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Protein Science : a Publication of the... Sep 2011A brief personal perspective is provided for green fluorescent protein (GFP), covering the period 1994-2011. The topics discussed are primarily those in which my... (Review)
Review
A brief personal perspective is provided for green fluorescent protein (GFP), covering the period 1994-2011. The topics discussed are primarily those in which my research group has made a contribution and include structure and function of the GFP polypeptide, the mechanism of fluorescence emission, excited state protein transfer, the design of ratiometric fluorescent protein biosensors and an overview of the fluorescent proteins derived from coral reef animals. Structure-function relationships in photoswitchable fluorescent proteins and nonfluorescent chromoproteins are also briefly covered.
Topics: Animals; Biosensing Techniques; Fluorescence; Green Fluorescent Proteins; Luminescent Proteins
PubMed: 21714025
DOI: 10.1002/pro.684 -
Methods and Applications in Fluorescence Aug 2021Fluorescence guided surgery (FGS) is an imaging technique that allows the surgeon to visualise different structures and types of tissue during a surgical procedure that... (Review)
Review
Fluorescence guided surgery (FGS) is an imaging technique that allows the surgeon to visualise different structures and types of tissue during a surgical procedure that may not be as visible under white light conditions. Due to the many potential advantages of fluorescence guided surgery compared to more traditional clinical imaging techniques such as its higher contrast and sensitivity, less subjective use, and ease of instrument operation, the research interest in fluorescence guided surgery continues to grow over various key aspects such as fluorescent probe development and surgical system development as well as its potential clinical applications. This review looks to summarise some of the emerging opportunities and developments that have already been made in fluorescence guided surgery in recent years while highlighting its advantages as well as limitations that need to be overcome in order to utilise the full potential of fluorescence within the surgical environment.
Topics: Fluorescence; Fluorescent Dyes
PubMed: 34399409
DOI: 10.1088/2050-6120/ac1dbb -
Methods and Applications in Fluorescence Dec 2020
Topics: Fluorescence
PubMed: 33238256
DOI: 10.1088/2050-6120/abce06 -
Biomolecules Nov 2023BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) derivatives have attracted attention as probes in applications like imaging and sensing due to their unique... (Review)
Review
BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) derivatives have attracted attention as probes in applications like imaging and sensing due to their unique properties like (1) strong absorption and emission in the visible and near-infrared regions of the electromagnetic spectrum, (2) strong fluorescence and (3) supreme photostability. They have also been employed in areas like photodynamic therapy. Over the last decade, BODIPY-based molecules have even emerged as candidates for cancer treatments. Cancer remains a significant health issue world-wide, necessitating a continuing search for novel therapeutic options. BODIPY is a flexible fluorophore with distinct photophysical characteristics and is a fascinating drug development platform. This review provides a comprehensive overview of the most recent breakthroughs in BODIPY-based small molecules for cancer or disease detection and therapy, including their functional potential.
Topics: Boron Compounds; Photochemotherapy; Fluorescence; Fluorescent Dyes
PubMed: 38136594
DOI: 10.3390/biom13121723 -
Acta Biochimica Polonica 2016The phenomenon of fluorescence in immunosensors is described in this paper. Both structure and characteristics of biosensors and immunosensors are presented. Types of... (Review)
Review
The phenomenon of fluorescence in immunosensors is described in this paper. Both structure and characteristics of biosensors and immunosensors are presented. Types of immunosensors and the response of bioreceptor layers to the reaction with analytes as well as measurements of electrochemical, piezoelectric and optical parameters in immunosensors are also presented. In addition, detection techniques used in studies of optical immunosensors based on light-matter interactions (absorbance, reflectance, dispersion, emission) such as: UV/VIS spectroscopy, reflectometric interference spectroscopy (RIfs), surface plasmon resonance (SPR), optical waveguide light-mode spectroscopy (OWLS), fluorescence spectroscopy. The phenomenon of fluorescence in immunosensors and standard configurations of immunoreactions between an antigen and an antibody (direct, competitive, sandwich, displacement) is described. Fluorescence parameters taken into account in analyses and fluorescence detection techniques used in research of immunosensors are presented. Examples of immunosensor applications are given.
