A simple method to sense DNA, as well as potential biomarker proteins of cancer or other diseases such as Alzheimer’s, may soon be within reach – thanks to the work of a team of Yokohama National University researchers in Japan.
As the team reports in Applied Physics Letters, from AIP Publishing, they created a photonic crystal nanolaser biosensor capable of detecting the adsorption of biomolecules based on the laser’s wavelength shift.
Equally impressive, the nanolaser biosensor enables detection of the surface charge from its laser emission intensity, which in turn can also be used to sense the adsorption of biomolecules. Using laser intensity to detect biomolecules is potentially less expensive than the fluorescent tagging or spectroscopy techniques typically used in biosensors because it is a simpler procedure.
When the team first set out to explore photonic crystal nanolaser sensors, they weren’t focusing on the intensity of the laser emission because it’s sensitive to the quality of the fabricated laser and, frankly, they didn’t expect it to show sensing signals.
This image shows a top view of the group’s nanolaser, in which the center narrow slot (horizontal line) is the main part of the sensor. The periodic holes form a photonic crystal, and although the size of the holes appears to fluctuate they’ve been intentionally modified so the laser’s emission is effectively extracted to the top.
CREDIT: Toshihiko Baba/Yokohama National University
Simultaneous detection of refractive index and surface charges in nanolaser biosensors, Keisuke Watanabe, Yoji Kishi, Shoji Hachuda, Takumi Watanabe, Mai Sakemoto, Yoshiaki Nishijima and Toshihiko Baba, Applied Physics Letters, DOI: 10.1063/1.4904481, published 13 January 2015.