Center for Functional Nanomaterials Seminar

Rapid and accurate identification of the pathogen(s) responsible for infection is a critical step in determining an effective treatment and thus impacting patient outcomes. Molecular diagnostics (MDx) can identify infecting species in times as short as hours or less. However, the fundamental complexity of current MDx modalities has hindered their widespread clinical use in point-of-care (PoC) applications. This talk is about developing both the fundamental understanding and the technology associated with a new materials platform compatible with PoC pathogen detection. Our approach exploits electron-beam lithography to pattern functional poly(ethylene glycol) [PEG] microgels. Their functionality enables oligonucleotide tethering that achieves liquid-like hybridization and enzymatic amplification on a solid substrate. We use patterned microgels to integrate a novel combination of self-reporting molecular beacons, self-assembled dielectric microlenses, and solid-phase and/or solution-phase nucleic-acid amplification primers in a viral-detection microarray model. Importantly, tethered microlenses effectively increase the numerical aperture of the collection optics and can increase the collected fluorescent signal by as much as 10 times. The assays give attomolar sensitivity. The assays are validated with three different and clinically important respiratory viruses: influenza A virus (Flu A); influenza B virus (Flu B); and respiratory syncytial virus (RSV). We furthermore demonstrate the surface patterning of discrete microgels with orthogonal chemical functionality, induced by dose-dependent radiation chemistry, which open possibilities to differentially locate bioactive species for amplification and detection. Finally, we introduce a new concept of patterning functional microgels in the form of covalently connected microgel strings with complex 3-D morphology, which manifest macromolecular conformational properties at an entirely new length scale (~10-100 μm) and open new opportunities to create diagnostic spots with 3-D rather than just 2-D structure.