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Hambly BP, Sears C, Pendley BD, Thompson LL, Lindner E. A Potentially Versatile Enzyme Sensor Platform: Enzyme-Loaded, Tagged, Porous Polymeric Nanocapsules. ACS Sens 2024; 9:1199-1207. [PMID: 38372695 DOI: 10.1021/acssensors.3c01980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Enzymes are essential to life and indispensable in a wide range of industries (food, pharmaceutical, medical, biosensing, etc.); however, a significant shortcoming of these fragile biological catalysts is their poor stability. To address this challenge, a variety of immobilization methods have been described to enhance the enzyme's stability. These immobilization methods generally are specific to an individual enzyme or optimal for a particular application. The aim of this study is to explore the utility of porous, indicator moiety-tagged, polymeric nanocapsules (NCs) for the encapsulation of enzymes and measurement of the enzyme's substrate. As a model enzyme, glucose oxidase (GOx) is used. The GOx enzyme-loaded, fluorophore-tagged NCs were synthesized by using self-assembled surfactant vesicle templates. To show that the biological activity of GOx is preserved during entrapment, the rate of the GOx enzyme catalyzed reaction was measured. To evaluate the protective features of the porous NCs, the encapsulated GOx enzyme activity was followed in the presence of hydrolytic enzymes. During the encapsulation of GOx and the purification of the GOx-loaded NCs, the GOx activity decayed less than 10%, and up to 30% of the encapsulated GOx activity could be retained for 3-5 days in the presence of hydrolytic enzymes. In support of the potentially unique advantages of the enzyme-loaded NCs, as a proof-of-concept example, the fluorophore-tagged, GOx-loaded NCs were used for the determination of glucose in the concentration range between 18 and 162 mg/dL and for imaging the distribution of glucose concentration in imaging experiments.
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Affiliation(s)
- Bradley P Hambly
- Department of Biomedical Engineering, University of Memphis, Memphis, Tennessee 38152, United States
| | - Chandler Sears
- Department of Biomedical Engineering, University of Memphis, Memphis, Tennessee 38152, United States
| | - Bradford D Pendley
- Department of Biomedical Engineering, University of Memphis, Memphis, Tennessee 38152, United States
| | - Lauren L Thompson
- Integrated Microscopy Center, University of Memphis, Memphis, Tennessee 38152, United States
| | - Ernő Lindner
- Department of Biomedical Engineering, University of Memphis, Memphis, Tennessee 38152, United States
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2
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Schulz F, Hühn J, Werner M, Hühn D, Kvelstad J, Koert U, Wutke N, Klapper M, Fröba M, Baulin V, Parak WJ. Local Environments Created by the Ligand Coating of Nanoparticles and Their Implications for Sensing and Surface Reactions. Acc Chem Res 2023; 56:2278-2285. [PMID: 37607332 PMCID: PMC10552541 DOI: 10.1021/acs.accounts.3c00139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Indexed: 08/24/2023]
Abstract
ConspectusThe ligand shells of colloidal nanoparticles (NPs) can serve different purposes. In general, they provide colloidal stability by introducing steric repulsion between NPs. In the context of biological applications, the ligand shell plays a critical role in targeting, enabling NPs to achieve specific biodistributions. However, there is also another important feature of the ligand shell of NPs, namely, the creation of a local environment differing from the bulk of the solvent in which the NPs are dispersed. It is known that charged ligand shells can attract or repel ions and change the effective charge of a NP through Debye-Hückel screening. Positively charged ions, such as H+ (or H3O+) are attracted to negatively charged surfaces, whereas negatively charged ions, such as Cl- are repelled. The distribution of the ions around charged NP surfaces is a radial function of distance from the center of the NP, which is governed by a balance of electrostatic forces and entropy of ions and ligands. As a result, the ion concentration at the NP surface is different from its bulk equilibrium concentration, i.e., the charged ligand shell around the NPs has formed a distinct local environment. This not only applies to charged ligand shells but also follows a more general principle of induced condensation and depletion. Polar/apolar ligand shells, for example, result in a locally increased concentration of polar/apolar molecules. Similar effects can be seen for biocatalysts like enzymes immobilized in nanoporous host structures, which provide a special environment due to their surface chemistry and geometrical nanoconfinement. The formation of a local environment close to the ligand shell of NPs has profound implications for NP sensing applications. As a result, analyte concentrations close to the ligand shell, which are the ones that are measured, may be very different from the analyte concentrations in bulk. Based on previous work describing this effect, it will be discussed herein how such local environments, created by the choice of used ligands, may allow for tailoring the NPs' sensing properties. In general, the ligand shell around NPs can be attractive/repulsive for molecules with distinct properties and thus forms an environment that can modulate the specific response. Such local environments can also be optimized to modulate chemical reactions close to the NP surface (for example, by size filtering within pores) or to attract specific low abundance proteins. The importance hereby is that this is based on interaction with low selectivity between the ligands and the target molecules.
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Affiliation(s)
- Florian Schulz
- Fachbereich
Physik, Universität Hamburg, 22607 Hamburg, Germany
| | - Jonas Hühn
- Fachbereich
Physik, Philipps Universität Marburg, 35037 Marburg, Germany
| | - Marco Werner
- Leibniz-Institut
fur Polymerforschung Dresden e.V., 01069 Dresden, Germany
| | - Dominik Hühn
- Fachbereich
Physik, Philipps Universität Marburg, 35037 Marburg, Germany
| | - Julia Kvelstad
- Fachbereich
Chemie, Philipps Universität Marburg, 35043 Marburg, Germany
| | - Ulrich Koert
- Fachbereich
Chemie, Philipps Universität Marburg, 35043 Marburg, Germany
| | - Nicole Wutke
- Max Planck
Institute für Polymerforschung, 55128 Mainz, Germany
| | - Markus Klapper
- Max Planck
Institute für Polymerforschung, 55128 Mainz, Germany
| | - Michael Fröba
- Fachbereich
Chemie, Universität Hamburg, 20146 Hamburg, Germany
| | - Vladimir Baulin
- Departament
Quimica Fisica i Inorganica, Universitat
Rovira i Virgili, 43007 Tarragona, Spain
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3
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Ir(III)-based Ratiometric Hypoxic Probe for Cell Imaging. CHINESE JOURNAL OF POLYMER SCIENCE 2023. [DOI: 10.1007/s10118-023-2922-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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4
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Lee R, Erstling JA, Hinckley JA, Chapman DV, Wiesner UB. Addressing Particle Compositional Heterogeneities in Super-Resolution-Enhanced Live-Cell Ratiometric pH Sensing with Ultrasmall Fluorescent Core-Shell Aluminosilicate Nanoparticles. ADVANCED FUNCTIONAL MATERIALS 2021; 31:2106144. [PMID: 34899116 PMCID: PMC8659865 DOI: 10.1002/adfm.202106144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Indexed: 06/13/2023]
Abstract
The interrogation of metabolic parameters like pH in live-cell experiments using optical super-resolution microscopy (SRM) remains challenging. This is due to a paucity of appropriate metabolic probes enabling live-cell SRM-based sensing. Here we introduce ultrasmall fluorescent core-shell aluminosilicate nanoparticle sensors (FAM-ATTO647N aC' dots) that covalently encapsulate a reference dye (ATTO647N) in the core and a pH-sensing moiety (FAM) in the shell. Only the reference dye exhibits optical blinking enabling live-cell stochastic optical reconstruction microscopy (STORM). Using data from cells incubated for 60 minutes with FAM-ATTO647N aC' dots, pixelated information from total internal reflection fluorescence (TIRF) microscopy-based ratiometric sensing can be combined with that from STORM-based localizations via the blinking reference dye in order to enhance the resolution of ratiometric pH sensor maps beyond the optical diffraction limit. A nearest-neighbor interpolation methodology is developed to quantitatively address particle compositional heterogeneity as determined by separate single-particle fluorescence imaging methods. When combined with STORM-based estimates of the number of particles per vesicle, vesicle size, and vesicular motion as a whole, this analysis provides detailed live-cell spatial and functional information, paving the way to a comprehensive mapping and understanding of the spatiotemporal evolution of nanoparticle processing by cells important, e.g. for applications in nanomedicine.
