1
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Luminescence encoding of polymer microbeads with organic dyes and semiconductor quantum dots during polymerization. Sci Rep 2022; 12:12061. [PMID: 35835808 PMCID: PMC9283474 DOI: 10.1038/s41598-022-16065-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/04/2022] [Indexed: 01/15/2023] Open
Abstract
Luminescence-encoded microbeads are important tools for many applications in the life and material sciences that utilize luminescence detection as well as multiplexing and barcoding strategies. The preparation of such beads often involves the staining of premanufactured beads with molecular luminophores using simple swelling procedures or surface functionalization with layer-by-layer (LbL) techniques. Alternatively, these luminophores are sterically incorporated during the polymerization reaction yielding the polymer beads. The favorable optical properties of semiconductor quantum dots (QDs), which present broadly excitable, size-tunable, narrow emission bands and low photobleaching sensitivity, triggered the preparation of beads stained with QDs. However, the colloidal nature and the surface chemistry of these QDs, which largely controls their luminescence properties, introduce new challenges to bead encoding that have been barely systematically assessed. To establish a straightforward approach for the bead encoding with QDs with minimized loss in luminescence, we systematically assessed the incorporation of oleic acid/oleylamine-stabilized CdSe/CdS-core/shell-QDs into 0.5-2.5 µm-sized polystyrene (PS) microspheres by a simple dispersion polymerization synthesis that was first optimized with the organic dye Nile Red. Parameters addressed for the preparation of luminophore-encoded beads include the use of a polymer-compatible ligand such as benzyldimethyloctadecylammonium chloride (OBDAC) for the QDs, and crosslinking to prevent luminophore leakage. The physico-chemical and optical properties of the resulting beads were investigated with electron microscopy, dynamic light scattering, optical spectroscopy, and fluorescence microscopy. Particle size distribution, fluorescence quantum yield of the encapsulated QDs, and QD leaking stability were used as measures for bead quality. The derived optimized bead encoding procedure enables the reproducible preparation of bright PS microbeads encoded with organic dyes as well as with CdSe/CdS-QDs. Although these beads show a reduced photoluminescence quantum yield compared to the initially very strongly luminescent QDs, with values of about 35%, their photoluminescence quantum yield is nevertheless still moderate.
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2
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Akhmadeev BS, Gerasimova TP, Gilfanova AR, Katsyuba SA, Islamova LN, Fazleeva GM, Kalinin AA, Daminova AG, Fedosimova SV, Amerhanova SK, Voloshina AD, Tanysheva EG, Sinyashin OG, Mustafina AR. Temperature-sensitive emission of dialkylaminostyrylhetarene dyes and their incorporation into phospholipid aggregates: Applicability for thermal sensing and cellular uptake behavior. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 268:120647. [PMID: 34840053 DOI: 10.1016/j.saa.2021.120647] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/25/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
A series of dialkylaminostyrylhetarene dyes constructed from electron-rich and electron-deficient moieties of various structures connected via vinylene π-bridges are introduced as temperature-sensitive luminophores. The temperature dependent emission of the dyes in the acidified dichloromethane solutions derives from temperature-induced shift of the equilibrium between neutral and protonated forms of the dyes. The heating-induced blue shift and intensification of emission of neutral form of the dyes make them a promising basis for development of nanoparticles exhibiting temperature-sensitivity in aqueous solutions at pH typical of biological liquids. Hydrophobicity-driven incorporation of the water insoluble dyes into L-α-phosphatidylcholine(PC)-based bilayers allows to obtain water dispersible dye-PC aggregates, and to follow their emission in the aqueous solutions. Structure of the dyes has strong impact on the efficacy of the dyes incorporation into the PC-based bilayers, temperature sensitivity of emission of the dye-PC aggregates and its reversibility under the heating/cooling cycles. This enables structural optimization of the dyes in order to obtain the dye-PC species demonstrating maximal temperature dependence and reversibility of their luminescence in aqueous solutions. The selected leader exhibits low cytotoxicity exemplified for M-HeLa and Chang Liver cell lines, while the efficient cell internalization of the dye, manifested in the staining of the cell cytoplasm, opens further opportunities for biosensing applications.
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Affiliation(s)
- B S Akhmadeev
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation.
| | - T P Gerasimova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - A R Gilfanova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - S A Katsyuba
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - L N Islamova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - G M Fazleeva
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - A A Kalinin
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - A G Daminova
- Kazan (Volga region) Federal University, 18 Kremlyovskaya st., 420008 Kazan, Russian Federation
| | - S V Fedosimova
- Kazan (Volga region) Federal University, 18 Kremlyovskaya st., 420008 Kazan, Russian Federation
| | - S K Amerhanova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - A D Voloshina
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - E G Tanysheva
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - O G Sinyashin
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
| | - A R Mustafina
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 8 Arbuzov st., 420088 Kazan, Russian Federation
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3
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Perazzo A, Gallier S, Liuzzi R, Guido S, Caserta S. Quantitative methods to detect phospholipids at the oil-water interface. Adv Colloid Interface Sci 2021; 290:102392. [PMID: 33740709 DOI: 10.1016/j.cis.2021.102392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/23/2021] [Accepted: 02/23/2021] [Indexed: 01/29/2023]
Abstract
Phospholipids are the main constituents of cell membranes and act as natural stabilizers of milk fat globules. Phospholipids are used in a wide range of applications, e.g. as emulsifiers in cosmetic, pharmaceutical and food products. While processed emulsion droplets are usually stabilized by a monolayer of phospholipids, cell membranes have a phospholipid bilayer structure and milk fat globules are stabilized by a complex phospholipid trilayer membrane. Despite the broad relevance of phospholipids, there are still many scientific challenges in understanding how their behavior at the fluid-fluid interface affects microstructure, stability, and physico-chemical properties of natural and industrial products. Most of these challenges arise from the experimental difficulties related to the investigation of the molecular arrangement of phospholipids in situ at the fluid-fluid interface and the quantification of their partitioning between the bulk phase and the interface, both under static and flow conditions. This task is further complicated by the presence of other surface-active components, such as proteins, that can interact with phospholipids and compete for space at the interface. Here, we review the methodologies available from the literature to detect and quantify phospholipids, focusing on oil-water interfaces, and highlight current limitations and future perspectives.
