Application In Cell Imaging Research Articles

Galla chinensis residue-derived carbon dots for sensitive detection of doxorubicin hydrochloride and cell imaging

As an antibiotic, the imbalance of the concentration of doxycycline hydrochloride (DOX) can cause many harms, so real-time detection of the DOX content is crucial. In this study, Galla chinensis residue (GCR) was used as a carbon source, m-phenylenediamine was used as an N-doping agent, and blue-green fluorescent carbon dots (N-GCRCDs) were prepared by a simple hydrothermal synthesis method, with a high quantum yield of 27.31 %. Under optimized conditions, a specific fluorescent probe was established to detect DOX. The addition of DOX resulted in a significant decrease in fluorescence intensity, with a detection range of 5.7–114.9 μM and the detection limit was 1.38 μM. Finally, the feasibility of this method was validated in human urine and the experimental results exhibited a DOX recovery rate of 97.45–104.41 % and an RSD of 0.91–2.64 %. The quenching mechanism was mainly attributed to the inner filter effect and static quenching. Furthermore, the potential application of N-GCRCDs in cells was studied and biocompatibility was evaluated using HepG2 cells, which showed low toxicity at concentrations of 0–50 μg/mL and successful application for HepG2 cell imaging. This study provides reference for resource utilization of GCR and quantitative detection of antibiotics.

Concentration dependent carbon nanodots: Tunable luminescent color and fluorescence excitation-wavelength dependence

Carbon nanodots (CNDs) exhibiting concentration dependent properties have been synthesized through a one-pot hydrothermal reaction process utilizing diethylenetriamine and l-aspartic acid. At solid-state or high concentrations, the CNDs display excitation-wavelength independent fluorescence (FL) emissions, while at low concentrations, they exhibit excitation-wavelength dependent FL emissions. Detailed characterization of the structure and optical properties reveals that the concentration dependent FL properties can be ascribed to the intrinsic-state luminescence of the CNDs at low concentrations and the assembled-state luminescence at solid-state/high concentrations. With the increase of concentration, the self-assembly behavior of CNDs may cause the transition from intrinsic-state dominant luminescence to assembled-state dominant luminescence, and finally lead to the red-shift of FL color. Furthermore, the CNDs@Urea composites possess adjustable room-temperature phosphorescence (RTP) from turquoise to yellow by controlling the CNDs doping concentration. CNDs with concentration dependent optical properties have shown certain potentials in the fields of cell imaging, fingerprint recognition and anti-counterfeiting applications.

Synthesis of a novel water-soluble pyridine dicarboxylate and its application in fluorescence cell imaging

Abstract A novel water-soluble substituted pyridine dicarboxylate containing a quaternary ammonium ion with potential applications in fluorescence cell imaging was synthesized and characterized. Remarkably, this compound exhibited water solubility in the absence of additional solubilizers, enabling direct dissolution in phosphate-buffered saline for cell studies. No obvious cytotoxicity was observed in 4T1 cells (mouse breast cancer cells) within the concentration range of 0.2–25 μmol L−1, with a cell survival rate above 89%. Furthermore, the compound exhibited a maximum two-photon absorption cross-section of 86 GM at an excitation wavelength of 780 nm, demonstrating high cell permeability, effective distribution in the cytoplasm, and preferential targeting of organelles. Single- and two-photon fluorescence imaging of cells revealed a distinctive blue emission and strong bright green emission, respectively. The newly synthesized substituted pyridine dicarboxylate exhibited low cytotoxicity and strong fluorescence imaging properties, demonstrating its potential in cell imaging applications.