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Affiliation(s)
- Rachel Lee
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Jacob A Erstling
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States; Department of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Joshua A Hinckley
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Dana V Chapman
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Ulrich B Wiesner
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
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5
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Elistratova AA, Kritchenkov IS, Lezov AA, Gubarev AS, Solomatina AI, Kachkin DV, Shcherbina NA, Liao YC, Liu YC, Yang YY, Tsvetkov NV, Chelushkin PS, Chou PT, Tunik SP. Lifetime oxygen sensors based on block copolymer micelles and non-covalent human serum albumin adducts bearing phosphorescent near-infrared iridium(III) complex. Eur Polym J 2021. [DOI: 10.1016/j.eurpolymj.2021.110761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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6
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Huynh GT, Kesarwani V, Walker JA, Frith JE, Meagher L, Corrie SR. Review: Nanomaterials for Reactive Oxygen Species Detection and Monitoring in Biological Environments. Front Chem 2021; 9:728717. [PMID: 34568279 PMCID: PMC8461210 DOI: 10.3389/fchem.2021.728717] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/25/2021] [Indexed: 12/19/2022] Open
Abstract
Reactive oxygen species (ROS) and dissolved oxygen play key roles across many biological processes, and fluorescent stains and dyes are the primary tools used to quantify these species in vitro. However, spatio-temporal monitoring of ROS and dissolved oxygen in biological systems are challenging due to issues including poor photostability, lack of reversibility, and rapid off-site diffusion. In particular, ROS monitoring is hindered by the short lifetime of ROS molecules and their low abundance. The combination of nanomaterials and fluorescent detection has led to new opportunities for development of imaging probes, sensors, and theranostic products, because the scaffolds lead to improved optical properties, tuneable interactions with cells and media, and ratiometric sensing robust to environmental drift. In this review, we aim to critically assess and highlight recent development in nanosensors and nanomaterials used for the detection of oxygen and ROS in biological systems, and their future potential use as diagnosis tools.
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Affiliation(s)
- Gabriel T. Huynh
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC, Australia
| | - Vidhishri Kesarwani
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC, Australia
| | - Julia A. Walker
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC, Australia
| | - Jessica E. Frith
- Monash Institute of Medical Engineering, Monash University, Clayton, VIC, Australia
- Department of Material Science and Engineering, Monash University, Clayton, VIC, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC, Australia
| | - Laurence Meagher
- Department of Material Science and Engineering, Monash University, Clayton, VIC, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC, Australia
| | - Simon R. Corrie
- Department of Chemical Engineering, Monash University, Clayton, VIC, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Node, Clayton, VIC, Australia
- ARC Training Centre for Cell and Tissue Engineering Technologies, Monash University, Clayton, VIC, Australia
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7
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Gao Z, Li C, Shen J, Ding D. Organic optical agents for image-guided combined cancer therapy. Biomed Mater 2021; 16. [PMID: 33873169 DOI: 10.1088/1748-605x/abf980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 04/19/2021] [Indexed: 01/10/2023]
Abstract
As a promising non-invasive treatment method, phototherapy has attracted extensive attention in the field of combined cancer therapy. Among various optical agents, organic ones have been considered as a promising clinical phototheranostic agent due to its high safety and non-toxic property. In addition, due to the clear structure, facile processability, organic optical agents can be easily endowed with multiple imaging and phototherapeutic functions, significantly simplifying the relatively complex system of imaging-guided combined cancer therapy. This review summarizes the recent research on organic optical agents in imaging-guided combined cancer therapy. The application of organic optical agents in a variety of combined cancer therapeutic modes guided by imaging are introduced respectively, including photodynamic and photothermal combined therapy, phototherapy-combined cancer chemotherapy, and phototherapy-combined cancer immunotherapy. Finally, the concluding remarks and the future prospects are discussed.
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Affiliation(s)
- Zhiyuan Gao
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, People's Republic of China.,Key Laboratory of Bioactive Materials, Ministry of Education, and College of Life Sciences, Nankai University, Tianjin 300071, People's Republic of China
| | - Cong Li
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, People's Republic of China
| | - Jing Shen
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, People's Republic of China
| | - Dan Ding
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, People's Republic of China.,Key Laboratory of Bioactive Materials, Ministry of Education, and College of Life Sciences, Nankai University, Tianjin 300071, People's Republic of China
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8
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Cheng Q, Hao A, Xing P. Stimulus-responsive luminescent hydrogels: Design and applications. Adv Colloid Interface Sci 2020; 286:102301. [PMID: 33160099 DOI: 10.1016/j.cis.2020.102301] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/24/2020] [Accepted: 10/25/2020] [Indexed: 11/15/2022]
Abstract
Luminescent hydrogels are emerging soft materials with applications in photoelectric, biomedicine, sensors and actuators, which are fabricated via covalently conjugation of luminophors to hydrogelators or physical loading of luminescent organic/inorganic materials into hydrogel matrices. Due to the intrinsic stimulus-responsiveness for hydrogels such as thermo-, pH, ionic strength, light and redox, luminescent hydrogels could respond to external physical or chemical stimuli through varying the luminescent properties such as colors, fluorescent intensity and so on, affording diverse application potential in addition to the pristine individual hydrogels or luminescent materials. Based on the rapid development of such area, here we systematically summarize and discuss the design protocols, properties as well as the applications of stimulus-responsive luminescent hydrogels. Because of the stimuli-responsiveness, biocompatibility, injectable and controllability of luminescent hydrogels, they are widely used as functional smart materials. We illustrate the applications of luminescent hydrogels. The future developments about luminescent hydrogels are also presented.
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Affiliation(s)
- Qiuhong Cheng
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China
| | - Aiyou Hao
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China
| | - Pengyao Xing
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China.