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Affiliation(s)
- Antonio Perazzo
- Novaflux Inc., 1 Wall Street, Princeton, NJ, 08540, United States; Advanced BioDevices LLC., 1 Wall Street, Princeton, NJ, 08540, United States
| | - Sophie Gallier
- Dairy Goat Co-operative (N.Z.) Limited, 18 Gallagher Drive, PO Box 1398, Hamilton 3240, New Zealand
| | - Roberta Liuzzi
- Department of Chemical, Materials and Production Engineering, University of Naples "Federico II", P.le Ascarelli 80, 80125 Napoli, Italy
| | - Stefano Guido
- Department of Chemical, Materials and Production Engineering, University of Naples "Federico II", P.le Ascarelli 80, 80125 Napoli, Italy; Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), UdR INSTM Napoli Federico II, P.le Ascarelli 80, 80125 Napoli, Italy; CEINGE - Biotecnologie Avanzate, Via G. Salvatore 486, 80145 Napoli, Italy.
| | - Sergio Caserta
- Department of Chemical, Materials and Production Engineering, University of Naples "Federico II", P.le Ascarelli 80, 80125 Napoli, Italy; Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), UdR INSTM Napoli Federico II, P.le Ascarelli 80, 80125 Napoli, Italy; CEINGE - Biotecnologie Avanzate, Via G. Salvatore 486, 80145 Napoli, Italy
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4
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Steinegger A, Wolfbeis OS, Borisov SM. Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications. Chem Rev 2020; 120:12357-12489. [PMID: 33147405 PMCID: PMC7705895 DOI: 10.1021/acs.chemrev.0c00451] [Citation(s) in RCA: 181] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Indexed: 12/13/2022]
Abstract
This is the first comprehensive review on methods and materials for use in optical sensing of pH values and on applications of such sensors. The Review starts with an introduction that contains subsections on the definition of the pH value, a brief look back on optical methods for sensing of pH, on the effects of ionic strength on pH values and pKa values, on the selectivity, sensitivity, precision, dynamic ranges, and temperature dependence of such sensors. Commonly used optical sensing schemes are covered in a next main chapter, with subsections on methods based on absorptiometry, reflectometry, luminescence, refractive index, surface plasmon resonance, photonic crystals, turbidity, mechanical displacement, interferometry, and solvatochromism. This is followed by sections on absorptiometric and luminescent molecular probes for use pH in sensors. Further large sections cover polymeric hosts and supports, and methods for immobilization of indicator dyes. Further and more specific sections summarize the state of the art in materials with dual functionality (indicator and host), nanomaterials, sensors based on upconversion and 2-photon absorption, multiparameter sensors, imaging, and sensors for extreme pH values. A chapter on the many sensing formats has subsections on planar, fiber optic, evanescent wave, refractive index, surface plasmon resonance and holography based sensor designs, and on distributed sensing. Another section summarizes selected applications in areas, such as medicine, biology, oceanography, bioprocess monitoring, corrosion studies, on the use of pH sensors as transducers in biosensors and chemical sensors, and their integration into flow-injection analyzers, microfluidic devices, and lab-on-a-chip systems. An extra section is devoted to current challenges, with subsections on challenges of general nature and those of specific nature. A concluding section gives an outlook on potential future trends and perspectives.
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Affiliation(s)
- Andreas Steinegger
- Institute
of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Otto S. Wolfbeis
- Institute
of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, D-93040 Regensburg, Germany
| | - Sergey M. Borisov
- Institute
of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
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5
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Properties of POPC/POPE supported lipid bilayers modified with hydrophobic quantum dots on polyelectrolyte cushions. Colloids Surf B Biointerfaces 2017; 158:667-674. [PMID: 28763774 DOI: 10.1016/j.colsurfb.2017.07.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/19/2017] [Accepted: 07/19/2017] [Indexed: 11/21/2022]
Abstract
The formation and properties of supported lipid bilayers (SLB) containing hydrophobic nanoparticles (NP) was studied in relation to underlying cushion obtained from selected polyelectrolyte multilayers. Lipid vesicles were formed from zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) in phosphate buffer (PBS). As hydrophobic nanoparticles - quantum dots (QD) with size of 3.8nm (emission wavelength of 420nm) were used. Polyelectrolyte multilayers (PEM) were constructed by the sequential, i.e., layer-by-layer (LbL) adsorption of alternately charged polyelectrolytes from their solutions. Liposomes and Liposome-QDs complexes were studied with Transmission Cryo-Electron Microscopy (Cryo-TEM) to verify the quality of vesicles and the position of QD within lipid bilayer. Deposition of liposomes and liposomes with quantum dots on polyelectrolyte films was studied in situ using quartz crystal microbalance with dissipation (QCM-D) technique. The fluorescence emission spectra were analyzed for both: suspension of liposomes with nanoparticles and for supported lipid bilayers containing QD on PEM. It was demonstrated that quantum dots are located in the hydrophobic part of lipid bilayer. Moreover, we proved that such QD-modified liposomes formed supported lipid bilayers and their final structure depended on the type of underlying cushion.
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6
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Guo P, Liu L, Shi Q, Yin C, Shi X. A rhodamine 6G derived Schiff base as a fluorescent and colorimetric probe for pH detection and its crystal structure. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.10.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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7
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Grossutti M, Seenath R, Noël JA, Lipkowski J. Infrared and fluorescence spectroscopic studies of a phospholipid bilayer supported by a soft cationic hydrogel scaffold. J Colloid Interface Sci 2016; 473:162-71. [PMID: 27064742 DOI: 10.1016/j.jcis.2016.03.055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/24/2016] [Accepted: 03/24/2016] [Indexed: 10/22/2022]
Abstract
Polarized attenuated total reflection (ATR-IR) spectroscopy and fluorescence microscopy techniques were used to characterize a 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) membrane supported on porous, cationic hydrogel beads. Fluorescence microscopy images showed that the DPhPC coated the external surface of the hydrogel scaffold. In addition, a fluorescence assay of the emission intensity of the Tb(3+)/dipicolinic acid complex demonstrated that the DPhPC coating acted as a barrier to Tb(3+) efflux from the scaffolded vesicle and successfully sealed the porous hydrogel bead. Fluorescence quenching and ATR-IR spectroscopic measurements revealed that the lipid coating has a bilayer structure. The phytanoyl chains were found to exhibit significant trans-gauche isomerization, characteristic of the fluid liquid phase. However, no lipid lateral mobility was observed by fluorescence recovery after photobleaching (FRAP) measurements. The phosphocholine headgroup was found to be well hydrated and oriented such that the cationic choline group tucked in behind the anionic phosphate group, consistent with an electrostatic attraction between the cationic scaffold and zwitterionic lipid. The absence of lipid lateral mobility may be due to the strength of this attraction.
