Read by QxMD icon Read

fluorescence lifetime imaging microscopy

Kasipandi Vellaisamy, Guodong Li, Chung-Nga Ko, Hai-Jing Zhong, Sarwat Fatima, Hiu-Yee Kwan, Chun-Yuen Wong, Wai-Jing Kwong, Weihong Tan, Chung-Hang Leung, Dik-Lung Ma
Dopamine receptor expression is correlated with certain types of cancers, including lung, breast and colon cancers. In this study, we report luminescent iridium(iii) complexes ( 11-14 ) as intracellular dopamine receptor (D1R/D2R) cell imaging agents. Complexes 11 and 13 , which are conjugated with a dopamine receptor agonist, showed superior cell imaging characteristics, high stability and low cytotoxicity (>100 μM) in A549 lung cancer cells. siRNA knockdown and dopamine competitive assays indicated that complexes 11 and 13 could selectively bind to dopamine receptors (D1R/D2R) in A549 cells...
February 7, 2018: Chemical Science
Lorenzo Angiolini, Sabrina Valetti, Boiko Cohen, Adam Feiler, Abderrazzak Douhal
We report on the encapsulation of the antibiotic clofazimine (CLZ) within the pores of mesoporous silica particles having hydrophilic (CBET value of 137) and more hydrophobic (CBET value of 94 after calcination at 600 °C) surfaces. We studied the effect of pH on the released amount of CLZ in aqueous solutions and observed a maximum at pH 4.1 in correlation with the solubility of the drug. Less release of the drug was observed from the more hydrophobic particles which was attributed to a difference in the affinity of the drug to the carrier particles...
April 18, 2018: Physical Chemistry Chemical Physics: PCCP
Wang Li, Chunyang Geng, Bo Liu
Synaptic vesicle (SV) will be transported to the bouton along the axon, once it is formed in a cell body. After docking in the active zone, neurotransmitters will be released upon the stimulation, and then transmission of chemical signals will be initiated. Presently, many advanced technologies and burgeoning molecular sensors are being used to explore the synaptic transmission. These studies provide a new sight into the presynaptic structure and its function. The present review summarizes the application of fluorescent proteins (FPs) for SV tracking and recycling...
2018: Folia Neuropathologica
Kieran F Fox, Caner Ünlü, Vytautas Balevičius, Baboo Narottamsing Ramdour, Carina Kern, Xiaowei Pan, Mei Li, Herbert van Amerongen, Christopher D P Duffy
The bioenergetics of light-harvesting by photosynthetic antenna proteins in higher plants is well understood. However, investigation into the regulatory non-photochemical quenching (NPQ) mechanism, which dissipates excess energy in high light, has led to several conflicting models. It is generally accepted that the major photosystem II antenna protein, LHCII, is the site of NPQ, although the minor antenna complexes (CP24/26/29) are also proposed as alternative/additional NPQ sites. LHCII crystals were shown to exhibit the short excitation lifetime and several spectral signatures of the quenched state...
April 3, 2018: Biochimica et Biophysica Acta
Aleksandra V Meleshina, Olga S Rogovaya, Varvara V Dudenkova, Marina A Sirotkina, Maria M Lukina, Alena S Bystrova, Victoria G Krut, Daria S Kuznetsova, Ekaterina P Kalabusheva, Andrey V Vasiliev, Ekaterina A Vorotelyak, Elena V Zagaynova
BACKGROUND: Despite the significant progress in the development of skin equivalents (SEs), the problem of noninvasively assessing the quality of the cell components and the collagen structure of living SEs both before and after transplantation remains. Undoubted preference is given to in vivo methods of noninvasive, label-free monitoring of the state of the SEs. Optical bioimaging methods, such as cross-polarization optical coherence tomography (CP OCT), multiphoton tomography (MPT), and fluorescence lifetime imaging microscopy (FLIM), present particular advantages for the visualization of such SEs...
April 3, 2018: Stem Cell Research & Therapy
Lingling Li, Kun Li, Meng-Yang Li, Lei Shi, Yan-Hong Liu, Hong Zhang, Sheng-Lin Pan, Nan Wang, Qian Zhou, Xiaoqi Yu
The viscosity of lysosome is reported to be a key indicator of lysosomal functionality. However, the existing mechanical methods of viscosity measurement can hardly be applied at the cellular or sub-cellular level. Herein, a BODIPY-based two-photon fluorescent probe was presented for monitoring lysosomal viscosity with high spatial and temporal resolution. By installing two morpholine moieties to the fluorophore as target and rotational groups, the TICT effect between the two morpholine rings and the main fluorophore scaffold endowed the probe with excellent viscosity sensitivity...
