In the past, in order to analyze the types of bacteria in liquid samples, researchers had to cultivate bacteria for several hours or even days in the laboratory. However, a new laser technology can achieve this goal in a few minutes.
It is well known that when bacteria are exposed to lasers, they will reflect light back in a spectral mode unique to a particular species. Other microscopic substances in the sample, such as blood cells or viruses, will also reflect light, bringing unique changes to it. This means that the spectrum "fingerprint" of bacteria will disappear in the background noise, so it cannot be recognized.
The new technology recently developed by researchers in the Cornell University laboratory abroad combines an improved inkjet printer to print out small dots of liquid using acoustic pulse. After printing on the slide, the volume of each point is only 2 parts per trillion of 1 liter. Because these spots are too small, they only contain dozens of cells at most, so any existing bacteria are rarely found.
During their operation, the researchers injected gold nanorods into the sample. If the bacteria existed, the nanorods would attach to the bacteria, just like an antenna, guiding the laser to the bacteria, and increasing the signal intensity by about 1500 times. This makes it easy for software based on machine learning to find "fingerprints" and match them with specific types of bacteria, finally achieving a sensitive observation and detection effect.
Although this technology is mainly developed using infected mouse blood as a liquid, researchers believe that it should be equally effective when analyzing other liquids - it can even be applied to other types of cells, such as viruses. This innovative solution is expected to be commercialized, help redefine the standards for bacterial detection and single cell characterization, and play a key role in saving lives.
Source: OFweek laser network
