Researchers at the Holonyak Micro & Nanotechnology Laboratory and the Beckman Institute for Advanced Science and Technology developed a microscope that visualizes the invisible forces exerted by light at the nanoscale. This groundbreaking tool reveals the intimate tango between light, force, and temperature with unprecedented detail and speed.
Decoupled Optical Force Nanoscopy, or Dofn, is the brainchild of a team led by Yang Zhao, a professor of electrical & computer engineering at the University of Illinois Urbana-Champaign, and Zhao's colleagues at the Beckman Institute: Catherine Murphy, a professor of chemistry and Beckman's interim director; and Yun-Sheng Chen, a professor of electrical & computer engineering.
Their work appears in Nature Communications.
“Dofn is more than just a microscope," Zhao said. "It's a groundbreaking tool that deciphers the complex light-matter interactions on a scale so small it defies the limits of traditional microscopy, something that was once beyond our observational capabilities.”
The researchers explored the mechanics of how light can generate minute forces upon nanoscale specimens — a topic that has baffled scientists because of the elusive nature of these interactions. Dofn peels back the layers of this nanoscopic enigma, allowing for the observation of how these forces work and evolve in real time.
In the interaction between light and nanomaterials, a complex array of forces comes into play: the photothermal force, the photogradient force and the photoacoustic pressure. Capturing this intricate interplay at the nanoscale has long been a challenge, as these light-induced forces typically emerge simultaneously from the same source. The crux of the study lies in uncovering how light imparts minute forces upon nanoscale objects, a question that has long intrigued scientists.
The elusive nature of these interactions has made them a challenging study subject, but Dofn is changing that. It peels back the layers of this nanoscopic enigma, allowing observers to see these forces in action, evolving in real-time. Imagine being able to witness a gold nanoparticle as it responds to light: heating up, expanding and cooling in response to the gentle nudge of photons. Dofn makes this possible. It's akin to giving us a pair of glasses that can translate the subtle play of thermal and kinetic changes into a visual narrative.
This research underscores the potential of interdisciplinary collaboration in pushing the boundaries of biological and medical science.
"Dofn acts as a bridge over previous technological gaps, giving us the ability to explore and quantify how light-induced forces manifest as both pressure and heat at the nanoscale," said Hanwei Wang, the study’s lead author and a graduate student in electrical & computer engineering.
Zhao added, "With this innovative tool, we're not just observing the effects of light's touch upon nanoscale objects; we're also seeing the thermal response of these objects to light's caress, something that has been out of reach until now."
These observations mark a paradigm shift in our ability to understand and harness the power of light in nanotechnology and beyond. From improving the precision of drug delivery to refining the design of nano-devices, the implications of these findings are a beacon for future innovations in molecules and cells.
“The development of a technique capable of probing rapid photothermal dynamics in nanosecond resolution at the level of single nanoparticles marks a significant stride forward in the precise characterization of nanomaterials," Murphy said. "The potential of this technique is immense; it promises a wide range of applications, from nanophononics, nanomedicine, mechanochemistry, mechanobiology and biophysics.”
This research underscores the potential of interdisciplinary collaboration in pushing the boundaries of biological and medical science.
“The advent of Dofn is not merely an advancement in microscopy,” Zhao said. "It's a lens that brings the micro-dynamics of heat and light forces into focus, revolutionizing our ability to manipulate and control the very building blocks of nanotechnology.
“We're not just peeking into the nanoworld. We're stepping into it with a newfound clarity that promises to reshape our understanding of the universe at its most fundamental level.”
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This story originally appeared from the Beckman Institute for Advanced Science and Technology here.
The paper, “Visualizing ultrafast photothermal dynamics with decoupled optical force nanoscopy,” can be accessed online. DOI: 10.1038/s41467-023-42666-9
Research reported in this press release was supported in part by the National Institute of General Medical Sciences of the National Institutes of Health under award number R21GM139022. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Additional financial support was provided by the Innovative Science Accelerator Program (DK128851), the National Science Foundation (CHE-2107793) and the Hong, McCully, and Allen Fellowship.