March 30, 2018: Analytical Chemistry
C Li, S Liu, W Wang, W Liu, C Kuang, X Liu
Stimulated emission depletion (STED) microscopy is a useful tool in investigation for super-resolution realm. By silencing the peripheral fluorophores of the excited spot, leaving only the very centre zone vigorous for fluorescence, the effective point spread function (PSF) could be immensely squeezed and subcellular structures, such as organelles, become discernable. Nevertheless, because of the low cross-section of stimulated emission and the short fluorescence lifetime, the depletion power density has to be extremely higher than the excitation power density and molecules are exposed in high risk of photobleaching...
March 30, 2018: Journal of Microscopy
Susana F Silva, José Paulo Domingues, António Miguel Morgado
Time-gated fluorescence lifetime imaging microscopy (FLIM) is a powerful technique to assess the biochemistry of cells and tissues. When applied to living thick samples, it is hampered by the lack of optical sectioning and the need of acquiring many images for an accurate measurement of fluorescence lifetimes. Here, we report on the use of processing techniques to overcome these limitations, minimizing the acquisition time, while providing optical sectioning. We evaluated the application of the HiLo and the rapid lifetime determination (RLD) techniques for accurate measurement of fluorescence lifetimes with optical sectioning...
2018: Journal of Healthcare Engineering
Ruth Leben, Lennard Ostendorf, Sofie van Koppen, Asylkhan Rakhymzhan, Anja E Hauser, Helena Radbruch, Raluca A Niesner
Time-correlated single-photon counting combined with multi-photon laser scanning microscopy has proven to be a versatile tool to perform fluorescence lifetime imaging in biological samples and, thus, shed light on cellular functions, both in vitro and in vivo. Here, by means of phasor-analyzed endogenous NAD(P)H (nicotinamide adenine dinucleotide (phosphate)) fluorescence lifetime imaging, we visualize the shift in the cellular metabolism of healthy human neutrophil granulocytes during phagocytosis of Staphylococcus aureus pHrodo™ beads...
March 29, 2018: International Journal of Molecular Sciences
Renee V Goreham, Kathryn L Schroeder, Amy Holmes, Siobhan J Bradley, Thomas Nann
The authors describe the synthesis of water-soluble and fluorescent graphene oxide quantum dots via acid exfoliation of graphite nanoparticles. The resultant graphene oxide quantum dots (GoQDs) were then modified with folic acid. Folic acid receptors are overexpressed in cancer cells and hence can bind to functionalized graphene oxide quantum dots. On excitation at 305 nm, the GoQDs display green fluorescence with a peak wavelength at ~520 nm. The modified GoQDs are non-toxic to macrophage cells even after prolonged exposure and high concentrations...
January 24, 2018: Mikrochimica Acta
Tuğba Köker, Anthony Fernandez, Fabien Pinaud
Many biotechniques use complementary split-fluorescent protein (sFPs) fragments to visualize protein-protein interactions, image cells by ensemble or single molecule fluorescence microscopy, or assemble nanomaterials and protein superstructures. Yet, the reassembly mechanisms of sFPs, including fragment binding rates, folding, chromophore maturation and overall photophysics remain poorly characterized. Here, we evolved asymmetric and self-complementing green, yellow and cyan sFPs together with their full-length equivalents (flFPs) and described their biochemical and photophysical properties in vitro and in cells...
March 28, 2018: Scientific Reports
Hanquan Su, Zheng Liu, Yang Liu, Victor Pui-Yan Ma, Aaron Blanchard, Jing Zhao, Kornelia Galior, R Brian Dyer, Khalid Salaita
Single-molecule force spectroscopy techniques are powerful tools for investigating the mechanical unfolding of biomolecules. However, they are limited in throughput and require dedicated instrumentation. Here, we report a force-generating particle that can unfold target molecules on-demand. The particle consists of a plasmonic nanorod core encapsulated with a thermoresponsive polymer shell. Optical heating of the nanorod leads to rapid collapse of the polymer, thus transducing light into mechanical work to unfold target molecules...
March 28, 2018: Nano Letters
Kaisa Rautaniemi, Elina Vuorimaa-Laukkanen, Clare J Strachan, Timo Laaksonen
Pharmaceutical scientists are increasingly interested in amorphous drug formulations especially due to their higher dissolution rates. Consequently, thorough characterization and analysis of these formulations are becoming more and more important for the pharmaceutical industry. Here, fluorescence lifetime imaging microscopy (FLIM) was used to monitor the crystallization of an amorphous pharmaceutical compound indomethacin. Initially, we identified different solid indomethacin forms, amorphous, γ- and α-crystalline, based on their time-resolved fluorescence...
