Small, Cheap, Portable Spectrometer for Biological Sample Imaging Anywhere

Optical spectrometers provide a unique view of biological samples. How objects reflect different frequencies of light reveals quite a bit about them, but precise, highly sensitive spectrometers tend to be bulky and expensive. This technical limitation has prevented the use of spectrometry in many potential medical applications, particularly in field medicine and in areas with a shortage of medical facilities. A team of Chinese researchers have developed a small, portable spectrometer that uses a smartphone as the display and data processing device. The technology is relatively cheap and may help make spectrometry more accessible, potentially opening up many use cases that haven’t yet been properly explored.

The device is only 5 ounces (140 grams) in weight, 1.2 inches (3.1 cm) in diameter, and 6 inches (15.5 cm) in length. It costs less than $300 to produce using existing, commercially available components, and is easy to use. It has a wavelength resolution of about 17 nanometers, detecting in the range from 400 to 675 nanometers thanks to a white LED array for illumination.

The device has its own CMOS camera chip and transmits its readings to the smartphone. The user can move the spectrometer across a sample and take pictures. The smartphone, in turn, receives all the exposures and digitally stitches them together, producing the final resulting dataset.

Using the new spectrometer, the researchers were able to detect the iron rich protein myoglobin in a cut of pork. They were also able to measure the hemoglobin distribution in a volunteer’s hand by creating a 16 second video from 200 images of it.