Imagine a technology that can manipulate tiny objects like cells and nanoparticles using lasers. Well, this is not just a science fiction concept but a reality in the field of scientific research. Optical tweezers, as they are called, have gained significant attention, so much so that they were recognized with a Nobel Prize in 2018. These extraordinary tools have now taken a major leap forward, thanks to the application of supercomputers. By harnessing the power of supercomputers, scientists have made optical tweezers safer to use on living cells, unlocking a plethora of potential applications in cancer therapy, environmental monitoring, and more.
In a groundbreaking study published in Nature Communications in August 2023, researchers from The University of Texas at Austin introduced a novel concept called hypothermal opto-thermophoretic tweezers (HOTTs). Pavana Kollipara, a recent graduate in mechanical engineering from UT Austin and one of the study’s co-authors, believes that this research marks a significant step towards the industrialization of optical tweezers in biological applications such as selective cellular surgery and targeted drug delivery.
Optical tweezers work based on the principle that light possesses momentum, which allows it to transfer its momentum to particles it interacts with. By using intensified laser light, scientists can further amplify this effect. Kollipara and her colleagues took this concept a step further by developing a method to keep the targeted particles cool while being manipulated by the optical tweezers. This temperature control is achieved through the use of a heat sink and a thermoelectric cooler.
The primary advantage of HOTTs lies in their potential to overcome the limitations of current laser light tweezers, which tend to inflict thermal damage on biological samples. By effectively cooling the entire system, HOTTs can trap biological cells at lower laser power while maintaining a temperature close to the ambient temperature of 27–34 °C. This breakthrough eliminates photon or thermal damage, ensuring the safety and viability of the cells being manipulated.
The team’s experiments focused on human red blood cells, highly sensitive to temperature changes. Conventional optical tweezers often damage these cells, leading to their immediate death. However, with the application of HOTTs, the researchers demonstrated the ability to safely trap and manipulate red blood cells, regardless of the solution they were dispersed in. This finding opens up new possibilities for cellular surgery and drug delivery applications.
One of the most promising applications of the HOTT technology lies in drug delivery. The ability to precisely focus and deliver drugs to specific targets can significantly reduce the amount of medication a patient needs to consume. With HOTTs, researchers can trap plasmonic vesicles – tiny gold nanoparticle-coated bio-containers – and guide them to targeted cancer tumors. Once these vesicles reach the intended location, a secondary laser beam is used to burst them open, releasing the drug cargo directly into the tumor.
The development and optimization of the HOTT technology required extensive computational simulations. Pavana Kollipara and her team relied on the power of supercomputers, particularly TACC’s Stampede2, to compute full-scale 3D force magnitudes acting on the particles. By leveraging the capabilities of Stampede2, the researchers obtained results significantly faster than with any other computational resource available to them. Such unprecedented computational power proved essential in realizing the full potential of the HOTT system.
Kollipara’s work is a testament to the invaluable contribution of high-performance computing in scientific research and development. She emphasizes that complex models, like the ones used in her research, cannot be effectively supported by local workstations or laptop computers. The computational demands are immense, requiring simulations that run for days to acquire just one data point. High-performance computing resources, such as TACC’s Stampede2 and Lonestar5 systems, provide researchers with the means to conduct thorough analysis and produce results at a scale and speed that would otherwise be unattainable.
The development of hypothermal opto-thermophoretic tweezers (HOTTs) represents a significant milestone in the advancement of optical tweezers. By using supercomputers and temperature control, researchers have overcome the limitations of conventional optical tweezers, enabling the safe manipulation of living cells. This breakthrough has opened up exciting possibilities in cancer therapy, drug delivery, and beyond. As Pavana Kollipara and her team continue their research and development efforts, one thing becomes clear – the future of optical tweezers is incredibly bright. Through continued innovation and collaboration, these laser-based tools will undoubtedly revolutionize the field of biological applications.
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