Hidden multiple bond effects in dynamic force spectroscopy

TL;DR

This paper investigates how hidden multiple bonds in dynamic force spectroscopy experiments can influence rupture force data, developing a detailed model to identify and interpret these effects despite their indistinguishability from single bonds.

Contribution

The study introduces a comprehensive numerical model that accounts for clustering, bond formation, and rupture, revealing hidden multiple bonds' impact on force measurements.

Findings

Hidden multiple bonds significantly affect rupture force distributions.

Model can distinguish effects of hidden bonds from true single bonds.

Results improve interpretation accuracy of force spectroscopy data.

Abstract

In dynamic force spectroscopy, a (bio-)molecular complex is subjected to a steadily increasing force until the chemical bond breaks. Repeating the same experiment many times results in a broad distribution of rupture forces, whose quantitative interpretation represents a formidable theoretical challenge. In this study we address the situation that more than a single molecular bond is involved in one experimental run, giving rise to multiple rupture events which are even more difficult to analyze and thus are usually eliminated as far as possible from the further evaluation of the experimental data. We develop and numerically solve a detailed model of a complete dynamic force spectroscopy experiment including a possible clustering of molecules on the substrate surface, the formation of bonds, their dissociation under load, and the post processing of the force extension curves. We show that the data, remaining after elimination of obvious multiple rupture events, may still contain a considerable number of "hidden" multiple bonds, which are experimentally indistinguishable from "true" single bonds, but which have considerable effects on the resulting rupture force statistics and its consistent theoretical interpretation.