Thiophene appended schiff base probe for selective ‘turn-on’ response for copper (ii) ion and their applications in live cell imaging Thiophene appended schiff base probe for selective ‘turn-on’ response for copper (ii) ion and their applications in live cell imaging

In this research, we have synthesized a thiophene Schiff base from 5-phenyl thiophene-2-carboxaldehyde and 2-thiophene carboxylic acid hydrazide and characterized by using FT-IR NMR, HRMS and SC-XRD analysis techniques. The probe exhibited a selective turn-on fluorescence response for Cu2+ over 20 other common metal ions in a CH3CN (9:1, v/v) solution. The Job’s plot represents a 1:1 binding complexation mode and further DFT study was carried out to aid in understanding the geometric structure and interaction of the ligand and Cu2+. The detection limit (LOD) and limit of quantification (LOQ) were found to be 20 nM and 69 nM respectively. Furthermore, the probe’s sensing ability was tested in HeLa cells and their fluorescence imaging also supported the effective turn-on response towards Cu2+ ion.

Fluorescence and Circular Dichroism Dual-Mode Probe for Chiral Recognition of Tyrosine and Its Applications in Bioimaging.

Chiral amino acids (AAs) are essential in metabolism and understanding physiological processes, and they could be used as biomarkers for the diagnosis of different diseases. In this study, chiral Cdots@Van were prepared by postmodifying an achiral Cdots core with vancomycin for recognizing and determining the enantiomeric excess (ee) of tyrosine (Tyr) enantiomers. The fluorescence response of Cdots@Van is based on an "on-off" strategy, with different quenching percentages for d- and l-tyrosine. Interestingly, the circular dichroism (CD) spectrum of Cdots@Van responded to only one form of Tyr enantiomer, specifically d-Tyr, and remained nearly unchanged upon the addition of l-Tyr. Quantum mechanical (QM) calculations were in excellent agreement with the experimental results, confirming the stronger binding affinity of Cdots@Van for d-Tyr compared to l-Tyr. We further investigated the chiral recognition ability of the interconnected vancomycin particles, which was synthesized using the EDC/NHS coupling reaction between vancomycin molecules without a Cdots core. Surprisingly, unlike free vancomycin molecules, interconnected vancomycin displayed an enantiomeric recognition ability by CD spectroscopy, similar to what was observed for Cdots@Van. Crucially, this chiral probe has been successfully utilized for cell imaging applications.

Corrigendum to "In Vivo Stem Cell Imaging Principles and Applications".

Corrigendum to "In Vivo Stem Cell Imaging Principles and Applications".

Enhanced adsorptive removal of methylene blue dye from aqueous media by potato peel-derived carbon quantum dots and their application in cell imaging

Enhanced adsorptive removal of methylene blue dye from aqueous media by potato peel-derived carbon quantum dots and their application in cell imaging

Precise determination of human serum albumin levels in blood serum by a D-π-A based near-infrared fluorescent probe via TICT mechanism

Human serum albumin (HSA) levels in the body are crucial for the accurate diagnosis of various health issues, necessitating continuous monitoring and novel detection methods. This study focused on the development and synthesis of two novel D-π-A small molecule near-infrared fluorescent probes, PTPA-B and CPTPA-B. The probes demonstrated selective detection of HSA with a rapid response time of 1 min and high sensitivity, featuring limits of detection (LOD) of 0.102 μM and 1.702 μM. Under physiological conditions, the intrinsic fluorescence of these probes is minimal due to intramolecular charge transfer (TICT). Upon entering the hydrophobic cavity of HSA, the probes exhibit red fluorescence by inhibiting the TICT process. Additionally, the probes exhibited enhanced biocompatibility in living cells and enabled fluorescence imaging of L-02 live cells. Therefore, the PTPA-B fluorescent probe serves as an effective tool for serum detection, revealing its potential applications in live cell imaging and precise clinical diagnosis.

Supramolecular J- and H-Aggregation of Naphthalimide-Conjugated Dipeptide in Mixed-Solvent Systems and its Application in Cell Imaging.

