New ‘molecular flashlight’ technique detects brain metastases in mice using ultra-thin light probe

Monitoring molecular changes in the brain caused by cancer and other neurological pathologies in a non-invasive way is one of the major challenges in biomedical research. A new experimental technique has achieved this by introducing light into the brains of mice using an ultra-thin probe. The study is published in the journal Nature Methods by an international team that includes groups from the Spanish National Cancer Research Centre (CNIO) and the Spanish National Research Council (CSIC).

The authors describe the new technique as a “molecular flashlight” because it provides information about the chemical composition of nerve tissue by illuminating it. This makes it possible to analyze molecular changes caused by tumors, whether primary or metastatic, as well as injuries such as a traumatic brain injury.

The molecular flashlight is a probe less than 1 mm thick, with a tip just one micron wide—about one thousandth of a millimeter—and invisible to the naked eye. It can be inserted deep into the brain without causing damage (for comparison, a human hair measures between 30 and 50 microns in diameter).

This flashlight-probe is not yet ready to be tested in patients, and for now it is primarily a “promising” research tool in animal models that allows “monitoring molecular changes caused by traumatic brain injury, as well as detecting diagnostic markers of brain metastasis with high accuracy,” explain the authors of the paper.

The work has been carried out by the European NanoBright consortium, which includes two Spanish groups: the one led by Manuel Valiente, who heads the CNIO’s Brain Metastasis Group, and the CSIC’s Neuronal Circuits Laboratory of the Cajal Institute, led by Liset Menéndez de la Prida. Both teams have been responsible for the biomedical research at NanoBright, while groups from Italian and French institutions have developed the instrumentation.

Exploring the brain with light without altering it previously

Using light to activate or record brain function is a remarkable achievement, but it is not a new technique. For example, so-called optogenetic techniques make it possible to control the activity of individual neurons with light. However, these methods require the introduction of a gene into the neurons to make them light-sensitive. With the new technology introduced by NanoBright, the brain can be studied without prior alteration, representing a paradigm shift in biomedical research.

The technical name of the method on which the new molecular fl