1
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Wamsley M, Zou S, Zhang D. Advancing Evidence-Based Data Interpretation in UV-Vis and Fluorescence Analysis for Nanomaterials: An Analytical Chemistry Perspective. Anal Chem 2023; 95:17426-17437. [PMID: 37972233 DOI: 10.1021/acs.analchem.3c03490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
UV-vis spectrophotometry and spectrofluorometry are indispensable tools in education, research, and industrial process controls with widespread applications in nanoscience encompassing diverse nanomaterials and fields. Nevertheless, the prevailing spectroscopic interpretations and analyses often exhibit ambiguity and errors, particularly evident in the nanoscience literature. This analytical chemistry Perspective focuses on fostering evidence-based data interpretation in experimental studies of materials' UV-vis absorption, scattering, and fluorescence properties. We begin by outlining common issues observed in UV-vis and fluorescence analysis. Subsequently, we provide a summary of recent advances in commercial UV-vis spectrophotometric and spectrofluorometric instruments, emphasizing their potential to enhance scientific rigor in UV-vis and fluorescence analysis. Furthermore, we propose potential avenues for future developments in spectroscopic instrumentation and measurement strategies, aiming to further augment the utility of optical spectroscopy in nano research for samples where optical complexity surpasses existing tools. Through a targeted focus on the critical issues related to UV-vis and fluorescence properties of nanomaterials, this Perspective can serve as a valuable resource for researchers, educators, and practitioners.
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Affiliation(s)
- Max Wamsley
- Department of Chemistry, Mississippi State University, Starkville, Mississippi 39762, United States
| | - Shengli Zou
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Starkville, Mississippi 39762, United States
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2
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Wathudura P, Wamsley M, Wang A, Chen K, Nawalage S, Wang H, Zou S, Zhang D. Effects of Cascading Optical Processes: Part II: Impacts on Experimental Quantification of Sample Absorption and Scattering Properties. Anal Chem 2023; 95:4461-4469. [PMID: 36787490 DOI: 10.1021/acs.analchem.2c05055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
In Part I of the three companion articles, we reported the effects of light scattering on experimental quantification of scattering extinction, intensity, and depolarization in solutions that contain only scatterers with no significant absorption and photoluminescence activities. The present work (Part II) studies the effects of light scattering and absorption on a series of optical spectroscopic measurements done on samples that contain both absorbers and scatterers, but not emitters. The experimental UV-vis spectrum is the sum of the sample absorption and scattering extinction spectra. However, the upper limit of the experimental Beer's-law-abiding extinction can be limited prematurely by the interference of forward scattered light. Light absorption reduces not only the sample scattering intensity but also the scattering depolarization. The impact of scattering on sample light absorption is complicated, depending on whether the absorption of scattered light is taken into consideration. Scattering reduces light absorption along the optical path length from the excitation source to the UV-vis detector. However, the absorption of the scattered light can be adequate to compensate the reduced light absorption along such optical path, making the impacts of light scattering on the sample total light absorption negligibly small (<10%). The latter finding constitutes a critical validation of the integrating-sphere-assisted resonance synchronous spectroscopic method for experimental quantification of absorption and scattering contribution to the sample UV-vis extinction spectra. The techniques and general guidelines provided in this work should help improve the reliability of optical spectroscopic characterization of nanoscale or larger materials, many of which are simultaneous absorbers and scatterers. The insights from this work are foundational for Part III of this series of work, which is on the cascading optical processes on spectroscopic measurements of fluorescent samples.