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9
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Roy S, Zhu D, Parak WJ, Feliu N. Lysosomal Proton Buffering of Poly(ethylenimine) Measured In Situ by Fluorescent pH-Sensor Microcapsules. ACS NANO 2020; 14:8012-8023. [PMID: 32568521 DOI: 10.1021/acsnano.9b10219] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Poly(ethylenimine) (PEI) is frequently used as transfection agent for delivery of nucleic acids to the cytosol. After endocytosis of complexes of PEI and nucleic acids, a fraction of them can escape endosomes/lysosomes and reach the cytosol. One proposed mechanism is the so-called proton sponge effect, which involves buffering of the lysosomal pH by PEI. There are however also reports that report the absence of such buffering. In this work, the buffering capacity of PEI of the lysosomal pH was investigated in situ by combining PEI and pH-sensing ratiometric fluorophores in a single carrier particle. As carrier particles, hereby capsules were used, which were composed of polyelectrolyte walls based on layer-by-layer assembly, with the pH sensors located inside the capsule cavities. In this way, the local pH around individual particles could be monitored during the whole process of endocytosis. Results demonstrate the pH-buffering capability of PEI, which prevents the strong acidification of lysosomes containing PEI. This effect was related to the presence of PEI and was not related to the overall charge of the carrier particles. In case PEI was added in molecular form, no buffering of pH could be observed by endocytosed encapsulated pH-sensing ratiometric fluorophores. Co-localization experiments demonstrated that this was due to the fact that internalized free PEI and the encapsulated pH-sensing ratiometric fluorophores were not located in the same lysosomes. Missing co-localization might explain why also in other studies no pH buffering was found; in the case of co-delivery of PEI, the pH sensors could be clearly observed.
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Affiliation(s)
- Sathi Roy
- Center for Hybrid Nanostructures (CHyN), Universität Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany
| | - Dingcheng Zhu
- Center for Hybrid Nanostructures (CHyN), Universität Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany
| | - Wolfgang J Parak
- Center for Hybrid Nanostructures (CHyN), Universität Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany
- CIC Biomagune, Miramon Pasealekua 182, 20014 San Sebastian, Spain
| | - Neus Feliu
- Center for Hybrid Nanostructures (CHyN), Universität Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany
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10
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Ashraf S, Hassan Said A, Hartmann R, Assmann M, Feliu N, Lenz P, Parak WJ. Quantitative Particle Uptake by Cells as Analyzed by Different Methods. Angew Chem Int Ed Engl 2020; 59:5438-5453. [PMID: 31657113 PMCID: PMC7155048 DOI: 10.1002/anie.201906303] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 10/21/2019] [Indexed: 12/21/2022]
Abstract
There is a large number of two-dimensional static in vitro studies about the uptake of colloidal nano- and microparticles, which has been published in the last decade. In this Minireview, different methods used for such studies are summarized and critically discussed. Supplementary experimental data allow for a direct comparison of the different techniques. Emphasis is given on how quantitative parameters can be extracted from studies in which different experimental techniques have been used, with the goal of allowing better comparison.
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Affiliation(s)
- Sumaira Ashraf
- Fachbereich PhysikPhilipps Universität Marburg35037MarburgGermany
- Institute of Industrial BiotechnologyGovernment College University LahorePunjab54000Pakistan
| | - Alaa Hassan Said
- Fachbereich PhysikPhilipps Universität Marburg35037MarburgGermany
- Electronics and Nano Devices lab (END)Department of PhysicsFaculty of SciencesSouth Valley University83523QenaEgypt
| | - Raimo Hartmann
- Fachbereich PhysikPhilipps Universität Marburg35037MarburgGermany
| | - Marcus‐Alexander Assmann
- Fachbereich PhysikPhilipps Universität Marburg35037MarburgGermany
- Fraunhofer Institute for High-Speed DynamicsErnst Mach Institute79104FreiburgGermany
| | - Neus Feliu
- Fachbereich Physik und Chemie, CHyNUniversität Hamburg20146HamburgGermany
| | - Peter Lenz
- Fachbereich PhysikPhilipps Universität Marburg35037MarburgGermany
| | - Wolfgang J. Parak
- Fachbereich Physik und Chemie, CHyNUniversität Hamburg20146HamburgGermany
- Institute of Nano Biomedicine and EngineeringKey Laboratory for Thin Film and Microfabrication Technology of the Ministry of EducationDepartment of Instrument Science and EngineeringSchool of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghaiChina
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11
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Analyse quantitativer Partikelaufnahme von Zellen über verschiedene Messmethoden. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201906303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Shehata N, Kandas I, Samir E. In-Situ Gold-Ceria Nanoparticles: Superior Optical Fluorescence Quenching Sensor for Dissolved Oxygen. NANOMATERIALS 2020; 10:nano10020314. [PMID: 32059378 PMCID: PMC7075203 DOI: 10.3390/nano10020314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 12/30/2019] [Accepted: 01/03/2020] [Indexed: 11/21/2022]
Abstract
Cerium oxide (ceria) nanoparticles (NPs) have been proved to be an efficient optical fluorescent material through generating visible emission (~530 nm) under violet excitation. This feature allowed ceria NPs to be used as an optical sensor via the fluorescence quenching Technique. In this paper, the impact of in-situ embedded gold nanoparticles (Au NPs) inside ceria nanoparticles was studied. Then, gold–ceria NPs were used for sensing dissolved oxygen (DO) in aqueous media. It was observed that both fluorescence intensity and lifetime were changed due to increased concentration of DO. Added gold was found to enhance the sensitivity of ceria to DO quencher detection. This enhancement was due to optical coupling between the fluorescence emission spectrum of ceria with the surface plasmonic resonance of gold nanoparticles. In addition, gold caused the decrease of ceria nanoparticles’ bandgap, which indicates the formation of more oxygen vacancies inside the non-stoichiometric crystalline structure of ceria. The Stern–Volmer constant, which indicates the sensitivity of optical sensing material, of ceria–gold NPs with added DO was found to be 893.7 M−1, compared to 184.6 M−1 to in case of ceria nanoparticles only, which indicates a superior optical sensitivity to DO compared to other optical sensing materials used in the literature to detect DO. Moreover, the fluorescence lifetime was found to be changed according to the variation of added DO concentration. The optically-sensitivity-enhanced ceria nanoparticles due to embedded gold nanoparticles can be a promising sensing host for dissolved oxygen in a wide variety of applications including biomedicine and water quality monitoring.
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Affiliation(s)
- Nader Shehata
- Center of Smart Nanotechnology and Photonics (CSNP), SmartCI Research Center, Alexandria University, Alexandria 21544, Egypt;
- Department of Engineering Mathematics and Physics, Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt
- USTAR Bio-innovation center, Utah State University, Logan, UT 84341, USA
- Kuwait College of Science and Technology, Doha Area, 7th Ring Road, Safat 13133, Kuwait
- The Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24061, USA
- Correspondence: ; Tel.: +20-109-116-5300
| | - Ishac Kandas
- Center of Smart Nanotechnology and Photonics (CSNP), SmartCI Research Center, Alexandria University, Alexandria 21544, Egypt;
- Department of Engineering Mathematics and Physics, Faculty of Engineering, Alexandria University, Alexandria 21544, Egypt
- Kuwait College of Science and Technology, Doha Area, 7th Ring Road, Safat 13133, Kuwait
| | - Effat Samir
- Department of Electrical Engineering, Old Dominion University, Norfolk, VA 23508, USA;
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13
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Wang L, Zhu F, Liao S, Chen M, Zhu YQ, Liu Q, Chen X. Single-stranded DNA modified protonated graphitic carbon nitride nanosheets: A versatile ratiometric fluorescence platform for multiplex detection of various targets. Talanta 2019; 197:422-430. [PMID: 30771957 DOI: 10.1016/j.talanta.2019.01.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/04/2019] [Accepted: 01/16/2019] [Indexed: 12/12/2022]
Abstract
Facile and cost-effective detection of multiple targets is essential for a variety of applications ranging from life sciences to environmental monitoring. Here, we report a versatile ratiometric fluorescence platform for multiple detection of various targets based on the conjugation of single-stranded DNA (ssDNA) with protonated graphitic carbon nitride nanosheets (Pg-C3N4 NSs). We demonstrate that intrinsic peroxidase-like activity of Pg-C3N4 NSs is enhanced by conjugating with ssDNA, and thus the oxidation of substrate o-phenylenediamine (OPD) is promoted in the presence of H2O2. The oxidation product 2,3-diaminophenazine (DAP) can deliver a new fluorescence signal at 564 nm, and concurrently quench the intrinsic fluorescence of conjugates ssDNA/Pg-C3N4 NSs at 443 nm upon excitation at 370 nm. The transformation of fluorescence provides us a novel strategy for ratiometric fluorescence-based analytical sensing. Taking ssDNA as the target-recognition element of the conjugates ssDNA/Pg-C3N4 NSs, we favorably present ratiometric fluorescence detection of various targets including heavy metal ions (Hg2+) and biomolecules (Aflatoxin B1 (AFB1) and adenosine triphosphate (ATP)) in real samples by varying the ssDNA sequences. The present work provides a new strategy to develop facile methods for quantitative determination of various analytes and uncovers an innovative horizon for Pg-C3N4 NSs-based sensing platform fabrication.
