While trying to examine forces on single biomolecules with great precision, researchers have solved their requirement of a dual trap optical tweezers system by inventing their own version of the tool, making the technology accessible to scientists in India. This could ignite a wave of new discoveries not only in neuroscience, but also in areas like drug development and other medical research.
Optical tweezers, a discovery that won the Nobel Prize in 2018, have become a key tool in modern research, allowing for the manipulation and movement of extremely small objects using light. Their application to measure minuscule forces has been useful in many disciplines including biology, bioengineering, materials science, and nanotechnology.
Decades after the invention of optical tweezers, some designs still face the challenge of versatility for current applications. Interactions between trapped micron-sized particles, mechanical properties of biopolymer filaments, and force generation by protein nanomachines are most often researched in a dual-trap system, where two beams are used to control the trapped particles. But there is a problem: traditional systems rely on detecting light that passes through the trapped particles, and this method has limitations.
Raman Research Institute, an autonomous institute supported by the Department of Science and Technology (DST), Government of India, has worked out a new optical trapping scheme which overcomes the shortcomings of traditional dual-trap optical tweezers. The novelty is in using a confocal detection scheme, a system where each detector looks only at the light coming back from its own trap, and ignores everything else. This way, the signals from two traps do not interfere with each other and stay completely independent.
Most remarkably, the detectors used for sensing the particle position within the traps remain perfectly aligned even when the traps are in motion. By eliminating all signal interference, the system provides for each trap to provide distinct, reliable measurements.