Taking analytical biochemistry to the single molecule level by photon-upoconverting nanoparticles and femtoliter arrays
HANS H. GORRIS
The ability to detect and analyze individual biomolecules has led to widespread research interest in biosensing and biochemistry. We have designed upconversion nanoparticles (UCNPs) as labels for conventional (analog) and single-molecule (digital) bioassays because the anti-Stokes emission of UCNPs can be detected without any optical background interference.
In this lecture, I will highlight the advantages of UCNP labels in immunoassays for the detection of SARS-CoV-2 and other diagnostically relevant biomarkers as well as in DNA hybridization assays. In immunocytochemistry, upconversion microscopy achieves a much higher imaging contrast than standard fluorescence microscopy. The lecture will also cover methods for the surface modification and characterization of UCNPs.
Single molecule experiments also provided fundamental insights into the catalytic heterogeneity of enzymes, enzyme inhibition as well as molecular evolution. For this purpose, we designed large arrays of 250×250 (62 500) femtoliter chambers to isolate hundreds of single enzyme molecules and observe their individual catalytic rates in parallel.