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Affiliation(s)
- Michael Grossutti
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Ryan Seenath
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - John A Noël
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Jacek Lipkowski
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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8
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Zhou J, Hu W, Tang L. Non-invasive Characterization of Immune Responses to Biomedical Implants. Ann Biomed Eng 2015; 44:693-704. [DOI: 10.1007/s10439-015-1470-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 09/22/2015] [Indexed: 01/08/2023]
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9
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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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10
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Abstract
Within a large clonal population, such as cancerous tumor entities, cells are not identical, and the differences between intracellular pH levels of individual cells may be important indicators of heterogeneity that could be relevant in clinical practice, especially in personalized medicine. Therefore, the detection of the intracellular pH at the single-cell level is of great importance to identify and study outlier cells. However, quantitative and real-time measurements of the intracellular pH of individual cells within a cell population is challenging with existing technologies, and there is a need to engineer new methodologies. In this paper, we discuss the use of nanopipette technology to overcome the limitations of intracellular pH measurements at the single-cell level. We have developed a nano-pH probe through physisorption of chitosan onto hydroxylated quartz nanopipettes with extremely small pore sizes (~100 nm). The dynamic pH range of the nano-pH probe was from 2.6 to 10.7 with a sensitivity of 0.09 units. We have performed single-cell intracellular pH measurements using non-cancerous and cancerous cell lines, including human fibroblasts, HeLa, MDA-MB-231 and MCF-7, with the pH nanoprobe. We have further demonstrated the real-time continuous single-cell pH measurement capability of the sensor, showing the cellular pH response to pharmaceutical manipulations. These findings suggest that the chitosan-functionalized nanopore is a powerful nano-tool for pH sensing at the single-cell level with high temporal and spatial resolution.
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Affiliation(s)
- Rıfat Emrah Özel
- Biomolecular Engineering Department, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Akshar Lohith
- Biomolecular Engineering Department, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Wai Han Mak
- Biomolecular Engineering Department, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Nader Pourmand
- Biomolecular Engineering Department, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
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11
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Qi J, Liu D, Liu X, Guan S, Shi F, Chang H, He H, Yang G. Fluorescent pH Sensors for Broad-Range pH Measurement Based on a Single Fluorophore. Anal Chem 2015; 87:5897-904. [DOI: 10.1021/acs.analchem.5b00053] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Jing Qi
- Department
of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, P.R. China
| | - Daying Liu
- Department
of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, P.R. China
| | - Xiaoyan Liu
- Department
of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, P.R. China
| | - Shiquan Guan
- Heowns Biochem Technologies LLC, 6 Lanyuan Road, Tianjin 300384, P.R. China
| | - Fengli Shi
- Heowns Biochem Technologies LLC, 6 Lanyuan Road, Tianjin 300384, P.R. China
| | - Hexi Chang
- Heowns Biochem Technologies LLC, 6 Lanyuan Road, Tianjin 300384, P.R. China
| | - Huarui He
- Heowns Biochem Technologies LLC, 6 Lanyuan Road, Tianjin 300384, P.R. China
| | - Guangming Yang
- Department
of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, P.R. China
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12
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Saura AV, Marín MJ, Burguete MI, Russell DA, Galindo F, Luis SV. The synthesis of new fluorescent bichromophoric compounds as ratiometric pH probes for intracellular measurements. Org Biomol Chem 2015; 13:7736-49. [DOI: 10.1039/c5ob00704f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Three different bichromophoric compounds (1–3) containing an aminomethyl anthracene moiety linked to a second chromophore have been prepared and their fluorescent properties studied.
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Affiliation(s)
- A. Vanessa Saura
- Departamento de Química Inorgánica y Orgánica
- Universitat Jaume I
- Castellón
- Spain
| | | | - M. Isabel Burguete
- Departamento de Química Inorgánica y Orgánica
- Universitat Jaume I
- Castellón
- Spain
| | | | - Francisco Galindo
- Departamento de Química Inorgánica y Orgánica
- Universitat Jaume I
- Castellón
- Spain
| | - Santiago V. Luis
- Departamento de Química Inorgánica y Orgánica
- Universitat Jaume I
- Castellón
- Spain
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13
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A profluorescent ratiometric probe for intracellular pH imaging. Talanta 2015; 131:666-71. [DOI: 10.1016/j.talanta.2014.08.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 08/11/2014] [Accepted: 08/15/2014] [Indexed: 11/23/2022]
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14
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Design, calibration and application of broad-range optical nanosensors for determining intracellular pH. Nat Protoc 2014; 9:2841-58. [PMID: 25411952 DOI: 10.1038/nprot.2014.196] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Particle-based nanosensors offer a tool for determining the pH in the endosomal-lysosomal system of living cells. Measurements providing absolute values of pH have so far been restricted by the limited sensitivity range of nanosensors, calibration challenges and the complexity of image analysis. This protocol describes the design and application of a polyacrylamide-based nanosensor (∼60 nm) that covalently incorporates two pH-sensitive fluorophores, fluorescein (FS) and Oregon Green (OG), to broaden the sensitivity range of the sensor (pH 3.1-7.0), and uses the pH-insensitive fluorophore rhodamine as a reference fluorophore. The nanosensors are spontaneously taken up via endocytosis and directed to the lysosomes where dynamic changes in pH can be measured with live-cell confocal microscopy. The most important focus areas of the protocol are the choice of pH-sensitive fluorophores, the design of calibration buffers, the determination of the effective range and especially the description of how to critically evaluate results. The entire procedure typically takes 2-3 weeks.
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15
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Huang J, He Y, Yang X, Wang K, Ying L, Quan K, Yang Y, Yin B. I-motif-based nano-flares for sensing pH changes in live cells. Chem Commun (Camb) 2014; 50:15768-71. [PMID: 25370524 DOI: 10.1039/c4cc08054h] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Here, we report an intracellular probe termed i-motif-based nano-flares. They could sense pH change in a live cell since they combine cellular transfection, enzymatic protection, and pH detection.
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Affiliation(s)
- Jin Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha 410082, China.
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16
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Chen YN, Chen PC, Wang CW, Lin YS, Ou CM, Ho LC, Chang HT. One-pot synthesis of fluorescent BSA–Ce/Au nanoclusters as ratiometric pH probes. Chem Commun (Camb) 2014; 50:8571-4. [DOI: 10.1039/c4cc03949a] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Wang H, Shi Y, Yan J, Dong J, Li S, Xiao H, Xie H, Fan LY, Cao CX. Retardation Signal for Fluorescent Determination of Total Protein Content via Rapid and Sensitive Chip Moving Reaction Boundary Electrophoretic Titration. Anal Chem 2014; 86:2888-94. [DOI: 10.1021/ac403963f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Houyu Wang
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yongting Shi
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jian Yan
- Institute of Refrigeration
and Cryogenics, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jingyu Dong
- School
of Chemistry and Molecule Engineering, East China University of Science and Technology, Shanghai 200234, China
| | - Si Li
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hua Xiao
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School
of Chemistry and Chemical Engieering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Haiyang Xie
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School
of Chemistry and Chemical Engieering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Liu-Yin Fan
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School
of Chemistry and Chemical Engieering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Cheng-Xi Cao
- Laboratory of
Bioseparation and Analytical Biochemistry, State Key Laboratory of
Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School
of Chemistry and Chemical Engieering, Shanghai Jiao Tong University, Shanghai 200240, China
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Tsai YT, Zhou J, Weng H, Shen J, Tang L, Hu WJ. Real-time noninvasive monitoring of in vivo inflammatory responses using a pH ratiometric fluorescence imaging probe. Adv Healthc Mater 2014; 3:221-9. [PMID: 23828849 DOI: 10.1002/adhm.201200365] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/31/2013] [Indexed: 12/31/2022]
Abstract
It is often difficult to continuously monitor and quantify inflammatory responses in vivo. These dynamic responses however are often accompanied by specific pH changes. A new ratiometric optical pH probe is developed by combining pH-sensitive (CypHer5E) and pH-insensitive (Oyster800) fluorescent dyes into nanoparticles for in vivo optical imaging. By taking the ratio of fluorescence intensities at different wavelengths, these nanosized sensors provide excellent measurement capabilities, and unique mapping, of the continuous in vivo pH changes for three different inflammation models. In each model a strong positive correlation is found between ratiometric pH changes and the corresponding inflammatory response measured by histological analyses. These results indicate that ratiometric imaging can provide a noninvasive, rapid, and highly sensitive optical readout for the pH-ratio changes in vivo. Furthermore this technique may be used to monitor the real-time dynamics of inflammatory processes.
