Application In Cell Imaging Research Articles

A novel probe for tetracyclines detection and its applications in cell imaging based on fluorescent WS2 quantum dots

In this study, a novel fluorescence sensor for tetracyclines (TCs) detection was designed using WS2 quantum dots (WS2 QDs). WS2 QDs could be quenched by TCs through the inner filter effect (IFE). The limit of detection of this proprosed method is 39 nM, 52 nM, and 28 nM for tetracycline (TC), doxycycline (DC), and oxytetracycline (OTC), respectively. The as-proposed strategy was successfully applied to detect TC in milk samples and human serum samples. The WS2 QDs were highly biocompatible and showed lower toxicity. Moreover, the WS2 QDs was successfully applied to imaging TC in HeLa cells owing to its excellent optical performance and great biocompatibility.

Carbon dots and gold nanocluster–based hybrid microgels and their application in cells imaging

Carbon dots and gold nanocluster–based hybrid microgels and their application in cells imaging

Fluorescent Nitrogen-Doped Carbon Dots for Label Live Elder Blood-Stage Plasmodium falciparum through New Permeability Pathways.

To verify the size and emergence time of new permeability pathways (NPPs) in malaria parasites, the permeability of the Plasmodium falciparum-infected erythrocytes was tested with different particle sizes of nanomaterials by flow cytometry assay. The results confirmed the permeability of the host cell membrane increases with parasite maturation for the stage-development evolution of NPPs, and especially found that a particle size of about 50 nm had higher efficiency. As a kind of the novel nanomaterials, nitrogen-doped carbon dots (NCDs) showed no toxicity, specificity binding ability to the malaria parasites, and could label live elder blood-stage P. falciparum through NPPs, indicating the potential application in cell imaging. NPPs and some nanomaterials such as NCDs deserve more attention and exploration for the elimination and prevention of malaria.

Highly selective zinc(II) triggered “Turn-ON” [5]helicene-based fluorescence sensor: Its application in liver and brain cells imaging

A novel fluorescence sensor (MT) was successfully designed and synthesized based on a [5]helicene derivative bearing tris(2-pyridylmethyl)amine as a selective zinc ion (Zn2+) recognition. MT allowed a favorable Zn2+-triggered “turn-on” hypsochromic fluorescence response through the intramolecular charge transfer process. The limit of detection of MT was 29 nM (1.91 ppb), which was considerably below the limit recommended by the World Health Organisation for the amount of Zn2+ in drinking water (76 μM). MT showed an excellent selectivity toward Zn2+ in HEPES buffer: MeOH (5 mM, pH 7.2, 3:2) over other competitive metal ions through a fluorogenic color change from orange to blue, which was easily observed with the naked-eye. The good fluorogenic sensing of the Zn2+ probe helped to determine a small amount of Zn2+ in practical utilization such as a Zn2+-marking agent for intracellular applications in human hepatoma (HepG2) and glioblastoma astrocytoma (U251) cells.

Surface-Fabrication of Fluorescent Hydroxyapatite for Cancer Cell Imaging and Bio-Printing Applications.

Hydroxyapatite (HAP) materials are widely applied as biomedical materials due to their stable performance, low cost, good biocompatibility and biodegradability. Here, a green, fast and efficient strategy was designed to construct a fluorescent nanosystem for cell imaging and drug delivery based on polyethyleneimine (PEI) and functionalized HAP via simple physical adsorption. First, HAP nanorods were functionalized with riboflavin sodium phosphate (HE) to provide them with fluorescence properties based on ligand-exchange process. Next, PEI was attached on the surface of HE-functionalized HAP (HAP-HE@PEI) via electrostatic attraction. The fluorescent HAP-HE@PEI nanosystem could be rapidly taken up by NIH-3T3 fibroblast cells and successfully applied to for cell imaging. Additionally, doxorubicin hydrochloride (DOX) containing HAP-HE@PEI with high loading capacity was prepared, and in-vitro release results show that the maximum release of DOX at pH 5.4 (31.83%) was significantly higher than that at pH 7.2 (9.90%), which can be used as a drug delivery tool for cancer therapy. Finally, HAP-HE@PEI as the 3D inkjet printing ink were printed with GelMA hydrogel, showing a great biocompatible property for 3D cell culture of RAW 264.7 macrophage cells. Altogether, because of the enhanced affinity with the cell membrane of HAP-HE@PEI, this green, fast and efficient strategy may provide a prospective candidate for bio-imaging, drug delivery and bio-printing.

