A very different approach for a nanovalve for drug delivery from the one that we cited a couple weeks ago is described by Michael Berger at Nanowerk. Researchers in The Netherlands have combined several different nanotechnology techniques to introduce a switchable pore-forming protein into a stable polymeric nanocontainer. If a way is found to mass-produce such particles, they could have a number of nanotech applications, from basic research to targeted drug delivery.

By combining the advantages of both lipid and polymer containers, researchers in The Netherlands have generated an advanced bio-hybrid nanocontainer. The main components of this hybrid nanocontainer are the scaffold, which is made of a polymer; a lipid membrane patch that was sealed over a hole in the scaffold; and a remote-controlled channel protein, which is reconstituted in the lipid patch before sealing the hole. It allows the loading and unloading of a payload at a desired time and/or location.

…this system offers the controlled communication between the interior and exterior of the vesicle containers.

…[Dr. Alma] Dudia explains that, by combining the advantages of both lipid and polymer containers, the researchers have generated, for the first time, an advanced biohybrid nanocontainer. “It is composed of a polymer vesicle with a lipid membrane patch covering a nanohole fabricated in the vesicle wall” she says. “The lipid membrane patch itself contains an engineered channel protein designed to allow for the passage of molecules up to a diameter of 3 nm.”

…As containers, liposomes suffer from limited stability and are leaky structures, whereas polymersomes are stable but do not allow instant release. In this novel hybrid system, polymer scaffolds form a robust architecture while a patch of sealed membrane serves as a natural environment for embedding pore-forming channel proteins and provides enough flexibility for the conformational changes that the channel requires to open a pore and release the payload.

“The exciting feature of this hybrid system as a triggered delivery device is that these pore-forming channels can be engineered in order to respond to the unique triggers necessary for release at the target delivery site” says [Dr. Armağan] Koçer.