March 27, 2018: Molecular Pharmaceutics
Wollis Jude Vas, Mittal Shah, Thomas Stephen Blacker, Michael Roland Duchen, Paul Sibbons, Scott John Roberts
Complications that arise from impaired fracture healing have considerable socioeconomic implications. Current research in the field of bone tissue engineering predominantly aims to mimic the mature bone tissue microenvironment. This approach, however, may produce implants that are intrinsically unresponsive to the cues present during the initiation of fracture repair. As such, this study describes the development of decellularised xenogeneic hyaline cartilage matrix in an attempt to mimic the initial reparative phase of fracture repair...
March 27, 2018: Tissue Engineering. Part A
Pavel Banerjee, Arghajit Pyne, Siddhartha Pal, Chandan Kumar Karan, Nilmoni Sarkar
Studying the self-assembly of uracil derivatives has great importance in biochemistry and nanotechnology. Now, in order to architect unique and interesting nucleobase nanostructures, herein, we report a simple, yet robust uracil moiety based platform which is potentially capable to self-assemble into fibrils. The system is validated using eight uracil moiety derivatives and the effect is examined via fluorescence lifetime imaging microscopy (FLIM), field emission scanning electron microscopy (FESEM), steady state DCM fluorescence and fluorescence correlation spectroscopy (FCS)...
March 17, 2018: Journal of Colloid and Interface Science
Susanne Kossatz, Brandon Carney, Christoper Farley, Charles M Drain, Wolfgang A Weber, Thomas Reiner
PARP inhibitors have emerged as potent anti-tumor drugs. Here, we describe the intrinsic fluorescence properties of the FDA approved PARP inhibitor rucaparib and its potential to directly measure drug distribution and target engagement - a critical factor for understanding drug action and improving efficacy. Methods: We characterized the photophysical properties of rucaparib and determined its quantum yield and lifetime. Using confocal microscopy and flow cytometry, we imaged the intracellular distribution of rucaparib and measured uptake and release kinetics...
March 23, 2018: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
Kok Leong Chong, Benjamin A Chalmers, Jason K Cullen, Amandeep Kaur, Jacek L Kolanowski, Benjamin J Morrow, Kathryn E Fairfull-Smith, Martin J Lavin, Nigel L Barnett, Elizabeth J New, Michael P Murphy, Steven E Bottle
Here we describe new fluorescent probes based on fluorescein and rhodamine that provide reversible, real-time insight into cellular redox status. The new probes incorporate bio-imaging relevant fluorophores derived from fluorescein and rhodamine linked with stable nitroxide radicals such that they cannot be cleaved, either spontaneously or enzymatically by cellular processes. Overall fluorescence emission is determined by reversible reduction and oxidation, hence the steady state emission intensity reflects the balance between redox potentials of critical redox couples within the cell...
March 19, 2018: Free Radical Biology & Medicine
Yoko Miura
Retinal pigment epithelium (RPE), a monolayer of epithelial cells located between the neural retina and the choroid, plays a significant role in the maintenance of retinal function. Its in vivo imaging is still technically challenging in human eye. With the mouse eye, there is a possibility to look into the RPE through the sclera using two-photon microscopy (TPM). TPM is a two photon-excited nonlinear fluorescence microscopy that enables the observation of deep tissues up to several hundred micrometers. Since the simultaneous absorption of two photons occurs only at the focal plane, spatial resolution of the TPM is quite high, such that pinhole as used in a confocal microscope is not necessary...
2018: Methods in Molecular Biology
Sorina Suarasan, Emilia Licarete, Simion Astilean, Ana-Maria Craciun
Nowadays, the non-linear optical effect of two-photon excited (TPE) fluorescence has recently grown in interest in recent years over other optical imaging method, due to improved 3D spatial resolution, deep penetrability and less photodamage of living organism owing to the excitation in near-infrared region (NIR). In parallel, gold nanoparticles (AuNPs) have gain considerable attention for NIR TPE bio-imaging applications due to their appealing ability to generate strong intrinsic photoluminescence (PL). Here, we demonstrate the capability of differently shaped gelatin-coated AuNPs to perform as reliable label-free contrast agents for the non-invasive NIR imaging of NIH:OVCAR-3 ovary cancer cells via TPE Fluorescence Lifetime Imaging Microscopy (FLIM)...
March 14, 2018: Colloids and Surfaces. B, Biointerfaces
Alice Sherrard, Paul Bishop, Melanie Panagi, Maria Beatriz Villagomez, Dominic Alibhai, Abderrahmane Kaidi
Changes in chromatin structure are key determinants of genomic responses. Thus, methods that enable such measurements are instrumental for investigating genome regulation and function. Here, we report further developments and validation of a streamlined method of histone-based fluorescence lifetime imaging microscopy (FLIM) that robustly detects chromatin compaction states in fixed and live cells, in 2D and 3D. We present a quality-controlled and detailed method that is simpler and faster than previous methods, and uses FLIMfit open-source software...
March 13, 2018: Biology Open
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"