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Affiliation(s)
- Pathum Wathudura
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39759, United States
| | - Max Wamsley
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39759, United States
| | - Ankai Wang
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Kexun Chen
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Samadhi Nawalage
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39759, United States
| | - Hui Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Shengli Zou
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39759, United States
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3
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Nawalage S, Wathudura P, Wang A, Wamsley M, Zou S, Zhang D. Effects of Cascading Optical Processes: Part I: Impacts on Quantification of Sample Scattering Extinction, Intensity, and Depolarization. Anal Chem 2023; 95:1899-1907. [PMID: 36598877 DOI: 10.1021/acs.analchem.2c03917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Light scattering is a universal matter property that is especially prominent in nanoscale or larger materials. However, the effects of scattering-based cascading optical processes on experimental quantification of sample absorption, scattering, and emission intensities, as well as scattering and emission depolarization, have not been adequately addressed. Using a series of polystyrene nanoparticles (PSNPs) of different sizes as model analytes, we present a computational and experimental study on the effects of cascading light scattering on experimental quantification of NP scattering activities (scattering cross-section or molar coefficient), intensity, and depolarization. Part II and Part III of this series of companion articles explore the effects of cascading optical processes on sample absorption and fluorescence measurements, respectively. A general theoretical model is developed on how forward scattered light complicates the general applicability of Beer's law to the experimental UV-vis spectrum of scattering samples. The correlation between the scattering intensity and PSNP concentration is highly complicated with no robust linearity even when the scatterers' concentration is very low. Such complexity arises from the combination of concentration-dependence of light scattering depolarization and the scattering inner filter effects (IFEs). Scattering depolarization increases with the PSNP scattering extinction (thereby, its concentration) but can never reach unity (isotropic) due to the polarization dependence of the scattering IFE. The insights from this study are important for understanding the strengths and limitations of various scattering-based techniques for material characterization including nanoparticle quantification. They are also foundational for quantitative mechanistic understanding on the effects of light scattering on sample absorption and fluorescence measurements.
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Affiliation(s)
- Samadhi Nawalage
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Pathum Wathudura
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Ankai Wang
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Max Wamsley
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Shengli Zou
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
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4
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Wamsley M, Wathudura P, Hu J, Zhang D. Integrating-Sphere-Assisted Resonance Synchronous Spectroscopy for the Quantification of Material Double-Beam UV-Vis Absorption and Scattering Extinction. Anal Chem 2022; 94:11610-11618. [PMID: 35960824 DOI: 10.1021/acs.analchem.2c02037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Integrating spheres (IS) have been used extensively for the characterization of light absorption in turbid samples. However, converting the IS-based sample absorption coefficient to the UV-vis absorbance quantified with a double-beam UV-vis spectrophotometer is challenging. Herein, we report an integrating-sphere-assisted resonance synchronous (ISARS) spectroscopy method performed with conventional spectrofluorometers equipped with an integrating-sphere accessory. Mathematical models and experimental procedures for quantifying the sample, solvent, and instrument-baseline ISARS intensity spectra were provided. A three-parameter analytical model has been developed for correlating the ISARS-based UV-vis absorbance and the absorbance measured with double-beam instruments. This ISARS method enables the quantitative separation of light absorption and scattering contribution to the sample UV-vis extinction spectrum measured with double-beam UV-vis spectrophotometers. Example applications of this ISARS technique are demonstrated with a series of representative samples differing significantly in their optical complexities, from approximately pure absorbers, pure scatterers, to simultaneous light absorbers, scatterers, and emitters under resonance excitation and detection conditions.
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Affiliation(s)
- Max Wamsley
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Pathum Wathudura
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Juan Hu
- Department of Mathematical Sciences, DePaul University, Chicago, Illinois 60604, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
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5
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An Y, Sedinkin SL, Venditti V. Solution NMR methods for structural and thermodynamic investigation of nanoparticle adsorption equilibria. NANOSCALE ADVANCES 2022; 4:2583-2607. [PMID: 35769933 PMCID: PMC9195484 DOI: 10.1039/d2na00099g] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 05/07/2022] [Indexed: 05/09/2023]
Abstract
Characterization of dynamic processes occurring at the nanoparticle (NP) surface is crucial for developing new and more efficient NP catalysts and materials. Thus, a vast amount of research has been dedicated to developing techniques to characterize sorption equilibria. Over recent years, solution NMR spectroscopy has emerged as a preferred tool for investigating ligand-NP interactions. Indeed, due to its ability to probe exchange dynamics over a wide range of timescales with atomic resolution, solution NMR can provide structural, kinetic, and thermodynamic information on sorption equilibria involving multiple adsorbed species and intermediate states. In this contribution, we review solution NMR methods for characterizing ligand-NP interactions, and provide examples of practical applications using these methods as standalone techniques. In addition, we illustrate how the integrated analysis of several NMR datasets was employed to elucidate the role played by support-substrate interactions in mediating the phenol hydrogenation reaction catalyzed by ceria-supported Pd nanoparticles.