Topics: Antibodies; Biosensing Techniques; Fluorescence; Fluorescent Dyes; Immunoassay; Spectrometry, Fluorescence
PubMed: 27192088
DOI: 10.18388/abp.2015_1231 -
Molecules (Basel, Switzerland) Jan 2021In this review, the experimental set-up and functional characteristics of single-wavelength and broad-band femtosecond upconversion spectrophotofluorometers developed in... (Review)
Review
In this review, the experimental set-up and functional characteristics of single-wavelength and broad-band femtosecond upconversion spectrophotofluorometers developed in our laboratory are described. We discuss applications of this technique to biophysical problems, such as ultrafast fluorescence quenching and solvation dynamics of tryptophan, peptides, proteins, reduced nicotinamide adenine dinucleotide (NADH), and nucleic acids. In the tryptophan dynamics field, especially for proteins, two types of solvation dynamics on different time scales have been well explored: ~1 ps for bulk water, and tens of picoseconds for "biological water", a term that combines effects of water and macromolecule dynamics. In addition, some proteins also show quasi-static self-quenching (QSSQ) phenomena. Interestingly, in our more recent work, we also find that similar mixtures of quenching and solvation dynamics occur for the metabolic cofactor NADH. In this review, we add a brief overview of the emerging development of fluorescent RNA aptamers and their potential application to live cell imaging, while noting how ultrafast measurement may speed their optimization.
Topics: Biophysics; Fluorescence; Nucleic Acids; Peptides; Proteins; Spectrometry, Fluorescence; Tryptophan
PubMed: 33401638
DOI: 10.3390/molecules26010211 -
Accounts of Chemical Research Jun 2019Electronic transistors have revolutionized the fields of microelectronics, computers, and mobile devices. Their ability to digitize electronic signals allows high... (Review)
Review
Electronic transistors have revolutionized the fields of microelectronics, computers, and mobile devices. Their ability to digitize electronic signals allows high fidelity data transfer as well as formation of logic gates. Inspired by electronic transistors, transistor-like organic materials have been under intensive investigation to amplify biological signals in a broad range of applications such as biosensing, diagnostic imaging, and therapeutic delivery. This Account highlights the inception and implementation of a "proton transistor" nanoparticle that can digitize acidotic pH signals in biological systems. Similar to electronic transistors, the ultra-pH-sensitive (UPS) nanoparticles derive their binary threshold response from phase separation phenomena. Hydrophobic micellization drives nanophase separation from unimers to aggregated polymeric micelles, which is responsible for the all-or-nothing proton distribution between the micelle and unimer states. Depending on the assembly status, conjugated fluorophores are quenched (micelle state) or freely fluoresce (solution unimer state) allowing robust detection of the phase transition behavior across a narrow pH range. Based on this mechanistic insight, we created a UPS nanoparticle library encompassing a broad physiological pH range from 4.0 to 7.4. For biological applications, we engineered a barcode-like nanosensor capable of digitizing multiple pH signals at a single organelle resolution in live cells. The barcode system allowed easy identification of mutant Kirsten rat sarcoma viral oncogene (KRAS), a common mutation involved in tumorigenesis, which leads to rapid cellular proliferation, as the protein driver for accelerated organelle acidification and lysosome catabolism in a broad set of isogenic as well as heterogeneous cancer cell lines. Adoption of the technology to an ON-OFF/Always-ON design allowed the quantification of proton flux across the membranes of endocytic organelles. For medical applications, we demonstrate the ability to achieve binary detection of solid cancers with clear tumor margin delineation by near-infrared fluorescence imaging. Image-guided resection of head/neck and breast tumors resulted in significantly improved long-term survival over white light or tumor debulking surgeries in tumor-bearing mice, catapulting the clinical evaluation of the UPS nanosensor in cancer patients. This Account serves as the first comprehensive summary of the molecular mechanism and biological applications of the digital pH threshold sensors. Building on the concept of cooperative phase transition behavior, we hope this Account will promote the rational design and development of additional transistor-like chemical sensors to digitize analog biological signals.
