Selective Cell Imaging Research Articles

Turn-on fluorescence probe for BSA detection and selective cell imaging

In this paper, a cationic amphiphile (denoted by DPP-10) with diketopyrrolopyrrole decorated with methoxylated tetraphenylethylene via a phenyl bridge was designed, synthesized, and applied as a turn-on fluorescence probe for bovine serum albumin (BSA) detection and selective cell imaging. DPP-10 showed very weak fluorescence emission when dispersed in the solution, while its emission was drastically enhanced upon the addition of BSA, which should be attributed to the electrostatic interaction-driven assembly between DPP-10 and BSA. The limit of detection was as low as 0.08 μmol/L, which is lower than that reported for most probes. The fluorescence probe shows good selectivity for BSA among the tested proteins, high photostability, and immunity to the disturbance of ions. DPP-10 with excellent cytocompatibility was applied to HeLa cell imaging, where only the BSA-rich cells showed a strong signal-to-background contrast.

Diverse 3-Methylthio-4-Substituted Maleimides through a Novel Rearrangement Reaction: Synthesis and Selective Cell Imaging.

A transition metal-free protocol for the preparation of fluorescent and non-fluoresent 3-methylthio-4-arylmaleimides in a single step through a new rearrangement from thiazolidine-2,4-diones is described. By employing the optimized reaction conditions, a broad scope of derivatives was prepared in ≤97% yield. The reaction tolerated several substituted aryl groups, including the challenging preparation of pyridyl-containing derivatives. A series of control experiments strongly suggested that the new rearrangement involves a key isocyanate intermediate and a further reaction with in situ-generated methylthiomethyl acetate. The photophysical properties of some of the synthesized derivatives as well as their use in live cell imaging were also investigated, revealing that some of the substituted maleimides are capable of selectively staining different regions of the cells.

Deciphering the Dynamics of Organic Nanoaggregates with AIEE Effect and Excited States: Lipophilic Benzothiadiazole Derivatives as Selective Cell Imaging Probes.

An aggregation-induced emission enhancement (AIEE) effect in fluorescent lipophilic 2,1,3-benzothiadiazole (BTD) derivatives and their organic nanoaggregates were studied. A set of techniques such as single-crystal X-ray, dynamic light scattering (DLS), electron paramagnetic resonance (EPR), UV-vis, fluorescence, and density functional theory (DFT) calculations have been used to decipher the formation/break (kinetics), properties, and dynamics of the organic nanoaggregates of three BTD small organic molecules. An in-depth study of the excited-state also revealed the preferential relaxation emissive pathways for the BTD derivatives and the dynamics associated with it. The results described herein, for the first time, explain the formation of fluorescent BTD nanoaggregate derivatives and allow for the understanding of their dynamics in solution as well as the ruling forces of both aggregation and break processes along with the involved equilibrium. One of the developed dyes could be used at a nanomolar concentration to selectively stain lipid droplets emitting an intense and bright fluorescence at the red channel. The other two BTDs could also stain lipid droplets at very low concentrations and were visualized preferentially at the blue channel.

Conjugated polymer nanoparticles as fluorescence switch for selective cell imaging

Fluorescence switch plays a vital role in bioelectronics and bioimaging. Herein, we presented a new kind of facile electrostatic complex nanoparticles (ECNs) for fluorescence switching in cells and marking of individual cell. The ECNs were prepared by mixing positively charged poly(6-(2-(thiophen-3-yl)ethoxy)hexyl trimethylammonium bromide) (PT) and negatively charged diarylethene sodium salt (DAE-COONa). DAE-COONa is a photoswitchable molecule which can be transformed between the ring-closed form and ring-open form under the irradiation of UV or visible light. The closed-form of DAE-COONa can efficiently quench the fluorescence of PT through intermolecular energy transfer, while the open form of DAE-COONa does not influence the emission of PT. Thus, the fluorescence of ECNs can be modulated by light irradiation, and the ECNs with good fluorescence switching performance have been employed for fluorescence imaging and individual cell lighting up process successfully. We demonstrate that the electrostatic complex strategy provides a facile method to construct fluorescence switch for selective cell marking and imaging applications.

Rapid cancer diagnosis by highly fluorescent carbon nanodots-based imaging.

