A valve is a mechanical device that regulates the flow of fluids by opening, closing, or partially obstructing various passageways. For example, our hearts have four valves, which help in regulating the blood flow in, out and throughout the heart.
The smaller the valve, greater is the control the user has in regulating the flow of the fluid. With this in mind, UCLA chemists have created the first nano-valve that can be opened and closed at will to trap and release molecules:).

The research is published in the in the Proceedings of the National Academy of Sciences. According to the lead researcher Thoi Nguyen from California NanoSystems Institute (CNI) in UCLA, the new valve can trap and release molecules on demand, unlike other valves which can only control flow of liquids.
This nano valve consists of moving parts - switchable Rotaxane molecules that resemble linear motors designed by CNI director Fraser Stoddart's team - attached to a tiny piece of glass (porous silica), which measures about 500 nanometers, and which Nguyen is currently reducing in size. Tiny pores in the glass are only a few nanometers in size. It's big enough to let molecules in and out, but small enough so that the switchable rotaxane molecules can block the hole:):).
The Rotaxane molecules can switch between two alternate structures. By controlling this switching, and putting the molecule at the mouth of a hole, the researchers were able to control the opening and closing of the hole. The research can pave the way to new techniques in drug delivery, molecular electronics, and industrial processes:).