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Affiliation(s)
- Yi-Ting Tsai
- Bioengineering Department, University of Texas at Arlington, P.O. Box 19138, Arlington, TX 76019-0138
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19
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Chauhan VM, Orsi G, Brown A, Pritchard DI, Aylott JW. Mapping the pharyngeal and intestinal pH of Caenorhabditis elegans and real-time luminal pH oscillations using extended dynamic range pH-sensitive nanosensors. ACS NANO 2013; 7:5577-87. [PMID: 23668893 DOI: 10.1021/nn401856u] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Extended dynamic range pH-sensitive ratiometric nanosensors, capable of accurately mapping the full physiological pH range, have been developed and used to characterize the pH of the pharyngeal and intestinal lumen of Caenorhabditis elegans in real-time. Nanosensors, 40 nm in diameter, were prepared by conjugating pH-sensitive fluorophores, carboxyfluorescein (FAM) and Oregon Green (OG) in a 1:1 ratio, and a reference fluorophore, 5-(and-6)-carboxytetramethylrhodamine (TAMRA) to an inert polyacrylamide matrix. Accurate ratiometric pH measurements were calculated through determination of the fluorescence ratio between the pH-sensitive and reference fluorophores. Nanosensors were calibrated with an automated image analysis system and validated to demonstrate a pH measurement resolution of ±0.17 pH units. The motility of C. elegans populations, as an indicator for viability, showed nematodes treated with nanosensors, for concentrations ranging from 50.00 to 3.13 mg/mL, were not statistically different to nematodes not challenged with nanosensors up to a period of 4 days (p < 0.05). The nanosensors were also found to remain in the C. elegans lumen >24 h after nanosensor challenge was removed. The pH of viable C. elegans lumen was found to range from 5.96 ± 0.31 in the anterior pharynx to 3.59 ± 0.09 in the posterior intestine. The pharyngeal pumping rate, which dictates the transfer of ingested material from the pharynx to the intestine, was found to be temperature dependent. Imaging C. elegans at 4 °C reduced the pharyngeal pumping rate to 7 contractions/min and enabled the reconstruction of rhythmic pH oscillations in the intestinal lumen in real-time with fluorescence microscopy.
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Affiliation(s)
- Veeren M Chauhan
- Laboratory of Biophysics and Surface Analysis, School of Pharmacy, University of Nottingham, Boots Sciences Building, University Park, Nottingham, United Kingdom NG7 2RD
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Zhang J, Gao G, Liu F, Foster NR, Chen J. Preparation of polystyrene/poly[2-methoxy-5-(2′-ethylhexyloxy)-p-phenylenevinylene] fluorescent microspheres by miniemulsion polymerization. POLYM INT 2012. [DOI: 10.1002/pi.4346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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21
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Lapresta-Fernández A, Doussineau T, Moro A, Dutz S, Steiniger F, Mohr G. Magnetic core–shell fluorescent pH ratiometric nanosensor using a Stöber coating method. Anal Chim Acta 2011; 707:164-70. [DOI: 10.1016/j.aca.2011.09.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 08/31/2011] [Accepted: 09/07/2011] [Indexed: 11/26/2022]
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22
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Zhou J, Tsai YT, Weng H, Baker DW, Tang L. Real time monitoring of biomaterial-mediated inflammatory responses via macrophage-targeting NIR nanoprobes. Biomaterials 2011; 32:9383-90. [PMID: 21893338 DOI: 10.1016/j.biomaterials.2011.08.064] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 08/19/2011] [Indexed: 01/21/2023]
Abstract
Medical implant-mediated inflammatory responses, often involving high levels of macrophages, are typically determined by histological analyses. These methods however are time consuming and require many animals to monitor the kinetics of inflammatory reactions and to generate reproducible outcomes. Recent studies have shown that activated macrophages in inflamed tissue express high levels of folate receptor (FR). In this study, FR-targeting NIR nanoprobes were fabricated and then tested for their ability to detect and quantify the extent of biomaterial-mediated inflammatory responses in vivo. Indeed, FR-targeting nanoprobes preferentially accumulate on activated macrophage surfaces. When administered intravenously, we found that the FR-targeting nanoprobes distinctively gathered in the inflamed tissues and that a different extent of FR-targeting nanoprobe gathering could be found in tissues implanted with different types of biomaterials. Most importantly, we found that there was a good relationship between the extent of inflammatory reactions and the intensity of nanoprobe-associated NIR signal in tissue. Our results support that FR-targeting NIR nanoprobes can be used to monitor and quantify the extent of macrophage recruitment and the degree of an implants' biocompatibility in real time.
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Affiliation(s)
- Jun Zhou
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
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23
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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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New fluorescent perylene bisimide indicators--a platform for broadband pH optodes. Anal Bioanal Chem 2011; 400:2475-85. [PMID: 21258785 PMCID: PMC3100492 DOI: 10.1007/s00216-010-4647-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 12/03/2010] [Accepted: 12/22/2010] [Indexed: 10/27/2022]
Abstract
Asymmetric perylene bisimide (PBI) dyes are prepared and are shown to be suitable for the preparation of fluorescence chemosensors for pH. They carry one amino-functional substituent which introduces pH sensitivity via photoinduced electron transfer (PET) while the other one increases solubility. The luminescence quantum yields for the new indicators exceed 75% in the protonated form. The new indicators are non-covalently entrapped in polyurethane hydrogel D4 and poly(hydroxyalkylmethacrylates). Several PET functions including aliphatic and aromatic amino groups were successfully used to tune the dynamic range of the sensor. Because of their virtually identical spectral properties, various PBIs with selected PET functions can easily be integrated into a single sensor with enlarged dynamic range (over 4 pH units). PBIs with two different substitution patterns in the bay position are investigated and possess variable spectral properties. Compared with their tetrachloro analogues, tetra-tert-butyl-substituted PBIs yield more long-wave excitable sensors which feature excellent photostability. Cross-sensitivity to ionic strength was found to be negligible. The practical applicability of the sensors may be compromised by the long response times (especially in case of tetra-tert-butyl-substituted PBIs).