Carbon dots (Cdots) with bright green fluorescence were applied to the rapid and selective cell imaging for a variety of cell lines. Different labeling distributions of hepatoma cells (HepG2) and normal human liver cells (LO2) were achieved using Cdots as imaging agents. For HepG2 cells, the Cdots could rapidly permeate the cell membrane and diffuse into the cytoplasm and nucleus within 3min, and retained their location in the targets for 24h. However, the Cdots exhibited bright fluorescence only in the cytoplasm of LO2 cell lines. Moreover, the Cdots were almost non-cytotoxic and exhibited superior photostability over a wide range of pH. Therefore, these Cdots have great potential for rapid, luminous and selective bioimaging applications, and are expected to be used as a nucleus-staining agent in cancer diagnosis. Graphical abstract ᅟ.

Renovation of Glycomolecules for Molecular Imaging Studies: Low-Affinity Glycan Ligands can be Used for Selective Cell Imaging?

Renovation of Glycomolecules for Molecular Imaging Studies: Low-Affinity Glycan Ligands can be Used for Selective Cell Imaging?

Blue and cyan fluorescent carbon dots: one-pot synthesis, selective cell imaging and their antiviral activity

Two types of carbon dots were prepared by using the powder of young barley leaves as the precursor, which have the capability of selective cell imaging and antiviral activity.

Kinetics of Reactive Modules Adds Discriminative Dimensions for Selective Cell Imaging.

Living cells are chemical mixtures of exceptional interest and significance, whose investigation requires the development of powerful analytical tools fulfilling the demanding constraints resulting from their singular features. In particular, multiplexed observation of a large number of molecular targets with high spatiotemporal resolution appears highly desirable. One attractive road to address this analytical challenge relies on engaging the targets in reactions and exploiting the rich kinetic signature of the resulting reactive module, which originates from its topology and its rate constants. This review explores the various facets of this promising strategy. We first emphasize the singularity of the content of a living cell as a chemical mixture and suggest that its multiplexed observation is significant and timely. Then, we show that exploiting the kinetics of analytical processes is relevant to selectively detect a given analyte: upon perturbing the system, the kinetic window associated to response read-out has to be matched with that of the targeted reactive module. Eventually, we introduce the state-of-the-art of cell imaging exploiting protocols based on reaction kinetics and draw some promising perspectives.

Biscarbazolylmethane-based cyanine: a two-photon excited fluorescent probe for DNA and selective cell imaging.

Here, we have introduced a novel biscarbazolylmethane-based cyanine as a two-photon excited fluorescent probe, 6,6'-bis[2-(1-methylpyridinium)vinyl]-bis(9-methyl-carbazol-3-yl)methane diiodide, which has two vinylpyridinium carbazole moieties connected by a non-rigid methylene bridge. This molecule possesses a larger Stokes shift and enhanced two-photon absorption cross-section than the previously reported vinylpyridinium carbazole monocyanine, which is mainly attributed to the "through-space" type intramolecular charge transfer. The low fluorescence quantum yield and 30-fold fluorescence enhancement once binding with calf thymus DNA highlight this molecule as a promising fluorescence light-up probe for DNA. The obvious induced circular dichroism signals have proved that the molecule with soft-connected bis-cationic centers can specifically interact with various DNA structures. Cell viability study shows that the probe has very low cytotoxicity. The probe exhibits high staining selectivity for mitochondria in living HeLa cells. Its capability to stain nuclear DNA has been confirmed by fixed cell staining. Furthermore, the application for two-photon excited fluorescence imaging demonstrates high potential of the probe for nonlinear bioimaging with 3D resolution.

Fabrication and characterization of multimodal magnetic - fluorescent polystyrene nanowires as selective cell imaging probes

The work presented here describes the preparation of new fluorescent, magnetic polystyrene (PS) nanowiresvia vacuum assisted infiltration of porous anodised aluminium oxide (AAO) membranes. A polymer solution of high molecular weight PS in THF, superparamagnetic magnetite nanoparticles and coumarin-153 dye is used to create the nanowires (NW) within the 200 nm diameter membranes. NW released by membrane dissolution have a high aspect ratio and a curled ‘bamboo’ like structure to them. NW have been characterised by optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). These wires were strongly luminescent and show good response to an external magnetic field. VSM measurements of these samples have shown presence of both superparamagnetic (SPM) and non-superparamagnetic components. The biological application potential of NW was also investigated by functionalising them with primary and secondary antibodies and incubation with epithelial lung cancer cells (A549 cell line). NW showed binding affinity to the surface of the cells and also endocytotic internalisation in the case of short wires. These structures have good potential for use in bio-medical imaging and diagnostic applications due to their additional modalities linked to their intrinsic material properties.