Abstract

Rapid and Ultrasensitive Point of Care Digital Resolution Diagnostics using Nucleic Acid Engineering and Photonic Crystals

Brian Cunningham, Donald Biggar Willett Professor in Engineering, University of Illinois at Urbana-Champaign

Detection of viral pathogens and circulating nucleic acid biomarkers typically relies upon enzymatic amplification of a targeted nucleic acid sequence using laboratory-based methods that require complex workflows and expensive equipment.  Translating diagnostic tests from the laboratory toward point-of-care environments is a key towards increasing the efficiency of the healthcare system while improving outcomes for people with a variety of health inequities.  This presentation will describe efforts at the Center for Genomic Diagnostics at the University of Illinois to develop technology platforms and assay methods intended to overcome the inherent limitations of laboratory-based nucleic acid testing for viral pathogens and circulating nucleic acid cancer biomarkers, representing collaborations between engineers, chemists, biologists, and clinicians.  We utilize Photonic Crystal (PC) nanostructured surfaces to amplify the interaction between light and biological materials, to enable digital resolution, single unit detection of molecules and viruses without sample partitioning (as in droplet digital PCR), enzymatic amplification, or thermal cycles.  Amplification of fluorescence, scattering, and absorption by the PC enables utilization of simple and inexpensive detection instruments.  The PC biosensor technology operates in concert with precisely designed target-selective nanostructures built from DNA.  Using nets and hand-like nano-grippers comprised of self-assembled DNA, intact viruses can be selectively recognized, captured, and linked to a biosensor for digital counting.  We have also adapted the CRISPR/Cas technology towards a rapid, highly selective assay for detection of circulating tumor DNA.  Our approach does not require PCR pre-amplification due to the use of PC biosensors, engineered nucleic acid tethers, and gold nanoparticle tags.  The presentation will share recent results and a vision towards approaches that can be adapted for clinics and specialty physician offices.