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25
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Nandi M, Mondal J, Sarkar K, Yamauchi Y, Bhaumik A. Highly ordered acid functionalized SBA-15: a novel organocatalyst for the preparation of xanthenes. Chem Commun (Camb) 2011; 47:6677-9. [DOI: 10.1039/c1cc11007a] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Ji R, Yu T, Gu XM, Zuo XL, An K, Zhou CJ, Li YQ. Gastric metaplasia of the duodenum: in vivo diagnosis by endomicroscopy and its relationship with functional dyspepsia. J Gastroenterol Hepatol 2011; 26:73-7. [PMID: 21175797 DOI: 10.1111/j.1440-1746.2010.06479.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND AND AIM Gastric metaplasia (GM) of the duodenum is difficult to assess because of its patchy distribution, and the role of GM in functional dyspepsia (FD) is not clear. The aims of this study were to determine if endomicroscopy could identify GM of the duodenum and whether GM has associations with FD. METHODS A series of 51 patients with FD and 25 asymptomatic controls were enrolled. Confocal laser endomicroscopy was performed to evaluate villi changes in vivo. Targeted biopsy specimens were then compared with histopathological results. RESULTS The accuracy of the endomicroscopy diagnosis of GM during endoscopy was 92.8%, and the sensitivity, specificity, and positive and negative predictive values were 86.2%, 97.4%, 89.3%, and 96.6%, respectively. The mean κ-value for interobserver agreement was 0.89. GM in the duodenal bulb was more frequent in patients with FD than in the controls (33.3% vs 12%, P<0.05), especially in patients with epigastric pain syndrome (47.6% vs 12%, P<0.01). CONCLUSIONS Endomicroscopy is useful for identifying GM, and GM might be related to FD. These findings could have potential applicability for duodenal screening, and suggest a possible targeting therapy in FD.
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Affiliation(s)
- Rui Ji
- Department of Gastroenterology, Qilu Hospital, Shandong University, Jinan, China
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27
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Tian Y, Su F, Weber W, Nandakumar V, Shumway BR, Jin Y, Zhou X, Holl MR, Johnson RH, Meldrum DR. A series of naphthalimide derivatives as intra and extracellular pH sensors. Biomaterials 2010; 31:7411-22. [PMID: 20619451 PMCID: PMC2940253 DOI: 10.1016/j.biomaterials.2010.06.023] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2010] [Accepted: 06/15/2010] [Indexed: 10/19/2022]
Abstract
A series of new naphthalimide derivatives were synthesized and studied. Three of the materials (SM1, SM2, and SM3) possess methacrylate(s) moieties as pH sensor monomers, enabling these compounds to be polymerized with other monomers for thin film preparation for extracellular pH sensing. Herein, poly(2-hydroxyethyl methacrylate)-co-poly(acrylamide) (PHEMA-co-PAM) was chosen as the polymer matrix. Structure influences on pH responses and pK(a) values were studied. The film P3 composed of the sensing moiety SM3 has a pK(a) close to the usual biological environmental pH of approximately 7. It was used as an extracellular pH sensor to monitor pH change during the metabolism of prokaryotic Escherichia coli (E. coil). On the other hand, the three sensor monomers are new intracellular biomarkers to sense lysosomes of eukaryotic cells since (1) their pK(a) values are in a range of 5.9-6.8; (2) their emission intensities at acidic conditions (such as at pH 5) are much stronger than those at a neutral condition of pH 7; (3) lysosomes range in size from 0.1 to 1.2 mum in diameter with pH ranging from 4.5 to 5.0, which is much more acidic than the pH value of the cytoplasm (usually with a pH value of approximately 7.2); and (4) the acidity of lysosomes enables a protonation of the amino groups of the pH probes making the sensors emit brightly in acidic organelles by inhibiting the photo-induced electron transfer from the amino groups to the fluorophores. Lysosome sensing was demonstrated using live human brain glioblastoma U87MG cell line, human cervical cancer HeLa cell line, and human esophagus premalignant CP-A and CP-D cell lines by observations of small acidic spherical organelles (lysosomes) and significant colocalizations (82-95%) of the sensors with a commercially available lysosome-selective staining probe LysoTracker Red under confocal fluorescence microscopy.
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Affiliation(s)
- Yanqing Tian
- Center for Biosignatures Discovery Automation, Biodesign Institute, Arizona State University, 1001 McAllister Ave, Tempe, AZ 85287, USA.
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28
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Christie RJ, Tadiello CJ, Chamberlain LM, Grainger DW. Optical properties and application of a reactive and bioreducible thiol-containing tetramethylrhodamine dimer. Bioconjug Chem 2010; 20:476-80. [PMID: 19249862 DOI: 10.1021/bc800367e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thiolated dimeric tetramethylrhodamine (TAMRA) was synthesized in a straightforward procedure utilizing commercially available 5(6)-succinimidyl TAMRA and cystamine hydrochloride. The thiol-containing TAMRA dimer displayed distinct spectral properties in reduced and oxidized forms; covalent dimer formation produced greater effects on the spectral properties than previously reported for noncovalent TAMRA dimers or dimers formed with shorter carbon spacers. The resulting TAMRA disulfide dimer exhibited a hypsochromic shift of 34 nm relative to the reduced monomer species and an isosbestic point at 532 nm between reduced monomeric and oxidized dimeric forms. Molar extinction coefficients of the monomer and dimer relative to moles of TAMRA were similar (6.61 x 10(4) M(-1) cm(-1) and 6.42 x 10(-4) M(-1) cm(-1), respectively). However, fluorescence emission was altered with >93% of dye fluorescence quenched in phosphate buffered saline upon dimer formation. A 520:554 nm absorbance intensity ratio of 2.64 was observed for the oxidized ssTAMRA dimer, almost twice as high as values reported for noncovalent TAMRA dimers. The resulting disulfide dye was easily reduced using both soluble and agarose gel immobilized tris(2-carboxyethyl) phosphine and fresh cell lysate from cultured RAW 264.7 macrophage cells. Absorbance intensity ratios at 554 and 520 nm were used to determine the oxidation half-life of a 1.2 x 10(-5) M solution of reduced TAMRA stored in ambient atmosphere to be approximately 50 h at 22 degrees C. The free thiol dye was further reacted with maleimide-derivatized poly(hydroxypropyl methacrylamide) to yield the dye-labeled polymer conjugate. This dye derivative should prove useful as a dithiol reduction-sensitive fluorescent probe in cellular tracking systems, as well as a thiol-based dye-labeling reagent due to its easy preparation from readily available materials, environmental sensitivity, and simple activation to produce distinct spectral states. The enhanced spectral properties of the covalent TAMRA dimer described here could be useful to prepare more advanced reporter molecules and bioconjugates.
