Imaging Of HeLa Cells 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.

PH-responsive aldehyde-bearing cyclometalated iridium(III) complex for tracking intracellular pH fluctuations under external stimulation

Intracellular pH undertakes critical functions in various biological and pathological processes. It is important to monitor intracellular pH fluctuations for understanding physiological and pathological processes. Here, one aldehyde-bearing cyclometalated iridium(III) complex ([(4-pba)2Ir(dcphen)]PF6, 4-pba = 4-(2-pyridyl) benzaldehyde, dcphen = 4,7-dichloro-1,10-phenanthroline, probe 1) was synthesized and used to track intracellular pH fluctuations. Probe 1 displayed pH-dependent luminescence property in pH range of 1.81–6.81 with an evaluated pKa value of 4.30 in BR buffer-DMSO (v:v = 99:1). An intramolecular hydrogen bonds assisted pH-responsive mechanism was proposed for the pH-responsive behavior of probe 1. Probe 1 was successfully applied for imaging and tracking pH fluctuations in HeLa cells under external stimulation with fast response time, good photostability as well as low cytotoxicity and high cell permeability. This work demonstrates that aldehyde-bearing cyclometalated iridium(III) complex can be used as alternative pH-responsive probe for real-time tracking intracellular pH fluctuations, which provides a strategy for the design of pH-responsive probe in versatile applications.

Fluorenone-Based Fluorescent and Colorimetric Sensors for Selective Detection of I- Ions: Applications in HeLa Cell Imaging and Logic Gate.

Fluorenone-based fluorescent and colorimetric sensors 1 and 2 have been developed that displayed selective detection of iodide ions in the presence of interferences. Sensors displayed the fluorescence emission enhancement response toward I– with detection limits of 8.0 and 11.0 nM, respectively, which is accomplished through inhibition of intramolecular charge transfer and C=N isomerization. Excellent sensitivity and unique fluorescence enhancement response of sensors toward I– make them superior because most of the previously reported iodide sensors are based on the fluorescence quenching mechanism and are less sensitive. The sensing potential of sensors toward I– ions was investigated through 1H NMR titration, dynamic light scattering, Job’s plots, and density functional theory analysis. Further, sensors displayed reversible behavior by the alternate addition of I– and Cu2+ ions that substantiate their role as recyclable sensors for the on-site detection of I– ions. Advantageously, fluorescence enhancement response of sensors was favorably used for fluorescence imaging of I– in live HeLa cells and the design of the logic gate. These sensors were successfully applied in diversified applications such as the preparation of sensors’ coated paper strips and the determination of I– ions in blood serum, food, and real water samples.

In Vitro Anticancer Ability of Nano Fluorescent 111 In-MIL-68/PEG-FA on Hela Cells.

In past decades, nanoscale metal-organic frameworks (NMOFs) have drawn more and more attention in multimodal imaging and targeting therapy of various malignant cancers. Here, we proposed to dope 111 In into fluorescent In-based NMOFs (In-MIL-68-NH2 ), with an attempt to prepare a new nanomedicine with great anticancer potential. As a proof of concept, the obtained NMOF (In-MIL-68/PEG-FA) with targeting motifs is able to act as a fluorescent probe to achieve Hela cell imaging. Moreover, the Auger electron emitter 111 In built in corresponding radioactive NMOF (111 In-MIL-68/PEG-FA) can bring clear damage to cancer cells, leading to a high cell killing rate of 59.3 % within 48 h. In addition, the cell cycle presented a significant dose-dependent G2/M inhibiting mode, which indicates that 111 In-MIL-68/PEG-FA has the ability to facilitate the cancer cells to enter apoptotic program. This work demonstrated the potential of 111 In-labelled NMOFs in specific killings of cancer cells, providing a new approach to develop nanomedicines with theranostic function.

