Enzymes May Qualify as Nano- and Micromotors

Enzymes, the workhorse molecules of life that underpin almost every biological process, may be destined for a new role as "intelligent" micro- and nanomotors with applications in medicine, engineering and other fields, hope Pennsylvania State University researchers Peter J. Butler, Ayusman Sen, and colleagues.

They have found in experiments that two common enzymes, catalase and urease, show movement in the presence of their respective substrate (hydrogen peroxide or urea, which act as fuel), and generate enough force to cause movement in specific directions. (Catalase protects the body from harmful effects of hydrogen peroxide formed naturally in the course of life. Urease, found in many plants, converts urea to ammonia and carbon dioxide.)

The finding has "important implications in areas ranging from biological transport to the design of 'intelligent,' enzyme-powered, autonomous nano- and micromotors, which are expected to find applications in bottom-up assembly of structures, pattern formation, cargo (drug) delivery at specific locations, roving sensors, and related functions," the researchers note.

And importantly the movement can be controlled in the intended direction by using a substrate gradient, causing the enzymes to move toward areas of higher substrate concentration, a form of chemotaxis (chemical attraction of living things toward sources of food), similar to the chemotaxis of whole cells.

Funding is from The Pennsylvania State University Materials Research Science and Engineering Center, supported by the National Science Foundation.

Paper:
Samudra Sengupta et al., Enzyme Molecules as Nanomotors, Journal of the American Chemical Society, 2013, DOI: 10.1021/ja3091615