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Affiliation(s)
- Yeongseo An
- Department of Chemistry, Iowa State University Hach Hall, 2438 Pammel Drive Ames Iowa 50011 USA +1-515-294-7550 +1-515-294-1044
| | - Sergey L Sedinkin
- Department of Chemistry, Iowa State University Hach Hall, 2438 Pammel Drive Ames Iowa 50011 USA +1-515-294-7550 +1-515-294-1044
| | - Vincenzo Venditti
- Department of Chemistry, Iowa State University Hach Hall, 2438 Pammel Drive Ames Iowa 50011 USA +1-515-294-7550 +1-515-294-1044
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University Ames Iowa 50011 USA
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6
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Wang Z, Wang W, Wamsley M, Zhang D, Wang H. Colloidal Polydopamine Beads: A Photothermally Active Support for Noble Metal Nanocatalysts. ACS APPLIED MATERIALS & INTERFACES 2022; 14:17560-17569. [PMID: 35380793 DOI: 10.1021/acsami.2c03183] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Polydopamine (PDA) is a unique bioinspired synthetic polymer that integrates broadband light absorption, efficient photothermal transduction, and versatile surface-adhesion functions in a single material entity. Here, we utilize colloidal PDA beads in the submicron particle size regime as an easily processable and photothermally active support for sub-10 nm Pd nanocatalysts to construct a multifunctional material system that allows us to kinetically boost thermal catalytic reactions through visible and near-infrared light illuminations. Choosing the Pd-catalyzed nitrophenol reduction by ammonium formate as a model transfer hydrogenation reaction exhibiting temperature-dependent reaction rates, we demonstrate that interfacial molecule-transforming processes on metal nanocatalyst surfaces can be kinetically modulated by harnessing the thermal energy produced through photothermal transduction in the PDA supports.
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Affiliation(s)
- Zixin Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Wei Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Max Wamsley
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Hui Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
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7
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Zhou H, Li M, Diao N, Wu S, Wang J, Wu P. A removing resonance fluorescence method for light scattering spectroscopy. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2021.139244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Xu JX, Yuan Y, Liu M, Zou S, Chen O, Zhang D. Quantification of the Photon Absorption, Scattering, and On-Resonance Emission Properties of CdSe/CdS Core/Shell Quantum Dots: Effect of Shell Geometry and Volumes. Anal Chem 2020; 92:5346-5353. [PMID: 32126174 DOI: 10.1021/acs.analchem.0c00016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Reliable quantification of the optical properties of fluorescent quantum dots (QDs) is critical for their photochemical, -physical, and -biological applications. Presented herein is the experimental quantification of photon scattering, absorption, and on-resonance-fluorescence (ORF) activities of CdSe/CdS core/shell fluorescent QDs as a function of the shell sizes and geometries. Four spherical QDs (SQDs) with different diameters and four rod-like QDs (RQDs) with different aspect ratios (ARs) have been analyzed using UV-vis, fluorescence, and the recent polarized resonance synchronous spectroscopic (PRS2) methods. All quantum dots are simultaneous absorbers and scatterers in the UV-vis wavelength region, and they all exhibit strong ORF emission in the wavelength regions where the QDs both absorb and emit. The absorption and scattering cross-sections of the CdS shell are linearly and quadratically, respectively, proportional to the shell volume for both the SQDs and RQDs. However, the effects of CdS shell coating on the core optical properties are different between SQDs and RQDs. For RQDs, increasing the CdS shell volume through the length elongation has no effect on either the peak wavelength or intensity of the CdSe core UV-vis absorption and ORF, but it reduces the QD fluorescence depolarization. In contrast, increasing CdS shell volume in the SQDs induces red-shift in the CdSe core peak UV-vis absorption and ORF wavelengths, and increases their peak cross-sections, but it has no effect on the SQD fluorescence depolarization. The RQD ORF cross-sections and quantum yields are significantly higher than their respective counterparts for the SQDs with similar particle sizes (volumes). While these new insights should be significant for the QD design, characterization, and applications, the methodology presented in this work is directly applicable for quantifying the optical activities of optically complex materials where the common UV-vis spectrometry and fluorescence spectroscopy are inadequate.