In this work, a core-substituted NMI-conjugated dipeptide (4MNLV) was extensively studied in mixed solvent systems to explore the polarity effect on the self-assembly pattern and their photophysical property. 4MNLV adopted J- or H- type aggregation pattern depending upon the polarity index of the solvent system chosen. The self-assembly process was achieved through the anti-solvent effect. UV-vis study suggested that if the stock solution of 4MNLV was diluted with a relatively more polar solvent (compared to the stock solvent), then the system acquired J- type of aggregation pattern by showing a red-shift in their absorption maxima (λmax). Conversely, when the stock was diluted by a relatively less polar solvent, H-type of aggregation was observed, where blue shift of λmax was noticed. The emission spectra and the lifetime of the self-assembled materials were also influenced by the chosen solvent system. The chirotopic behaviour of these self-assembled materials was studied through CD spectroscopy. Morphological study indicated the formation of helical nanofibrillar structures. The bright green fluorescence of these highly biocompatible naphthalimide-peptide conjugate was used for cell imaging application, indicating its futuristic scope.

Novel benzothiazole-based fluorescent probe for efficient detection of Cu2+/S2− and Zn2+ and its applicability in cell imaging

BackgroundIn recent years, environmental pollution has been increasing due to the excessive emission of toxic ions, which has caused serious harm to human health and ecological environment. There are various methods for detecting Cu2+, S2− and Zn2+, but the traditional ion detection methods have obvious disadvantages, such as poor selectivity and long detection time. Therefore, it is still crucial to develop simple, efficient and rapid detection methods. ResultsA fluorescent probe based on benzothiazole, (E)-N'-(3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylbenzylidene)-3,4,5-tris(benzyloxy)benzohydrazide (BT), was designed and synthesized. It was characterized using ESI-MS, 1H NMR, and 13C NMR. BT can be used as a chemosensor to detect Cu2+, S2− and Zn2+ in CH3CN/H2O (7:3, v/v, pH = 7.4, HEPES buffer: 0.1 M), with detection limits of 0.301 μM, 0.017 μM, and 0.535 μM, respectively. At an excitation wavelength of 320 nm, BT exhibits an “on-off-on” response to Cu2+/S2− and enhanced fluorescence response to Zn2+, with a change in fluorescence color from orange to green. The coordination ratio of ions to the probe was determined to be 1:1 through Job's plot and hydrogen spectral titration. The recognition mechanism was discussed in conjunction with theoretical calculations. Furthermore, the probe has been successfully used in test strips and medical swabs colorimetry, as well as live cell imaging. SignificanceThe probe BT lays the foundation for the design and synthesis of multifunctional fluorescent probes. As a portable detection method, probe BT was used to detect Cu2+, S2− and Zn2+ on strips. Furthermore, the probe was applied to biological cells to detect target ions with low cytotoxicity and excellent cell permeability. This indicating that it can be used as a potential candidate for tracking Cu2+ and S2− in clinical diagnostics and biological systems.

A rhodamine-based AIE chemodosimeter for ratiometric fluorescent sensing Hg2+ and cell imaging application

In this work, a tetraphenyl ethylene functionalized rhodamine chemodosimeter, namely, TRP, has been designed, built, and structurally determined. The chemodosimeter exhibited an AIE effect in an EtOH-H2O mixture with the maximal emission intensity at 463 nm at a water fraction of 70 %. Then TRP was applied for ratiometric monitoring of Hg2+ ions in EtOH/H2O solution (v/v = 3/7), presenting about a 35-fold fluorescence intensity ratio enhancement (F649/F463), visible color changes, and well-resolved emission bands (187 nm). In addition, TRP showed high selectivity and sensitivity in Hg2+ ions sensing and achieved a limit of detection (LOD) of 10.0 nM, which was mainly attributed to the production of an oxadiazole functionalized and spirolactam ring opened rhodamine derivative-induced by Hg2+ ions. Significantly, using TRP as a tracer, ratiometric fluorescent detection of Hg2+ ion has been successfully conducted via living cell imaging, demonstrating its potential for practical applications in biological systems.

