Mechanosensitive membrane probes: push-pull papillons

Humeniuk, Heorhii V.; Licari, Giuseppe; Vauthey, Eric; Sakai, Naomi; Matile, Stefan

doi:10.1080/10610278.2019.1702193

Cited by 4 publications

(8 citation statements)

References 11 publications

(8 reference statements)

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“…Here, a continuous change of force alters the degree of conjugation and thus modulates optical properties through changes in absorption and photoluminescence (PL) spectra. The mechanical stimulus may be applied in a supramolecular fashion, , or through force transduction to molecularly linked mechanophores. To this end, we have reported a DA torsional spring based on diketopyrrolopyrrole (DPP) and its covalent incorporation into a polyphenylene matrix, which allowed for continuous and reversible force sensing in bulk samples, enabling a linear correlation of color change with force .…”

Section: Introductionmentioning

confidence: 99%

Conformer Ring Flip Enhances Mechanochromic Performance of ansa-Donor–Acceptor–Donor Mechanochromic Torsional Springs

et al. 2022

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Mechanochromophores based on conformational changes of donor−acceptor−donor (DAD) springs allow sensing of forces acting on polymer chains by monotonic changes of absorbance or photoluminescence (PL) wavelength. Here, we identify a series of thiophene (D)-flanked quinoxalines (A) as molecular torsional springs for force sensing in bulk polymers at room temperature. The mode of DAD linkage to the polymer matrix and linker rigidity are key parameters that influence the efficacy of force transduction to the DAD spring and thus mechanochromic response, as probed by in situ PL spectroscopy of bulk films during stress−strain experiments. The largest shift of the PL maximum, and thus the highest sensitivity, is obtained from an ansa-DAD spring exhibiting bridged D units and a stiff A linker. Using detailed spectroscopy and density functional theory calculations, we reveal conformer redistribution in the form of a thiophene ring flip as the major part of the overall mechanochromic response. At forces as low as 27 pN at early stages of deformation, the ring flip precedes mechanically induced planarization of the ansa-DAD spring, the latter process producing a PL shift of 21 nm nN −1 . Within the stress−strain diagram, the thiophene ring flip and DAD planarization are thus two separated processes that also cause irreversible and reversible mechanochromic responses, respectively, upon sample failure. As the thiophene ring flip requires much smaller forces than planarization of the DAD spring, such micromechanical motion gives access to sensing of tiny forces and expands both sensitivity and the force range of conformational mechanochromophores.

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Section: Introductionmentioning

confidence: 99%

Conformer Ring Flip Enhances Mechanochromic Performance of ansa-Donor–Acceptor–Donor Mechanochromic Torsional Springs

et al. 2022

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“…(B) Normalized excitation and emission spectra of 3 ( P380) in DPPC LUVs (solid), DOPC LUVs (dashed) at 55 °C (red) and 25 °C (blue). Reproduced with permission from ref . Copyright 2020 Taylor & Francis.…”

Section: Fluorescent Probes For Mechanical Force Detectionmentioning

confidence: 99%

Design and Application of Fluorescent Probes to Detect Cellular Physical Microenvironments

Ma,

Sun,

Xia

et al. 2024

Chem. Rev.

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The microenvironment is indispensable for functionality of various biomacromolecules, subcellular compartments, living cells, and organisms. In particular, physical properties within the biological microenvironment could exert profound effects on both the cellular physiology and pathology, with parameters including the polarity, viscosity, pH, and other relevant factors. There is a significant demand to directly visualize and quantitatively measure the fluctuation in the cellular microenvironment with spatiotemporal resolution. To satisfy this need, analytical methods based on fluorescence probes offer great opportunities due to the facile, sensitive, and dynamic detection that these molecules could enable in varying biological settings from in vitro samples to live animal models. Herein, we focus on various types of small molecule fluorescent probes for the detection and measurement of physical parameters of the microenvironment, including pH, polarity, viscosity, mechanical force, temperature, and electron potential. For each parameter, we primarily describe the chemical mechanisms underlying how physical properties are correlated with changes of various fluorescent signals. This review provides both an overview and a perspective for the development of small molecule fluorescent probes to visualize the dynamic changes in the cellular environment, to expand the knowledge for biological process, and to enrich diagnostic tools for human diseases.