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Affiliation(s)
- Joanna Xiuzhu Xu
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Yucheng Yuan
- Department of Chemistry, Brown University, 324 Brook Street, Providence, Rhode Island 02912, United States
| | - Muqiong Liu
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Shengli Zou
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Ou Chen
- Department of Chemistry, Brown University, 324 Brook Street, Providence, Rhode Island 02912, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
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9
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Perera YR, Hill RA, Fitzkee NC. Protein Interactions with Nanoparticle Surfaces: Highlighting Solution NMR Techniques. Isr J Chem 2019; 59:962-979. [PMID: 34045771 PMCID: PMC8152826 DOI: 10.1002/ijch.201900080] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 09/02/2019] [Indexed: 12/14/2022]
Abstract
In the last decade, nanoparticles (NPs) have become a key tool in medicine and biotechnology as drug delivery systems, biosensors and diagnostic devices. The composition and surface chemistry of NPs vary based on the materials used: typically organic polymers, inorganic materials, or lipids. Nanoparticle classes can be further divided into sub-categories depending on the surface modification and functionalization. These surface properties matter when NPs are introduced into a physiological environment, as they will influence how nucleic acids, lipids, and proteins will interact with the NP surface. While small-molecule interactions are easily probed using NMR spectroscopy, studying protein-NP interactions using NMR introduces several challenges. For example, globular proteins may have a perturbed conformation when attached to a foreign surface, and the size of NP-protein conjugates can lead to excessive line broadening. Many of these challenges have been addressed, and NMR spectroscopy is becoming a mature technique for in situ analysis of NP binding behavior. It is therefore not surprising that NMR has been applied to NP systems and has been used to study biomolecules on NP surfaces. Important considerations include corona composition, protein behavior, and ligand architecture. These features are difficult to resolve using classical surface and material characterization strategies, and NMR provides a complementary avenue of characterization. In this review, we examine how solution NMR can be combined with other analytical techniques to investigate protein behavior on NP surfaces.
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Affiliation(s)
- Y Randika Perera
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Rebecca A Hill
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
| | - Nicholas C Fitzkee
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA
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10
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Cuevasanta E, Benchoam D, Ferrer-Sueta G, Zeida A, Denicola A, Alvarez B, Möller MN. Commentary on "Using resonance synchronous spectroscopy to characterize the reactivity and electrophilicity of biologically relevant sulfane sulfur". Evidence that the methodology is inadequate because it only measures unspecific light scattering. Redox Biol 2019; 26:101281. [PMID: 31351822 PMCID: PMC6831858 DOI: 10.1016/j.redox.2019.101281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/18/2019] [Accepted: 07/19/2019] [Indexed: 11/25/2022] Open
Affiliation(s)
- Ernesto Cuevasanta
- Laboratorio de Enzimología, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, 11400, Uruguay; Centro de Investigaciones Biomédicas, Universidad de la República, Montevideo, 11800, Uruguay; Unidad de Bioquímica Analítica, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Montevideo, 11400, Uruguay.
| | - Dayana Benchoam
- Laboratorio de Enzimología, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, 11400, Uruguay; Centro de Investigaciones Biomédicas, Universidad de la República, Montevideo, 11800, Uruguay
| | - Gerardo Ferrer-Sueta
- Centro de Investigaciones Biomédicas, Universidad de la República, Montevideo, 11800, Uruguay; Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, 11400, Uruguay
| | - Ari Zeida
- Centro de Investigaciones Biomédicas, Universidad de la República, Montevideo, 11800, Uruguay; Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, 11800, Uruguay
| | - Ana Denicola
- Centro de Investigaciones Biomédicas, Universidad de la República, Montevideo, 11800, Uruguay; Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, 11400, Uruguay
| | - Beatriz Alvarez
- Laboratorio de Enzimología, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, 11400, Uruguay; Centro de Investigaciones Biomédicas, Universidad de la República, Montevideo, 11800, Uruguay
| | - Matías N Möller
- Centro de Investigaciones Biomédicas, Universidad de la República, Montevideo, 11800, Uruguay; Laboratorio de Fisicoquímica Biológica, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, 11400, Uruguay.
