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Kromer C, Katz A, Feldmann I, Laux P, Luch A, Tschiche HR. A targeted fluorescent nanosensor for ratiometric pH sensing at the cell surface. Sci Rep 2024; 14:12302. [PMID: 38811698 PMCID: PMC11137054 DOI: 10.1038/s41598-024-62976-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Accepted: 05/23/2024] [Indexed: 05/31/2024] Open
Abstract
The correlation between altered extracellular pH and various pathological conditions, including cancer, inflammation and metabolic disorders, is well known. Bulk pH measurements cannot report the extracellular pH value at the cell surface. However, there is a limited number of suitable tools for measuring the extracellular pH of cells with high spatial resolution, and none of them are commonly used in laboratories around the world. In this study, a versatile ratiometric nanosensor for the measurement of extracellular pH was developed. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with the pH-inert reference dye Nile red and is surface functionalized with a pH-responsive fluorescein dye. Equipped with a targeting moiety, the nanosensor can adhere to cell membranes, allowing direct measurement of extracellular pH at the cell surface. The nanosensor exhibits a sensitive ratiometric pH response within the range of 5.5-9.0, with a calculated pKa of 7.47. This range optimally covers the extracellular pH (pHe) of most healthy cells and cells in which the pHe is abnormal, such as cancer cells. In combination with the nanosensors ability to target cell membranes, its high robustness, reversibility and its biocompatibility, the pHe nanosensor proves to be well suited for in-situ measurement of extracellular pH, even over extended time periods. This pH nanosensor has the potential to advance biomedical research by improving our understanding of cellular microenvironments, where extracellular pH plays an important role.
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Affiliation(s)
- Charlotte Kromer
- Product Materials and Nanotechnology, Department Chemical and Product Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589, Berlin, Germany.
- Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany.
| | - Aaron Katz
- Product Materials and Nanotechnology, Department Chemical and Product Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Ines Feldmann
- Material-Microbiome Interactions, Department Materials and the Environment, Federal Institute for Materials Research and Testing, Berlin, Germany
| | - Peter Laux
- Product Materials and Nanotechnology, Department Chemical and Product Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Andreas Luch
- Product Materials and Nanotechnology, Department Chemical and Product Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
- Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Harald R Tschiche
- Product Materials and Nanotechnology, Department Chemical and Product Safety, German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
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Debata S, Sahu S, Panda SK, Singh DP. Light-driven micromotors for on-demand and local pH sensing applications. J Mater Chem B 2024; 12:2150-2157. [PMID: 38318681 DOI: 10.1039/d3tb02760k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
In recent years, self-propelled light-driven micromotors have gained significant attention due to their capabilities for a wide range of applications, including cargo delivery, chemical sensing, environmental monitoring, etc. Here, we demonstrate the design of light-driven micromotors for local pH sensing applications. The micromotors are spherical Janus particles with multiple functional coatings that provide them with interesting features, like a dual optical response, i.e., controlled swimming under UV light (320-400 nm) and pH-dependent fluorescence signal emission when excited with blue light (450 nm), and moving path guidance using a weak external uniform magnetic field (50 G). All of these features allow the micromotors to sense the pH of the medium on-demand and locally or of a target location by guiding them to swim to the target location. The pH-dependent change in the fluorescence signal intensity is used for the measurement of the local pH of the medium. It is observed that the careful measurement of small pH changes requires a spectrometer that precisely measures the intensity change. However, the fluorescence signal of the micromotors was good enough to provide a clear visual demarcation for large pH changes. Systematic experimental studies supported by controlled experiments are performed to optimize the system as well as to calibrate the micromotors for local pH sensing applications. The characteristics like easy-to-design structure, light activation, directional swimming, and ability to measure the pH on-demand and locally prove that micromotors have the potential to revolutionize pH monitoring in various domains, including lab-on-a-chip devices, biomedical research, environmental monitoring, quality control in industrial processes, etc.
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Affiliation(s)
- Srikanta Debata
- Department of Physics, IIT Bhilai, Kutelabhata, Durg, 491001, Chhattisgarh, India.
| | - Shivani Sahu
- Department of Physics, IIT Bhilai, Kutelabhata, Durg, 491001, Chhattisgarh, India.
| | - Suvendu Kumar Panda
- Department of Physics, IIT Bhilai, Kutelabhata, Durg, 491001, Chhattisgarh, India.
| | - Dhruv Pratap Singh
- Department of Physics, IIT Bhilai, Kutelabhata, Durg, 491001, Chhattisgarh, India.
