The University of Alberta’s Faculty of Science is pleased to welcome renowned biophysicist Steven Block for a public lecture on the ground-breaking applications of optical tweezers for understanding molecular activity at the nanoscsale. 

A professor at Stanford University, Block is known as a founder of the field of single molecule biophysics. His research is focused at the intersection of physics and biology and his research group pioneered the use of laser-based optical tweezers–a topic that received the 2018 Nobel Prize in Physics, and a technology that Block describes as “the closest thing to a tractor beam humans have achieved.”

Michael Woodside, biophysics researcher on campus and associate professor in the Department of Physics, speaks to Block’s expertise in the field. “Dr. Block was the second person in the world to build optical tweezers, within a week of the first report of optical tweezers by 2018 Nobel Laureate Art Ashlin. He has made many of the pioneering measurements showing what a powerful tool optical tweezers can be for studying biological molecules.”

Block’s public talk will take place on Thursday, October 17 at 7 p.m. in CCIS L2-200. For more information, visit the event page

Tell us about your research program.

My research program is in the area of biophysics, and involves the use of single-molecule methods—and especially laser-based ‘optical tweezers,’ which work through microscopes—to study how biomolecules work.

What are some potential applications of this research area?

My research in biophysics is fundamental, not applied. It’s aimed at acquiring a basic understanding of how molecular machines function. All life depends upon the efficient functioning of many types of complex molecular machines inside our cells, composed of proteins and nucleic acids. These machines include molecular motors, like myosin and kinesin, which do things like make muscles contract, transport organelles inside cells, or move chromosomes during cell division. They include nucleic acid-based enzymes, like DNA and RNA polymerase, which are responsible for replicating our genomes and transcribing these into the gene-sized pieces that code for proteins. They include the driving forces behind the correct folding of biopolymers that allow these to form specific highly shapes that can carry out biochemical functions.

Research into single-molecule techniques has led to a number of ultra-sensitive biomedical diagnostic tests that can work down to the level of individual cells to detect the presence of certain genes or gene expression patterns. It has also led to new ways to visualize cells and biomolecules at unprecedented resolution. 

My lab develops the foundational technologies that make such cutting-edge tests possible. We currently hold the record for the smallest displacement measurements ever conducted on an individual protein—in this case, measuring the angstrom-sized steps taken by RNA polymerase as it steps from one basepair to the next along the DNA double helix. To put this in perspective, an angstrom is the diameter of a single hydrogen atom.

Tell us about your upcoming talk.

In my public lecture, I will discuss laser-based optical tweezers. Laser-based optical tweezers represent the closest thing to a tractor beam that humans have achieved, and the Nobel Prize in Physics for 2018 was awarded to Arthur Ashkin for their invention. Unlike the tractor beams of sci-fi fantasies, optical tweezers work in the realm of the microscopic. This talk will describe how these laser-based tweezers can be used to manipulate objects as small as single biomolecules, and how they have advanced our current understanding of biophysics.

I will also be speaking at the Department of Physics Colloquium on October 18.


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