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Angiolini L, Valetti S, Cohen B, Feiler A, Douhal A. Fluorescence imaging of antibiotic clofazimine encapsulated within mesoporous silica particle carriers: relevance to drug delivery and the effect on its release kinetics. Phys Chem Chem Phys 2018; 20:11899-11911. [PMID: 29666860 DOI: 10.1039/c7cp08328a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We report on the encapsulation of the antibiotic clofazimine (CLZ) within the pores of mesoporous silica particles having hydrophilic (CBET value of 137) and more hydrophobic (CBET value of 94 after calcination at 600 °C) surfaces. We studied the effect of pH on the released amount of CLZ in aqueous solutions and observed a maximum at pH 4.1 in correlation with the solubility of the drug. Less release of the drug was observed from the more hydrophobic particles which was attributed to a difference in the affinity of the drug to the carrier particles. Fluorescence lifetime imaging microscopy, emission spectra, and fluorescence lifetimes of single drug loaded particles provided detailed understanding and new knowledge of the physical form of the encapsulated drug and the distribution within the particles. The distribution of CLZ within the particles was independent of the surface chemistry of the particles. The confirmation of CLZ molecules as monomers or aggregates was revealed by controlled removal of the drug with solvent. Additionally, the observed optical "halo effect" in the fluorescent images was interpreted in terms of specific quenching of high concentration of molecules. The emission lifetime experiments suggest stronger interaction of CLZ with the more hydrophobic particles, which is relevant to its release. The results reported in this work demonstrate that tuning the hydrophilicity/hydrophobicity of mesoporous silica particles can be used as a tool to control the release without impacting their loading ability.
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Affiliation(s)
- Lorenzo Angiolini
- Departamento de Química Física, Facultad de Ciencias del Medio Ambiente y Bioquímica and INAMOL, Universidad de Castilla-La Mancha, Avenida Carlos III, S/N, 45071 Toledo, Spain.
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Alarcos N, Cohen B, Ziółek M, Douhal A. Photochemistry and Photophysics in Silica-Based Materials: Ultrafast and Single Molecule Spectroscopy Observation. Chem Rev 2017; 117:13639-13720. [PMID: 29068670 DOI: 10.1021/acs.chemrev.7b00422] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Silica-based materials (SBMs) are widely used in catalysis, photonics, and drug delivery. Their pores and cavities act as hosts of diverse guests ranging from classical dyes to drugs and quantum dots, allowing changes in the photochemical behavior of the confined guests. The heterogeneity of the guest populations as well as the confinement provided by these hosts affect the behavior of the formed hybrid materials. As a consequence, the observed reaction dynamics becomes significantly different and complex. Studying their photobehavior requires advanced laser-based spectroscopy and microscopy techniques as well as computational methods. Thanks to the development of ultrafast (spectroscopy and imaging) tools, we are witnessing an increasing interest of the scientific community to explore the intimate photobehavior of these composites. Here, we review the recent theoretical and ultrafast experimental studies of their photodynamics and discuss the results in comparison to those in homogeneous media. The discussion of the confined dynamics includes solvation and intra- and intermolecular proton-, electron-, and energy transfer events of the guest within the SBMs. Several examples of applications in photocatalysis, (photo)sensors, photonics, photovoltaics, and drug delivery demonstrate the vast potential of the SBMs in modern science and technology.