Graphene oxide/zinc ferrite nanocomposite loaded with doxorubicin as a potential theranostic mediu in cancer therapy and magnetic resonance imaging

Hybrid functional biomaterials are attracting increasing interest due to their biocompatibility and therapeutic and diagnostic characteristics. The theranostic properties of functional biomaterials favor their application. When these materials are responded to stimuli, they confer target site delivery. Although various types of nanocomposites have been developed for drug delivery and diagnostics, no ideal composites have been reported yet. Here, we report the synthesis of graphene oxide–zinc ferrite hybrid nanocomposites (GO-ZnFe2O4) conjugated with doxorubicin (GO-ZnFe2O4/DOX) for cancer therapy and magnetic resonance (MR) imaging-based diagnosis. The optical properties, crystal phase, particle size, functional groups, elemental composition, surface morphology, and magnetism of GO-ZnFe2O4 nanocomposites were characterized using state-of-the-art available techniques, including Fourier-Transform Infrared Spectroscopy (FTIR), Ultraviolet visible spectroscopy (UV–Vis), Transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Dynamic light scattering (DLS), Vibrating sample magneto meter (VSM) Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectra (XPS). The in vitro analysis showed that GO-ZnFe2O4 conjugated with DOX is more cytotoxic than GO-ZnFe2O4. GO-ZnFe2O4/DOX induced the production of reactive oxygen species (ROS), which induced damage to nuclear DNA and mitochondrial DNA (mtDNA) when internalized by cells. This damage consequently drove mitochondrial malfunction and ultimately the apoptosis of cancer cells. Further studies were performed to investigate the diagnostic efficacy of these nanocomposites using MR imaging. GO-ZnFe2O4/DOX nanocomposites were developed and successfully employed in the MR imaging of HeLa cells. As shown in the present study, GO-ZnFe2O4/DOX might play a potential role in the development of chemotherapy and noninvasive MR imaging of tumor cells.

The Two-Steps Reaction Fluorescent Probe for the Selective Detection of Cysteine and Its Applications.

We reported the specific fluorescent probe (MC-BOD-XDS) with two-steps reaction based on monosulfanyl-coumarin-BODIPY for selective detection of cysteine, high activity sulfanyl-coumarin as the multiple reaction group instead of a group internal standard fluorophore. The reaction mechanism of MC-BOD-XDS for detecting cysteine was different from the reported probes about the nucleophilic aromatic substitution reaction (SNAr) of chlorinated BODIPY. The fluorescent color of MC-BOD-XDS changed from yellow to red, and then to orange. The linear calibration diagram showed that it can potentially be used for quantitatively detection of Cys. Its potential applications were demonstrated by employing it for detection of Cys in artificial urine and in fluorescent imaging in HeLa cells.

Single-path single-shot phase-shifting digital holographic microscopy without a laser light source.

We propose single-path single-shot phase-shifting digital holographic microscopy (SSP-DHM) in which the quantitative phase information of an object wave is acquired without a laser light source. Multiple phase-shifted holograms are simultaneously obtained using a linear polarizer, a liquid crystal on a silicon spatial light modulator (LCoS-SLM), and a polarization-imaging camera. Complex amplitude imaging of a USAF1951 test target and phase imaging of transparent HeLa cells are performed to show its quantitative phase-imaging ability. We also conduct an experiment for the motion-picture imaging of transparent particles to highlight the single-shot imaging ability of SSP-DHM.

A reasonably constructed fluorescent chemosensor based on the dicyanoisophorone skeleton for the discriminative sensing of Fe3+ and Hg2+ as well as imaging in HeLa cells and zebrafish.

In this study, a new fluorescent sensor dicyanoisophorone Rhodanine-3-acetic acid (DCI-RDA) (DCI-RDA) has been developed by employing a DCI-based push–pull dye as the fluorophore and RDA as the recognition moiety for the simultaneous sensing of Fe3+ and Hg2+ with a large Stokes Shift (162 nm), high selectivity and sensitivity, and low LOD (1.468 μM for Fe3+ and 0.305 μM for Hg2+). In particular, DCI-RDA has a short response time (30 s). The Job's plot method in combination with 1H NMR titration and theoretical calculations was used to determine the stoichiometry of both DCI-RDA-Fe3+/Hg2+ complexes to be 1 : 1. Moreover, DCI-RDA is applied as a fluorescent probe for imaging in HeLa cells and zebrafish, indicating that it can be potentially applied for Fe3+/Hg2+ sensing in the field of biology.

