Changhuei Yang's ePetri Allows Efficient Cell Study

Caltech professor Changhuei Yang has created the equivalent of a wired laboratory on a chip by combining inexpensive cellphone electronics with software for stitching sensor input into high-resolution images of cells.

Yang’s ePetri uses a tiny image-sensor chip as the bottom of the petri dish on which the sample cells are placed directly for cultivation. An Android phone’s LED screen serves as the light source. The setup is placed in an incubator. Rather than periodically placing a sample onto a microscope slide at regular intervals, the experimenter turns on the laptop to which the image-sensor chip is wired. The growing cells are recorded in real time by the sensor chip and fed to a software in the laptop that knits them together to form high-resolution pictures of the cells’ progress.

The ePetri produces images with sufficient resolution to reveal the contents of a cell nuclei — comparable to that of a conventional microscope, says Yang who is the senior author of a paper describing the prototype ePetri published this week in the Proceedings of the National Academy of Sciences. Yang is a Caltech electrical and bioengineering professor who has been recognized as one of the top 20 scientists under the age of 40 by Discover magazine.

“With ePetri, it’s like getting continuous tweets from the cells rather than an occasional postcard,” says the paper’s co-author Michael Elowitz, a Caltech biology professor.

The ePetri offers other advantages beyond being able to monitor cells automatically and continuously on a laptop. Because the entire petri dish is under surveillance by the image sensor, esearchers get a picture of what all the cells are doing. This can be a big advantage in studies in which cells change into different types and move around, as with stem cells, for example.

Yang’s team is also working on an even more self-contained system built into its own portable incubator to be used as a desktop diagnostic tool in a doctor’s office to eliminate the costly and time-consuming practice of sending bacterial samples to labs for testing.

Changhuei Yang’s formal higher education has been received entirely at MIT — a BS in electrical engineering and computer science and a BS in physics and a masters in EECS in 1997; a BS in mathematics and PhD in EECS in 2002.

After a brief stint at ESPCI in Paris and at Duke University, in 2003 Yang moved out to Southern California in pursuit of warmer weather and settled into a teaching and research career at Caltech. He has focused his research in biophotonics — the imaging and extraction of information from biological targets through the use of light. He categorizes his research efforts into two major groups — Optofluidics for biosensing and interferometry-based imaging.

In optofluidics Yang’s group is developing a microscope-on-a-chip system that is tiny, high resolution and cheap with the aim of dramatically improving third world healthcare and simplifying bioscience research. His ePetri is first step in that effort. Yang is Caltech’s associate director of DARPA funded Center for Optofluidic Integration.

In interferometry-based imaging Yang’s group is developing novel imaging schemes to enable high-sensitivity cell dynamic studies and fast microscopy imaging. He has also been developing a narrow-bore imaging needle scope that can see ahead of a needle tip during surgical procedures.

Yang has received the NSF Career Award, the Coulter Foundation Early Career Phase I and II Awards, and the NIH Director’s New Innovator Award.