Space- and time-resolved spectrophotometry in microsystems

Abstract

This work describes a simple optical method for obtaining, in a single still-capture image, the continuous absorbance spectra of samples at multiple locations of microsystems. This technique uses an unmodified bright-field microscope, an array of microlenses, and a diffraction grating to disperse the light transmitted by samples of 10- to 500-μm dimensions. By analyzing in a single image the first-order diffracted light, it is possible to collect the full and continuous absorbance spectra of samples at multiple locations (to a spatial resolution of ≈8 μm) in microwells and microchannels to examine dynamic chemical events (to a time resolution of <10 ms). This article also discusses the optical basis of this method. The simultaneous resolution of wavelength, time, and space at a scale <10 μm provides additional capabilities for chemical and biological analysis. © 2005 by The National Academy of Sciences of the USA.