A highly potential acyclic Schiff base fluorescent turn on sensor for Zn2+ ions and colorimetric chemosensor for Zn2+, Cu2+ and Co2+ ions and its applicability in live cell imaging.

Herein, we report two acyclic Schiff base receptors CS-1 and CS-2 capable of being selective fluorescent turn on for Zn2+ions and colorimetric chemosensor for Zn2+, Cu2+, and Co2+ ions by showing a colour change from colourless to yellow in 1:1 ratio of acetonitrile and HEPES buffer (1:1, v/v, pH7.4) without the interference from other metal ions screened (Cd2+, Hg2+, Sn2+, Ni2+, Cr3+, Mn2+, Pb2+, Ba2+, Al3+, Ca2+, Mg2+, K+ and Na+). The fluorescence turn on enhancement towards Zn2+ ions is ascribed to PET blocking, suppression of -C=N- isomerisation, and the ESIPT process. The selectivity, competitivity and reversibility of the synthesised probes (CS-1 and CS-2) made them promising chemosensors for the detection of Zn2+, Cu2+, and Co2+ ions. The density functional theory (DFT) calculations have theoretically endorsed the colorimetric changes in the examined absorption spectra and binding mode of both CS-1/CS-2 with metals ions. In addition, 1H NMR titrations were also consistent with the recognition mechanism of Zn2+ ions with the CS-1/CS-2. Further, the Jobs plot analysis infers a 1:1 stoichiometric ratio for both evaluating receptors CS-1 and CS-2 with Zn2+, Cu2+ and Co2+ ions and was supported by DFT, NMR (only for Zn2+ ions), UV-Visible, and fluorescence spectroscopic studies. Moreover, the detection limits of CS-1 and CS-2 for Zn2+ ions were determined to be 7.69 and 5.35nM, respectively, which is less compared to the detection limit of Cu2+, Co2+ ions as well as the limit approved by the United State Environmental Protection Agency (US EPA). The probes CS-1 and CS-2 found to show high fluorescence quantum yields at pH=7 during the titration with Zn2+ as compared with other pHs (5-6 and 8-11). Gratifyingly, fluorescence microscopy imaging in HeLa cells revealed that the pair of receptors can be employed as an excellent fluorescent probe for the detection of Zn2+ions in living cells, indicating that this facile chemosensor has a huge potential in cellular imaging.

Nearly monodispersed, emission-tuneable conjugated polymer nanoparticles

We describe the synthesis of monodispersed, silica encapsulated conjugated polymer nanoparticles, their colour tunability and use in imaging HeLa cells.

Folic acid functionalized aggregation-induced emission nanoparticles for tumor cell targeted imaging and photodynamic therapy.

Recently, molecules with aggregation-induced luminescence (AIE) characteristics have received more and more attention due to the fluorescence of traditional dyes being easily quenched in the aggregated state. AIE molecules have significant advantages, such as excellent light stability, bright fluorescence, high contrast, and large Stokes shift. These characteristics have aroused wide interest of researchers and opened up new applications in many fields, especially in the field of biological applications. However, AIE molecules or their aggregates have certain limitations in multifunctional biological research due to their low specific targeting ability, poor biocompatibility, and poor stability in physiological body fluids. In order to overcome these problems, a novel nanoparticle, FFM1, was fabricated and characterized. FFM1 displayed good water solubility, biocompatibility, and AIE emission properties. It could target HeLa cells specifically by recognizing their folate receptor. Reactive oxygen triggered by light irradiation induced tumor cell apoptosis. Summarily, FFM1 displayed excellent capacity in target imaging and photodynamic killing of HeLa cells. It has shown potential application value in targeted diagnosis and photodynamic therapy of tumors, and has important guiding significance for the treatment of malignant tumors. It paves a way for the development of a novel strategy for tumor theranostics.

Water-soluble bright NIR AIEgens with hybrid ROS for wash-free mitochondrial "off-on" imaging and photodynamic therapy.

Several aggregation-induced emission luminogens (AIEgens) with excellent water-solubility and near-infrared emission were designed and synthesized for wash-free "off-on" mitochondrial imaging and photodynamic therapy of HeLa cells. The AIEgen TEPP exhibits both bright near-infrared emission (φF = 17.8%) and high hybrid ROS productivity (including OH˙ and 1O2).