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Affiliation(s)
- Noemí Alarcos
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha , Avenida Carlos III, S.N., 45071 Toledo, Spain
| | - Boiko Cohen
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha , Avenida Carlos III, S.N., 45071 Toledo, Spain
| | - Marcin Ziółek
- Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University , Umultowska 85, 61-614 Poznań, Poland
| | - Abderrazzak Douhal
- Departamento de Química Física, Facultad de Ciencias Ambientales y Bioquímica, and INAMOL, Universidad de Castilla-La Mancha , Avenida Carlos III, S.N., 45071 Toledo, Spain
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Kennes K, Dedecker P, Hutchison JA, Fron E, Uji-i H, Hofkens J, Van der Auweraer M. Field-Controlled Charge Separation in a Conductive Matrix at the Single-Molecule Level: Toward Controlling Single-Molecule Fluorescence Intermittency. ACS OMEGA 2016; 1:1383-1392. [PMID: 30023508 PMCID: PMC6044678 DOI: 10.1021/acsomega.6b00207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/09/2016] [Indexed: 06/07/2023]
Abstract
The fluorescence intermittency or "blinking" of single molecules of ATTO647N (ATTO) in the conductive matrix polyvinylcarbazole (PVK) is described in the presence of an external applied electric field. It is shown that due to the energy distribution of the highest occupied molecular orbital (HOMO) level of PVK, which is energetically close to the HOMO of ATTO, sporadic electron transfer occurs. As a result, the on/off dynamics of blinking can be influenced by the electric field. This field will, depending on the respective position and orientation of the dye/polymer system with respect to those of the electrodes, either enhance or suppress electron transfer from PVK to ATTO as well as the back electron transfer from reduced ATTO to PVK. After the charge-transfer step, the applied field will pull the hole in PVK away from the dye, increasing the overall time the dye resides in a dark state.
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Affiliation(s)
- Koen Kennes
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
| | - Peter Dedecker
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
| | - James A. Hutchison
- ISIS
& icFRC, University of Strasbourg and
CNRS UMR 7006, 8 allée
Gaspard Monge, Strasbourg 67000, France
- School
of Chemistry and Bio21 Institute, University
of Melbourne, Melbourne, Victoria 3010, Australia
| | - Eduard Fron
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
| | - Hiroshi Uji-i
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
- RIES, Hokkaido
University, N20W10, Kita-Ward, Sapporo 001-0020, Japan
| | - Johan Hofkens
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
- RIES, Hokkaido
University, N20W10, Kita-Ward, Sapporo 001-0020, Japan
| | - Mark Van der Auweraer
- Molecular
Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Leuven 3001, Belgium
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Martin C, Bhattacharyya S, Patra A, Douhal A. Single and multistep energy transfer processes within doped polymer nanoparticles. Photochem Photobiol Sci 2015; 13:1241-52. [PMID: 24969364 DOI: 10.1039/c4pp00086b] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Herein, we demonstrate the design of multiple fluorophores Coumarin 153 (C153) and Nile Red (NR) encapsulated in semiconducting poly[N-vinylcarbazole] (PVK) polymer nanoparticles (50-70 nm in diameter) by a simple re-precipitation technique, and elucidate their photophysical properties by steady-state and picosecond (ps) time resolved emission spectroscopy. It is interesting to note that multistep cascaded energy transfer occurs from the excited host PVK molecules to NR dye molecules through C153. The energy transfer time constants are found to be 180 ps for PVK→C153, 360 ps for PVK→NR, and 140 ps for the overall energy transfer process from PVK to NR through C153 dye molecules. The multistep energy transfer allows tuning of the wide range emission from 350 nm to 700 nm by changing the relative concentrations of the encapsulated dye molecules. Bright, stable, and white light emission of the dye doped polymer nanoparticles with a quantum yield of 14% is achieved at a particular concentration ratio of the C153 : NR dye. The generation of "cool" white emission in suspension and in the solid state film opens up new possibilities to obtain white light OLEDs based on single nanoparticles.
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Affiliation(s)
- Cristina Martin
- Departamento de Química Física, Facultad de Ciencias del Medio Ambiente y Bioquímica e INAMOL, Universidad de Castilla-La Mancha, Avda. Carlos III, S.N., 45071 Toledo, Spain.
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Miletto I, Massa A, Ugazio E, Musso G, Caputo G, Berlier G. The protective effect of the mesoporous host on the photo oxidation of fluorescent guests: a UV-Vis spectroscopy study. Phys Chem Chem Phys 2014; 16:12172-7. [DOI: 10.1039/c4cp01143k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The inclusion of fluorescent molecules within the pores of an inorganic host system ensures an outstanding improvement of stability against photo oxidation under different experimental conditions.
