Light spectroscopy is a method of detecting all sorts of compounds in biological samples, but they can be bulky and difficult to implement in small devices. Researchers at UCLA and École polytechnique fédérale de Lausanne, Switzerland have developed a portable sensor capable of detecting viruses and protein monolayers and bilayers without using a spectroscope at all. Instead of measuring how a sample disperses light into different wavelengths, the new sensor watches for changes in the intensity of light propagating through a sample.
The “optical lab on a chip” weighs only 60 grams and is about the size of a bottle of pills. A centimeter square gold plate with pores less than 200 nanometers in diameter is used to spread the sample into arrays of tiny compartments that hold biofilms that attract proteins being searched for. An LED then shines light into the pores and through the samples, while a CMOS chip below measures its intensity. The technique doesn’t require any labeling, relies on off-the-shelf, inexpensive parts, and can be used in remote and hard to service areas of the world. Moreover, the device uses iterative phase retrieval-based image reconstruction to allow for high-throughput testing on the go.
Article in journal Light: Science & Applications: Handheld high-throughput plasmonic biosensor using computational on-chip imaging