Photon Sensor Could Allow for Super-Fast Biodetection

The new technique allows for extreme high speed photonic sensing of the mechanical properties of free flowing particles--providing a new understanding of how human cells assemble in tissues and bones that could lead to enhanced diagnostics.

Kristopher Sturgis

For years researchers have understood the correlation between cancer and the mechanical properties of cells, but have lacked the ability to measure and use these mechanical properties diagnostically. Researchers from the University of Illinois at Urbana-Champaign recently developed a technique that will could that gap, and enhance our understanding of how diseases modify the mechanical property of cells in the human body.

"It is established that many diseases like various cancers and anemia do cause changes to the mechanical properties of cells," says Gaurav Bahl, assistant professor of mechanical science and engineering at the university and one of the authors on the research. "However, these properties cannot yet be used diagnostically due to the absence of tools with enough speed and sensitivity to perform the measurement in practical settings. Because of this, we have barely scratched the surface of understanding of how diseases modify the mechanical properties of cells in our body."

Traditionally, high-speed optical detection methods like flow cytometry have been used to analyze large populations of particles, with analysis speeds around 50,000 particles per second. Unfortunately optical sensors cannot directly measure mechanical properties like density, mass, or compressibility. Now, Bahl and his colleagues believe that they have found a way to bring mechanical sensors up to speed to provide a tool that can be used to make routine measurements on large cell populations.

"We aimed to blend the best features of optical sensing (like extremely high bandwidth and sensitivity) with mechanical sensing, which allows the ability to measure mechanical properties without binding," Bahl says. "To achieve this, we have developed a novel microfluidic opto-mechanical device that enables high speed measurements of single particles within the microchannel. Sensing is performed by coupling light to vibrations in the structure--the vibrations are perturbed by the particles as they flow past at high speed, while light captures this information with very high bandwidth."

Bahl says that with our current limited knowledge of cell mechanics, it has been tough to make a prediction on whether future diagnoses and treatments would routinely employ mechanical measurements of cells. However, this new technique represents an enhancement in the basic resolution of information that can be obtained from commonly analyzed biological samples--a discovery that could bring us one step closer towards enhanced and more accurate diagnostics.

"Developing knowledge around the mechanics of cells and bioparticles may advance our knowledge in understanding the mobility of these micro-objects throughout the human body, about how cells assemble mechanically to form tissues and bones, about how tumors form, and about how cells and bacteria can propagate through us."

As they move forward with their research, Bahl says that their aim is to develop better control over the system so that more consistent measurements can be made. Once they can establish a basic sense of control and better understand the physics of the sensing mechanism, Bahl believes the next step will be to develop new diagnostic measurements.

"We are excited to see what the community comes up with, now that we have shown the measurements are possible with this new sensing mechanism." 

Kristopher Sturgis is a contributor to Qmed.

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