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Kwon YH, Joh YA, Leonard BM, Balaz M, Varga K. Threonine functionalized colloidal cadmium sulfide (CdS) quantum dots: The role of solvent and counterion in ligand induced chiroptical properties. J Colloid Interface Sci 2023; 642:771-778. [PMID: 37037081 PMCID: PMC10164713 DOI: 10.1016/j.jcis.2023.03.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 03/21/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The functionalization of semiconductor nanocrystals, quantum dots (QDs), with small organic molecules has been studied extensively to gain better knowledge on how to tune the electronic, optical and chiroptical properties of QDs. Chiral QDs have progressively emerged as key materials in a vast range of applications including biosensing and biorecognition, imaging, asymmetric catalysis, optoelectronic devices, and spintronics. To engage the full potential of the unique properties of chiral nanomaterials and be able to prepare them with tailorable chiroptical characteristics, it is essential to understand how chirality is rendered from chiral molecular ligands at the surface of nanocrystals to the electronic states of QDs. Using a series of polar protic and aprotic solvents together with ammonium (NH4+), tetramethylammonium (TMA+), and tetrabutylammonium (TBA+) countercations in the preparation of threonine-functionalized cadmium sulfide (Thr-CdS) QDs by phase transfer ligand exchange approach, we demonstrated the significance of the role both the solvent and the countercations play in the transfer of chirality from chiral molecular ligand to achiral semiconductor QDs as apparent by the modulations of the signatures and anisotropy of the circular dichroism (CD) spectra. Moreover, we have utilized tetrabutylammonium countercation to successfully synthesize chiral QDs in nonpolar cyclohexane solvent for the first time. This study provides further insights into the origin of the ligand induced chirality of colloidal nanomaterials and facilitates the synthesis of tailormade chiral QDs.
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Affiliation(s)
- Yuri H Kwon
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, 46 College Road, Durham, NH 03824, United States
| | - Yoonbin A Joh
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, 46 College Road, Durham, NH 03824, United States
| | - Brian M Leonard
- Department of Chemistry, University of Wyoming, 1000 E. University Ave, Laramie, WY 82071, United States
| | - Milan Balaz
- Integrated Science and Engineering Division, Underwood International College, Yonsei University, 50 Yonsei-ro Seodaemun-gu, Seoul 03722, Republic of Korea.
| | - Krisztina Varga
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, 46 College Road, Durham, NH 03824, United States.
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Hlaváček A, Křivánková J, Brožková H, Weisová J, Pizúrová N, Foret F. Absolute Counting Method with Multiplexing Capability for Estimating the Number Concentration of Nanoparticles Using Anisotropically Collapsed Gels. Anal Chem 2022; 94:14340-14348. [PMID: 36194835 DOI: 10.1021/acs.analchem.2c02989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Number concentration─the number of nanoparticles in a given volume─is an important characteristic of any nanoparticle dispersion. However, its estimation for small nanoparticles (∼30 nm) is generally challenging. We introduce an absolute and widely applicable method for analyzing aqueous dispersions of nanoparticles. An innovative immobilization of nanomaterials in the anisotropically collapsed agarose gel is pioneered, followed by optical microscopy and nanoparticle counting. The number of counted nanoparticles is inherently coupled with sampled volume (517 pL) and translates to the number concentration. Photon-upconversion, fluorescence, bright-field, and dark-field microscopy techniques have been proven applicable and used for imaging lanthanide-doped photon-upconversion nanoparticles, their bioconjugates with antibodies, silica dye-doped fluorescent nanoparticles, quantum dots, and pure silica submicron particles. The precision and linearity were characterized by constructing a dilution series of photon-upconversion nanoparticles. The limit of detection was 2.0 × 106 mL-1, and the working range was from 4.4 × 107 to 2.2 × 1010 mL-1. The quantification of nanoparticle clusters was achieved by a thorough analysis of the micrographs. The accuracy was confirmed using gravimetric analysis and transmission electron microscopy as a reference. Multiplexed detection of two nanoparticle types in a mixed dispersion was feasibly demonstrated. The low thickness of the collapsed gel (<1 μm) supported extremely sensitive imaging. This was proven by imaging Tm3+-doped photon-upconversion nanoparticles (17 nm hydrodynamic diameter) with a nanoparticle emission rate of only ∼900 photons/s at a wavelength of 800 nm (excitation wavelength 976 nm).