Synthesis of a new environment-sensitive fluorescent probe based on TICT and application for detection of human serum albumin and specific lipid droplets imaging

Environment-sensitive fluorescent probes have always been as forceful tools to understand the pathophysiological processes of relevant diseases. In this work, a new fluorescent probe with typical D-π-A structure was designed and showed high sensitivity to polarity and viscosity changes. DPAR could selectively detect human serum albumin (HSA) with turn-on orange emission in aqueous PBS buffer (pH 7.4), which showed advantages such as rapid response (4 min), high sensitivity (LOD 0.98 μg/mL). Therefore, it was successfully used for achieving HSA levels in urine samples and HSA imaging in HeLa cells. DPAR also exhibited the capability to recognize the cancer cells over the normal cells by lower polarity guided lipid droplets (LDs) imaging (in green emission channel). The detection mechanism for HSA and cancer diagnosis was convinced that DPAR encountered the lower-polarity and higher-viscosity microenvironment, resulting in the confinement of the TICT process and intramolecular rotation. These facts showed that DPAR had good application prospects in environment-related biomedical research and clinical diagnosis.

Lactobacillus rhamnosus reduces the cytotoxic effects of group B streptococcus on HeLa cells

Group B Streptococcus (GBS) is an opportunistic pathogen found in the vaginal tract and is a leading cause of preterm birth and neonatal illness. Aside from GBS, the vaginal tract is predominantly colonized by commensal Lactobacillus species that are thought to protect the vaginal tract from pathogens, including GBS. Studies that examined if, and how Lactobacilli modulate GBS pathogenicity remain limited. This study sought to investigate the potential protective role of Lactobacillus rhamnosus against GBS, using an in vitro model system. Immunofluorescence microscopy and Scanning Electron Microscopy (SEM) captured images of infected HeLa cells and were analyzed using the image analysis program ImageJ. Results indicate that GBS causes HeLa cell detachment unless L. rhamnosus is present. SEM images show that GBS reduces length and number of microvilli on HeLa cell surface, as well as size of secreted vesicles. L. rhamnosus partially inhibits GBS-dependent microvilli and vesicle disruption. GBS also disrupts HeLa cell F-actin fibers unless L. rhamnosus is present. These results reveal effects of GBS infection on the host cell cytoskeleton and implies a protective role of L. rhamnosus against GBS colonization.

Aggregation-Induced Fluorogens in Bio-Detection, Tumor Imaging, and Therapy: A Review

Aggregation-Induced Fluorogens in Bio-Detection, Tumor Imaging, and Therapy: A Review

Collaborative Low-Rank Matrix Approximation-Assisted Fast Hyperspectral Raman Imaging and Tip-Enhanced Raman Spectroscopic Imaging.

Fast acquisition of Raman images is essential for accurately characterizing the analytes' information. In this paper, we developed a collaborative low-rank matrix approximation method for fast hyperspectral Raman imaging as well as tip-enhanced Raman spectroscopy (TERS) imaging. This method combines high signal-to-noise ratio (SNR) data with the target data to perform collaborative singular value decomposition. The high-quality reference data can impose constraints on factorization, which will force its components to approximate the true signal or noise components. The simulation demonstrated that this method offers state-of-the-art signal extraction performance and, thus, can be used to accelerate data acquisition. Specifically, the results indicate that the CLRMA can largely decrease the root-mean-square error by 20.92-54.12% compared with the baseline method of our previous study. We then applied this method to the fast TERS imaging of a Au/Pd bimetallic surface and significantly decreased the integration time down to 0.1 s/pixel, which is about 10 times faster than that of conventional experiments. High-SNR TERS spectra and clear TERS images that are well consistent with scanning tunneling microscopy (STM) images can be obtained even under such a weak signal condition. We further applied this method to the fast Raman imaging of HeLa cells and obtained clear Raman images at a short integration time of 2 s/line, which is about 5 times faster than that of conventional experiments. This method offers a promising tool for TERS imaging as well as conventional Raman imaging where fast data acquisition is required.

