Flow Cytometry for Adherent Cell Assays
Cynthia Jensen-McMullin, Stephen Ng
Faculty Advisors: G.-P. Li & Mark Bachman & Nancy Allbritton & Chris Sims
Department of Electrical Engineering and Computer Science / Department of Physiology and Biophysics
The Henry Samueli School of Engineering / College of Medicine / University of California, Irvine
The Problem Optical Detection Standard Assays
Flow cytometry and other flow-based assays are powerful The surfboards are detected by using an inexpensive diode laser Boards with cell growth are subjected to standard assays. In
technology for non-adherent cells but not for adherent cell and photodiode detection scheme. As the surfboard passes, the the images below, RBL cells grown on SU-8 plastic
lines--adherent cells need a surface to stick to. Flow beam intensity to the photodiode is blocked. The output from “surfboards” are processed through wash steps and stained
cytometry is useless for 95% of cells that matter to the photodiode can be coupled to a high speed imaging system, using Oregon Green Diacetate.
biologists and medical researchers! enabling us to
view the high speed
sheath flow A typical flow cell for a flow surfboards and
cytometer. The sample flow their cargo with in
contains cells in suspension standard optical
(non-adherent). Due to measuring tools. photodiode
laminar flow, the sheath flow
and sample flow do not mix.
sample or Instead, pressure differences
(with cells) are used to hydrodynamically Surfboards can be manipulated in Optical image of a plastic Same image under
focus the sample flow. standard flow cells (e.g., flow “surfboard” with cell growth. fluorescence excitation
cytometers) were passed through a
The Solution micromachined acrylic flow cell. The Automated Assays sample stream
Go surfing of course! blue stream represents the sample reagent
flow (horizontal orientation). We envision a system where a
single cell (or cells) grown on a laser
substrate (surfboard) are
transported through a fluorescence
programmable, automated assay detector
system. This system could perform
Microfabrication techniques are Cells are grown on the surface of the
functions such as washing, laser
used to fabricate micro-pallets with “surfboards.” In this example, RBL cells have labeling, detection and sorting.
barcodes. The “surfboards” can been cultured on the boards. Surfboards can contain bar codes fluorescence
transport the cells. detector
Video frames of surfboard and would be designed such that
transported through microfluidic the onboard cell could be
Surfboard Dynamics channel. Boards are readily identified.
Laminar flow and board shape is used to guide and orient the manipulated and imaged.
surfboards down the channels.
A micro-pallet system (“surfboards”) is being developed to enable high speed flow cytometry on adherent cells. Thousands of micro-
surfboards will enable adherent cells to be manipulated in micro-factories that can perform automated cell analysis and sorting.
Cell cargo on microscopic
surfboard laminar flow
Microfabrication of surfboards Optical detection of surfboards in flow channel
Optical image of a plastic Parabolic profile of laminar flow
Tested flow of surfboards in various geometries Fluorescent labeling/imaging of RBL cells on surfboards
surfboard passing through a velocity, illustrating maximum velocity at Growth of RBL cells on plastic surfboards confirmed
Micromachined PMMA channel the center and near-zero at the walls.
Acknowledgements: Ruisheng Chang and the INRF staff.