Molecular force probes

Yang Q-Z, Huang Z, Kucharski TJ, Khvostichenko D, Choi J, Boulatov R (2009) A molecular force probe. Nat Nanotechnol 4 302... 

The spiropyran unit has since been established as an effective molecular force probe. Following their initial discovery, the Moore group published detailed studies investigating the role of polymer architecture, mobility [16] and chain orientatiOTi [17, 18] in the mechanical response of PMA and PMMA, rubbery and glassy polymers, respectively, upon the application of tensile and torsional stress. A study by Beiermann et al. examined the fluorescence anisotropy of the ring-opened merocyanines as a means to characterise their degree of orientation relative to the direction of the applied tensile force. In PMA, they found strong preferential activation of the spiropyrans in the direction of the tensile force [17]. On tensile... 

Gossweiler GR, Kouznetsova TB, Craig SL (2015) Force-rate characterization of two spiropyran-based molecular force probes. J Am Chem Soc 137 6148-6151... 

Huang Z, Boulatov R (2010) Chemomechanics with molecular force probes. Pure Appl Chem 82 931-951... 

Photoinduced (E)-(Z) isomerization. The photoinduced (E)-(Z) isomerization of 5tzj -stilbenes (7) will be expected as novel chemomechanics such as molecular force probes and close-cycle storage of solar energy in the future. 

GRIN/GRID nonbonded force probe of active sites Eran-cisco Molecular Discovery, Ltd. (Goodford)... 

We begin with an abstract of the physics that underlies the kinetics of bond dissociation and structural transitions in a liquid environment. Developed from Einstein s theory of Brownian motion, these well-known concepts take advantage of the huge gap in time scale that separates rapid thermal impulses in liquids (< 10 s) from slow processes in laboratory measurements (e.g. from 10 s to min in the case of force probe tests). Three equivalent formulations describe molecular kinetics in an overdamped liquid environment. The first is a microscopic perspective where molecules behave as particles with instantaneous positions or states x(t) governed by an overdamped Langevin equation of motion,... 

B. A. Heymann and H. Grubmiiller (2001) Molecular dynamics force probe simulations of antibody/antigen unbinding Entropic control and nonadditivity of unbinding forces. Biophys. J. 81, pp. 1295-1313... 

Molecular probes, such as optical or magnetic tweezers,64-71 micropipets,72 and microfibers,73-74 have been developed to manipulate single molecules and to measure their response to mechanical actions such as stretching, torsion, and compression. A force resolution down to 0.1 pN enabled quantitative measurement of the molecular forces and provided novel information on the basic principles of folding, motion, and interactions of individual molecules. Complementary to the local mechanical probes, actions of external fields were monitored on individual polymer molecules.75 77... 

Stanch T, Dreuw A (2014) Force-spectrum relations for molecular optical force probes. Angew Chem Int Ed Engl 53 2759-2761... 

Lee CK, Beiermatm BA, Silberstein MN, Wang J, Moore JS, Sottos NR, Braim PV (2013) Exploiting force sensitive spiropyrans as molecular level probes. Macromolecules 46 3746-3752... 

As Newton recognized, this short range of action of molecular forces has made the force measurement extremely difficult. Only in the past few years or so has it been possible to make the necessary measurements at the nanometer level to prove these ideas. Two problems have been overcome. The first one was the measurement technique. Optical methods, such as multiple beam interferometry and laser optical levers, have been developed to measure atomic distances. Piezoelectric actuators were invented to control nanomovements. The second issue was surface smoothness. Smooth surfaces of oxides such as mica, silica ot alumina have been found. Also tiny smooth probes have been made on a large scale by electronic wafer fabrication routes. Tbese new techniques have allowed a new and proper definition of molecular adhesion. 

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