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Lulic K, Wang J, Li X, Markandeya N, Huc I, Maurizot V, Duhamel J. Probing the Closed Association of Oligoquinoline Foldamers by Time-Resolved Fluorescence Anisotropy. J Phys Chem B 2024; 128:10297-10308. [PMID: 39359059 DOI: 10.1021/acs.jpcb.4c04929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2024]
Abstract
The metal-mediated dimerization of oligoquinoline foldamers terminated at one end with an oligo(phenylenevinylene) and at the other with a carboxylic acid (OPV-QnA, where n = 4, 8, 17, and 33), and the complexation of OPV-Q8A and Q16A was promoted in chloroform by the addition of a concentrated 16 M aqueous sodium hydroxide solution. UV-vis absorption and time-resolved fluorescence anisotropy (TRFA) experiments were conducted to determine, respectively, the concentration and the average rotational time ⟨ϕ⟩ of the mixture of unassociated and associated foldamers across a range of foldamer concentrations spanning 5 orders of magnitude. Plots of ⟨ϕ⟩ as a function of acid group concentration revealed that ⟨ϕ⟩ increased with increasing foldamer concentration only when the foldamer solution in chloroform was vigorously mixed with the 16 M sodium hydroxide aqueous solution. Furthermore, all plots showed that ⟨ϕ⟩ reached a plateau at high foldamer concentration. The increase in ⟨ϕ⟩ reflected the association of foldamers into larger objects through metal ion coordination with the carboxylate anions generated by deprotonation of the carboxylic acid of OPV-QnA with NaOH, while the plateau obtained at high foldamer concentration indicated that these interactions led to the dimerization of the foldamers via a closed association mechanism. Analysis of the ⟨ϕ⟩ trends yielded the equilibrium constants (K) describing the foldamer dimerization, whose value equaled 1.0 (±0.2) × 106 M-1 for the three longer OPV-QnA foldamers, but was about 10 times smaller for the shortest one (n = 4). Association of OPV-Q8A and Q16A yielded a complex with a ⟨ϕ⟩ matching that of OPV-Q24A, and K for this complexation was similar to that for dimerization. These experiments illustrate the robust nature of TRFA as an experimental method to probe the size of rigid, self-assembled foldamers in solution.
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Affiliation(s)
- Kristijan Lulic
- Institute for Polymer Research, Waterloo Institute for Nanotechnology, Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Jingqi Wang
- Institute for Polymer Research, Waterloo Institute for Nanotechnology, Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Xuesong Li
- University of Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France
| | - Nagula Markandeya
- University of Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France
| | - Ivan Huc
- Department Pharmazie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, D-81377 Munich, Germany
| | - Victor Maurizot
- University of Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, F-33600 Pessac, France
| | - Jean Duhamel
- Institute for Polymer Research, Waterloo Institute for Nanotechnology, Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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Yahav G, Weber Y, Duadi H, Pawar S, Fixler D. Classification of fluorescent anisotropy decay based on the distance approach in the frequency domain. OPTICS EXPRESS 2022; 30:6176-6192. [PMID: 35209559 DOI: 10.1364/oe.453108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
Frequency-domain (FD) fluorometry is a widely utilized tool to probe unique features of complex biological structures, which may serve medical diagnostic purposes. The conventional data analysis approaches used today to extract the fluorescence intensity or fluorescence anisotropy (FA) decay data suffer from several drawbacks and are inherently limited by the characteristics and complexity of the decay models. This paper presents the squared distance (D2) technique, which categorized samples based on the direct frequency response data (FRD) of the FA decay. As such, it improves the classification ability of the FD measurements of the FA decay as it avoids any distortion that results from the challenged translation into time domain data. This paper discusses the potential use of the D2 approach to classify biological systems. Mathematical formulation of D2 technique adjusted to the FRD of the FA decay is described. In addition, it validates the D2 approach using 2 simulated data sets of 6 groups with similar widely and closely spaced FA decay data as well as in experimental data of 4 samples of a fluorophore-solvent (fluorescein-glycerol) system. In the simulations, the classification accuracy was above 95% for all 6 groups. In the experimental data, the classification accuracy was 100%. The D2 approach can help classify samples whose FA decay data are difficult to extract making FA in the FD a realistic diagnostic tool. The D2 approach offers an advanced method for sorting biological samples with differences beyond the practical temporal resolution limit in a reliable and efficient manner based on the FRD of their time-resolved fluorescence measurements thereby achieving better diagnostic quality in a shorter time.
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Howe ME, Barbour NA, Garcia RV, Garcia-Garibay MA. Fluorescence Anisotropy Decay of Molecular Rotors with Acene Rotators in Viscous Solution. J Org Chem 2020; 85:6872-6877. [DOI: 10.1021/acs.joc.9b03398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Morgan E. Howe
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Nicole A. Barbour
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Ronnie V. Garcia
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Miguel A. Garcia-Garibay
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
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