Single Cell Biosensor. Allan Fierro David Sehrt Doug Trujillo Evan Vlcek Michael Bretz. Fabrication. Flow Control. Introduction. Optical Detection Circuit. Allan Fierro. Cell Trapping. What is Flow Cytometry?. Technique for counting cells Examining cells Sorting cells.
Analysis of a marine sample of photosynthetic picoplankton by flow cytometry showing three different populations (Prochlorococcus,Synechococcus and picoeukaryotes)
*diagrams courtesy of L. Shao, Ph.D.
from Ph.D. Defense Presentation
Images courtesy of Weina Wang
1. 30 nm Chrome Deposition
2. 120 nm Gold Deposition
3. Spin Photoresist
6. Gold Etch
7. Chrome Etch
8. Resist Removal
Detect the presence of a cell in proximity of a trap
Interface with the pump flow controller
Provide triggering for the RF traps
Circuit Design Flow Chart
Low pass filter
Signal to DAQ
The light source is set up as shown in the figure. The LED is a high-intensity Infrared LED.
Lear, Kevin L., Hua Shao, Weina Wang, and Susan E. Lana. "Optofluidic Intracavity Spectroscopy of Canine Lymphoma and Lymphocytes." IEEE Explore (2007). 4 Dec. 2007.
50/125 multimode fiber
infrared source LEDs
~2mV Output from Diode
A1 signal to USB DAQ
Rise Time: 128 µs
Figure of Time Response of Optical Detection Circuit
Data Acquisition Unit
The digital signal from the Data Acquisition Unit is input into an ADG-452 (basically a digital switch) chip. This allows an AC signal to be applied to the DEP traps
Sphere must be traveling at 40 micron/second or less
Signal used to generate the electric field must be a time varying signal in order to produce a non-uniform electric field.
Signal used to generate the electric field must have an amplitude greater than 5 Volts peak to peak
Both of these requirements are necessary in order for the for the force caused by the electric field to overcome the force caused by the flow of water. i.e. an object in motion stays in motion unless acted upon by a net external force.