Bridging pico-to-nanonewtons with a ratiometric force probe for monitoring nanoscale polymer physics before damage

Ryota Kotani,Shigehiro Yamaguchi,Atsuhiro Osuka,Hiroshi Yabu,Soichi Yokoyama,Shunpei Nobusue,Shohei Saito

doi:10.1038/s41467-022-27972-y

Ryota Kotani, Shigehiro Yamaguchi + Show 5 more

Open Access

PDF Available

https://doi.org/10.1038/s41467-022-27972-y

Copy DOI

Export

Save

Cite

Abstract
Highlights/Summary
Full-Text PDF
Similar Papers

Abstract

Listen

Understanding the transmission of nanoscale forces in the pico-to-nanonewton range is important in polymer physics. While physical approaches have limitations in analyzing the local force distribution in condensed environments, chemical analysis using force probes is promising. However, there are stringent requirements for probing the local forces generated before structural damage. The magnitude of those forces corresponds to the range below covalent bond scission (from 200 pN to several nN) and above thermal fluctuation (several pN). Here, we report a conformationally flexible dual-fluorescence force probe with a theoretically estimated threshold of approximately 100 pN. This probe enables ratiometric analysis of the distribution of local forces in a stretched polymer chain network. Without changing the intrinsic properties of the polymer, the force distribution was reversibly monitored in real time. Chemical control of the probe location demonstrated that the local stress concentration is twice as biased at crosslinkers than at main chains, particularly in a strain-hardening region. Due to the high sensitivity, the percentage of the stressed force probes was estimated to be more than 1000 times higher than the activation rate of a conventional mechanophore.

Highlights

Understanding the transmission of nanoscale forces in the pico-to-nanonewton range is important in polymer physics
Understanding the transmission of pico-to-nanonewton forces in complex hierarchical structures is a primary goal in polymer physics[1,2,3] and mechanobiology[4,5]. Physical approaches such as optical/magnetic tweezers and atomic force microscopy (AFM) are widely used to evaluate piconewton force, but it is difficult to visualize the distribution of forces in condensed matter or molecular crowding environments with these techniques (Fig. 1a)[6,7,8]
While there are several instruments, such as surface force apparatuses (SFAs), rheometers, and tensile testing machines, that can analyze physical forces transmitted in meso-to-macroscopic structures, methods to directly quantify the distribution of forces at the molecular level are still being pursued

Summary

Introduction

Understanding the transmission of nanoscale forces in the pico-to-nanonewton range is important in polymer physics. There are still stringent requirements for the design of force probes that can quantitatively monitor local stress concentrations before the polymer chain network is structurally damaged but without changing the intrinsic properties of the polymer by chemical doping.

Results

Conclusion