Light source
CHANGHUEI YANG AND DEMETRI PSALTIS Condensor
Filter
Sample
Imaging stystem
TFilter he term optofluidics defines an emergent Sen sor array research field that combines microfluidics and optics (see “Devices abound in nascent FIGURE 1. In an adjustable-focal-depth optofluidic transmission discipline” on p. 87). In many biological microscope, the light source, the condensor, the spectral filters, and the imaging system are replaced with optofluidic compo- applications the two technologies are used nents, which can enable the creation of cheap, easily configu- in combination—microfluidics for sample delivery and rable, and compact microscope systems. optics for sensing. The implementation of optics in the microfluidic platform enables an unprecedented level of technologies can be adapted for biophotonics applica-integration. Moreover, optofluidic devices are easily and tions to create inexpensive and compact devices. highly reconfigurable, which can be a significant advantage for manipulating and The implementation of optics Optofluidic handling biological samples. conventional
The use of fluid as a medium for trans- in the microfluidic platform microscope port is appropriate for a significant class yields an unprecedented level A classic biomedical of clinically important biological entities, imaging tool, the con-ranging from DNA strands, viruses, and of integration. ventional microscope, bacteria to cells and microorganisms. In for instance, provides addition, microfluidics-based devices require very low a vehicle for applying optofluidic technology to create a input sample volumes (nanoliters or less) and can be compact and low-cost version of the microscope (see Fig. very conservative in terms of the samples—samples can- 1). A conventional microscope contains many optical ele-not easily be lost in the devices. This nascent cross-dis- ments—light source, condenser, spectral filters, sample, ciplinary field already offers a few excellent examples, and imaging system—and therefore serves as a good illus-such as the fluorescence-based microfluidic cell sorter. 1 trative example.
In addition, numerous recently developed optofluidic The light source for the microscope can be an array of
LEDs embedded in polydimethylsioxane (PDMS) or other
CHANGHUEI YANG is an assistant professor and DEME TRI PSALTIS transparent material used as the fluidic channel. The LEDs is the Thomas G. Myers Professor in the Electrical Engineering Depart- can be placed in the liquid monomer solution and a solid ment and Bioengineering Department, 13 Moore, Caltech, 1200 E. Cal- ifornia Blvd, MC136-93, Pasadena, CA 91125; e-mail: Chyang@caltech.st ructure is formed when the PDMS containing the LEDs edu; www.optofluidics.caltech.edu/. is cured. In some applications, such as two-photon sensing,
References:
http://www.optofluidics.caltech.edu/
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