Emerging Designs of Aggregation-Induced Emission Agents for Enhanced Phototherapy Applications

Emerging Designs of Aggregation-Induced Emission Agents for Enhanced Phototherapy Applications

A new recognition moiety diphenylborinate in the detection of pyruvate via Lewis acid/base sensing pathway and its bioimaging applications

Developing new reaction based recognizing units can enhance the specificity of target analyte molecules in practical applications of real samples and biosystems. Therefore, introducing a recognizing moiety diphenylborinate was encountered for the detection of pyruvate biomolecule through Lewis acid-base reaction based sensing strategy. The construction of the Schiff-base back bone between quinoline and N-(diethylamino)salicylaldehyde-diphenylborinate (QSB) were expressed the red shift from blue emission of quinoline in to green as that of dative bond developed between Schiff base nitrogen and boron atoms. The new sensing approach was involved such a way that fluorophore QSB is a Lewis acid while pyruvate acts as Lewis base, where the elimination of Lewis pair produced a weak green fluorescence including the formation of quinoline, N-(diethylamino)salicylaldehyde (QS). The switching products were witnessed through 1H NMR titration, HR-MS and FT-IR studies. The good selectivity and interference ability were achieved in presence of 1000-fold excess of possible interferences with LOD of 16 nM. Moreover, the tracking ability of the probe was employed towards pyruvate in live HeLa cell imaging for evaluating an exogenous and endogenous signals producing ability and its mitochondria targeting property was investigated successfully. Further, the practical utility of the probe was tested with milk samples and obtained good recovery results.

Novel lysosome-targeted fluorescent molecular rotors based on a cyanine-like modular system and their application in living cells

Two novel fluorescence molecular rotors DpIn and NaIn were designed and synthesized involving of indolium units linked with meta-diphenol or ortha-naphthalenediol moiety, respectively. They underwent intramolecular charge transfer to form a cyanine-like modular system at a physiological pH. In glycerol aqueous solutions, the probe DpIn exhibited NIR strong emission (3-fold) at ca. 700 nm, while the probe NaIn displayed a turn-on emission (8-fold) with a larger Stokes shift (⊿λ ≈ 97 nm). The HeLa cell imaging experiments indicated probe DpIn and NaIn both exhibited excellent selectivity for staining intracellular lysosomes instead of mitochondria. 1H NMR spectra revealed that more electrons were accumulated around benzene ring of indolium groups, which could be the evidence for its basic character leading to the lysosomes targeted staining. Furthermore, the probe NaIn proved to be an ideal lysosome-targeting tracer for monitor the changes of viscosity caused by stimuli in living cells.

A Novel Fluorescence Probe for the Reversible Detection of Bisulfite and Hydrogen Peroxide Pair in Vitro and in Vivo.

The detection of changes in the reactive oxygen species (ROS)/reactive sulfur species (RSS) couple is important for studying the cellular redox state. Herein, we developed a 1,8-naphthalimide-based fluorescence probe (NI) for the reversible detection of bisulfite (HSO3 - ) and hydrogen peroxide (H2 O2 ) in vitro and in vivo. NI has been designed with a reactive ethylene unit which specifically reacts with HSO3 - by a Michael addition reaction mechanism, resulting in the quenching of yellow fluorescence at 580 nm and the appearing of green fluorescence at 510 nm upon excitation at 500 nm and 430 nm, respectively. The addition product (NI-HSO3 ) could be specifically oxidized to form the original C=C bond of NI, recovering the fluorescence emission and color. The detection limits of NI for HSO3 - and NI-HSO3 for H2 O2 were calculated to be 2.05 μM and 4.23 μM, respectively. The reversible fluorescence response of NI towards HSO3 - /H2 O2 couple can be repeated for at least five times. NI is reliable at a broad pH range (pH 3.0-11.5) and features outstanding selectivity, which enabled its practical applications in biological and food samples. Monitoring the reversible and dynamic inter-conversion between HSO3 - and H2 O2 in vitro and in vivo has been verified by fluorescence imaging in live HeLa cells, adult zebrafish and nude mice. Moreover, NI has been successfully applied to detect of HSO3 - levels in food samples.