Programmable Multivalent DNA-Origami Tension Probes for Reporting Cellular Traction Forces

Nano Lett. 2018 Aug 8;18(8):4803-4811. doi: 10.1021/acs.nanolett.8b01374. Epub 2018 Jul 5.

Abstract

Mechanical forces are central to most, if not all, biological processes, including cell development, immune recognition, and metastasis. Because the cellular machinery mediating mechano-sensing and force generation is dependent on the nanoscale organization and geometry of protein assemblies, a current need in the field is the development of force-sensing probes that can be customized at the nanometer-length scale. In this work, we describe a DNA origami tension sensor that maps the piconewton (pN) forces generated by living cells. As a proof-of-concept, we engineered a novel library of six-helix-bundle DNA-origami tension probes (DOTPs) with a tailorable number of tension-reporting hairpins (each with their own tunable tension response threshold) and a tunable number of cell-receptor ligands. We used single-molecule force spectroscopy to determine the probes' tension response thresholds and used computational modeling to show that hairpin unfolding is semi-cooperative and orientation-dependent. Finally, we use our DOTP library to map the forces applied by human blood platelets during initial adhesion and activation. We find that the total tension signal exhibited by platelets on DOTP-functionalized surfaces increases with the number of ligands per DOTP, likely due to increased total ligand density, and decreases exponentially with the DOTP's force-response threshold. This work opens the door to applications for understanding and regulating biophysical processes involving cooperativity and multivalency.

Keywords: DNA origami; biomembrane force probe; cellular traction forces; platelets.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biosensing Techniques / instrumentation*
  • Biosensing Techniques / methods
  • Blood Platelets / physiology
  • Cell Adhesion
  • Cell Line
  • Computer Simulation
  • DNA / chemistry*
  • DNA Probes / chemistry*
  • Erythrocytes / chemistry
  • Gene Library
  • Humans
  • Ligands
  • Mechanotransduction, Cellular
  • Monte Carlo Method
  • Nanoparticles / chemistry
  • Nucleic Acid Conformation
  • Particle Size
  • Proof of Concept Study
  • Streptavidin / chemistry

Substances

  • DNA Probes
  • Ligands
  • DNA
  • Streptavidin