
• σm = 1.5 S/m (~ PBS)
3 22 Re[ ]DEP mF r K E
Joel Voldman, “Electrical Forces For Microscale Cell Manipulation”, Annu. Rev. Biomed. Eng. 2006. 8:425-54
14
Polarization factor (K factor):* *
* *2p m
p m
K
K > 0: Positive DEP K < 0: Negative DEP
* j
,
Experimental Setup
15
Impedance of Channel
Voltage Divider
http://en.wikipedia.org/wiki/Voltage_divider16
more heat dissipated at lower impedance
17
Impedance of Channel
Budget
Materials 1st semesterbudget
1st semesteractual
2nd semesterbudget
Syringes $15 $0 $15
Glass $75 $0 $0
Nanoports $0 $0 $60
Nanotubing $0 $0 $25
Flexible mirror $10 $0 $0
Total $100 $0 $100
18
• Know trapping requirements for various fluid velocities
• Possible to model cell trap through simulations– Electric field
– DEP force
• The fluid properties can affect results– K factor
– Impedance of channel19
Conclusions
• Design better cell trap through simulations
• Further understand spectra– Cancerous vs. non-cancerous cells
– Different types of cancer
• Save Rover!
20
Future Work