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Yang D, Cohen AE. Chirality-dependent friction of bulk molecular solids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9972-9976. [PMID: 25102409 DOI: 10.1021/la500699z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We show that the solid-solid friction between bulk chiral molecular solids can depend on the relative chirality of the two materials. In menthol and 1-phenyl-1-butanol, heterochiral friction is smaller than homochiral friction, while in ibuprofen, heterochiral friction is larger. Chiral asymmetries in the coefficient of sliding friction vary with temperature and can be as large as 30%. In the three compounds tested, the sign of the difference between heterochiral and homochiral friction correlated with the sign of the difference in melting point between racemate (compound or conglomerate) and pure enantiomer. Menthol and ibuprofen each form a stable racemic compound, while 1-phenyl-1-butanol forms a racemic conglomerate. Thus, a difference between heterochiral and homochiral friction does not require the formation of a stable interfacial racemic compound. Measurements of chirality-dependent friction provide a unique means to distinguish the role of short-range intermolecular forces from all other sources of dissipation in the friction of bulk molecular solids.
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Affiliation(s)
- Dian Yang
- School of Engineering and Applied Sciences and ‡Departments of Chemistry and Chemical Biology and of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
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da Silva AC, Deda DK, da Róz AL, Prado RA, Carvalho CC, Viviani V, Leite FL. Nanobiosensors based on chemically modified AFM probes: a useful tool for metsulfuron-methyl detection. SENSORS 2013; 13:1477-89. [PMID: 23348034 PMCID: PMC3649369 DOI: 10.3390/s130201477] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/06/2013] [Accepted: 01/06/2013] [Indexed: 11/16/2022]
Abstract
The use of agrochemicals has increased considerably in recent years, and consequently, there has been increased exposure of ecosystems and human populations to these highly toxic compounds. The study and development of methodologies to detect these substances with greater sensitivity has become extremely relevant. This article describes, for the first time, the use of atomic force spectroscopy (AFS) in the detection of enzyme-inhibiting herbicides. A nanobiosensor based on an atomic force microscopy (AFM) tip functionalised with the acetolactate synthase (ALS) enzyme was developed and characterised. The herbicide metsulfuron-methyl, an ALS inhibitor, was successfully detected through the acquisition of force curves using this biosensor. The adhesion force values were considerably higher when the biosensor was used. An increase of ~250% was achieved relative to the adhesion force using an unfunctionalised AFM tip. This considerable increase was the result of a specific interaction between the enzyme and the herbicide, which was primarily responsible for the efficiency of the nanobiosensor. These results indicate that this methodology is promising for the detection of herbicides, pesticides, and other environmental contaminants.
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Affiliation(s)
- Aline C.N. da Silva
- Multidisciplinary Laboratory of Nanoneurobiophysics, Nanoneurobiophysics Research Group, Department of Physics, Chemistry and Mathematics, Federal University of São Carlos, CP 3031, Sorocaba-SP, 18052-780, Brazil; E-Mails: (A.C.N.S.); (A.L.R.)
| | - Daiana K. Deda
- Multidisciplinary Laboratory of Nanoneurobiophysics, Nanoneurobiophysics Research Group, Department of Physics, Chemistry and Mathematics, Federal University of São Carlos, CP 3031, Sorocaba-SP, 18052-780, Brazil; E-Mails: (A.C.N.S.); (A.L.R.)
- Authors to whom correspondence should be addressed; E-Mails: (D.K.D.); (F.L.L.); Tel./Fax: +55-3229-6014
| | - Alessandra L. da Róz
- Multidisciplinary Laboratory of Nanoneurobiophysics, Nanoneurobiophysics Research Group, Department of Physics, Chemistry and Mathematics, Federal University of São Carlos, CP 3031, Sorocaba-SP, 18052-780, Brazil; E-Mails: (A.C.N.S.); (A.L.R.)
| | - Rogilene A. Prado
- Laboratory of Biochemistry and Biotechnology of Bioluminescence, Department of Physics, Chemistry and Mathematics, Federal University of São Carlos, CP 3031, Sorocaba-SP, 18052-780, Brazil; E-Mails: (R.A.P.); (C.C.C.); (V.V.)
| | - Camila C. Carvalho
- Laboratory of Biochemistry and Biotechnology of Bioluminescence, Department of Physics, Chemistry and Mathematics, Federal University of São Carlos, CP 3031, Sorocaba-SP, 18052-780, Brazil; E-Mails: (R.A.P.); (C.C.C.); (V.V.)
| | - Vadim Viviani
- Laboratory of Biochemistry and Biotechnology of Bioluminescence, Department of Physics, Chemistry and Mathematics, Federal University of São Carlos, CP 3031, Sorocaba-SP, 18052-780, Brazil; E-Mails: (R.A.P.); (C.C.C.); (V.V.)
| | - Fabio L. Leite
- Multidisciplinary Laboratory of Nanoneurobiophysics, Nanoneurobiophysics Research Group, Department of Physics, Chemistry and Mathematics, Federal University of São Carlos, CP 3031, Sorocaba-SP, 18052-780, Brazil; E-Mails: (A.C.N.S.); (A.L.R.)
- Authors to whom correspondence should be addressed; E-Mails: (D.K.D.); (F.L.L.); Tel./Fax: +55-3229-6014
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Malti WE, Mongin O, Blanchard-Desce M, Raehm L, Durand JO. Functionalisation of mesoporous silica nanoparticles with 3-isocynatopropyltrichlorosilane. CR CHIM 2011. [DOI: 10.1016/j.crci.2011.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Affiliation(s)
- Michael Rapp
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - William A. Ducker
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
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