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11
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Xu JX, Yuan Y, Zou S, Chen O, Zhang D. A Divide-and-Conquer Strategy for Quantification of Light Absorption, Scattering, and Emission Properties of Fluorescent Nanomaterials in Solutions. Anal Chem 2019; 91:8540-8548. [DOI: 10.1021/acs.analchem.9b01803] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Joanna Xiuzhu Xu
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Yucheng Yuan
- Department of Chemistry, Brown University, 324 Brook Street, Providence, Rhode Island 02912, United States
| | - Shengli Zou
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Ou Chen
- Department of Chemistry, Brown University, 324 Brook Street, Providence, Rhode Island 02912, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
- Department of Chemistry, Xihua University, Chengdu, 610039, China
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12
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Xu J, Liu M, Athukorale S, Zou S, Zhang D. Linear Extrapolation of the Analyte-Specific Light Scattering and Fluorescence Depolarization in Turbid Samples. ACS OMEGA 2019; 4:4739-4747. [PMID: 31459660 PMCID: PMC6648588 DOI: 10.1021/acsomega.8b03354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/19/2019] [Indexed: 05/14/2023]
Abstract
Anisotropy and depolarization are two interconvertible parameters in fluorescence and light scattering spectroscopy that describe the polarization distribution of emitted and scattered photons generated with linearly polarized excitation light. Whereas anisotropy is more frequently used in fluorescence literature for studying association/dissociation of fluorophore-bearing reagents, depolarization is more popular in the light-scattering literature for investigating the effect of scatterers' geometries and chemical compositions. Presented herein is a combined computational and experimental study of the scattering and fluorescence depolarization enhancement induced by light scattering in turbid samples. The most important finding is that sample light scattering and fluorescence depolarization increases linearly with sample light-scattering extinction. Therefore, one can extrapolate the analyte-specific scattering and fluorescence depolarization through linear curve fitting of the sample light scattering and fluorescence depolarization as a function of the sample concentration or the path length of the sampling cuvettes. An example application of this linear extrapolation method is demonstrated for quantifying the fluorophore-specific fluorescence depolarization and consequently its anisotropy for an aggregation-induced-emission sample. This work should be important for a wide range of macromolecular, supramolecular, and nanoscale fluorescent materials that are often strong light scatterers due to their large sizes.
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Affiliation(s)
- Joanna
Xiuzhu Xu
- Department
of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Muqiong Liu
- Department
of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Sumudu Athukorale
- Department
of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Shengli Zou
- Department
of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Dongmao Zhang
- Department
of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
- Department
of Chemistry, Xihua University, Chengdu 610039, China
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13
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Athukorale S, Leng X, Xu JX, Perera YR, Fitzkee NC, Zhang D. Surface Plasmon Resonance, Formation Mechanism, and Surface Enhanced Raman Spectroscopy of Ag +-Stained Gold Nanoparticles. Front Chem 2019; 7:27. [PMID: 30838197 PMCID: PMC6382679 DOI: 10.3389/fchem.2019.00027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 01/11/2019] [Indexed: 12/26/2022] Open
Abstract
A series of recent works have demonstrated the spontaneous Ag+ adsorption onto gold surfaces. However, a mechanistic understanding of the Ag+ interactions with gold has been controversial. Reported herein is a systematic study of the Ag+ binding to AuNPs using several in-situ and ex-situ measurement techniques. The time-resolved UV-vis measurements of the AuNP surface plasmonic resonance revealed that the silver adsorption proceeds through two parallel pseudo-first order processes with a time constant of 16(±2) and 1,000(±35) s, respectively. About 95% of the Ag+ adsorption proceeds through the fast adsorption process. The in-situ zeta potential data indicated that this fast Ag+ adsorption is driven primarily by the long-range electrostatic forces that lead to AuNP charge neutralization, while the time-dependent pH data shows that the slow Ag+ binding process involves proton-releasing reactions that must be driven by near-range interactions. These experimental data, together with the ex-situ XPS measurement indicates that adsorbed silver remains cationic, but not as a charged-neutral silver atom proposed by the anti-galvanic reaction mechanism. The surface-enhanced Raman activities of the Ag+-stained AuNPs are slightly higher than that for AuNPs, but significantly lower than that for the silver nanoparticles (AgNPs). The SERS feature of the ligands on the Ag+-stained AuNPs can differ from that on both AuNPs and AgNPs. Besides the new insights to formation mechanism, properties, and applications of the Ag+-stained AuNPs, the experimental methodology presented in this work can also be important for studying nanoparticle interfacial interactions.