Implications of liver metastasis for cancer immunotherapy

<h4>Watch the video or read the poster to learn:</h4> <ul><li>Why advanced cell models and advanced high throughput flow cytometry offer great promise for translational biology &amp; therapeutics</li><li>How the iQue® platform, kits and fully validated spheroid dissociation protocol provide a simple streamlined workflow for quantifying T cell responses in 3D spheroids</li><li>How multiparametric analysis using iQue® T cell characterization kits enable assessment of T cell phenotype and function over time</li></ul><div class="authors authors-lg"><div class="author"><div class="author-img"><img src="https://cdn.insights.bio/uploads/Minnie Oliver 2 copy.jpg" data-image="1"></div><div class="author-det"> <b>Miniver Oliver</b> is a Senior Scientist at Sartorius, working in the cell imaging and analysis application group within the European-based Bio Analytics research team. Over the past 5 years, she has specialized in the development of novel kinetic advanced cellular oncology models for the Incucyte® Live Cell Analysis System and provided expertise to support the development of 3D assays for the iQue® Advanced Flow Cytometry Platform. Miniver previously worked across several divisions at GlaxoSmithKline, supporting assay development and compound screening. </div></div></div>

A Rapid Near-Infrared Fluorescent Probe for Cysteine Based on Isophorone and its Application in B16 Cell Imaging.

A novel near-infrared fluorescent probe SWJT-5 based on dicyanoisophorone was synthesized. It achieved the rapid (within 40s) and discriminative detection of Cys over Hcy and GSH with a large Stokes shift (205nm). It showed high selectivity and sensitivity for Cys, and had an obvious enhancement of fluorescence emission. The detection limit was 0.43μM. This probe also had low background interference and little damage to biological samples. Therefore, SWJT-5 had been applied to bioimaging in living cells successfully.

A Naphthalimides‐Based Probe for Sequential Detection of Cu2+ and PPi and Its Application in Cells Imaging

AbstractA novel naphthalimides‐based fluorescent probe (NPHD) selectively detected Cu2+ and PPi through “strong yellow‐weak green‐strong yellow” photonic response in a sequential manner. The formation of NPHD‐Cu2+ resulted in obvious fluorescence decreased and wavelength shift from 595 nm to 525 nm by adding Cu2+ to NPHD solution. The mechanism could be attributed to d→π* electron transfer (ET) from Cu2+ to NPHD. Furthermore, the NPHD‐Cu2+ complex exhibited high selectivity toward PPi through via emission recovery of chemosensor NPHD. The detection limits of NPHD to Cu2+ and NPHD‐Cu2+ to PPi were estimated to be 5.72×10&lt;M‐&gt;8M and 2.39×10&lt;M‐&gt;8M. In addition, NPHD could be employed to detect exogenous Cu2+ and PPi in Hep G2 cells.

Tetraphenylethylene-Incorporated Macrocycles and Nanocages: Construction and Applications

Dyes exhibiting aggregation-induced emission (AIE) properties can efficiently circumvent the aggregation-caused quenching phenomenon presented in conventional fluorophores in their solid state. As one of the AIE dyes, tetraphenylethylene (TPE) has attracted tremendous attention because of its concise synthesis, stability, at least four reaction sites, and so on, making it a splendid building block for macrocycles and nanocages. In TPE-incorporated macrocycles and nanocages, the AIE effect can be not only preserved but also enhanced as a result of the geometrical constraint of the otherwise rotatable phenylene rings in the TPE units, which endows them with various applications involving the encapsulation and detection of explosives and dyes. This review surveys the recent developments of TPE-incorporated macrocycles and nanocages all the way from the perspective of synthetic strategies involving dynamic covalent chemistry, covalent bonding, and metal coordination to their potential applications in explosives detection, chemical sensing, cell imaging, and catalysis. Finally, we summarize the state-of-the-art status and challenges in this area, which we hope will guide future investigations.

Structural Design of Multidentate Copolymers as Compact Quantum Dot Coatings for Live-Cell Single-Particle Imaging.

