University of Illinois

Ji Sun Choi

Brian T Cunningham

Brendan Harley

Yue Zhuo

Thibault Marin

Yi Lu

A digital assay for a micro RNA (miRNA) or other target analyte in a sample makes use of nanoparticles that absorb light at the resonant wavelength of a photonic crystal (PC). Such nanoparticles locally quench the resonant reflection of light from the PC when present on the surface of the PC. The nanoparticles are functionalized to specifically bind to the target analyte, and the PC surface is functionalized to specifically bind to the nanoparticles that have bound to the target analyte. The sample is exposed to the functionalized nanoparticles, and the individual nanoparticles bound to the PC surface can be identified and counted based on reduced intensity values in the reflected light from the PC. The number of bound nanoparticles that are counted in this way can be correlated to the abundance of the target analyte in the sample.

Photonic resonator absorption microscopy (PRAM) for digital resolution biomolecular diagnostics

Photonic Resonator Outcoupler Microscopy (PROM) is a novel, label-free approach for dynamic, long-term, quantitative imaging of a sample on a surface of a photonic crystal (PC) biosensor, in which components of the sample outcouple photons from the resonant evanescent field, resulting in highly localized reductions of the reflected light intensity. By mapping changes in the resonant reflected peak intensity from the PC surface, components of a sample (e.g., focal adhesions) can be detected and dynamically tracked. To demonstrate the simplicity and utility of PROM for focal adhesion imaging, PROM images are compared with biosensor images of surface-bound dielectric permittivity and with fluorescence microscopy images of labeled adhesion molecules in dental stem cells. PROM can dynamically quantify the surface-attached cellular mass density and lateral dimensions of focal adhesion clusters.

Growing community of inventors

Urbana, IL, United States of America

Ji Sun Choi