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Affiliation(s)
- Sumudu Athukorale
- Department of Chemistry, Mississippi State University, Starkville, MS, United States
| | - Xue Leng
- Department of Chemistry, Chengdu University of Technology, Chengdu, China
| | - Joanna Xiuzhu Xu
- Department of Chemistry, Mississippi State University, Starkville, MS, United States
| | - Y Randika Perera
- Department of Chemistry, Mississippi State University, Starkville, MS, United States
| | - Nicholas C Fitzkee
- Department of Chemistry, Mississippi State University, Starkville, MS, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Starkville, MS, United States.,Department of Chemistry, Xihua University, Chengdu, China
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14
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Vithanage BCN, Xu JX, Zhang D. Optical Properties and Kinetics: New Insights to the Porphyrin Assembly and Disassembly by Polarized Resonance Synchronous Spectroscopy. J Phys Chem B 2018; 122:8429-8438. [PMID: 30102542 DOI: 10.1021/acs.jpcb.8b05965] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
With their unique photochemical properties, porphyrins have remained for decades the most interested chemicals as photonic materials for applications ranging from chemistry, biology, medicine, to photovoltaic. Porphyrins can self-assemble into higher order structures. However, information has been scant on the kinetics and structural evolution during porphyrin assembly and disassembly. Furthermore, quantitative understanding of the porphyrin optical activities is complicated by the complex interplay of photon absorption, scattering, and fluorescence emission that can concurrently occur in porphyrin samples. Using meso-tetrakis(4-sulfonatophenyl)porphyrin as the model molecule, reported herein is a combined UV-vis extinction, polarized Stokes-shifted fluorescence, and polarized resonance synchronous spectroscopic (PRS2) study of porphyrin assembly and disassembly in acidic solutions. Although porphyrin assembly and disassembly occur instantaneously upon the sample preparation, both processes last at least a few months before reaching their approximate equilibrium states. The two processes were monitored in situ by quantifying the porphyrin fluorescence and scattering depolarizations as well as its extinction, absorption, scattering, and fluorescence emission cross sections. In addition to a series of new insights to the porphyrin assembly and disassembly, the methodology described in this work opens the door for the in situ study of the structural and optical properties of photonic materials comprising molecular assembly.
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Affiliation(s)
- Buddhini C N Vithanage
- Department of Chemistry , Mississippi State University , Mississippi State , Mississippi 39762 , United States
| | - Joanna Xiuzhu Xu
- Department of Chemistry , Mississippi State University , Mississippi State , Mississippi 39762 , United States
| | - Dongmao Zhang
- Department of Chemistry , Mississippi State University , Mississippi State , Mississippi 39762 , United States.,Department of Chemistry , Xihua University , Chengdu 610039 , China
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15
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Xu JX, Hu J, Zhang D. Quantification of Material Fluorescence and Light Scattering Cross Sections Using Ratiometric Bandwidth-Varied Polarized Resonance Synchronous Spectroscopy. Anal Chem 2018; 90:7406-7414. [DOI: 10.1021/acs.analchem.8b00847] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Joanna Xiuzhu Xu
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Juan Hu
- Department of Mathematical Sciences, DePaul University, Chicago, Illinois 60604, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
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16
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Xu JX, Vithanage BCN, Athukorale SA, Zhang D. Scattering and absorption differ drastically in their inner filter effects on fluorescence, resonance synchronous, and polarized resonance synchronous spectroscopic measurements. Analyst 2018; 143:3382-3389. [DOI: 10.1039/c8an00790j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Reported herein is the finding that photon scattering and absorption differ drastically in inducing the sample IFE in SSF, RS2, and the PRS2 spectra measurements.
