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Fluorescent Technology in the Assessment of Metabolic Disorders in Diabetes
Published in Andrey V. Dunaev, Valery V. Tuchin, Biomedical Photonics for Diabetes Research, 2023
Elena V. Zharkikh, Viktor V. Dremin, Andrey V. Dunaev
Noninvasive optical methods are increasingly used in biomedical diagnostics. Fluorescence spectroscopy, in particular, has found its application in chemistry, biology, and various fields of medicine. This method is highly sensitive and allows us to study various pathological changes of biological tissues in the development of socially significant diseases. Fluorescence spectroscopy and imaging techniques are probably the most common biomedical photonics methods used in skin research. By analyzing fluorescence data, one can extract information about the structure and component composition of the biological tissue and its functional state. Fluorescence provides insight into both the conformation of fluorescent molecules and their binding as well as their interactions within biological tissues.
Smart structures and materials
Published in Jun Ohta, Smart CMOS Image Sensors and Applications, 2020
The other method for contact mode imaging is to use an image wherein a specimen is directly placed on a sensor surface [362, 363]. This type is mainly used for fluorescent imaging, because fluorescence emits in every direction with a wavelength different from the wavelength of the excitation light, so that no interference is produced and thus, the holographic methods are difficult to apply. In this case, the degradation of resolution is more critical, because more space between the specimen and the sensor surface is produced by inserting an emission filter on the sensor surface to eliminate the excitation light. Figure 3.45 shows the contact type for fluorescence imaging [361]. To suppress the excitation light intensity compared to the fluorescence light intensity, several methods have been reported such as using a prism [364], nano-plasmonic filter [365], interference filter [363], light pipe structure [366], combination of absorption and interference filters [362, 367], etc. It is not difficult to suppress the excitation light if the Stokes shift is large. The Stokes shift means the difference between the peak wavelength of excitation light and the fluorescence light. For example, the difference of the peak wavelength between the excitation and fluorescence light in Hoechst®3342 is about 120 nm, while in GFP, it is about 30 nm. Thus, in this case, detecting the GFP is more difficult than in Hoechst®3342.
Review of Nanoscale Spectroscopy in Medicine
Published in Sarhan M. Musa, Nanoscale Spectroscopy with Applications, 2018
Chintha C. Handapangoda, Saeid Nahavandi, Malin Premaratne
Fluorescence spectroscopy is a powerful, highly sensitive analytical technique that has a number of promising applications and that is widely used in biology and medicine (Engels and Wilson 1992, Patterson and Pogue 1994, Schneckenburger 2005). Fluorescence is used extensively in biotechnology, flow cytometry, medical diagnostics, DNA sequencing, forensics, and genetic analysis (Lakowicz 2010). Fluorescence imaging can be used for measurements of intracellular molecules, even at the level of single-molecule detection (Lakowicz 2010). Fluorescence spectroscopy has been applied to the analysis of many different types of samples, ranging from individual biochemical species to live organs (Vo-Dinh and Cullum 2003).
Greener approach for gold nanoparticles synthesis from fruit peel extract of Manilkara zapota: a fluorometric assay for determination of thiourea
Published in Inorganic and Nano-Metal Chemistry, 2022
Varsha Chandrakar, Kavita Tapadia, Saurabh Kumar Gupta
Fluorescence is an advanced and ultrasensitive optical technique to determine the smaller concentration of the analyte and provide more information about it. Fluorescence resonance energy transfer (FRET) is a non-radiative distance-dependent procedure, taking place between fluorophore as a donor and quencher molecules as an acceptor.[25–27] In this process, the donor absorbs the energy from the excitation wavelength of light and transfers this energy to an acceptor leading to a decreased fluorescence emission intensity of the donor.[28,29] This energy transfer process usually depends on the extent of spectral overlap between the donor and acceptor molecules.[30] The fluorescence method can offer obvious sensitivity higher than that of the other conventional spectral methods. Because of its high sensitivity, simplicity of the instrument and short analysis time, this method is beneficial to use for the determination of TU with continuous and rapid monitoring. Most importantly, this method is cost favorable, portable and suitable for accurate detection.
Anthracene possessing amide functionality as a turn-on fluorescent probe for Cu2+ and Zn2+ ions
Published in Journal of Coordination Chemistry, 2021
Stock solutions of A1 (10−2 M) and metal ions (10−1 M) were prepared in DMSO and de-ionized water, respectively. All metals were added as their perchlorate salts for the UV-vis. and fluorescence experiments. The solutions were allowed to stand undisturbed for two hours before carrying out optical studies. In fluorescence, the excitation wavelength (λex) was 370 nm along with 5.0 nm of excitation and emission slit widths. The association constants were calculated using the Benesi-Hildebrand equation and LOD values were calculated using formula 3σ/s, where σ is standard deviation and s is slope of titration curve between absorption/fluorescence intensity and concentration of ion [23, 24].
Laser induced fluorescence detection of R6G dye adsorbed on Fe3O4 nanomaterials
Published in Journal of Applied Water Engineering and Research, 2022
Yasmin El-Dakrory, Mahmoud Sliem, Maha Abdelkreem, Salah Hassab Elnaby, Reham Rezk
Laser-induced fluorescence (LIF) spectroscopy is a sensitive and powerful technique for detecting molecules and atoms, measuring species concentrations, and energy-level population distributions. LIF provides fluorescent dye emission at longer wavelengths than the excitation wavelength. Fluorescence occurs when a molecule absorbs photons from the UV-visible light spectrum (200-900 nm), causing a transition to a high energy electronic state and then emitting photons as it returns to its initial state in 10–9 sec approximately. The molecule energy is lost through heat or vibration; so that emitted energy is less than the exciting energy; i.e. the emission wavelength is always longer than the excitation wavelength (Crimaldi, 2008).