Quantum dots (QDs) are a class of semiconductor nanocrystal used broadly as fluorescent emitters for analytical studies in the life sciences. These nanomaterials are particularly valuable for single-particle imaging and tracking applications in cells and tissues. An ongoing technological goal is to reduce the hydrodynamic size of QDs to enhance access to sterically hindered biological targets. Multidentate polymer coatings are a focus of these efforts and have resulted in compact and stable QDs with hydrodynamic diameters near 10 nm. New developments are needed to reach smaller sizes to further enhance transport through pores in cells and tissues. Here, we describe how structural characteristics of linear multidentate copolymers determine hydrodynamic size, colloidal stability, and biomolecular interactions of coated QDs. We tune copolymer composition, degree of polymerization, and hydrophilic group length, and coat polymers on CdSe and (core)shell (HgCdSe)CdZnS QDs. We find that a broad range of polymer structures and compositions yield stable colloidal dispersions; however, hydrodynamic size minimization and nonspecific binding resistance can only be simultaneously achieved within a narrow range of properties, requiring short polymers, balanced compositions, and small nanocrystals. In quantitative single-molecule imaging assays in synapses of live neurons, size reduction progressively increases labeling specificity of neurotransmitter receptors. Our findings provide a design roadmap to next-generation QDs with sizes approaching fluorescent protein labels that are the standard of many live-cell biomolecular studies.

Recent Progress of Squaraine-Based Fluorescent Materials and Their Biomedical Applications

Squaraines (SQs) are unusual cyanine dyes with a unique resonance-stabilized zwitterionic structure. These dyes have attracted significant attention in the fields of organic electronics and organic photonics, due to their facile synthesis, intense and narrow visible and near-infrared absorption/emission, high photostability, low biotoxicity, etc. In this review, we summarize the recent progress of SQ-based fluorescent materials and their biomedical applications. After a brief introduction to SQs, general synthetic routes and design principles of SQ-based fluorescent materials, as well as their aggregation-induced luminescence behaviors, are discussed. Subsequently, their biomedical applications for cell imaging and as fluorescent sensors and therapeutic agents are introduced. Finally, a summary and perspective are given for promoting the development of SQs-based fluorescent materials.

Chitosan@4,6-Dihydroxyisophthalaldehyde Microgels with Hydrazine-Induced Fluorescence for Cell Imaging Applications

Chitosan@4,6-Dihydroxyisophthalaldehyde Microgels with Hydrazine-Induced Fluorescence for Cell Imaging Applications

Perspective on fluorescence cell imaging with ionophore-based ion-selective nano-optodes.

Inorganic ions are ubiquitous in all kinds of cells with highly dynamic spatial and temporal distribution. Taking advantage of different types of fluorescent probes, fluorescence microscopic imaging and quantitative analysis of ion concentrations in cells have rapidly advanced. A family of fluorescent nanoprobes based on ionophores has emerged in recent years with the potential to establish a unique platform for the analysis of common biological ions including Na+, K+, Ca2+, Cl-, and so on. This article aims at providing a retrospect and outlook of ionophore-based ion-selective nanoprobes and the applications in cell imaging.

Real-Time Phase Imaging with an Asymmetric Transfer Function Metasurface

The conversion of phase variations in an optical wavefield into intensity information is of fundamental importance for optical imaging technology including microscopy of biological cells. While conventional approaches to phase-imaging commonly rely on bulky optical components or computational post processing, meta-optical devices have recently demonstrated all-optical, ultracompact image processing methods. Here we describe a metasurface that exploits photonic spin-orbit coupling to create an asymmetric optical transfer function for real time phase-imaging. The effect of the asymmetry on transmission through the device is demonstrated experimentally with the generation of high contrast pseudo-3D intensity images of phase variations in an optical wavefield without the need for post-processing. This non-interferometric method has potential applications in biological live cell imaging and real-time wavefront sensing.

Synthesis and Photoluminescence Characterization of 3- MPA Capped CdZnTe Quantum Dots

3-MPA capped CdZnTe alloy quantum dots synthesized using Na2TeO3 as the tellurium source under open atmosphere conditions in aqueous medium. The optical and photoluminescence properties of the CdZnTe quantum dots characterized using UV-Visible absorption and Photoluminescence spectrum. An excitonic peak at 527 nm observed in the absorption spectrum. Tauc relation and Urbach relation were employed to find the bandgap energy and urbach energy of the CdZnTe quantum dot. The quantum dot particle size was estimated using the bandgap energy from Tauc plot employing tight binding approximation, which was 4.75 nm. A high intense emission peak at 567 nm obtained in the photoluminescence spectrum. The emission peaks correspond to yellow fluorescence. The CIE chromaticity diagram gives color coordinate at (0.41,0.56) with a color purity of 92%. The high intense yellow fluorescent CdZnTe quantum can placed as potential candidates for fluorescent probes, biolabeling and cell imaging applications.

Dark-Field Microscopic Study of Cellular Uptake of Carbon Nanodots: Nuclear Penetrability.

