Congratulations to Ikjun Hong and the team members in Justus Ndukaife lab! Ikjun鈥檚 paper, 鈥淩apid trapping and label-free optical characterization of single nanoscale extracellular vesicles and nanoparticles in solution,鈥� has been featured as a VINSE Spotlight publication and published in Light: Science & Applications. This work was carried out with collaboration with 91吃瓜网 Medical Center (VUMC).
Despite the advances in single particle trapping and characterization, we note that a scalable platform that offers simultaneous high-efficiency trapping, label-free imaging, and molecular composition analysis of individual nanoparticles remains elusive. Such a tool would significantly advance single-particle analysis by enabling rapid, detailed characterization of both size and chemical composition at the nanoscale, with profound implications across a range of fields, from nanomedicine to environmental science. Although laser trapping Raman spectroscopy can trap micro-scale particles and collect Raman scattering signals, the process often requires at least several minutes to load, optically trap, and perform Raman analysis, which dramatically limits analysis throughput. To address this critical gap, we introduce an original interferometric electrohydrodynamic tweezers (IET). IET uses electrohydrodynamic flows to rapidly trap thousands of nanoscale objects, such as EVs and nanoparticles, in parallel鈥攚ithin seconds. Our platform integrates label-free interferometric imaging and molecular composition analysis using Raman spectroscopy, enabling precise, real-time characterization at the single particle level without the need for fluorescent labels or surface immobilization. Importantly, IET allows for the comprehensive analysis of nanoscale particles (including size, shape, and chemical composition) in their native state, avoiding artifacts introduced by traditional staining or fixation techniques.
Read article here in the .
Authors: Ikjun Hong, Chuchuan Hong, Theodore Anyika, Guodong Zhu, Maxwell Ugwu, James N Higginbotham, Jeffrey L Franklin, Robert Coffey, Justus C Ndukaife
Abstract: Achieving high-efficiency, comprehensive analysis of single nanoparticles to determine their size, shape, and composition is essential for understanding particle heterogeneity with applications ranging from drug delivery to environmental monitoring. Existing techniques are hindered by low throughput, lengthy trapping times, irreversible particle adsorption, or limited characterization capabilities. Here, we introduce Interferometric Electrohydrodynamic Tweezers (IET), an integrated platform that combines rapid molecular trapping, interferometric scattering imaging, and Raman scattering to rapidly trap and characterize single nanoparticles within seconds in one integrated platform. The IET platform enables to perform both trapping and Raman analysis within seconds in contrast with laser trapping Raman spectroscopy that often require several minutes per measurement. Furthermore, the IET platform can also operate under low particle concentration media, where particle loading is slow for conventional laser trapping Raman spectroscopy approach. We demonstrate the platform鈥檚 capabilities by trapping and characterizing the size and chemical composition of colloidal polymer beads and nanoscale extracellular vesicles (EVs), while trapped in solution. Our IET represents a powerful optofluidics platform for comprehensive characterization of nanoscale objects, opening new avenues in nanomedicine, environmental monitoring, and beyond.