INTEC   05402
INSTITUTO DE DESARROLLO TECNOLOGICO PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
MICROFABRICATION, MODELING AND SIMULATION OF A MICROFLUIDIC PROTOTYPE FOR ANALYTICAL PURPOSES
Autor/es:
PABLO A. KLER, FABIO A. GUARNIERI, CLAUDIO L. A. BERLI
Lugar:
Bariloche
Reunión:
Conferencia; PASI 2006; 2006
Institución organizadora:
National Science Foundation, USA
Resumen:
Microfluidic chips are miniaturized analytical devices used in chemical, biological
and medical applications. In most cases, fluids are conducted through microchannels by
applying electric potentials and/or pressure gradients. There has been a huge interest in
these devices in the past decade that led to a commercial range of products (Freemantle,
1999). Different methods to obtain microfluidic systems have been successfully
developed for several materials (Madou, 2002). This growing lab-on-a-chip technology
requires analytical models and numerical simulations to assist the design, control and
optimization of analytical manipulation (Patankar 1998).
The present work deals with the microfabrication, theoretical modeling and
simulation of a microfluidic chip aimed to perform analytical assays, namely capillary
electrophoresis (CE). The prototype has been manufactured integrally in glass, using
commercial microscopes slides as substrates (Stjerström et al 1998, Baldwin et al 2002).
In these substrates a microchannel network, and an electrode system have been
fabricated using photolithographic techniques, wet etching, physical vapour deposition,
and thermal bonding techniques. Wet etching was performed using photoresist as etch
mask, to avoid using metals mask, simplifying the usual process in glass etching (Che-
Hsin Lin et al 2001). The transport of electrolyte solution through the microchannels is
based on electroosmotic flow, it is obtained using a single DC high voltage source
(Flüke 415B) and electrodes at the ends of the channels (reservoirs) in order to apply the
potential. Basic manipulations, such as sample injection and focusing, were carried out
to evaluate the capability of the device.
An analytical unidirectional model was used to estimate values of flow rate and
electric current for a given configuration of applied electric potentials. Also a 3D
numerical simulation by finite elements method (FEM) was performed. These studies
allowed us to predict values of fluid velocity and electric current for both constructive
and functional parameters variations. Constructive parameters were channel dimensions,
while functional parameters were applied voltage, electrolyte composition, and channel
surface properties.
Experimental results from the injection and focusing process were compared with
those predicted by both analytical and numerical models. The magnitudes employed to
carry out this comparison were the velocity and the focus width.