"Previously, we had to average the Brownian (random) motion of our favorite cantilever for about 60 milliseconds to get a measurement that had a precision of 1 piconewton," JILA/NIST biophysicist Tom Perkins says. "Now, we can get the same precision in 1 millisecond or so."
JILA researchers demonstrated significant benefits for single molecule studies. For instance, the short, soft cantilevers can quickly measure abrupt changes in force when a protein unfolds. Protein folding is required for proper biological function and misfolding can lead to diseases such as Alzheimer's. The new cantilevers match the response of stiffer, unmodified cantilevers but with greater stability and precision. Force stability is crucial in this application because protein folding and unfolding rates are exponentially sensitive to tiny changes (smaller than 1 piconewton) in applied load. The new device also can track fleeting nanoscale events, including protein folding, over hundreds of secondsmuch longer periods than previously possible. The new design should also be applicable to rapid probing of the mechanical properties of materials at the nanoscale.
Significantly, the new cantilevers are robust enough to be reused for multiple days. Moreover, JILA researchers say the new design is simple and inexpensive to make, and thus, suitable for routine use.
"Amazingly, this project was spearheaded by a talented undergraduate. We hope other groups with similarly talented students will adopt these cantilevers. We certainly are," Perkins said.
|Contact: Laura Ost|
National Institute of Standards and Technology (NIST)