It is not often that we hear about actual living cells being turned into functioning lasers with the capacity to emit light. But that is exactly what a team of scientists at the Harvard Medical School has achieved – with their development of three different methods, all leading to the emission of visible light by cells. And while it may seem frivolous in the first instance, the genuine project was actually contrived to give experts the (theoretical) advantage in visually tracking the growth of various diseases such as cancer along cells.
The first of the methods conceived by the researchers involved the injection of special oil droplets into human cells (one droplet in each cell). This led to the formation of an optical cavity that could later filled with a fluorescent dye. So, when a pulse of light is incident on this formed cavity, the atoms of the dye get excited to further emit the light beam in a focused manner.
The second method entailed the ‘absorption’ of 10 micrometer-wide polystyrene beads by macrophages in a Petri dish. Macrophages pertain to a type of white blood cell that has the capacity to ingest foreign particles. So, when these particular white blood cells consume the polystyrene particles, they tend to emit light in the same manner as the aforementioned oil droplet incorporating cells.
The third and final method involved the use of naturally existing fatty droplets within the cells. For this experiment, the scientists utilized pig cells, and proceeded with the injection of fluorescent dye. These fatty cells (incorporating the dye) were once again made visually conspicuous – as they emitted their brand of light.
Now in terms of practicality, just tagging cells with fluorescent dyes is a pretty conventional method in medical research. But the predicament with this common practice is that it generates a wide range of various wavelengths; which makes it difficult for the observer to detect and distinguish any specific tagged cell (with its light emission). On the other hand, laser conforms to a very narrow range of wavelengths. In essence, it could be possible to detect and identify all kinds of human cells – by using the aforementioned techniques.
To that end, the researchers are looking forth to monitor the growth pattern of tumor cells via their focused visual ‘glow’. Moreover, the scientists are also confident of using similar methods to analyse the early developmental stages of complex organisms.
The study and its results were published in Nature Photonics and Nano Letters.
Source: NewScientist / Images Credit: Matjaž Humar and Seok Hyun Yun