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Affiliation(s)
- Antonín Hlaváček
- Institute of Analytical Chemistry of the Czech Academy of Sciences, 602 00Brno, Czech Republic
| | - Jana Křivánková
- Institute of Analytical Chemistry of the Czech Academy of Sciences, 602 00Brno, Czech Republic
| | - Hana Brožková
- Institute of Analytical Chemistry of the Czech Academy of Sciences, 602 00Brno, Czech Republic
| | - Julie Weisová
- Institute of Analytical Chemistry of the Czech Academy of Sciences, 602 00Brno, Czech Republic
| | - Naděžda Pizúrová
- Institute of Physics of Materials of the Czech Academy of Sciences, 616 00Brno, Czech Republic
| | - František Foret
- Institute of Analytical Chemistry of the Czech Academy of Sciences, 602 00Brno, Czech Republic
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Freimann SA, Prescimone A, Housecroft CE, Constable EC. Turning over on sticky balls: preparation and catalytic studies of surface-functionalized TiO 2 nanoparticles. RSC Adv 2021; 11:5537-5547. [PMID: 35423103 PMCID: PMC8694772 DOI: 10.1039/d0ra09319j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/22/2021] [Indexed: 12/21/2022] Open
Abstract
We have investigated the reactivity of rhodium(iii) complex-functionalized TiO2 nanoparticles and demonstrate a proof-of-principle study of their catalytic activity in an alcohol oxidation carried out under aqueous conditions water in air. TiO2 nanoparticles (NPs) have been treated with (4-([2,2':6',2''-terpyridin]-4'-yl)phenyl)phosphonic acid, 1, to give the functionalized NPs (1)@TiO2. Reaction between (1)@TiO2 NPs and either RhCl3·3H2O or [Rh2(μ-OAc)4(H2O)2] produced the rhodium(iii) complex-functionalized NPs Rh(1)2@TiO2. The functionalized NPs were characterized using thermogravimetric analysis (TGA), matrix-assisted laser desorption ionization (MALDI) mass spectrometry, 1H NMR and FT-IR spectroscopies; the single crystal structures of [Rh(1)2][NO3]3·1.25[H3O][NO3]·2.75H2O and of a phosphonate ester derivative were determined. 1H NMR spectroscopy was used to follow the reaction kinetics and to assess the recyclability of the NP-supported catalyst. The catalytic activity of the Rh(1)2@TiO2 NPs was compared to that of a homogeneous system containing [Rh(1)2]3+, confirming that no catalytic activity was lost upon surface-binding. Rh(1)2@TiO2 NPs were able to withstand reaction temperatures of up to 100 °C for 24 days without degradation.
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Affiliation(s)
- Sven A Freimann
- Department of Chemistry, University of Basel BPR 1096, Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Alessandro Prescimone
- Department of Chemistry, University of Basel BPR 1096, Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel BPR 1096, Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Edwin C Constable
- Department of Chemistry, University of Basel BPR 1096, Mattenstrasse 24a CH-4058 Basel Switzerland
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Chen M, Nguyen TT, Varongchayakul N, Grazon C, Chern M, Baer RC, Lecommandoux S, Klapperich CM, Galagan JE, Dennis AM, Grinstaff MW. Surface Immobilized Nucleic Acid-Transcription Factor Quantum Dots for Biosensing. Adv Healthc Mater 2020; 9:e2000403. [PMID: 32691962 DOI: 10.1002/adhm.202000403] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 06/17/2020] [Indexed: 12/23/2022]
Abstract
Immobilization of biosensors on surfaces is a key step toward development of devices for real-world applications. Here the preparation, characterization, and evaluation of a surface-bound transcription factor-nucleic acid complex for analyte detection as an alternative to conventional systems employing aptamers or antibodies are described. The sensor consists of a gold surface modified with thiolated Cy5 fluorophore-labeled DNA and an allosteric transcription factor (TetR) linked to a quantum dot (QD). Upon addition of anhydrotetracycline (aTc)-the analyte-the TetR-QDs release from the surface-bound DNA, resulting in loss of the Förster resonance energy transfer signal. The sensor responds in a dose-dependent manner over the relevant range of 0-200 µm aTc with a limit of detection of 80 nm. The fabrication of the sensor and the subsequent real-time quantitative measurements establish a framework for the design of future surface-bound, affinity-based biosensors using allosteric transcription factors for molecular recognition.
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Affiliation(s)
- Mingfu Chen
- Department of Biomedical Engineering Boston University Boston MA 02215 USA
| | - Thuy T. Nguyen
- Department of Biomedical Engineering Boston University Boston MA 02215 USA
| | | | - Chloé Grazon
- Department of Chemistry Boston University Boston MA 02215 USA
- CNRS Bordeaux INP LCPO UMR 5629 Univ. Bordeaux Pessac F‐33600 France
| | - Margaret Chern
- Division of Materials Science and Engineering Boston University Boston MA 02215 USA
| | - R. C. Baer
- Department of Microbiology Boston University Boston MA 02118 USA
| | | | - Catherine M. Klapperich
- Department of Biomedical Engineering Boston University Boston MA 02215 USA
- Division of Materials Science and Engineering Boston University Boston MA 02215 USA
| | - James E. Galagan
- Department of Biomedical Engineering Boston University Boston MA 02215 USA
- Department of Microbiology Boston University Boston MA 02118 USA
| | - Allison M. Dennis
- Department of Biomedical Engineering Boston University Boston MA 02215 USA
- Division of Materials Science and Engineering Boston University Boston MA 02215 USA
| | - Mark W. Grinstaff
- Department of Biomedical Engineering Boston University Boston MA 02215 USA
- Department of Chemistry Boston University Boston MA 02215 USA
- Division of Materials Science and Engineering Boston University Boston MA 02215 USA
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Abstract
Brightly luminescent semiconductor quantum dots (QDs) are ideal materials for cellular imaging and analysis because of their advantageous optical properties and surface area that supports multivalent conjugation of biomolecules. An important design consideration for effective use of these materials is a hydrophilic, biocompatible surface chemistry that provides colloidal stability and minimizes nonspecific interactions with biological molecules and systems. Dextran coatings are able to satisfy these criteria. Despite frequent use of dextran coatings with other nanomaterials (e.g., iron oxide nanoparticles), there has been little development and application of dextran coatings for QDs. In this chapter, we describe methods for the synthesis and characterization of a dextran ligand for QDs, including preparation of an immunoconjugate via tetrameric antibody complexes (TAC). The utility of these immunoconjugates is demonstrated through immunofluorescent labeling and imaging of overexpressed human epidermal growth factor receptor 2 (HER2) on the surface of SK-BR3 breast cancer cells.