Smartphone-Assisted and Optical Quantification of Copper and Glucose Using Palm Wine-Tailored Carbon Dots and Their Multiple Logic Gate Application.

In this work, potassium, sulfur, nitrogen, and chlorine self-doped carbon dots (CDs) were hydrothermally synthesized using palm wine as a carbon source. The palm wine-derived CDs (PW-CDs) are amorphous in nature and displayed an average particle size of 4.19 ± 0.89 nm. The as-synthesized CDs are used to fabricate a photoluminescent sensing probe to simultaneously detect Cu2+ and glucose via the "Turn ON-OFF-ON" mechanism. The PL quenching mechanism of PW-CDs enables the selective and sensitive detection of Cu2+ ions with a detection limit (LOD) of 0.8 ppb (4.7 nM). The sensing probe quantified Cu2+ in tap water, drinking water, and e-waste samples to prove its viability. Using CDs to quantify copper in e-waste leachate samples is a novel approach as no prior instances of such application have been reported. The system's performance is considered to be highly reproducible due to the relative standard deviation being <6.64%, along with excellent recoveries within the range of 93.24-109.86%. The quenched PL can be recovered by introducing glucose into the PW-CD + Cu2+ system; this strategy is employed to quantify glucose with a LOD of 0.11 ppm (0.61 μM). The feasibility of this sensor was confirmed by the determination of glucose in actual human plasma specimens of diabetic patients. It is to be noted that these samples were neither diluted nor spiked with glucose. The developed PW-CD + Cu2+ sensing system yields satisfactory recoveries of 93.45-107.37%. This probe was also incorporated into a smartphone-based sensing platform to detect Cu2+ and glucose with desirable recoveries. The proposed smartphone-based sensing platform is flexible, reliable, and accurate, making it suitable for resource-constrained areas. Furthermore, based on the effect of Cu2+ ions and glucose on the PL response and absorbance spectra of PW-CDs, four logic gates (YES, IMPLICATION, NOT, and OR) were designed, and PW-CDs were also used for cell imaging applications.

Ultrathin Boron Growth onto Nanodiamond Surfaces via Electrophilic Boron Precursors.

Diamond as a templating substrate is largely unexplored, and the unique properties of diamond, including its large bandgap, thermal conductance, and lack of cytotoxicity, makes it versatile in emergent technologies in medicine and quantum sensing. Surface termination of an inert diamond substrate and its chemical reactivity are key in generating new bonds for nucleation and growth of an overlayer material. Oxidized high-pressure high temperature (HPHT) nanodiamonds (NDs) are largely terminated by alcohols that act as nucleophiles to initiate covalent bond formation when an electrophilic reactant is available. In this work, we demonstrate a templated synthesis of ultrathin boron on ND surfaces using trigonal boron compounds. Boron trichloride (BCl3), boron tribromide (BBr3), and borane (BH3) were found to react with ND substrates at room temperature in inert conditions. BBr3 and BCl3 were highly reactive with the diamond surface, and sheet-like structures were produced and verified with electron microscopy. Surface-sensitive spectroscopies were used to probe the molecular and atomic structure of the ND constructs' surface, and quantification showed the boron shell was less than 1 nm thick after 1-24 h reactions. Observation of the reaction supports a self-terminating mechanism, similar to atomic layer deposition growth, and is likely due to the quenching of alcohols on the diamond surface. X-ray absorption spectroscopy revealed that boron-termination generated midgap electronic states that were originally predicted by density functional theory (DFT) several years ago. DFT also predicted a negative electron surface, which has yet to be confirmed experimentally here. The boron-diamond nanostructures were found to aggregate in dichloromethane and were dispersed in various solvents and characterized with dynamic light scattering for future cell imaging or cancer therapy applications using boron neutron capture therapy (BNCT). The unique templating mechanism based on nucleophilic alcohols and electrophilic trigonal precursors allows for covalent bond formation and will be of interest to researchers using diamond for quantum sensing, additive manufacturing, BNCT, and potentially as an electron emitter.

