Scientists in the US have illuminated the state-of-the-art in optical tweezer research, using laser beams to trap and move small biological objects.

Piero Bianco and Yuji Kimura from the University at Buffalo, highlight how researchers can now use optical tweezers to study interactions between DNA and proteins. 

Optical tweezers, or optical traps, are conceptually like eyebrow tweezers. An infrared laser is focused through an optical microscope on a precise spot, trapping objects as small as several nanometres across. Moving the laser beam allows these objects to be picked up and moved.

Numerous DNA binding proteins have been studied using optical tweezers, including members of the polymerase family. Polymerases are responsible for replicating DNA and transcribing DNA into RNA. Scientists have used optical tweezers to show how a polymerase pauses and back tracks during transcription. This is consistent with a proofreading process, said Bianco. 

Ulf Landegren from Uppsala University, Sweden, said that the research is proving 'fundamental for understanding how the genome is regulated.' 

Optical tweezers have significantly contributed to the understanding of the dynamic behaviour of individual protein molecules at single molecule levels, said Bianco.

He predicts that the method will eventually help scientists to discover how breaks in double stranded DNA are repaired. 

Nina Athey-Pollard