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Freimann SA, Zare D, Housecroft CE, Constable EC. The SALSAC approach: comparing the reactivity of solvent-dispersed nanoparticles with nanoparticulate surfaces. NANOSCALE ADVANCES 2020; 2:679-690. [PMID: 36133249 PMCID: PMC9418069 DOI: 10.1039/c9na00488b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 12/12/2019] [Indexed: 06/16/2023]
Abstract
We demonstrate that the 'surface-as-ligand, surface-as-complex' (SALSAC) approach that we have established for annealed nanoparticulate TiO2 surfaces can be successfully applied to nanoparticles (NPs) dispersed in solution. Commercial TiO2 NPs have been activated by initial treatment with aqueous HNO3 followed by dispersion in water and heating under microwave conditions. We have functionalized the activated NPs with anchoring ligands 1-4; 1-3 contain one or two phosphonic acid anchoring groups and 4 has two carboxylic acid anchors; ligands 1, 2 and 4 contain 6,6'-dimethyl-2,2'-bipyridine (Me2bpy) metal binding domains and 3 contains a 2,2':6',2''-terpyridine (tpy) unit. Ligand functionalization of the activated NPs has been validated using infrared and 1H NMR spectroscopies, and thermogravimetric analysis. NPs functionalized with 1, 2 and 4 react with [Cu(MeCN)4][PF6] and those with 3 react with FeCl2·4H2O; metal binding has been investigated using solid-state absorption spectroscopy and scanning electron microscopy (SEM). Competitive binding of ligands 1-4 to TiO2 NPs has been investigated and shows preferential binding of phosphonic acid over carboxylic acid anchors. For the phosphonic acids, the binding orders are 3 > 1 > 2 which is rationalized in terms of relative pK a values (phosphonic acid and [HMe2bpy]+ or [Htpy]+) and the number of anchoring groups in the ligands. Ligand exchange between ligand-functionalized NPs and homoleptic metal complexes gives NPs functionalized with heteroleptic copper(i) or iron(ii) complexes.
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Affiliation(s)
- Sven A Freimann
- Department of Chemistry, University of Basel BPR 1096, Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Davood Zare
- Department of Chemistry, University of Basel BPR 1096, Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel BPR 1096, Mattenstrasse 24a CH-4058 Basel Switzerland
| | - Edwin C Constable
- Department of Chemistry, University of Basel BPR 1096, Mattenstrasse 24a CH-4058 Basel Switzerland
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La Rosa M, Payne EH, Credi A. Semiconductor Quantum Dots as Components of Photoactive Supramolecular Architectures. ChemistryOpen 2020; 9:200-213. [PMID: 32055433 PMCID: PMC7008307 DOI: 10.1002/open.201900336] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/08/2020] [Indexed: 11/10/2022] Open
Abstract
Luminescent quantum dots (QDs) are colloidal semiconductor nanocrystals consisting of an inorganic core covered by a molecular layer of organic surfactants. Although QDs have been known for more than thirty years, they are still attracting the interest of researchers because of their unique size-tunable optical and electrical properties arising from quantum confinement. Moreover, the controlled decoration of the QD surface with suitable molecular species enables the rational design of inorganic-organic multicomponent architectures that can show a vast array of functionalities. This minireview highlights the recent progress in the use of surface-modified QDs - in particular, those based on cadmium chalcogenides - as supramolecular platforms for light-related applications such as optical sensing, triplet photosensitization, photocatalysis and phototherapy.
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Affiliation(s)
- Marcello La Rosa
- CLAN-Center for Light Activated Nanostructures Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, ViaGobetti 10140129BolognaItaly
- Dipartimento di Scienze e Tecnologie Agro-alimentariUniversità di BolognaViale Fanin 5040127BolognaItaly
| | - Emily H. Payne
- CLAN-Center for Light Activated Nanostructures Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, ViaGobetti 10140129BolognaItaly
- EaStChem School of ChemistryThe University of EdinburghDavid Brewster RoadEdinburghEH9 3FJUK
| | - Alberto Credi
- CLAN-Center for Light Activated Nanostructures Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, ViaGobetti 10140129BolognaItaly
- Dipartimento di Chimica Industriale “Toso Montanari”Università di BolognaViale Risorgimento 440136BolognaItaly
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