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Affiliation(s)
- Lumin Wang
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China
| | - Fawei Zhu
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China
| | - Sen Liao
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China
| | - Miao Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China
| | - Yu Qiu Zhu
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China
| | - Qi Liu
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China.
| | - Xiaoqing Chen
- College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan, China; Key Laboratory of Hunan Province for Water Environment and Agriculture Product Safety,Changsha 410083, Hunan, China.
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14
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Huang X, Song J, Yung BC, Huang X, Xiong Y, Chen X. Ratiometric optical nanoprobes enable accurate molecular detection and imaging. Chem Soc Rev 2018; 47:2873-2920. [PMID: 29568836 PMCID: PMC5926823 DOI: 10.1039/c7cs00612h] [Citation(s) in RCA: 441] [Impact Index Per Article: 73.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Exploring and understanding biological and pathological changes are of great significance for early diagnosis and therapy of diseases. Optical sensing and imaging approaches have experienced major progress in this field. Particularly, an emergence of various functional optical nanoprobes has provided enhanced sensitivity, specificity, targeting ability, as well as multiplexing and multimodal capabilities due to improvements in their intrinsic physicochemical and optical properties. However, one of the biggest challenges of conventional optical nanoprobes is their absolute intensity-dependent signal readout, which causes inaccurate sensing and imaging results due to the presence of various analyte-independent factors that can cause fluctuations in their absolute signal intensity. Ratiometric measurements provide built-in self-calibration for signal correction, enabling more sensitive and reliable detection. Optimizing nanoprobe designs with ratiometric strategies can surmount many of the limitations encountered by traditional optical nanoprobes. This review first elaborates upon existing optical nanoprobes that exploit ratiometric measurements for improved sensing and imaging, including fluorescence, surface enhanced Raman scattering (SERS), and photoacoustic nanoprobes. Next, a thorough discussion is provided on design strategies for these nanoprobes, and their potential biomedical applications for targeting specific biomolecule populations (e.g. cancer biomarkers and small molecules with physiological relevance), for imaging the tumor microenvironment (e.g. pH, reactive oxygen species, hypoxia, enzyme and metal ions), as well as for intraoperative image guidance of tumor-resection procedures.
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Affiliation(s)
- Xiaolin Huang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P. R. China. and Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA.
| | - Jibin Song
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA. and MOE Key Laboratory for Analytical Science of Food Safety and Biology, College of Chemistry, Fuzhou University, Fuzhou 350108, P. R. China
| | - Bryant C Yung
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA.
| | - Xiaohua Huang
- Department of Chemistry, University of Memphis, 213 Smith Chemistry Bldg., Memphis, TN 38152, USA
| | - Yonghua Xiong
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P. R. China.
| | - Xiaoyuan Chen
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA.
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15
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Gerold CT, Bakker E, Henry CS. Selective Distance-Based K+ Quantification on Paper-Based Microfluidics. Anal Chem 2018; 90:4894-4900. [DOI: 10.1021/acs.analchem.8b00559] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Chase T. Gerold
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80521, United States
- Department of Inorganic and Analytical Chemistry, The University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland
| | - Eric Bakker
- Department of Inorganic and Analytical Chemistry, The University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland
| | - Charles S. Henry
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80521, United States
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16
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17
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Zhang Y, Li S, Zhao Z. Using Nanoliposomes To Construct a FRET-Based Ratiometric Fluorescent Probe for Sensing Intracellular pH Values. Anal Chem 2016; 88:12380-12385. [DOI: 10.1021/acs.analchem.6b03632] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Yangyang Zhang
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
| | - Shilei Li
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
- Graduate
School, University of Chinese Academy of Sciences, Beijing, China
| | - Zhenwen Zhao
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, Institute of Chemistry Chinese Academy of Sciences, Beijing, China
- Graduate
School, University of Chinese Academy of Sciences, Beijing, China
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18
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Carrillo-Carrion C, Escudero A, Parak WJ. Optical sensing by integration of analyte-sensitive fluorophore to particles. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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19
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Long Y, Pfeiffer F, Mayer G, Schrøder TD, Özalp VC, Olsen LF. Selection of Aptamers for Metabolite Sensing and Construction of Optical Nanosensors. Methods Mol Biol 2016; 1380:3-19. [PMID: 26552812 DOI: 10.1007/978-1-4939-3197-2_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Optical nanosensors are based on particles with diameters from 20 to 200 nm containing sensory elements. The latter are comprised of one or more signaling molecules and one or more references, which allow measurements to be ratiometric and hence independent on the amount of sensor. The signaling molecules may range from simple ion-binding fluorophores, e.g., pH-sensitive dyes, to complex biochemical assays. Aptamers are ideal for use in nanosensors because they are relatively easy to modify chemically and hence to transform into signaling molecules, and their binding affinities may be fine-tuned to a desired measuring range in the selection process. Here we first describe the selection of metabolite binding aptamers, how they are transformed into signaling molecules using a molecular beacon construct and then how they are inserted into nanoparticles. Finally, we briefly describe how the sensors are calibrated before inserted into cells to measure metabolite concentration in real time. As examples we present aptamers binding to key metabolites in cells: ATP and fructose 1, 6-bisphosphate (FBP).
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Affiliation(s)
- Yi Long
- Institute of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.,LIMES Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
| | - Franziska Pfeiffer
- LIMES Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
| | - Günter Mayer
- LIMES Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany
| | - Tine Daa Schrøder
- Institute of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.,Lundbeckfonden Center of Excellence NanoCAN, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark
| | - Veli Cengiz Özalp
- Department of Medical Biology, School of Medicine, Istanbul Kemerburgaz University, 34217, Istanbul, Turkey
| | - Lars Folke Olsen
- Institute of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.
