Hydrodynamic focusing of conducting fluids for conductivity-based biosensors.
Hydrodynamic focusing of a conducting fluid by a non-conducting fluid to form a constricted current path between two sensing electrodes is implemented in order to enhance the sensitivity of a 4-electrode conductance-based biosensor. The sensor has a simple two-inlet T-junction design and performs four-point conductivity measurements to detect particles immobilized between the sensing electrode pair. Computational simulations conducted in conjunction with experimental flow studies using confocal microscopy show that a flat profile for the focused layer is dependent on the Reynolds number for the chosen flow parameters. The results also indicate that a flat focused layer is desirable for both increased sensitivity as well as surface-binding efficiency. Proof of concept for conductance measurements in a hydrodynamically focused conducting fluid was demonstrated with entrapped magnetic beads.
Nasir
Mansoor
M
Naval Research Laboratory, Center for Bio/Molecular Science and Engineering, Washington, DC 20375, USA.
Ateya
Daniel A
DA
Burk
Diana
D
Golden
Joel P
JP
Ligler
Frances S
FS
D015374:Biosensing Techniques / Q000295:instrumentation*; D017076:Computer-Aided Design; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017022:Flow Injection Analysis / Q000295:instrumentation*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D011312:Pressure; D012996:Solutions / Q000737:chemistry*
D012996:Solutions