On Decenber 21 st, 2017, Prof. Ye invited Dr. Judith Su and Dr. Euan Mcleod from Arizona University to give reports named “Label-free ultra-sensitive biomolecular detection for basic science and translational medicine” and “3D Nanophotonic Systems for Environmental and Biological Sensing” respectively. Here are the abstracts of these two reports:

1.      Label-free single molecule detection has been a long-standing goal of bioengineers and physicists. The main obstacle in the detection of single molecules, however, is to sufficiently decrease the noise level of the measurements such that a single molecule can be distinguished from background fluctuations. We have used laser frequency locking in combination with balanced detection and data processing techniques to improve the signal-to-noise ratio of microtoroid optical resonators and report the detection of a wide range of nanoscale objects including nanoparticles with radii from 100 to 2.5 nm, exosomes, ribosomes, and single protein molecules (mouse immunoglobulin G and human interleukin-2). We further extend the exosome results toward the creation of a minimally-invasive tumor biopsy assay. Our results agree with established model predictions for the frequency shift of the resonator upon particle binding across several orders of magnitude of particle radius (100 nm to 2 nm). We anticipate that our results will enable many applications, including more sensitive medical diagnostics and fundamental studies of single receptor-ligand and protein-protein interactions in real time. Future research thrusts will also be discussed. 

2.  The fabrication of nanophotonic elements out of soft materials provides new frontiers for the integration of photonics with biosystems, and provides ways to realize microscopic devices that could not be made otherwise. Here we present one example: a nanoparticle and virus imaging platform enabled by nano-scale lenses that are self-assembled out of polyethylene glycol. Currently, nanoparticle sizing and imaging are typically performed using sophisticated laboratory-based electron microscopes or optical systems, even though such analyses can be time-intensive, costly, and/or not readily available in areas such as developing or rural regions. Rapid and inexpensive nanoparticle imaging and sizing is important in medical, environmental, and basic research, and could enable, for example, point-of-care quantification of viral load in HIV patients, multiplexed biochemical assays, or widespread air quality and water quality environmental monitoring. Here we perform accurate nanoparticle imaging and sizing using the combination of nanolenses and on-chip, in-line holography. This combined approach simultaneously provides high resolution, large field of view, and a cost-effective and field-portable hardware system. We can size particles of diameter 40 nm – 100 um, where the accuracy is +/- 11 nm for the 40 nm – 500 nm range. Our approach can size more than 10^5 particles simultaneously, can detect particles of various shapes, and can recover multi-modal distributions of sizes, all within a compact and inexpensive prototype device.