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20
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Duffy GF, Moore EJ. Electrochemical Immunosensors for Food Analysis: A Review of Recent Developments. ANAL LETT 2016. [DOI: 10.1080/00032719.2016.1167900] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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21
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Sierra-Martin B, Fernandez-Barbero A. Inorganic/polymer hybrid nanoparticles for sensing applications. Adv Colloid Interface Sci 2016; 233:25-37. [PMID: 26782148 DOI: 10.1016/j.cis.2015.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 11/30/2015] [Accepted: 12/01/2015] [Indexed: 10/22/2022]
Abstract
This paper reviews a wide set of sensing applications based on the special properties associated with inorganic/polymer composite nanoparticles. We first describe optical sensing applications performed with hybrid nanoparticles and hybrid microgels with special emphasis on photoluminescence detection and imaging. Analyte detection with molecularly imprinted polymers and HPLC-based sensing using hybrid nanoparticles as stationary phase is also summarized. The final part is devoted to the study of ultra-sensitive molecule detection by surface-enhanced Raman spectroscopy using core-shell hybrid materials composed of noble metal nanoparticles and cross-linked polymers.
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22
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Quevedo PD, Behnke T, Resch-Genger U. Streptavidin conjugation and quantification-a method evaluation for nanoparticles. Anal Bioanal Chem 2016; 408:4133-49. [PMID: 27038055 DOI: 10.1007/s00216-016-9510-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/19/2016] [Accepted: 03/21/2016] [Indexed: 12/17/2022]
Abstract
Aiming at the development of validated protocols for protein conjugation of nanomaterials and the determination of protein labeling densities, we systematically assessed the conjugation of the model protein streptavidin (SAv) to 100-, 500-, and 1000-nm-sized polystyrene and silica nanoparticles and dye-encoded polymer particles with two established conjugation chemistries, based upon achievable coupling efficiencies and labeling densities. Bioconjugation reactions compared included EDC/sulfo NHS ester chemistry for direct binding of the SAv to carboxyl groups at the particle surface and maleimide-thiol chemistry in conjunction with heterobifunctional PEG linkers and aminated nanoparticles (NPs). Quantification of the total and functional amounts of SAv on these nanomaterials and unreacted SAv in solution was performed with the BCA assay and the biotin-FITC (BF) titration, relying on different signal generation principles, which are thus prone to different interferences. Our results revealed a clear influence of the conjugation chemistry on the amount of NP crosslinking, yet under optimized reaction conditions, EDC/sulfo NHS ester chemistry and the attachment via heterobifunctional PEG linkers led to comparably efficient SAv coupling and good labeling densities. Particle size can obviously affect protein labeling densities and particularly protein functionality, especially for larger particles. For unstained nanoparticles, direct bioconjugation seems to be the most efficient strategy, whereas for dye-encoded nanoparticles, PEG linkers are to be favored for the prevention of dye-protein interactions which can affect protein functionality specifically in the case of direct SAv binding. Moreover, an influence of particle size on achievable protein labeling densities and protein functionality could be demonstrated.
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Affiliation(s)
- Pablo Darío Quevedo
- Department 1, Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Richard Willstaetter Strasse 11, 12489, Berlin, Germany
| | - Thomas Behnke
- Department 1, Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Richard Willstaetter Strasse 11, 12489, Berlin, Germany
| | - Ute Resch-Genger
- Department 1, Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Richard Willstaetter Strasse 11, 12489, Berlin, Germany.
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23
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Schäferling M. Nanoparticle-based luminescent probes for intracellular sensing and imaging of pH. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2015; 8:378-413. [PMID: 26395962 DOI: 10.1002/wnan.1366] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 07/06/2015] [Accepted: 07/22/2015] [Indexed: 12/13/2022]
Abstract
Fluorescence imaging microscopy is an essential tool in biomedical research. Meanwhile, various fluorescent probes are available for the staining of cells, cell membranes, and organelles. Though, to monitor intracellular processes and dysfunctions, probes that respond to ubiquitous chemical parameters determining the cellular function such as pH, pO2 , and Ca(2+) are required. This review is focused on the progress in the design, fabrication, and application of photoluminescent nanoprobes for sensing and imaging of pH in living cells. The advantages of using nanoprobes carrying fluorescent pH indicators compared to single molecule probes are discussed as well as their limitations due to the mostly lysosomal uptake by cells. Particular attention is paid to ratiometric dual wavelength nanosensors that enable intrinsic referenced measurements. Referencing and proper calibration procedures are basic prerequisites to carry out reliable quantitative pH determinations in complex samples such as living cells. A variety of examples will be presented that highlight the diverseness of nanocarrier materials (polymers, micelles, silica, quantum dots, carbon dots, gold, photon upconversion nanocrystals, or bacteriophages), fluorescent pH indicators for the weak acidic range, and referenced sensing mechanisms, that have been applied intracellularly up to now. WIREs Nanomed Nanobiotechnol 2016, 8:378-413. doi: 10.1002/wnan.1366 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Michael Schäferling
- Division 1.10 Biophotonics, Federal Institute for Materials Research and Testing, Berlin, Germany
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24
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Functional Imaging of Chemically Active Surfaces with Optical Reporter Microbeads. PLoS One 2015; 10:e0136970. [PMID: 26332766 PMCID: PMC4558047 DOI: 10.1371/journal.pone.0136970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 08/12/2015] [Indexed: 12/02/2022] Open
Abstract
We have developed a novel approach to allow for continuous imaging of concentration fields that evolve at surfaces due to release, uptake, and mass transport of molecules, without significant interference of the concentration fields by the chemical imaging itself. The technique utilizes optical “reporter” microbeads immobilized in a thin layer of transparent and inert hydrogel on top of the surface. The hydrogel has minimal density and therefore diffusion in and across it is like in water. Imaging the immobilized microbeads over time provides quantitative concentration measurements at each location where an optical reporter resides. Using image analysis in post-processing these spatially discrete measurements can be transformed into contiguous maps of the dynamic concentration field across the entire surface. If the microbeads are small enough relative to the dimensions of the region of interest and sparsely applied then chemical imaging will not noticeably affect the evolution of concentration fields. In this work colorimetric optode microbeads a few micrometers in diameter were used to image surface concentration distributions on the millimeter scale.
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25
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Christ S, Schäferling M. Chemical sensing and imaging based on photon upconverting nano- and microcrystals: a review. Methods Appl Fluoresc 2015; 3:034004. [PMID: 29148493 DOI: 10.1088/2050-6120/3/3/034004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The demand for photostable luminescent reporters that absorb and emit light in the red to near-infrared (NIR) spectral region continues in biomedical research and bioanalysis. In recent years, classical organic fluorophores have increasingly been displaced by luminescent nanoparticles. These consist of either polymer or silica based beads that are loaded with luminescent dyes, conjugated polymers, or inorganic nanomaterials such as semiconductor nanocrystals (quantum dots), colloidal clusters of silver and gold, or carbon dots. Among the inorganic materials, photon upconversion nanocrystals exhibit a high potential for application to bioimaging or biomolecular assays. They offer an exceptionally high photostability, can be excited in the NIR, and their anti-Stokes emission enables luminescence detection free of background and perturbing scatter effects even in complex biological samples. These lanthanide doped inorganic crystals have multiple emission lines that can be tuned by the selection of the dopants.This review article is focused on the applications of functionalized photon upconversion nanoparticles (UCNPs) to chemical sensing. This is a comparatively new field of research activity and mainly directed at the sensing and imaging of ubiquitous chemical analytes in biological samples, particularly in living cells. For this purpose, the particles have to be functionalized with suitable indicator dyes or recognition elements, as they do not show an intrinsic or specific luminescence response to most of these analytes (e.g. pH, oxygen, metal ions). We describe the strategies for the design of such responsive nanocomposites utilizing either luminescence resonance energy transfer or emission-reabsorption (inner filter effect) mechanisms and also highlight examples for their use either immobilized in sensor layers or directly as nanoprobes for intracellular sensing and imaging.
