A joint research team led by Associate Professor Yan Xu of the Osaka Metropolitan University Graduate School of Engineering has succeeded in regulating the flow of single molecules in solution by opening and closing a nanovalve in a nanofluidic device by applying external pressure.
This is not your usual (bulky) metal based valve but nevertheless a valve 😀.
The research team fabricated a nanofluidic device with a thin, flexible glass sheet on the top, and a hard glass plate with small structures that forms nanochannels and nanovalve seats on the bottom. By applying external pressure to the flexible glass sheet to open and close the valve, they succeeded in directly manipulating and controlling the flow of individual molecules in solution. They also found that when they trapped single fluorescent molecules in the nanospace inside the valve, the fluorescence of the single molecules became brighter. This happened because the small space made it harder for the single molecules to move around randomly. Professor Xu said that “this effect of fluorescence signal amplification could help with detecting very small amounts of pathogens for early diagnosis of diseases such as cancers and Parkinson’s disease, without requiring expensive equipment.” Read more about it here.