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Affiliation(s)
- Joanna Xiuzhu Xu
- Department of Chemistry
- Mississippi State University
- Mississippi State
- USA
| | | | | | - Dongmao Zhang
- Department of Chemistry
- Mississippi State University
- Mississippi State
- USA
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17
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Xu JX, Siriwardana K, Zhou Y, Zou S, Zhang D. Quantification of Gold Nanoparticle Ultraviolet–Visible Extinction, Absorption, and Scattering Cross-Section Spectra and Scattering Depolarization Spectra: The Effects of Nanoparticle Geometry, Solvent Composition, Ligand Functionalization, and Nanoparticle Aggregation. Anal Chem 2017; 90:785-793. [DOI: 10.1021/acs.analchem.7b03227] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Joanna Xiuzhu Xu
- Department
of Chemistry, Mississippi State University, Mississippi State Mississippi 39762, United States
| | - Kumudu Siriwardana
- Department
of Chemistry, Mississippi State University, Mississippi State Mississippi 39762, United States
| | - Yadong Zhou
- Department
of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Shengli Zou
- Department
of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Dongmao Zhang
- Department
of Chemistry, Mississippi State University, Mississippi State Mississippi 39762, United States
- Department
of Chemistry, Xihua University, Chengdu 610039, China
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18
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Athukorale SA, Zhou Y, Zou S, Zhang D. Determining the Liquid Light Scattering Cross Section and Depolarization Spectra Using Polarized Resonance Synchronous Spectroscopy. Anal Chem 2017; 89:12705-12712. [PMID: 29115124 DOI: 10.1021/acs.analchem.7b02721] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Rayleigh scattering is a universal material property because all materials have nonzero polarizability. Reliable quantification of the material light scattering cross section in the liquid phase and its depolarization spectra is, however, challenging due to a host of sample and instrument issues. Using the recently developed polarized resonance synchronous spectroscopic method, we reported the light scattering cross section and depolarization spectra measured for a total of 29 liquids including water, methanol, ethanol, 1-propanol, 1-butanol, dimethylformamide, carbon disulfide, dimethyl sulfoxide, hexane and two hexane isomers (3-methylpentane and 2,3-dimethylbutane), tetrahydrofuran, cyclohexane, acetonitrile, pyridine, chloromethanes including di-, tri, tetrachloromethane, acetone, benzene and eight benzene derivatives (toluene, fluorobenzene, 1,2-, 1,3-, and 1,4-difluorobenzene, chlorobenzene, 1,2- and 1,3-dichlorobenzene, and nitrobenzene). The solvent light scattering depolarization is wavelength-independent for the model solvents, and it varies from 0.023 ± 0.011 for CCl4 to 0.619 ± 0.022 for nitrobenzene. The light scattering cross-section spectra can be approximated with the function of σ(λ) = αλ-4 with the α value varying from 7.2 ± 0.2 × 10-45 cm6 for water to a maximum of 8.5 ± 0.6 × 10-43 cm6 for nitrobenzene. Structural isomerization has no significant effect on either the depolarization or the scattering cross sections for both hexanes and difluorobenzene isomers. This work represents the most comprehensive experimental study on liquid light scattering features. The insight from this work should be important for understanding the correlation between the material structure and optical properties. The described method can be readily implemented by researchers with access to conventional spectrofluorometers equipped with excitation and detection polarizers.
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Affiliation(s)
- Sumudu A Athukorale
- Department of Chemistry, Mississippi State University , Mississippi State, Mississippi 39762, United States
| | - Yadong Zhou
- Department of Chemistry, University of Central Florida , Orlando, Florida 32816, United States
| | - Shengli Zou
- Department of Chemistry, University of Central Florida , Orlando, Florida 32816, United States
| | - Dongmao Zhang
- Department of Chemistry, Mississippi State University , Mississippi State, Mississippi 39762, United States.,Department of Chemistry, Xihua University , Chengdu, 610039 China
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