DocumentCode :
842869
Title :
Characterization of implantable microfabricated fluid delivery devices
Author :
Rathnasingham, Ruben ; Kipke, Daryl R. ; Bledsoe, Sanford C., Jr. ; McLaren, John D.
Author_Institution :
Neural Eng. Lab., Univ. of Michigan, Ann Arbor, MI, USA
Volume :
51
Issue :
1
fYear :
2004
Firstpage :
138
Lastpage :
145
Abstract :
The formal characterization of the performance of microfluidic delivery devices is crucial for reliable in vivo application. A comprehensive laboratory technique was developed and used to optimize, calibrate and validate microfabricated fluid delivery devices. In vivo experiments were carried out to verify the accuracy and reliability of the pressure driven devices. Acute guinea pig experiments were conducted to measure the response to α-amino-3-hydroxy-5-methyl-4-isoxalone propionic acid, an excitatory neurotransmitter, at multiple locations in the inferior colliculus. A nondimensional parameter, Q˜, was successfully used to classify devices in terms of geometry alone (i.e., independent of fluid properties). Functional devices exhibited long-term linearity and reliability in delivering single phase, Newtonian fluids, in discrete volumes with a resolution of 500 picoliters at less than 0.45 lbf/in2 (30 mbar) pressure drop. Results for non-Newtonian fluids are not presented here. The acute results showed a proportional increase in the firing rate for delivered volumes of 2 nL up to 10 nL (at rates of between 0.1 and 1 nL/s). Flow characteristics are maintained during acute experiments and post-implant. A control experiment conducted with Ringer solution produced negligible effects, suggesting the results to be truly pharmacological. The experimental techniques employed have proven to be reliable and will be used for future calibration and testing of next generation chronic microfluidic delivery devices.
Keywords :
biological fluid dynamics; drug delivery systems; microfluidics; neurophysiology; /spl alpha/-amino-3-hydroxy-5-methyl-4-isoxalone propionic acid; 30 mbar; BioMEMS; controlled chemical delivery; excitatory neurotransmitter; flow characterization; implantable microfabricated fluid delivery devices; inferior colliculus; microfluidic delivery devices; pressure driven devices; single phase Newtonian fluids; Calibration; Fluid flow control; Geometry; In vivo; Laboratories; Linearity; Maintenance; Microfluidics; Neurotransmitters; Testing; Action Potentials; Animals; Calibration; Computer-Aided Design; Equipment Design; Equipment Failure Analysis; Flow Injection Analysis; Guinea Pigs; Inferior Colliculi; Infusion Pumps, Implantable; Infusions, Parenteral; Microfluidics; Miniaturization; Neurons; Reproducibility of Results; Sensitivity and Specificity; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid;
fLanguage :
English
Journal_Title :
Biomedical Engineering, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9294
Type :
jour
DOI :
10.1109/TBME.2003.820311
Filename :
1254003
Link To Document :
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