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Affiliation(s)
- R James Christie
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
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29
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Affiliation(s)
- Junyan Han
- Department of Chemistry, Texas A&M University, Box 30012, College Station, Texas 77841, USA
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30
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Chen YC, Ostafin A, Mizukami H. Synthesis and characterization of pH sensitive carboxySNARF-1 nanoreactors. NANOTECHNOLOGY 2010; 21:215503. [PMID: 20431200 DOI: 10.1088/0957-4484/21/21/215503] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A rapid response dual wavelength emission pH sensor consisting of carboxySNARF-1 nanoreactors has been synthesized and shown to provide accurate pH measurements even in complex biological media, where the unprotected pH responsive dyes have failed. The carboxySNARF-1 nanoreactor is made of a calcium phosphate shell covering phosphatidylcholine liposomes filled with the dye. Its mean diameter is 150 nm with dynamic light scattering, the shell thickness is 5-7 nm with TEM, and it contains about 10 dyes/particle. The nanoreactor's response time to pH change nearly equals that of the dye in solution. Its pH titration curves at two different wavelengths are equivalent to those of the dye in solution and fluorescence intensity ratio dependent pH analysis is possible using the modified Henderson-Hasselbalch equation. However, the pH dependent fluorescence ratios of the dye in solution in the presence of plasma and albumin are distorted, and application of the Henderson-Hasselbalch equation is not possible. We have found that the distortions may be restored using cSNARF-1 nanoreactors and the pK(a) of the dye in the nanoreactor then equals that in solution. These results suggest that the interference to the dye for the pH analyses with the environmental molecules may be reduced or prohibited by usage of cSNARF-1 nanoreactors.
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Affiliation(s)
- Yen-Chi Chen
- Department of Materials Science, University of Utah, Salt Lake City, UT, USA
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31
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Chemburu S, Fenton K, Lopez GP, Zeineldin R. Biomimetic silica microspheres in biosensing. Molecules 2010; 15:1932-57. [PMID: 20336023 PMCID: PMC6257317 DOI: 10.3390/molecules15031932] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 03/16/2010] [Accepted: 03/17/2010] [Indexed: 11/16/2022] Open
Abstract
Lipid vesicles spontaneously fuse and assemble into a lipid bilayer on planar or spherical silica surfaces and other substrates. The supported lipid bilayers (SLBs) maintain characteristics of biological membranes, and are thus considered to be biomembrane mimetic systems that are stable because of the underlying substrate. Examples of their shared characteristics with biomembranes include lateral fluidity, barrier formation to ions and molecules, and their ability to incorporate membrane proteins into them. Biomimetic silica microspheres consisting of SLBs on solid or porous silica microspheres have been utilized for different biosensing applications. The advantages of such biomimetic microspheres for biosensing include their increased surface area to volume ratio which improves the detection limits of analytes, and their amenability for miniaturization, multiplexing and high throughput screening. This review presents examples and formats of using such biomimetic solid or porous silica microspheres in biosensing.
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Affiliation(s)
- Sireesha Chemburu
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Kyle Fenton
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM 87131, USA
| | - Gabriel P. Lopez
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, NM 87131, USA
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Department of Mechanical Engineering & Materials Science, Duke University, Durham, NC 27708, USA
| | - Reema Zeineldin
- Department of Pharmaceutical Sciences, Massachusetts College of Pharmacy and Health Sciences, 19 Foster Street, Worcester, MA 01608, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-508-373-5762; Fax: +1- 508-890-5618
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Tallec G, Imbert D, Fries PH, Mazzanti M. Highly stable and soluble bis-aqua Gd, Nd, Yb complexes as potential bimodal MRI/NIR imaging agents. Dalton Trans 2010; 39:9490-2. [DOI: 10.1039/c0dt00994f] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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33
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Borisov SM, Mayr T, Mistlberger G, Klimant I. Dye-Doped Polymeric Particles for Sensing and Imaging. ADVANCED FLUORESCENCE REPORTERS IN CHEMISTRY AND BIOLOGY II 2010. [DOI: 10.1007/978-3-642-04701-5_6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Schulz A, Wotschadlo J, Heinze T, Mohr GJ. Fluorescent nanoparticles for ratiometric pH-monitoring in the neutral range. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b918427a] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Biondi M, Indolfi L, Ungaro F, Quaglia F, La Rotonda MI, Netti PA. Bioactivated collagen-based scaffolds embedding protein-releasing biodegradable microspheres: tuning of protein release kinetics. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2009; 20:2117-2128. [PMID: 19449203 DOI: 10.1007/s10856-009-3766-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 04/24/2009] [Indexed: 05/27/2023]
Abstract
In tissue engineering, the recapitulation of natural sequences of signaling molecules, such as growth factors, as occurring in the native extracellular matrix (ECM), is fundamental to support the stepwise process of tissue regeneration. Among the manifold of tissue engineering strategies, a promising one is based on the creation of the chrono-programmed presentation of different signaling proteins. This approach is based upon the integration of biodegradable microspheres, loaded with suitable protein molecules, within scaffolds made of collagen and, in case, hyaluronic acid, which are two of the fundamental ECM constituents. However, for the design of bioactivated gel-like scaffolds the determination of release kinetics must be performed directly within the tissue engineering template. In this work, biodegradable poly(lactic-co-glycolic)acid (PLGA) microspheres were produced by the multiple emulsion-solvent evaporation technique and loaded with rhodamine-labelled bovine serum albumin (BSA-Rhod), a fluorescent model protein. The microdevices were dispersed in collagen gels and collagen-hyaluronic acid (HA) semi-interpenetrating networks (semi-IPNs). BSA-Rhod release kinetics were studied directly on single microspheres through confocal laser scanning microscopy (CLSM). To thoroughly investigate the mechanisms governing protein release from PLGA microspheres in gels, BSA-Rhod diffusion in gels was determined by fluorescence correlation spectroscopy (FCS), and water transport through the microsphere bulk was determined by dynamic vapor sorption (DVS). Moreover, the decrease of PLGA molecular weight and glass transition temperature (T(g)) were determined by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC), respectively. Results indicate that protein release kinetics and delivery onset strongly depend on the complex interplay between protein transport through the PLGA matrix and in the collagen-based release media, and water sequestration within the scaffolds, related to the scaffold hydrophilicity, which is dictated by HA content. The proper manipulation of all these features may thus allow the obtainment of a fine control over protein sequential delivery and release kinetics within tissue-engineering scaffolds.
