Photonic resonator absorption microscopy for biosensing with digital resolution

Circulating exosomal miRNA represents a potentially useful class of blood-based biomarkers for cancer liquid biopsy. The detection of miRNA at a very low concentration and with single-base discrimination without the need for sophisticated equipment, large volumes, or elaborate sample processing is a challenge. To address this, we present an approach that is highly specific for a target miRNA sequence and has the ability to provide “digital” resolution of individual target molecules with high signal-to-noise ratio. Gold nanoparticle tags are prepared with thermodynamically optimized nucleic acid toehold probes that, when binding to a target miRNA sequence, displace a probe-protecting oligonucleotide and reveal a capture sequence that is used to selectively pull down the target-probe-nanoparticle complex to a photonic crystal (PC) biosensor surface. By matching the surface plasmon resonant wavelength of the nanoparticle tag to the resonant wavelength of the PC nanostructure, the reflected light intensity from the PC is dramatically and locally quenched by the presence of each individual nanoparticle, enabling a new form of biosensor microscopy that we call Photonic Resonator Absorption Microscopy (PRAM). Dynamic PRAM imaging of nanoparticle tag capture enables direct 100 aM limit of detection and single-base mismatch selectivity in a 2-hour kinetic discrimination assay. The PRAM assay demonstrates that ultrasensitivity (<1 pM) and high selectivity can be achieved on a direct read-out diagnostic.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2019

Author dc:creator

• Li, Nantao

Contributors dc:contributor

• Cunningham, Brian T

• Photonic crystal
• Diagnostics
• MicroRNA
• Microscopy
• Label-free

Statement dc:rights

• Copyright 2019 Nantao Li

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/105879

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/105879