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Affiliation(s)
- Simon Christ
- Department of Biochemistry/Biotechnology, University of Turku, Tykistökatu 6A FI-20520 Turku, Finland
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26
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Shehata N, Meehan K, Hassounah I, Hudait M, Jain N, Clavel M, Elhelw S, Madi N. Reduced erbium-doped ceria nanoparticles: one nano-host applicable for simultaneous optical down- and up-conversions. NANOSCALE RESEARCH LETTERS 2014; 9:231. [PMID: 24940173 PMCID: PMC4038360 DOI: 10.1186/1556-276x-9-231] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 04/07/2014] [Indexed: 06/03/2023]
Abstract
This paper introduces a new synthesis procedure to form erbium-doped ceria nanoparticles (EDC NPs) that can act as an optical medium for both up-conversion and down-conversion in the same time. This synthesis process results qualitatively in a high concentration of Ce(3+) ions required to obtain high fluorescence efficiency in the down-conversion process. Simultaneously, the synthesized nanoparticles contain the molecular energy levels of erbium that are required for up-conversion. Therefore, the synthesized EDC NPs can emit visible light when excited with either UV or IR photons. This opens new opportunities for applications where emission of light via both up- and down-conversions from a single nanomaterial is desired such as solar cells and bio-imaging.
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Affiliation(s)
- Nader Shehata
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA
- Department of Engineering Mathematics and Physics, Faculty of Engineering, Alexandria University, Alexandria, Egypt
| | - Kathleen Meehan
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Ibrahim Hassounah
- Institute for Critical Technology and Applied Science (ICTAS), Blacksburg, VA, USA
| | - Mantu Hudait
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Nikhil Jain
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Michael Clavel
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Sarah Elhelw
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Nabil Madi
- Center of Advanced Materials (CAM), Qatar University, Doha, Qatar
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27
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Liu H, Yang H, Hao X, Xu H, Lv Y, Xiao D, Wang H, Tian Z. Development of polymeric nanoprobes with improved lifetime dynamic range and stability for intracellular oxygen sensing. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:2639-48. [PMID: 23519925 DOI: 10.1002/smll.201203127] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/11/2013] [Indexed: 05/24/2023]
Abstract
A class of core-shell nanoparticles possessing a layer of biocompatible shell and hydrophobic core with embedded oxygen-sensitive platinum-porphyrin (PtTFPP) dyes is developed via a radical-initiated microemulsion co-polymerization strategy. The influences of host matrices and the PtTFPP incorporation manner on the photophysical properties and the oxygen-sensing performance of the nanoparticles are investigated. Self-loading capability with cells and intracellular-oxygen-sensing ability of the as-prepared nanoparticle probes in the range 0%-20% oxygen concentration are confirmed. Polymeric nanoparticles with optimized formats are characterized by their relatively small diameter (<50 nm), core-shell structures with biocompatible shells, covalent-attachment-imparted leak-free construction, improved lifetime dynamic range (up to 44 μs), excellent storage stability and photostability, and facile cell uptake. The nanoparticles' small sensor diameter and core-shell structure with biocompatible shell make them suitable for intracellular detection applications. For intracellular detection applications, the leak-free feature of the as-prepared nanoparticle sensor effectively minimizes potential chemical interferences and cytotoxicity. As a salient feature, improved lifetime dynamic range of the sensor is expected to enable precise oxygen detection and control in specific practical applications in stem-cell biology and medical research. Such a feature-packed nanoparticle oxygen sensor may find applications in precise oxygen-level mapping of living cells and tissue.
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Affiliation(s)
- Heng Liu
- School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences-UCAS, Beijing 100049, PR China
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28
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Shehata N, Meehan K, Leber D. Study of Fluorescence Quenching in Aluminum-Doped Ceria Nanoparticles: Potential Molecular Probe for Dissolved Oxygen. J Fluoresc 2013; 23:527-32. [DOI: 10.1007/s10895-013-1186-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 02/24/2013] [Indexed: 11/29/2022]
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Fan J, Jiang X, Hu Y, Si Y, Ding L, Wu W. A fluorescent double-network-structured hybrid nanogel as embeddable nanoglucometer for intracellular glucometry. Biomater Sci 2013; 1:421-433. [DOI: 10.1039/c2bm00162d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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31
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Fluorescent nanoparticles for intracellular sensing: A review. Anal Chim Acta 2012; 751:1-23. [DOI: 10.1016/j.aca.2012.09.025] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 09/13/2012] [Accepted: 09/16/2012] [Indexed: 12/31/2022]
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32
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Wang F, Widejko RG, Yang Z, Nguyen KT, Chen H, Fernando LP, Christensen KA, Anker JN. Surface-enhanced raman scattering detection of pH with silica-encapsulated 4-mercaptobenzoic acid-functionalized silver nanoparticles. Anal Chem 2012; 84:8013-9. [PMID: 22881392 DOI: 10.1021/ac3018179] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sensors based upon surface-enhanced Raman spectroscopy (SERS) are attractive because they have narrow, vibrationally specific spectral peaks that can be excited using red and near-infrared light which avoids photobleaching, penetrates tissue, and reduces autofluorescence. Several groups have fabricated pH nanosensors by functionalizing silver or gold nanoparticle surfaces with an acidic molecule and measuring the ratio of protonated to deprotonated Raman bands. However, a limitation of these sensors is that macromolecules in biological systems can adsorb onto the nanoparticle surface and interfere with measurements. To overcome this interference, we encapsulated pH SERS sensors in a 30 nm thick silica layer with small pores which prevented bovine serum albumin (BSA) molecules from interacting with the pH-indicating 4-mercaptobenzoic acid (4-MBA) on the silver surfaces but preserved the pH-sensitivity. Encapsulation also improved colloidal stability and sensor reliability. The noise level corresponded to less than 0.1 pH units from pH 3 to 6. The silica-encapsulated functionalized silver nanoparticles (Ag-MBA@SiO(2)) were taken up by J774A.1 macrophage cells and measured a decrease in local pH during endocytosis. This strategy could be extended for detecting other small molecules in situ.
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Affiliation(s)
- Fenglin Wang
- Department of Chemistry, Center for Optical Materials Science and Engineering and Environmental Toxicology Program, Clemson University, South Carolina 29634-0973, United States
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Recent advances in intracellular and in vivo ROS sensing: focus on nanoparticle and nanotube applications. Int J Mol Sci 2012; 13:10660-10679. [PMID: 23109815 PMCID: PMC3472707 DOI: 10.3390/ijms130910660] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 08/02/2012] [Accepted: 08/16/2012] [Indexed: 12/22/2022] Open
Abstract
Reactive oxygen species (ROS) are increasingly being implicated in the regulation of cellular signaling cascades. Intracellular ROS fluxes are associated with cellular function ranging from proliferation to cell death. Moreover, the importance of subtle, spatio-temporal shifts in ROS during localized cellular signaling events is being realized. Understanding the biochemical nature of the ROS involved will enhance our knowledge of redox-signaling. An ideal intracellular sensor should therefore resolve real-time, localized ROS changes, be highly sensitive to physiologically relevant shifts in ROS and provide specificity towards a particular molecule. For in vivo applications issues such as bioavailability of the probe, tissue penetrance of the signal and signal-to-noise ratio also need to be considered. In the past researchers have heavily relied on the use of ROS-sensitive fluorescent probes and, more recently, genetically engineered ROS sensors. However, there is a great need to improve on current methods to address the above issues. Recently, the field of molecular sensing and imaging has begun to take advantage of the unique physico-chemical properties of nanoparticles and nanotubes. Here we discuss the recent advances in the use of these nanostructures as alternative platforms for ROS sensing, with particular emphasis on intracellular and in vivo ROS detection and quantification.
