SHAPE-CHANGING NANOMAGNETS: A NEW APPROACH TO IN-VIVO BIOSENSING

摘要

The idea that optical color can be determined by size and shape is well known at the nanoscale. Colors of quantum dots and plasmonic nanostructures, for example, can be tuned through particle size and shape. Among others, this has directly enabled many different multi-colored nanoparticle labels that underpin a host of optically-based in vitro bioimaging applications, including multiplexed high-throughput bioassays and colorimetric sensing and visualization of biomolecular processes and function. Imaging and sensing in more realistic in vivo environments is more challenging, however. Optical probes can be sized or shaped to yield resonances closer to the more optically favorable near-infrared window, but optical penetration, signal intensity, and spatial resolution, still deteriorate rapidly with increasing depth beneath the surface. But what about in the radio-frequency (RF) portion of the spectrum? Are there any analogous nanoparticle structures that can shift the frequency, or equivalently color, of RF signals for which penetration and/or distortion through biological tissue would no longer be a limitation and where imaging and sensing would be naturally immune to any photostability, phototoxicity, and autofluoresence background issues?