Scientists Uncover Rapid Label-Free Detection at the Individual Virion Level with Optical Power

Rapid Label Free Detection at the Individual Virion Level with Optical Power

Scientists from École Polytechnique Fédérale de Lausanne (EPFL) have introduced a game-changing technique that uses light to handle and recognize individual bacteriophages, which are viruses that prey on bacteria. This innovation could revolutionize treatments for antibiotic-resistant bacterial infections, making the process much quicker and simpler.

Antibiotic resistance is becoming a major problem, so researchers are hunting for new ways to fight bacterial infections. Bacteriophages have emerged as a promising option. They're viruses that attack bacteria and could be used as therapy.

Phage therapy, as it's called, involves using these viruses to combat bacterial infections instead of antibiotics. This therapy is widely known for its personalized approach, whereby each case is treated as unique and investigated by screening the phage bank for a suitable candidate to treat a particular case, unlike antibiotic therapy, which follows a standardized approach for everyone. However, there's a challenge: determining which phage to use for a specific infection is like searching for a needle in a haystack.

In a joint effort with EPFL, CEA Grenoble, and Lausanne University Hospital (CHUV), scientists have created tiny nanotweezers that can trap and manipulate individual bacteria and virions (the infectious form of a virus) using just a little bit of light. There are other rapid methods, such as the one we recently wrote an article about, which involves barcoding the phage, but it appears to be complex to perform and requires advanced expertise.

These nanotweezers work like magic. They use a focused laser beam to handle microscopic objects such as virions without even touching them. Unlike regular tweezers, which operate in the open, these nanotweezers are part of a small chip.

This chip has tiny traps made of silicon-based photonic crystal cavities. These traps guide the phages into place using light, allowing scientists to control and monitor single bacteria and virions in real-time.

Illustration of the transmission properties during optical trapping of bacteria and phages utilizing the H2 hollow PhC cavity
Illustration of the transmission properties during optical trapping of bacteria and phages utilizing the H2 hollow PhC cavity ab SEM images demonstrating bacteria and phage respectively c Time series normalized to reveal shifts induced by a single phage blue and a single bacterium red on an H2 hollow nanocavity d Histograms displaying numerous single bacteriophage blue n = 16 and single bacterium red n = 9 trapping occurrences with the H2 hollow cavity

What's really cool is that this method can tell different types of phages apart without needing any chemicals or receptors. Instead, the nanotweezers analyze how each particle changes the light around it. This means researchers can pick the right therapeutic phages much faster, potentially speeding up the development of new treatments.

But it doesn't stop there. This research isn't just about phage therapy; it's also a game-changer for microbiology. Being able to study single virions in real time gives scientists a powerful tool for quick experiments and testing. This could help us understand viruses better and how they interact with hosts, which is crucial in the fight against infectious diseases.

Read more about this study: Nicolas Villa et al, Optical Trapping and Fast Discrimination of Label‐Free Bacteriophages at the Single Virion Level, Small (2024). DOI: 10.1002/smll.202308814. Image credit to the published study

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About the author

Hello there!

I'm Raphael Hans Lwesya. I have a deep interest in phage research and science communication. I strive to simplify complex ideas and present the latest phage-related research in an easy-to-digest format. Thank you for visiting The Phage blog. If you have any questions or suggestions, please feel free to leave a comment or contact me at [email protected].

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