From the wire: A team of international researchers has developed synthetic pores that mimic the activity of cellular ion channels. They are permeable to potassium ions and water but not to other ions such as sodium and lithium ions. The extreme selectivity, which is common in nature, is described as an unprecedented achievement in synthetic structures. The pores could be used to neutralise tumours and treat disease by regulating substances at the cellular level.
“The idea for this research originated from the biological world, from our hope to mimic biological structures, and we were thrilled by the results,” said University at Buffalo (NY, USA) chemistry professor Bing Gong, PhD, who led the study. “We have created the first quantitatively confirmed synthetic water channel. Few synthetic pores are so highly selective,” he noted in a press release on the university website.
To create the synthetic pores, the researchers developed a method to force donut-shaped molecules, called rigid macrocycles, to pile on top of one another. The scientists then stitched these stacks of molecules together using hydrogen bonding. The resulting structure was a nanotube with a pore less than a nanometer in diameter.
The research was published online on 17 July 2012 on the Nature Communications website.
“This nanotube can be viewed as a stack of many, many rings,” said Xiao Cheng Zeng, University of Nebraska-Lincoln Ameritas University Professor of Chemistry, and one of the study’s senior authors. “The rings come together through a process called self-assembly, and it’s very precise. It’s the first synthetic nanotube that has a very uniform diameter. It’s actually a sub-nanometer tube. It’s about 8.8 angstroms.”
The next step in the research is to tune the structure of the pores to allow different materials to selectively pass through, and to figure out what qualities govern the transport of materials through the pores, Gong said.
The study’s lead authors are Xibin Zhou of Beijing Normal University; Guande Liu of Shanghai Jiao Tong University; Kazuhiro Yamato, postdoctoral scientist at UB; and Yi Shen of Shanghai Jiao Tong University and the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. Other institutions that contributed to the work include the University of Nebraska-Lincoln and Argonne National Laboratory. Frank Bright, a SUNY Distinguished Professor of chemistry at UB, assisted with spectroscopic studies.