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Affiliation(s)
- Marco Biondi
- Interdisciplinary Research Centre on Biomaterials (CRIB), University of Naples Federico II, 80125 Naples, Italy
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Polyelectrolyte microcapsules and coated CaCO3 particles as fluorescence activated sensors in flowmetry. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.04.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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37
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38
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Swati M, Srivastava R. Stabilization of Sensing Assay within Polyelectrolyte-Coated Alginate Microspheres for Optical Urea Sensing. ANAL LETT 2009. [DOI: 10.1080/00032710802677175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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39
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Schulz A, Hornig S, Liebert T, Birckner E, Heinze T, Mohr GJ. Evaluation of fluorescent polysaccharide nanoparticles for pH-sensing. Org Biomol Chem 2009; 7:1884-9. [DOI: 10.1039/b900260j] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Allard E, Larpent C. Core-shell type dually fluorescent polymer nanoparticles for ratiometric pH-sensing. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/pola.22931] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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41
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Ruda-Eberenz TA, Nagy A, Waldman WJ, Dutta PK. Entrapment of ionic tris(2,2'-bipyridyl) ruthenium(II) in hydrophobic siliceous zeolite: O2 sensing in biological environments. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:9140-9147. [PMID: 18642937 DOI: 10.1021/la801204y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Synthesis of the ionic dye, tris(2,2'-bipyridyl) ruthenium(II) chloride (Ru(bpy) 3 2+.2Cl (-)) within the supercages of a highly hydrophobic zeolite Y is reported. Use of the neutral precursor Ru(bpy)Cl 2(CO) 2 allowed for high loading levels of Ru(bpy) 3 2+ (1 per 7 and 25 supercages). The emission quenching of the Ru(bpy) 3 2+-zeolite crystals dispersed in polydimethoxysiloxane (PDMS) films by dissolved oxygen in water was examined. The quenching data as a function of oxygen concentration was fit to a linear Stern-Volmer plot ( R2 = 0.98). Using the Stern-Volmer plot as calibration, changes in concentration of dissolved oxygen due to reaction with glucose in the presence of glucose oxidase was monitored. Human monocyte-derived macrophages internalized the submicron-sized Ru(bpy) 3 2+-zeolite crystals, and intracellular oxygen concentrations initiated by zymosan-mediated oxidative burst could be monitored by measuring the emission from Ru(bpy) 3 2+ by confocal fluorescence microscopy.
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Affiliation(s)
- Toni A Ruda-Eberenz
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
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42
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Chen AK, Cheng Z, Behlke MA, Tsourkas A. Assessing the sensitivity of commercially available fluorophores to the intracellular environment. Anal Chem 2008; 80:7437-44. [PMID: 18700780 DOI: 10.1021/ac8011347] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The use of fluorescence has become commonplace in the biological sciences, with many studies utilizing probes based on commercially available fluorophores to provide insight into cell function and behavior. As these imaging applications become more advanced, it becomes increasingly important to acquire accurate quantitative measurements of the fluorescence signal. Absolute quantification of fluorescence, however, requires the fluorophores themselves to be insensitive to environmental factors such as nonspecific protein interactions and pH. Here, we present a method for characterizing the sensitivity of fluorophores to the cytosolic environment by comparing their fluorescent intensity to an environment-insensitive reference signal before and after intracellular delivery. Results indicated that although the fluorescent intensity of a few fluorophores, e.g., fluorescein, were highly susceptible to the intracellular environment, other fluorophores, e.g., Dylight 649, Alexa647, and Alexa750, were insensitive to the intracellular environment. It was also observed that the sensitivity of the fluorophore could be dependent on the biomolecule to which it was attached. In addition to assessing the environmental sensitivity of fluorophores, a method for quantifying the amount of fluorophores within living cells is also introduced. Overall, the present study provides a means to select fluorophores for studies that require an absolute quantification of fluorescence in the intracellular environment.
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Affiliation(s)
- Antony K Chen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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43
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Hilderbrand SA, Kelly KA, Niedre M, Weissleder R. Near infrared fluorescence-based bacteriophage particles for ratiometric pH imaging. Bioconjug Chem 2008; 19:1635-9. [PMID: 18666791 DOI: 10.1021/bc800188p] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fluorogenic imaging agents emitting in the near-infrared are becoming important research tools for disease investigation in vivo. Often pathophysiological states such as cancer and cystic fibrosis are associated with disruptions in acid/base homeostasis. The development of optical sensors for pH imaging would facilitate the investigation of these diseased conditions. In this report, the design and synthesis of a ratiometric near-infrared emitting probe for pH quantification is detailed. The pH-responsive probe is prepared by covalent attachment of pH-sensitive and pH-insensitive fluorophores to a bacteriophage particle scaffold. The pH-responsive cyanine dye, HCyC-646, used to construct the probe, has a fluorogenic pKa of 6.2, which is optimized for visualization of acidic pH often associated with tumor hypoxia and other diseased states. Incorporation of pH-insensitive reference dyes enables the ratiometric determination of pH independent of the probe concentration. With the pH-responsive construct, measurement of intracellular pH and accurate determination of pH through optically diffuse biological tissue is demonstrated.
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Affiliation(s)
- Scott A Hilderbrand
- Center for Molecular Imaging Research and Center for Systems Biology, Massachusetts General Hospital/Harvard Medical School, USA.
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44
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Hornig S, Biskup C, Gräfe A, Wotschadlo J, Liebert T, Mohr GJ, Heinze T. Biocompatible fluorescent nanoparticles for pH-sensoring. SOFT MATTER 2008; 4:1169-1172. [PMID: 32907258 DOI: 10.1039/b800276b] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Dialysis of a mixture of fluorescein and sulforhodamine B marked dextran derivatives yields biocompatible and tuneable nanosensors that can be used for ratiometric pH measurements.
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Affiliation(s)
- Stephanie Hornig
- Center of Excellence for Polysaccharide Research, Member of the European Polysaccharide Network of Excellence, Friedrich Schiller University of Jena, Humboldtstrasse 10, 07743 Jena, Germany.
| | - Christoph Biskup
- Institute of Physiology II, Universitätsklinikum Jena, Teichgraben 8, 07740 Jena, Germany
| | - Anja Gräfe
- Institute of Physical Chemistry, Friedrich Schiller University of Jena, Lessingstrasse 10, 07743 Jena, Germany.
| | - Jana Wotschadlo
- Center of Excellence for Polysaccharide Research, Member of the European Polysaccharide Network of Excellence, Friedrich Schiller University of Jena, Humboldtstrasse 10, 07743 Jena, Germany.
| | - Tim Liebert
- Center of Excellence for Polysaccharide Research, Member of the European Polysaccharide Network of Excellence, Friedrich Schiller University of Jena, Humboldtstrasse 10, 07743 Jena, Germany.
| | - Gerhard J Mohr
- Institute of Physical Chemistry, Friedrich Schiller University of Jena, Lessingstrasse 10, 07743 Jena, Germany.
| | - Thomas Heinze
- Center of Excellence for Polysaccharide Research, Member of the European Polysaccharide Network of Excellence, Friedrich Schiller University of Jena, Humboldtstrasse 10, 07743 Jena, Germany.
