Biosensors and Bioelectronics 2005 21 303-312. A microbead array chemical sensor using capillary-based sample introduction: toward the development of an “electronic tongue” S. Sohn, A. Goodey, E. Anslyn, J. McDevitt, J. Shear, and D. Neikirk The development of a micromachined fluidic structure for the introduction
of liquid samples into a chip-based sensor array composed of individually
addressable polymeric microbeads is presented. The micromachined structure
consists of micromachined storage cavities combined with a covering glass
layer that confines the microbeads and fluidic channels. In our sensor
array transduction occurs via optical (colorimetric and fluorescence)
changes to receptors and indicator molecules that are covalently attached
to termination sites on the polymeric microbeads. Spectral data are acquired
for each of the individual microbeads using a charged-coupled device (CCD)
allowing for the nearreal-time analysis of liquid sample. Hence the micromachined
fluidic structure must allow for both optical access to the microbeads
and fluid flow through the micromachined cavities that serve as the microreactors/analysis
chambers. One of the key parts of the structure is a passive fluid introduction
system driven only by capillary force. This simple means of fluid introduction
realizes a compact device. The capillary flow on the inlet channel has
been studied, and the responses of the microbeads (alizarin complexone)
to a liquid sample have been characterized. The test results show
that this system is useful in a micro-total-analysis-system (-TAS) and
biomedical applications. |