High resolution miniature microscope

Dispensing with the expensive lenses that have been used in regular microscope for centuries, a Californian scientist has developed a small optical device that uses the same chip technology found in budget digital cameras to produce high resolution microscope images. According to a report in the online edition of the Technology Review the California Institute of Technology (Caltech) scientists who developed the device, estimate that the main body of the microscope could be mass produced for ten dollars a piece.

The device uses a system of small fluid channels to direct the samples being studied over a light-sensing chip. The sensor required for this microfluidic system was developed for digital photography. The scientists modified it, covering it with a thin layer of metal which blocks out most of the pixels. Several hundred small apertures punched into the metal along the fluid channels allow the light to penetrate. As the sample flows through the microscope, every aperture captures an individual image. One version of the microscope uses gravity to control the sample's flow across the apertures. Another variation of the design allows much more control using an electrical field.

The resulting 100 to 200 pictures per sample are subsequently assembled using simple image processing software. Caltech engineer Changhuei Yang, who designed the microscope, says that a PDA's processing power is more than enough to handle the calculations. The microscope must be illuminated from the top, but normal daylight is quite sufficient. The resolution of about one micrometre is equivalent to that of a conventional light microscope and depends on the respective size of the individual mini apertures. The technology is small enough to be incorporated into a PDA-like device.

See also:

• Optofluidic Microscopy report from the Biophotonics Laboratory at Caltech.

(trk)