Fluorescence has been the de facto method for analyzing biomolecules, but the technique has its limitations. When conditions are right, these fluorescent dyes and proteins will glow brightly, making them easy to detect with conventional tools. More often than not, there is background noise that drowns out the fluorescence and makes detection almost impossible. Not happy with that limitation, scientists have developed a “living laser” technology that uses biological components, usually proteins, to enhance the fluorescent signals and make it possible to detect the molecules even when the signals are weak. In the latest example of a living laser, scientists are pushing the envelope by using blood as a critical component.
Detailed in an article recently published in the Optical Society of America Technical Digest, the blood laser uses a dye called indocyanine green (ICG) that is popular in medical imaging and fluoresces in near-infrared light. On its own, the ICG molecule produces a weak light signal that is difficult to detect in situ. To improve the method, researchers started to search for living components to boost the resulting fluorescent signal and that’s when they stumbled upon blood. When the researchers added blood to the mix, they discovered that the ICG dye bound to the plasma proteins in the blood. This combination generated an intense light that the researchers could detect.
Though promising, the procedure faces scrutiny from the public, which likely will be leery of a technique that combines lasers with blood, a unusual combination that sounds like it was pulled straight from the pages of a sci-fi novel. Researchers also have to tweak the process, so the laser and the resulting fluorescence are within safe limits. “You don’t want to burn the tissue,” said researcher Xudong Fan to New Scientist. (We agree.)
The research team eventually hopes to use this blood-based system in the living tissue of a patient in order to detect cancer. In this future scenario, a doctor could wave a laser wand over a patient’s arm and use the resulting fluorescence to detect whether there was evidence of cancer under the patient’s skin.