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“…[42] Building on the design of these flipper-type motifs, a new type of papillon (butterfly) probe was recently reported by Matile and co-workers that adopts a bent conformation when exposed to mechanical stresses ( Figure 2b). [81] The transition between the bent and planar states is accomplished by the swiveling of four N-phenyl bonds around two amine fulcra. The conformation change to the bent state is accompanied by a pronounced shift of the emission maximum from 467 to 587 nm.…”

Section: Exploiting Conformational Changes In Moleculesmentioning

confidence: 99%

Section: Molecular Responses To Mechanical Stimulationmentioning

confidence: 99%

“…[ 82 ] Moreover, various derivatives with push–pull substituents were prepared. [ 81 ] The substitution thereby influenced the energy required to switch from the relaxed to the bent conformer, which in turn enabled the sensing of changes in tension in different types of membranes. In another approach, Sprakel and co‐workers recently reported the use of a phenyl‐substituted boron‐dipyrromethene (BODIPY) derivative as a highly sensitive probe for mechanobiological processes.…”

Section: Molecular Responses To Mechanical Stimulationmentioning

confidence: 99%

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From Molecules to Polymers—Harnessing Inter‐ and Intramolecular Interactions to Create Mechanochromic Materials

Traeger

Kiebala

Weder

et al. 2020

Macromol. Rapid Commun.

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tion occurs to avoid catastrophic materials failure and to possibly redirect degradation processes into useful responses. Consequently, research efforts directed toward the investigation and development of mechanoresponsive materials has drawn ever increasing attention. [2,3,5-8] Polymers that translate mechanical stresses into a defined response are thought to be useful for many different applications, including as tamper-proof packaging materials, [9] as degradable plastics, [10,11] or for structural health monitoring. [12] One possibility to render polymers mechanoresponsive is the integration of so-called mechanophores. The latter generally feature a weak covalent bond that undergoes either homo-or heterolytic cleavage upon experiencing a force that exceeds a certain threshold. [1,5,7,13,14] These motifs are covalently incorporated into a polymer and serve as predefined weak links that preferentially break or transform in response to an applied mechanical force. [1,6,14-16] Widely investigated mechanophores include spiropyrans, 1,2-dioxetanes, and Diels-Alder adducts. [16-18] The rate constants, threshold forces, and transition state bond-lengths and energies of many mechanophores have been well-characterized via techniques such as single-molecule force spectroscopy (SMFS), [19-22] force-modified potential energy surface modeling, [23] and in situ activation using sonication. [2,22,24] The insights gained in such studies have driven advancements in the field of mechanoresponsive materials and the mechanical activation has, for example, been harnessed to promote thermodynamically unfavorable reactions, [19] affect the intra-or intermolecular transfer of protons, [20,25,26] release small molecules, [27] initiate the depolymerization of the surrounding material, [10,28] or elicit changes in the material's color or fluorescence. [16,17,29] The fact that the active bond or functional group of a mechanophore is typically cleaved irreversibly can limit its utility. Some mechanophores can be returned to their original state through an additional stimulus such as light or heat, but unless the mechanophore undergoes a nonscissile cleavage (e.g., a ring-opening reaction, such as in spiropyrans), the reversal is generally hampered by kinetic factors that leave the mechanophore in its cleaved state. [30] An irreversible response can be desirable for some

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Mechanosensitive membrane probes: push-pull papillons

Cited by 4 publications

References 11 publications

Conformer Ring Flip Enhances Mechanochromic Performance of ansa-Donor–Acceptor–Donor Mechanochromic Torsional Springs

Conformer Ring Flip Enhances Mechanochromic Performance of ansa-Donor–Acceptor–Donor Mechanochromic Torsional Springs

Design and Application of Fluorescent Probes to Detect Cellular Physical Microenvironments

From Molecules to Polymers—Harnessing Inter‐ and Intramolecular Interactions to Create Mechanochromic Materials

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