Sensing technologies for the real-time monitoring of biomolecules will allow studies of dynamic changes in biological systems and the development of control strategies based on measured responses. Here, we describe a molecular architecture and coupling process that allow continuous measurements of low-concentration biomolecules over long durations in a sensing technology with single-molecule resolution. The sensor is based on measuring temporal changes of the motion of particles upon binding and unbinding of analyte molecules. The biofunctionalization involves covalent coupling by click chemistry to PLL-g-PEG bottlebrush polymers. The polymer is grafted to a surface by multivalent electrostatic interactions, while the poly(ethylene glycol) suppresses nonspecific binding of biomolecules. With this biofunctionalization strategy, we demonstrate the continuous monitoring of single-stranded DNA and a medically relevant small-molecule analyte (creatinine), in sandwich and competitive assays, in buffer and in filtered blood plasma, with picomolar, nanomolar, and micromolar analyte concentrations, and with continuous sensor operation over 10 h.
Bibliographical noteFunding Information:
We thank Human Gesellschaft für Biochemica und Diagnostica mbH for kindly providing the anticreatinine antibody. We thank Max Bergkamp and Emiel Visser for the particle tracking and event detection algorithms. Part of this work was funded by the Dutch Research Council (NWO), section Applied and Engineering Sciences, under grant number 15481. Part of this work was funded by the Safe-N-Medtech H2020 project under grant agreement no. 814607.
- click chemistry
- continuous monitoring biosensors