Topics: Animals; Fluorescence; Fluorescent Dyes; Fluorometry; HeLa Cells; Humans; Hydrogen-Ion Concentration; Micelles; Nanoparticles; Neoplasms; Organelles; Phase Transition; Polymers
PubMed: 31067025
DOI: 10.1021/acs.accounts.9b00080 -
Journal of the American Chemical Society Aug 2021Mid-infrared photothermal microscopy is a new chemical imaging technology in which a visible beam senses the photothermal effect induced by a pulsed infrared laser. This...
Mid-infrared photothermal microscopy is a new chemical imaging technology in which a visible beam senses the photothermal effect induced by a pulsed infrared laser. This technology provides infrared spectroscopic information at submicrometer spatial resolution and enables infrared spectroscopy and imaging of living cells and organisms. Yet, current mid-infrared photothermal imaging sensitivity suffers from a weak dependence of scattering on the temperature, and the image quality is vulnerable to the speckles caused by scattering. Here, we present a novel version of mid-infrared photothermal microscopy in which thermosensitive fluorescent probes are harnessed to sense the mid-infrared photothermal effect. The fluorescence intensity can be modulated at the level of 1% per Kelvin, which is 100 times larger than the modulation of scattering intensity. In addition, fluorescence emission is free of interference, thus much improving the image quality. Moreover, fluorophores can target specific organelles or biomolecules, thus augmenting the specificity of photothermal imaging. Spectral fidelity is confirmed through fingerprinting a single bacterium. Finally, the photobleaching issue is successfully addressed through the development of a wide-field fluorescence-detected mid-infrared photothermal microscope which allows video rate bond-selective imaging of biological specimens.
Topics: Fluorescence; Fluorescent Dyes; Microscopy, Fluorescence; Spectrophotometry, Infrared
PubMed: 34264654
DOI: 10.1021/jacs.1c03642 -
Nature Methods Dec 2023Despite the need for quantitative measurements of light intensity across many scientific disciplines, existing technologies for measuring light dose at the sample of a...
Despite the need for quantitative measurements of light intensity across many scientific disciplines, existing technologies for measuring light dose at the sample of a fluorescence microscope cannot simultaneously retrieve light intensity along with spatial distribution over a wide range of wavelengths and intensities. To address this limitation, we developed two rapid and straightforward protocols that use organic dyes and fluorescent proteins as actinometers. The first protocol relies on molecular systems whose fluorescence intensity decays and/or rises in a monoexponential fashion when constant light is applied. The second protocol relies on a broad-absorbing photochemically inert fluorophore to back-calculate the light intensity from one wavelength to another. As a demonstration of their use, the protocols are applied to quantitatively characterize the spatial distribution of light of various fluorescence imaging systems, and to calibrate illumination of commercially available instruments and light sources.
Topics: Fluorescence; Microscopy, Fluorescence; Fluorescent Dyes; Spectrometry, Fluorescence
PubMed: 37996751
DOI: 10.1038/s41592-023-02063-y -
International Journal of Molecular... Oct 2021Fluorescent labeling is an established method for visualizing cellular structures and dynamics. The fundamental diffraction limit in image resolution was recently... (Review)
Review
Fluorescent labeling is an established method for visualizing cellular structures and dynamics. The fundamental diffraction limit in image resolution was recently bypassed with the development of super-resolution microscopy. Notably, both localization microscopy and stimulated emission depletion (STED) microscopy impose tight restrictions on the physico-chemical properties of labels. One of them-the requirement for high photostability-can be satisfied by transiently interacting labels: a constant supply of transient labels from a medium replenishes the loss in the signal caused by photobleaching. Moreover, exchangeable tags are less likely to hinder the intrinsic dynamics and cellular functions of labeled molecules. Low-affinity labels may be used both for fixed and living cells in a range of nanoscopy modalities. Nevertheless, the design of optimal labeling and imaging protocols with these novel tags remains tricky. In this review, we highlight the pros and cons of a wide variety of transiently interacting labels. We further discuss the state of the art and future perspectives of low-affinity labeling methods.
Topics: Fluorescence; Fluorescent Dyes; Microscopy, Fluorescence; Photobleaching
PubMed: 34769228
DOI: 10.3390/ijms222111799