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Grasso G, Colella F, Forciniti S, Onesto V, Iuele H, Siciliano AC, Carnevali F, Chandra A, Gigli G, Del Mercato LL. Fluorescent nano- and microparticles for sensing cellular microenvironment: past, present and future applications. NANOSCALE ADVANCES 2023; 5:4311-4336. [PMID: 37638162 PMCID: PMC10448310 DOI: 10.1039/d3na00218g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 06/13/2023] [Indexed: 08/29/2023]
Abstract
The tumor microenvironment (TME) demonstrates distinct hallmarks, including acidosis, hypoxia, reactive oxygen species (ROS) generation, and altered ion fluxes, which are crucial targets for early cancer biomarker detection, tumor diagnosis, and therapeutic strategies. Various imaging and sensing techniques have been developed and employed in both research and clinical settings to visualize and monitor cellular and TME dynamics. Among these, ratiometric fluorescence-based sensors have emerged as powerful analytical tools, providing precise and sensitive insights into TME and enabling real-time detection and tracking of dynamic changes. In this comprehensive review, we discuss the latest advancements in ratiometric fluorescent probes designed for the optical mapping of pH, oxygen, ROS, ions, and biomarkers within the TME. We elucidate their structural designs and sensing mechanisms as well as their applications in in vitro and in vivo detection. Furthermore, we explore integrated sensing platforms that reveal the spatiotemporal behavior of complex tumor cultures, highlighting the potential of high-resolution imaging techniques combined with computational methods. This review aims to provide a solid foundation for understanding the current state of the art and the future potential of fluorescent nano- and microparticles in the field of cellular microenvironment sensing.
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Affiliation(s)
- Giuliana Grasso
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
| | - Francesco Colella
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
- Department of Mathematics and Physics ''Ennio De Giorgi", University of Salento c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
| | - Stefania Forciniti
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
| | - Valentina Onesto
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
| | - Helena Iuele
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
| | - Anna Chiara Siciliano
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
- Department of Mathematics and Physics ''Ennio De Giorgi", University of Salento c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
| | - Federica Carnevali
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
- Department of Mathematics and Physics ''Ennio De Giorgi", University of Salento c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
| | - Anil Chandra
- Centre for Research in Pure and Applied Sciences, Jain (Deemed-to-be-university) Bangalore Karnataka 560078 India
| | - Giuseppe Gigli
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
- Department of Mathematics and Physics ''Ennio De Giorgi", University of Salento c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
| | - Loretta L Del Mercato
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC) c/o Campus Ecotekne, via Monteroni 73100 Lecce Italy
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Yu C, Lu G, Yan C, Xu J, Zhang F. Preparation and pH Detection Performance of Rosin-Based Fluorescent Polyurethane Microspheres. J Fluoresc 2023:10.1007/s10895-023-03160-z. [PMID: 36790631 DOI: 10.1007/s10895-023-03160-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 01/25/2023] [Indexed: 02/16/2023]
Abstract
Rosin-based fluorescent polyurethane emulsion (FPU) was prepared using isophorone diisocyanate, ester of acrylic rosin and glycidyl methacrylate, 1,5-dihydroxy naphthalene (1,5-DN), and 1,4-butanediol as the raw materials. Then, rosin-based fluorescent polyurethane microspheres (FPUMs) were successfully prepared by suspension polymerization method using FPU as the main material, azodiisobutyronitrile as the initiator, and gelatin as the dispersant. FPUMs were characterized by Fourier transform infrared spectra, thermogravimetric analysis, optical microscopy, scanning electron microscopy and fluorescence spectra, and the response performance of FPUMs to pH was studied. The results showed that FPUMs were successfully prepared. With the increase of the level of 1,5-DN, the particle size of FPUMs increased gradually, and the fluorescence intensity increased first and then decreased. When the level of 1,5-DN was 3 wt.%, the average particle size was 49.3 μm, the particle distribution index (PDI) was 1.05, and the fluorescence intensity was the largest (3662 a.u.). The fluorescence intensity of FPUMs increased linearly with the decrease of pH, which can be used for pH detection in solution. Furthermore, the FPUMs exhibited good thermal stability, anti-interference and recoverability.
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Affiliation(s)
- Caili Yu
- College of Chemistry and Biology Engineering, Guilin University of Technology, Guilin, 541004, China
| | - Guangjie Lu
- College of Chemistry and Biology Engineering, Guilin University of Technology, Guilin, 541004, China
| | - Chengfei Yan
- College of Chemistry and Biology Engineering, Guilin University of Technology, Guilin, 541004, China
| | - Jianben Xu
- College of Materials Science and Engineering, Guilin University of Technology, No 12, Jiangan Road, Guilin, 541004, People's Republic of China.
| | - Faai Zhang
- College of Materials Science and Engineering, Guilin University of Technology, No 12, Jiangan Road, Guilin, 541004, People's Republic of China.