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Albelda MT, Frías JC, García-España E, Schneider HJ. Supramolecular complexation for environmental control. Chem Soc Rev 2012; 41:3859-77. [PMID: 22441360 DOI: 10.1039/c2cs35008d] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Supramolecular complexes offer a new and efficient way for the monitoring and removal of many substances emanating from technical processes, fertilization, plant and animal protection, or e.g. chemotherapy. Such pollutants range from toxic or radioactive metal ions and anions to chemical side products, herbicides, pesticides to drugs including steroids, and include degradation products from natural sources. The applications involve usually fast and reversible complex formation, due to prevailing non-covalent interactions. This is of importance for sensing as well as for separation techniques, where the often expensive host compounds can then be reused almost indefinitely. Immobilization of host compounds, e.g. on exchange resins or on membranes, and their implementation in smart new materials hold particular promise. The review illustrates how the design of suitable host compounds in combination with modern sensing and separation methods can contribute to solve some of the biggest problems facing chemistry, which arise from the everyday increasing pollution of the environment.
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Affiliation(s)
- M Teresa Albelda
- Departament de Química Inorgánica, ICMol, Universitat de València, C/Catedrático José Beltrán, 2. Paterna, Spain
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36
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Schäferling M. The Art of Fluorescence Imaging with Chemical Sensors. Angew Chem Int Ed Engl 2012; 51:3532-54. [PMID: 22422626 DOI: 10.1002/anie.201105459] [Citation(s) in RCA: 544] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 10/12/2011] [Indexed: 11/08/2022]
Affiliation(s)
- Michael Schäferling
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany.
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37
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Si D, Epstein T, Lee YEK, Kopelman R. Nanoparticle PEBBLE sensors for quantitative nanomolar imaging of intracellular free calcium ions. Anal Chem 2012; 84:978-86. [PMID: 22122409 DOI: 10.1021/ac202521e] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ca(2+) is a universal second messenger and plays a major role in intracellular signaling, metabolism, and a wide range of cellular processes. To date, one of the most successful approaches for intracellular Ca(2+) measurement involves the introduction of optically sensitive Ca(2+) indicators into living cells, combined with digital imaging microscopy. However, the use of free Ca(2+) indicators for intracellular sensing and imaging has several limitations, such as nonratiometric measurement for the most-sensitive indicators, cytotoxicity of the indicators, interference from nonspecific binding caused by cellular biomacromolecules, challenging calibration, and unwanted sequestration of the indicator molecules. These problems are minimized when the Ca(2+) indicators are encapsulated inside porous and inert polyacrylamide nanoparticles. We present PEBBLE nanosensors encapsulated with rhodamine-based Ca(2+) fluorescence indicators. The rhod-2-containing PEBBLEs presented here show a stable sensing range at near-neutral pH (pH 6-9). Because of the protection of the PEBBLE matrix, the interference of protein-nonspecific binding to the indicator is minimal. The rhod-2 PEBBLEs give a nanomolar dynamic sensing range for both in-solution (K(d) = 478 nM) and intracellular (K(d) = 293 nM) measurements. These nanosensors are useful quantitative tools for the measurement and imaging of the cytosolic nanomolar free Ca(2+) levels.
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Affiliation(s)
- Di Si
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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Ispas CR, Crivat G, Andreescu S. Review: Recent Developments in Enzyme-Based Biosensors for Biomedical Analysis. ANAL LETT 2012. [DOI: 10.1080/00032719.2011.633188] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Bae SW, Tan W, Hong JI. Fluorescent dye-doped silica nanoparticles: new tools for bioapplications. Chem Commun (Camb) 2012; 48:2270-82. [DOI: 10.1039/c2cc16306c] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Yanai N, Kitayama K, Hijikata Y, Sato H, Matsuda R, Kubota Y, Takata M, Mizuno M, Uemura T, Kitagawa S. Gas detection by structural variations of fluorescent guest molecules in a flexible porous coordination polymer. NATURE MATERIALS 2011; 10:787-93. [PMID: 21892178 DOI: 10.1038/nmat3104] [Citation(s) in RCA: 302] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 07/26/2011] [Indexed: 05/05/2023]
Abstract
The development of a new methodology for visualizing and detecting gases is imperative for various applications. Here, we report a novel strategy in which gas molecules are detected by signals from a reporter guest that can read out a host structural transformation. A composite between a flexible porous coordination polymer and fluorescent reporter distyrylbenzene (DSB) selectively adsorbed CO₂ over other atmospheric gases. This adsorption induced a host transformation, which was accompanied by conformational variations of the included DSB. This read-out process resulted in a critical change in DSB fluorescence at a specific threshold pressure. The composite shows different fluorescence responses to CO₂ and acetylene, compounds that have similar physicochemical properties. Our system showed, for the first time, that fluorescent molecules can detect gases without any chemical interaction or energy transfer. The host-guest coupled transformations play a pivotal role in converting the gas adsorption events into detectable output signals.
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Affiliation(s)
- Nobuhiro Yanai
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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Lee YEK, Ulbrich EE, Kim G, Hah H, Strollo C, Fan W, Gurjar R, Koo S, Kopelman R. Near infrared luminescent oxygen nanosensors with nanoparticle matrix tailored sensitivity. Anal Chem 2011; 82:8446-55. [PMID: 20849084 DOI: 10.1021/ac1015358] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The development of sensors for noninvasive determination of oxygen levels in live cells and tissues is critical for the understanding of cellular functions, as well as for monitoring the status of disease, such as cancer, and for predicting the efficacy of therapy. We describe such nontoxic, targeted, and ratiometric 30 nm oxygen nanosensors made of polyacrylamide hydrogel, near-infrared (NIR) luminescent dyes, and surface-conjugated tumor-specific peptides. They enabled noninvasive real-time monitoring of oxygen levels in live cancer cells under normal and hypoxic conditions. The required sensitivity, brightness, selectivity, and stability were achieved by tailoring the interaction between the nanomatrix and indicator dyes. The developed nanosensors may become useful for in vivo oxygen measurements.