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45
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Sando S, Narita A, Hayami M, Aoyama Y. Tuning the Hoechst Dye into Color-changing Fluorescent pH Indicator in an Acidic Range. CHEM LETT 2008. [DOI: 10.1246/cl.2008.246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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46
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Senarath-Yapa MD, Phimphivong S, Coym JW, Wirth MJ, Aspinwall CA, Saavedra SS. Preparation and characterization of poly(lipid)-coated, fluorophore-doped silica nanoparticles for biolabeling and cellular imaging. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:12624-12633. [PMID: 17975939 DOI: 10.1021/la701917w] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The fabrication, characterization, and implementation of poly(lipid)-coated, highly luminescent silica nanoparticles as fluorescent probes for labeling of cultured cells are described. The core of the probe is a sol-gel-derived silica nanoparticle, 65-100 nm in diameter, in which up to several thousand dye molecules are encapsulated (Lian, W.; et al. Anal. Biochem. 2004, 334, 135-144). The core is coated with a membrane composed of bis-sorbylphosphatidylcholine, a synthetic polymerizable lipid that is chemically cross-linked to enhance the environmental and chemical stability of the membrane relative to a fluid lipid membrane. The poly(lipid) coating has two major functions: (i) to reduce nonspecific interactions, based on the inherently biocompatible properties of the phosphorylcholine headgroup, and (ii) to permit functionalization of the particle, by doping the coating with lipids bearing chemically reactive or bioactive headgroups. Both functions are demonstrated: (i) Nonspecific adsorption of dissolved proteins to bare silica nanoparticles and of bare nanoparticles to cultured cells is significantly reduced by application of the poly(lipid) coating. (ii) Functionalization of poly(lipid)-coated nanoparticles with a biotin-conjugated lipid creates a probe that can be used to target both dissolved protein receptors as well as receptors on the membranes of cultured cells. Measurements performed on single nanoparticles bound to planar supported lipid bilayers verify that the emission intensity of these probes is significantly greater than that of single protein molecules labeled with several fluorophores.
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47
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Gao F, Tang L, Dai L, Wang L. A fluorescence ratiometric nano-pH sensor based on dual-fluorophore-doped silica nanoparticles. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 67:517-21. [PMID: 16965933 DOI: 10.1016/j.saa.2006.08.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2006] [Revised: 08/05/2006] [Accepted: 08/07/2006] [Indexed: 05/11/2023]
Abstract
We have synthesized dual-fluorophore-doped core-shell silica nanoparticles used as ratiometric pH sensor. The nanoparticles were prepared with a reverse microemulsion technique by simultaneously encapsulating two different fluorophores, the pH-sensitive dye fluorescein as a pH indicator and the pH-insensitive dye phenosafranine as an internal reference for fluorescence ratiometric measurement, into silica shell. The nanoparticles prevent the fluorescence dyes leaching from the silica matrix when immersed inside water. The hydrophilic silica shells were made by hydrolysing and polymerizing tetraethoxysilane (TEOS) in water-in-oil microemulsion. The fluorescence intensity ratio of the two dyes varied linearly as a function of pH in the range from 4.0 to 8.0. The sensor was also applied to measure pH of real water samples. The results are in good agreements with that using the conventional glass electrode method. The as-prepared fluorescent nanoparticles showed rapid response, excellent stability and high reproducibility as pH sensors.
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Affiliation(s)
- Feng Gao
- College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000, PR China
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48
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Reibetanz U, Halozan D, Brumen M, Donath E. Flow Cytometry of HEK 293T Cells Interacting with Polyelectrolyte Multilayer Capsules Containing Fluorescein-Labeled Poly(acrylic acid) as a pH Sensor. Biomacromolecules 2007; 8:1927-33. [PMID: 17508712 DOI: 10.1021/bm061200r] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Polyelectrolyte multilayer sensor capsules, 5 microm in diameter, which contained fluorescein-labeled poly(acrylic acid) (PAAAF) as pH-sensitive reporter molecules, were fabricated and employed to explore their endocytotic uptake into HEK 293T cells by flow cytometry. The percentage of capsules residing in the endolysosomal compartment was estimated from the fluorescence intensity decrease caused by acidification. Capsules attached to the extracellular surface of the plasma membrane were identified by trypan blue quenching. The number of capsules in the cytoplasm was rather small, being below the detection limit of the method. The advantages of polyelectrolyte multilayer capsules are that the fluorophore is protected from interaction with cellular compartments and that the multilayer can be equipped with additional functions.
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Affiliation(s)
- Uta Reibetanz
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstrasse 16-18, 04107 Leipzig, Germany
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49
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Peng J, He X, Wang K, Tan W, Wang Y, Liu Y. Noninvasive monitoring of intracellular pH change induced by drug stimulation using silica nanoparticle sensors. Anal Bioanal Chem 2007; 388:645-54. [PMID: 17440714 DOI: 10.1007/s00216-007-1244-9] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 03/01/2007] [Accepted: 03/06/2007] [Indexed: 11/25/2022]
Abstract
We have synthesized and applied a nanoparticle-based pH sensor for noninvasive monitoring of intracellular pH changes induced by drug stimulation. The pH sensor is a two-fluorophore-doped nanoparticle sensor (2DFNS) that contains a pH-sensitive indicator (fluorescein isothiocyanate, FITC) and a reference dye (tris(2,2'-bipyridyl)dichlororuthenium(II) hexahydrate, RuBPY). The nanoparticles have an average diameter of 42 +/- 3 nm and can easily be taken up by cells for noninvasive intracellular pH measurement. The 2DFNS exhibited excellent pH sensitivity, reversibility, and a dynamic range of pH 4-7 for biological studies. We have used 2DFNS to monitor pH changes in living cells by drug stimulation. Both lysosomal pH changes in murine macrophages stimulated by chloroquine and intracellular acidification in apoptotic cancer cells were monitored in real time and with high pH sensitivity. Hela cells underwent intracellular acidification with a drop in pH from 7.2 to 6.5 after 8 h of treatment with 2 mumol/L dexamethasone, and this intracellular pH drop in the apoptotic cells was not influenced by the addition of zinc ions. The application of 2DFNS to intracellular pH measurements yields some important advantages: excellent pH sensitivity, little environmental effect on the pH dye, excellent quantification, high stability and excellent reversibility.
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Affiliation(s)
- Jiaofeng Peng
- Biomedical Engineering Center, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
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50
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Research of the relationship of intracellular acidification and apoptosis in Hela cells based on pH nanosensors. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s11426-007-0012-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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