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Affiliation(s)
- Ivana Miletto
- Università degli Studi di Torino
- Dipartimento di Chimica
- 10125 Torino, Italy
- NIS (Nanostructured Interfaces and Surfaces) Interdepartmental Centre
- Università degli Studi di Torino
| | - Annalisa Massa
- Università degli Studi di Torino
- Dipartimento di Scienza e Tecnologia del Farmaco
- 10125 Torino, Italy
| | - Elena Ugazio
- Università degli Studi di Torino
- Dipartimento di Scienza e Tecnologia del Farmaco
- 10125 Torino, Italy
| | - Giorgia Musso
- Università degli Studi di Torino
- Dipartimento di Chimica
- 10125 Torino, Italy
- NIS (Nanostructured Interfaces and Surfaces) Interdepartmental Centre
- Università degli Studi di Torino
| | - Giuseppe Caputo
- NIS (Nanostructured Interfaces and Surfaces) Interdepartmental Centre
- Università degli Studi di Torino
- 10125 Torino, Italy
- Cyanine Technologies S.p.A
- 10036 Settimo Torinese, Italy
| | - Gloria Berlier
- Università degli Studi di Torino
- Dipartimento di Chimica
- 10125 Torino, Italy
- NIS (Nanostructured Interfaces and Surfaces) Interdepartmental Centre
- Università degli Studi di Torino
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Kaufman LJ. Heterogeneity in Single-Molecule Observables in the Study of Supercooled Liquids. Annu Rev Phys Chem 2013; 64:177-200. [DOI: 10.1146/annurev-physchem-040412-110033] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bulk approaches to studying heterogeneous systems obscure important details, as they report average behavior rather than the distribution of behaviors in such environments. Small-molecule and polymeric supercooled liquids, which display heterogeneity in their dynamics without an underlying structural heterogeneity that sets those dynamics, are important constituents of this category of condensed matter systems. A variety of approaches have been devised to unravel ensemble averaging in supercooled liquids. This review focuses on the ultimate subensemble approach, single-molecule measurements, as they have been applied to the study of supercooled liquids. We detail how three key experimental observables (single-molecule probe rotation, translation, and fluorescence lifetime) have been employed to provide detail on dynamic heterogeneity in supercooled liquids. Special attention is given to the potential for, but also the challenges in, discriminating spatial and temporal heterogeneity and detailing the length scales and timescales of heterogeneity in these systems.
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Affiliation(s)
- Laura J. Kaufman
- Department of Chemistry, Columbia University, New York, NY 10027
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Saxton MJ. Wanted: a positive control for anomalous subdiffusion. Biophys J 2012; 103:2411-22. [PMID: 23260043 DOI: 10.1016/j.bpj.2012.10.038] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/23/2012] [Accepted: 10/10/2012] [Indexed: 11/25/2022] Open
Abstract
Anomalous subdiffusion in cells and model systems is an active area of research. The main questions are whether diffusion is anomalous or normal, and if it is anomalous, its mechanism. The subject is controversial, especially the hypothesis that crowding causes anomalous subdiffusion. Anomalous subdiffusion measurements would be strengthened by an experimental standard, particularly one able to cross-calibrate the different types of measurements. Criteria for a calibration standard are proposed. First, diffusion must be anomalous over the length and timescales of the different measurements. The length-scale is fundamental; the time scale can be adjusted through the viscosity of the medium. Second, the standard must be theoretically well understood, with a known anomalous subdiffusion exponent, ideally readily tunable. Third, the standard must be simple, reproducible, and independently characterizable (by, for example, electron microscopy for nanostructures). Candidate experimental standards are evaluated, including obstructed lipid bilayers; aqueous systems obstructed by nanopillars; a continuum percolation system in which a prescribed fraction of randomly chosen obstacles in a regular array is ablated; single-file diffusion in pores; transient anomalous subdiffusion due to binding of particles in arrays such as transcription factors in randomized DNA arrays; and computer-generated physical trajectories.
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Affiliation(s)
- Michael J Saxton
- Department of Biochemistry and Molecular Medicine, University of California at Davis, Davis, California, USA.
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