Single molecule valves: a breakthrough in nanoscale control

Scientists dream of using small molecules as building blocks to build things, similar to the way we build things with mechanical parts. However, the molecules are very small – about one hundred millionth the size of a softball – and they move around chaotically in liquids, making it very difficult to manipulate them into a single shape. To address this challenge, “nanofluid devices” that can transport molecules in very narrow channels, about the size of a millionth of a straw, are attracting attention as a way to directly manipulate single molecules in solution.

A joint research team led by Associate Professor Yan Xu of the Graduate School of the Osaka Technical University has managed to regulate the flow of single molecules in solution by opening and closing nanovalve in a nanofluid device by applying external pressure.

The research team created a nanofluid device with a thin, flexible sheet of glass on top, and a hard glass plate with tiny structures that form the nanochannel and seat of the nanovalve on the bottom. By applying external pressure to flexible glass sheets to open and close valves, they managed to directly manipulate and control the flow of individual molecules in solution. They also found that when they trapped a single fluorescent molecule in a nano chamber inside the valve, the single molecule fluorescence became brighter. This happens because the small space makes it difficult for individual molecules to move around randomly. Professor Xu said that “this fluorescence signal amplification effect can help detect small amounts of pathogens for the early diagnosis of diseases such as cancer and Parkinson’s disease, without the need for expensive equipment.”

The findings of this study could be a significant step towards independent assembly of materials using single molecules as building blocks in solution. This technology has the potential to be useful in areas such as developing personalized medicines for rare diseases and creating better displays and batteries. The applications are limitless.

“We have overcome various challenges by proposing and promoting the concept of ‘Single-Molecule Regulated Chemistry (SMRC),’ in which molecules are treated as building blocks and all processes involved in chemical and biochemical reactions in solution are carried out on a single molecule. base. The single-molecular valve marks the first step towards the goal, which could one day revolutionize chemistry, biology and materials science, as well as transform various industries,” said Professor Xu.

Their findings are published in Nano Letters.

Videos

• Cy3 single molecule flow in nanochannel https://youtu.be/p8IpoqEGfQ8
• Brownian motion of one molecule (Cy3) confined in a nanospace valve https://youtube.com/shorts/Xs6X7V2kyBA

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