Chemists from The University of Texas at Austin and Texas State University have developed an environmentally friendly method for creating chemical structures with complex shapes like those found in living things. The results have implications for reducing toxic waste in chemical manufacturing and research, understanding basic biological processes and developing more effective medical therapies.
The researchers synthesized a complex chemical structure made of two interlocking molecules, like links in a chain, called a catenane, which is similar to structures commonly found in biology. In our cells, molecules of DNA or protein are often twisted, knotted or entwined to give them special functions like moving or storing things, or to stay compact and stable.
"These intertwined, knotted systems are found throughout biology," says Jonathan Sessler, professor in the Department of Chemistry and co-author on the paper describing the results this week in the journal Nature Chemistry. "They're found in biological pumps, in ATP generating machines, in DNA, proteins, and the list goes on and on."
The real technical breakthrough was in building these complex molecular structures in a solution of water. Other researchers have made similar structures using highly toxic solutions. This latest study adds an important new tool for chemists wanting to revamp their field around the principles of green chemistry.
"We need ways to make things that are more compatible with the modern world," says Sessler. "We're moving away from hazardous chemicals to ones that are more benign."
By synthesizing complex interlinked structures in the lab, scientists will be able to better understand how they form in biological systems and how their shapes allow them to function in a certain way. That understanding could lead to, among other things, new ideas for creating drugs that only release their payloads when they reach the right part of the body.
"As with any tool," predicts Sessler, "once it becomes available, others will start to use this approach to create wonderful new objects, but on the molecular, rather than macroscopic scale."
Along with Sessler, the research was led by Hao Li, a postdoctoral researcher in Sessler's lab and now an assistant professor at Zhejiang University in China.
The other team members from UT Austin are Huacheng Zhang, a postdoctoral researcher, Aaron Lammer, a graduate student and Vincent Lynch, a research scientist. Co-authors from Texas State University are Ming Wang, a graduate student, and Xiaopeng Li, a professor.
This work was supported in part by the National Science Foundation and the Welch Foundation.