Multichannel Optical Biosensor May Detect Cancer

An eight channel smartphone spectrometer has been developed that can detect human interleukin-6 (IL-6), a known biomarker for lung, prostate, liver, breast and epithelial cancers. Unlike current smartphone spectrometers, which are used to monitor or measure one sample at a time, the multichannel smartphone spectrometer (MSS) can optically analyze several samples simultaneously, adding to its potential value as a high-throughput device.

Washington State University researchers have developed a low-cost, portable laboratory on a smartphone that can analyze several samples at once to catch a cancer biomarker, producing lab quality results. Courtesy of Washington State University.

To achieve multichannel optical spectral sensing with nanometer resolution, researchers from Washington State University used a 3D- printed cradle to hold the smartphone, which was integrated with the optical components. They developed a custom smartphone multi-view App to control the optical sensing parameters and to align each sample to the corresponding channel. The captured images were converted to the transmission spectra in the visible wavelength range from 400 to 700 nm with the high resolution of 0.2521 nm per pixel.

The research team validated the performance of the MSS by measuring concentrations of protein and immunoassaying a type of known human cancer biomarker. When results of the analysis were compared to results from a standard laboratory instrument, they showed that the MSS could achieve analysis detection limits, accuracy and sensitivity comparable to the quality of a lab instrument. The multichannel spectrometer can measure up to eight different samples at once using a common test called ELISA.

Although the research team has only used the smartphone spectrometer with standard lab-controlled samples, their device has been shown to be up to 99 percent accurate. The researchers are now applying their portable spectrometer in real world situations.

"With our eight channel spectrometer, we can put eight different samples to do the same test, or one sample in eight different wells to do eight different tests. This increases our device's efficiency," said professor Lei Li, who has filed a provisional patent for the work.

The researchers envision that the multichannel smartphone optical biosensor could be useful in point-of-care diagnostics due to its small size, light weight, low cost and data transmission function.

"The spectrometer would be especially useful in clinics and hospitals that have a large number of samples without on-site labs, or for doctors who practice abroad or in remote areas," Li said. "They can't carry a whole lab with them. They need a portable and efficient device."

The MSS works with an iPhone 5. The research team is creating an adjustable design that will be compatible with any smartphone.

The research was published in Biosensors and Bioelectronics (doi: 10.1016/j.bios.2016.09.021).