Carbon nanodots are fascinating candidates for the field of biomedicine, in applications such as bioimaging and drug delivery. However, the nuclear penetrability and process are rarely studied and lack understanding, which limits their applications for drug carriers, single-molecule detection and live cell imaging. In this study, we attempt to examine the uptake of CNDs in cells with a focus on the potential nuclear penetrability using enhanced dark-field microscopy (EDFM) associated with hyperspectral imaging (HSI) to quantitatively determine the light scattering signals of CNDs in the cells. The effects of both CND incubation time and concentration are investigated, and plausible nuclear penetration involving the nuclear pore complex (NPC) is discussed. The experimental results and an analytical model demonstrate that the CNDs’ uptake proceeds by a concentration-dependent three-stage behavior and saturates at a CND incubation concentration larger than 750 µg/mL, with a half-saturated concentration of 479 μg/mL. These findings would potentially help the development of CNDs’ utilization in drug carriers, live cell imaging and other biomedical applications.

Stable red nanoparticles loaded neutral luminescent radicals for fluorescence imaging

Although neutral luminescent radicals have arisen much attention recently, their applications in fluorescence imaging are rarely reported due to their insolubility in water and weak luminescence in polar solvents. Herein, we encapsulated a luminescent radical and its precursor into nanoparticles (NPs) by an amphiphilic polymer matrix, DSPE-PEG2000, to avoid aggregation-caused quenching and poor solubility in water to further achieve its application in cell-imaging. The obtained radical NPs exhibited strong red emission, excellent stability and remarkable biocompatibility under physiological conditions. The radical NPs were incubated with live HCT116 cells and showed good cellular uptake, thus making fluorescence imaging possible in vitro. The results confirm the feasibility of stable neutral luminescent radical as a promising candidate for the application in fluorescence imaging.

Novel ratiometric fluorescent probe based on internal reference and its detection of hydrazine.

In this work, dual-emissive ratiometric fluorescent system was constructed by the introduction of an ideal internal reference. By virtue of its unique alkalinity, N2H4 could undergo a hydrazinolysis reaction with the ester group of F1, inducing remarkable fluorescence enhancement while the blue fluorescence of the internal reference DPA remained constant. Consequently, the fluorescence intensity ratios (I540/I440) were proportional to the concentrations of N2H4, which was beneficial for the exactly quantitative detection. The skillful strategy granted the sensing system advantages such as relative good solubility in aqueous media, easy-to-design, simple synthesis, large emission shift, good ratiometric response, as well as the successful application in real water samples and cell imaging.

An Efficient Inclusion Complex Based Fluorescent Sensor for Mercury (II) and its Application in Live-Cell Imaging.

The formation of an inclusion complex between hydroxypropyl-β-cyclodextrin (H-CD) and 4-acetylphenyl-4-(((6-chlorobenzo[d]thiazol-2-yl)-imino)-methyl)-benzoate (L) was investigated by FT-IR, 1H-NMR, X-ray diffraction (XRD), FT-Raman, scanning electron microscope (SEM) techniques in the solid-state, absorption and emission spectroscopy in the liquid state and the virtual state as molecular docking technique. The binding properties of the inclusion complex (H-CD: L) with cations in deionized water was observed via absorbance and photoluminescence (PL) emission spectroscopy. The fluorescence probe (H-CD: L) inclusion complex (IC) was examined for several heavy metal cations, and identified that the PL emission wavelength of the complex displayed a continuous rise in the fluorescence intensity for Hg2+. A linearity range of 1 × 10-8 - 11 × 10-8M and limit of detection value of 2.71 × 10-10M was found to be achieved for the detection of Hg2+. This outcome proves that the inclusion complex H-CD: L would be a promising material for the development a solid-state fluorescence probe for detecting Hg2+. It also shows application in real sample analysis and cell imaging.

Tuning the photoluminescence by engineering surface states/size of S, N co-doped carbon dots for cellular imaging applications

In this research, we have synthesized carbon dots (CDs) co-doped with nitrogen and sulfur by facile hydrothermal method, using citric acid and cysteine as carbon source. The effect of solid-state thermic treatment (STT) at 303–453 K on the size, surface, fluorescence and cellular cytotoxicity of the CDs were systematically investigated. Through a simple STT, it was possible to tune surface states and the average size of the CDs, causing a permanent red shift. Initially, CDs showed a decrease in cell viability with increasing concentration. However, after STT, its viability remained constant with an increase in concentration. Here, we show the possibility to label the cells cytoplasm according to the CDs fluorescence emission before (blue emission) and after STT (red emission). The CDs studied in this paper show selective luminescence properties, which are fundamental for any cell imaging application.