It is hard to visualize a world in which humans can control nanoscale objects at ease according to their own will or even manipulate their own biological matter at a cellular scale by using light. However, this is exactly what Yuebing Zheng, assistant professor of mechanical engineering at The University of Texas at Austin, is working to achieve by using his “nanotweezers” - an innovative tool for controlling nanoparticles with light, which can lead to opportunities for innovations in individual health monitoring and nanotechnology.
Zheng and his colleagues from the Cockrell School of Engineering have advanced several years of studies to develop opto-thermoelectric nanotweezers (OTENT) that will offer in-depth insights into the matter and biological systems and result in a broad array of probabilities for fundamental as well as technical innovation in the field of nanophotonics, which involved the study of interaction between light and matter at the nanoscale. The researchers have described their innovative study in the recent issue of the Nature Photonics journal.
“Until now, we simply did not know how to manipulate nanoparticles using optical heating,” stated Zheng. “With our nanotweezers, we can not only control particles at the nanoscale, we can also analyze the particles and control the coupling in-situ.”
For demonstrating one of the applications of nanotweezers, Zheng collaborated with Brian Korgel, a UT Austin chemical engineering professor who was elected this year to the National Academy of Engineering for his inventive research in nanowires and nanocrystals.
“This project was really interesting for me,” stated Korgel. “It was led by a group in mechanical engineering who had discovered a way to manipulate individual nanoparticles and nanowires. Their expertise was in building the photonics machines but not in making the materials to use for the experiments. So, my group developed the synthesis of the nanowires used in the study. It was a great collaboration.”
Ernst-Ludwig Florin, associate professor of physics and a member of UT’s Center for Nonlinear Dynamics, collaborated with Emanuel Lissek, a graduate student, to offer additional expertise in accurate measurements by exhibiting the strength of the nanotweezers.
This combination of nanophysics, nanochemistry, and nanophotonics research has offered the tools needed to control and study nanoparticles in ways that have not been achieved to date. The UT researchers have demonstrated the process of applying their nanotweezers to use light at the nanoscale in the same manner in which mechanical tweezers are used to handle larger samples.
As a common method, the nanotweezers can be applied to a broad array of dielectric, polymer, semiconductor, and metal nanostructures that include hydrophobic or charged surfaces. To date, scientists have been successful in “trapping” metal nanostructures, germanium nanowires, silicon nanowires, polystyrene beads, silica beads, and silicon nanospheres. Better insights into the way matter is organized and prospective discovery of innovative functional materials can be achieved by a further arrangement of these nanomaterials according to rational designs.
In a biological context, Zheng considers that cell-to-cell communication and live cell manipulation will possibly be a primary research focus for engineers who aim to take advantage of the capabilities offered by the nanotweezers.
Optimization of the current system to make it bio-compatible is the next step of our project. We expect to use our tweezers to manipulate biological cells and molecules at single-molecule resolution, to control drug release and to study the cell-cell interaction. The manipulation and analysis of biological objects will open a new door to early disease diagnosis and the discovery of nanomedicine.
Zheng believes that the technology will be commercialized, even to an extent where nanotweezers could be modified for use in a smartphone app, quite similar to a modern-day Swiss army knife.
“That’s what we hope,” he stated. “We also see great opportunities in outreach education, perhaps for students who want to see what a cell really looks like. In addition, it could be used to assess how healthy one’s immune system is functioning. It has the potential to be an important mobile diagnostic tool, giving people more autonomy over their own health care.”
The Beckman Young Investigator Program, the Army Research Office, the NASA Early Career Faculty Award, the National Institute of General Medical Sciences of the National Institutes of Health, the Robert A. Welch Foundation, and the National Science Foundation supported this study.