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Swanson WB, Durdan M, Eberle M, Woodbury S, Mauser A, Gregory J, Zhang B, Niemann D, Herremans J, Ma PX, Lahann J, Weivoda M, Mishina Y, Greineder CF. A library of Rhodamine6G-based pH-sensitive fluorescent probes with versatile in vivo and in vitro applications. RSC Chem Biol 2022; 3:748-764. [PMID: 35755193 PMCID: PMC9175114 DOI: 10.1039/d2cb00030j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/24/2022] [Indexed: 01/11/2023] Open
Abstract
Acidic pH is critical to the function of the gastrointestinal system, bone-resorbing osteoclasts, and the endolysosomal compartment of nearly every cell in the body. Non-invasive, real-time fluorescence imaging of acidic microenvironments represents a powerful tool for understanding normal cellular biology, defining mechanisms of disease, and monitoring for therapeutic response. While commercially available pH-sensitive fluorescent probes exist, several limitations hinder their widespread use and potential for biologic application. To address this need, we developed a novel library of pH-sensitive probes based on the highly photostable and water-soluble fluorescent molecule, Rhodamine 6G. We demonstrate versatility in terms of both pH sensitivity (i.e., pK a) and chemical functionality, allowing conjugation to small molecules, proteins, nanoparticles, and regenerative biomaterial scaffold matrices. Furthermore, we show preserved pH-sensitive fluorescence following a variety of forms of covalent functionalization and demonstrate three potential applications, both in vitro and in vivo, for intracellular and extracellular pH sensing. Finally, we develop a computation approach for predicting the pH sensitivity of R6G derivatives, which could be used to expand our library and generate probes with novel properties.
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Affiliation(s)
- W Benton Swanson
- Department of Biologic and Materials Science, School of Dentistry, University of Michigan 1011 North University Avenue Ann Arbor MI 48109 USA
| | - Margaret Durdan
- Biointerfaces Institute, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Cell and Molecular Biology Program, Medical School, University of Michigan Ann Arbor MI USA
| | - Miranda Eberle
- Department of Biologic and Materials Science, School of Dentistry, University of Michigan 1011 North University Avenue Ann Arbor MI 48109 USA
- Department of Chemistry, College of Literature, Science and the Arts, University of Michigan Ann Arbor MI USA
| | - Seth Woodbury
- Department of Biologic and Materials Science, School of Dentistry, University of Michigan 1011 North University Avenue Ann Arbor MI 48109 USA
- Department of Chemistry, College of Literature, Science and the Arts, University of Michigan Ann Arbor MI USA
| | - Ava Mauser
- Biointerfaces Institute, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Department of Biomedical Engineering, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
| | - Jason Gregory
- Biointerfaces Institute, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Department of Chemical Engineering, College of Engineering, University of Michigan Ann Arbor MI USA
| | - Boya Zhang
- Biointerfaces Institute, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Department of Pharmacology, Medical School, University of Michigan Ann Arbor MI USA
| | - David Niemann
- Department of Biologic and Materials Science, School of Dentistry, University of Michigan 1011 North University Avenue Ann Arbor MI 48109 USA
- Department of Chemistry, College of Literature, Science and the Arts, University of Michigan Ann Arbor MI USA
- Department of Chemical Engineering, College of Engineering, University of Michigan Ann Arbor MI USA
| | - Jacob Herremans
- Department of Biologic and Materials Science, School of Dentistry, University of Michigan 1011 North University Avenue Ann Arbor MI 48109 USA
- Department of Chemistry, College of Literature, Science and the Arts, University of Michigan Ann Arbor MI USA
| | - Peter X Ma
- Department of Biologic and Materials Science, School of Dentistry, University of Michigan 1011 North University Avenue Ann Arbor MI 48109 USA
- Department of Biomedical Engineering, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Department of Materials Science and Engineering, College of Engineering, University of Michigan Ann Arbor MI USA
- Macromolecular Science and Engineering Center, College of Engineering, University of Michigan Ann Arbor MI USA
| | - Joerg Lahann
- Biointerfaces Institute, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Department of Biomedical Engineering, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Department of Chemical Engineering, College of Engineering, University of Michigan Ann Arbor MI USA
- Department of Materials Science and Engineering, College of Engineering, University of Michigan Ann Arbor MI USA
- Macromolecular Science and Engineering Center, College of Engineering, University of Michigan Ann Arbor MI USA
| | - Megan Weivoda
- Biointerfaces Institute, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Department of Pharmacology, Medical School, University of Michigan Ann Arbor MI USA
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan Ann Arbor MI USA
| | - Yuji Mishina
- Department of Biologic and Materials Science, School of Dentistry, University of Michigan 1011 North University Avenue Ann Arbor MI 48109 USA
| | - Colin F Greineder
- Biointerfaces Institute, College of Engineering and Medical School, University of Michigan Ann Arbor MI USA
- Department of Pharmacology, Medical School, University of Michigan Ann Arbor MI USA
- Department of Emergency Medicine, Medical School, University of Michigan NCRC 2800 Plymouth Road, Bldg #26 Ann Arbor MI 48109 USA
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