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Affiliation(s)
- Yong-Eun Koo Lee
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA
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Chan YH, Wu C, Ye F, Jin Y, Smith PB, Chiu DT. Development of ultrabright semiconducting polymer dots for ratiometric pH sensing. Anal Chem 2011; 83:1448-55. [PMID: 21244093 PMCID: PMC3039106 DOI: 10.1021/ac103140x] [Citation(s) in RCA: 230] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Semiconducting polymer-based nanoparticles (Pdots) have recently emerged as a new class of ultrabright probes for biological detection and imaging. This paper describes the development of poly(2,5-di(3',7'-dimethyloctyl)phenylene-1,4-ethynylene) (PPE) Pdots as a platform for designing Förster resonance energy transfer (FRET)-based ratiometric pH nanoprobes. We describe and compare three routes for coupling the pH-sensitive dye, fluorescein, to PPE Pdots, which is a pH-insensitive semiconducting polymer. This approach offers a rapid and robust sensor for pH determination using the ratiometric methodology where excitation at a single wavelength results in two emission peaks, one that is pH sensitive and the other one that is pH insensitive for use as an internal reference. The linear range for pH sensing of the fluorescein-coupled Pdots is between pH 5.0 and 8.0, which is suitable for most cellular studies. The pH-sensitive Pdots show excellent reversibility and stability in pH measurements. In this paper, we use them to measure the intracellular pH in HeLa cells following their uptake by endocytosis, thus demonstrating their utility for use in cellular and imaging experiments.
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Affiliation(s)
- Yang-Hsiang Chan
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | - Changfeng Wu
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | - Fangmao Ye
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | - Yuhui Jin
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | - Polina B. Smith
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | - Daniel T. Chiu
- Department of Chemistry, University of Washington, Seattle, Washington 98195
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Ray A, Koo Lee YE, Epstein T, Kim G, Kopelman R. Two-photon nano-PEBBLE sensors: subcellular pH measurements. Analyst 2011; 136:3616-22. [DOI: 10.1039/c1an15046d] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ding L, Ju H. Biofunctionalization of nanoparticles for cytosensing and cell surface carbohydrate assay. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm13700j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Wu W, Zhou S. Hybrid micro-/nanogels for optical sensing and intracellular imaging. NANO REVIEWS 2010; 1:NANO-1-5730. [PMID: 22110866 PMCID: PMC3215222 DOI: 10.3402/nano.v1i0.5730] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2010] [Revised: 11/14/2010] [Accepted: 11/14/2010] [Indexed: 12/22/2022]
Abstract
Hybrid micro-/nanogels are playing an increasing important part in a diverse range of applications, due to their tunable dimensions, large surface area, stable interior network structure, and a very short response time. We review recent advances and challenges in the developments of hybrid micro-/nanogels toward applications for optical sensing of pH, temperature, glucose, ions, and other species as well as for intracellular imaging. Due to their unique advantages, hybrid micro-/nanogels as optical probes are attracting substantial interests for continuous monitoring of chemical parameters in complex samples such as blood and bioreactor fluids, in chemical research and industry, and in food quality control. In particular, their intracellular probing ability enables the monitoring of the biochemistry and biophysics of live cells over time and space, thus contributing to the explanation of intricate biological processes and the development of novel diagnoses. Unlike most other probes, hybrid micro-/nanogels could also combine other multiple functions into a single probe. The rational design of hybrid micro-/nanogels will not only improve the probing applications as desirable, but also implement their applications in new arenas. With ongoing rapid advances in bionanotechnology, the well-designed hybrid micro-/nanogel probes will be able to provide simultaneous sensing, imaging diagnosis, and therapy toward clinical applications.
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Affiliation(s)
- Weitai Wu
- Department of Chemistry of The College of Staten Island, and The Graduate Center, The City University of New York, Staten Island, NY, USA
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Grist SM, Chrostowski L, Cheung KC. Optical oxygen sensors for applications in microfluidic cell culture. SENSORS (BASEL, SWITZERLAND) 2010; 10:9286-316. [PMID: 22163408 PMCID: PMC3230974 DOI: 10.3390/s101009286] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 09/17/2010] [Accepted: 10/10/2010] [Indexed: 01/09/2023]
Abstract
The presence and concentration of oxygen in biological systems has a large impact on the behavior and viability of many types of cells, including the differentiation of stem cells or the growth of tumor cells. As a result, the integration of oxygen sensors within cell culture environments presents a powerful tool for quantifying the effects of oxygen concentrations on cell behavior, cell viability, and drug effectiveness. Because microfluidic cell culture environments are a promising alternative to traditional cell culture platforms, there is recent interest in integrating oxygen-sensing mechanisms with microfluidics for cell culture applications. Optical, luminescence-based oxygen sensors, in particular, show great promise in their ability to be integrated with microfluidics and cell culture systems. These sensors can be highly sensitive and do not consume oxygen or generate toxic byproducts in their sensing process. This paper presents a review of previously proposed optical oxygen sensor types, materials and formats most applicable to microfluidic cell culture, and analyzes their suitability for this and other in vitro applications.
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Affiliation(s)
- Samantha M. Grist
- Department of Electrical & Computer Engineering, University of British Columbia/2332 Main Mall, Vancouver, BC V6T 1Z4, Canada; E-Mails: (L.C.); (K.C.C.)
| | - Lukas Chrostowski
- Department of Electrical & Computer Engineering, University of British Columbia/2332 Main Mall, Vancouver, BC V6T 1Z4, Canada; E-Mails: (L.C.); (K.C.C.)
| | - Karen C. Cheung
- Department of Electrical & Computer Engineering, University of British Columbia/2332 Main Mall, Vancouver, BC V6T 1Z4, Canada; E-Mails: (L.C.); (K.C.C.)
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Dean SL, Stapleton JJ, Keating CD. Organically modified silicas on metal nanowires. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:14861-70. [PMID: 20715881 PMCID: PMC2938830 DOI: 10.1021/la102070c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 07/30/2010] [Indexed: 05/16/2023]
Abstract
Organically modified silica coatings were prepared on metal nanowires using a variety of silicon alkoxides with different functional groups (i.e., carboxyl groups, polyethylene oxide, cyano, dihydroimidazole, and hexyl linkers). Organically modified silicas were deposited onto the surface of 6-μm-long, ∼300-nm-wide, cylindrical metal nanowires in suspension by the hydrolysis and polycondensation of silicon alkoxides. Syntheses were performed at several ratios of tetraethoxysilane to an organically modified silicon alkoxide to incorporate desired functional groups into thin organosilica shells on the nanowires. These coatings were characterized using transmission electron microscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy. All of the organically modified silicas prepared here were sufficiently porous to allow the removal of the metal nanowire cores by acid etching to form organically modified silica nanotubes. Additional functionality provided to the modified silicas as compared to unmodified silica prepared using only tetraethoxysilane precursors was demonstrated by chromate adsorption on imidazole-containing silicas and resistance to protein adsorption on polyethyleneoxide-containing silicas. Organically modified silica coatings on nanowires and other nano- and microparticles have potential application in fields such as biosensing or nanoscale therapeutics due to the enhanced properties of the silica coatings, for example, the prevention of biofouling.
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Peng HS, Stolwijk JA, Sun LN, Wegener J, Wolfbeis OS. A nanogel for ratiometric fluorescent sensing of intracellular pH values. Angew Chem Int Ed Engl 2010; 49:4246-9. [PMID: 20446280 DOI: 10.1002/anie.200906926] [Citation(s) in RCA: 211] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hong-shang Peng
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany.
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Doussineau T, Schulz A, Lapresta-Fernandez A, Moro A, Körsten S, Trupp S, Mohr G. On the Design of Fluorescent Ratiometric Nanosensors. Chemistry 2010; 16:10290-9. [DOI: 10.1002/chem.201000829] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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