Highly Selective Drug-Derived Fluorescent Probes for the Cannabinoid Receptor Type 1 (CB1R).

The cannabinoid receptor type 1 (CB1R) is pivotal within the endocannabinoid system regulating various signaling cascades with effects in appetite regulation, pain perception, memory formation, and thermoregulation. Still, understanding of CB1R's cellular signaling, distribution, and expression dynamics is very fragmentary. Real-time visualization of CB1R is crucial for addressing these questions. Selective drug-like CB1R ligands with a defined pharmacological profile were investigated for the construction of CB1R fluorescent probes using a reverse design-approach. A modular design concept with a diethyl glycine-based building block as the centerpiece allowed for the straightforward synthesis of novel probe candidates. Validated by computational docking studies, radioligand binding, and cAMP assay, this systematic approach allowed for the identification of novel pyrrole-based CB1R fluorescent probes. Application in fluorescence-based target-engagement studies and live cell imaging exemplify the great versatility of the tailored CB1R probes for investigating CB1R localization, trafficking, pharmacology, and its pathological implications.

Unraveling the ability of electronically diverse 9H-carbazoles as potential fluorophores in cellular imaging applications with BSA binding affinities

In the present study, fluorophores based on 9H-carbazole have been synthesized from readily accessible 2-nitrochalcones in a single-step reductive cyclization reaction with methyl acetoacetate. The molecular geometry was confirmed based on IR, NMR and mass analysis. The ground state geometry for all the synthesized compounds was optimized using DFT-based methods to explore the localization of frontier molecular orbitals in electronically diverse carbazoles. The photophysical studies revealed a higher Stokes shift for PPM 17 due to the presence of the naphthyl group at C-1 of carbazole. The high stability of PPM14, as evidenced by high chemical hardness, prompted us to explore its BSA binding affinity using fluorescence titration, synchronous,3-D fluorescence and energy transfer analysis. The probe (PPM 14) displayed a “turn-off” response in the presence of Fe3+ ions. The less cytotoxic behavior of PPM 14, its “turn-off” fluorescence response with Fe3+, and its utility in cell imaging application establish it as a potential small organic framework-based bio-sensor.

A dual responsive bis-thiophene affixed thiosemicarbazide based chemosensor for colorimetrically Hg2+ and fluorometrically Cu2+ ions and their applications in live cell imaging

In this work, we developed a fast and straightforward colorimetric and photoluminescent chemosensor probe (P1), featuring bis-thiophene-thiosemicarbazide moieties as its signaling and binding unit. This probe exhibited rapid sensitivity to Hg2+ and Cu2+ ions in a semi-aqueous medium, resulting in distinct colorimetric and photoluminescent changes. In the presence of Cu2+, P1 displayed an impressive 50-fold increase in photoluminescence (PL) at 450 nm (with excitation at 365 nm). The probe P1 formed a 1:1 complex with Hg2+ and Cu2+ ions, featuring association constant values of 4.04 × 104 M−1 and 1.25 × 103 M−1, respectively. P1 has demonstrated its efficacy in the analysis of real samples, yielding promising results. Additionally, the probe successfully visualized copper ions on a mouse fibroblast cell line (NIH3T3), highlighting its potential as an intracellular probe for copper ion detection.

Highly stable, fluorescent, artificial lipoprotein nanoparticles.

Here, we report a novel kind of protein nanoparticles of 11 nm in size, which have a central protein core surrounded by two layers of lipid. One layer of the lipid was covalently attached to the protein, while the other layer has been physically assembled around the protein core. Particle synthesis is highly modular, while both the size and charge of the protein nanoparticles are controlled in a predictable manner. Circular dichroism studies of the conjugate showed that the protein secondary structure is retained, while biophysical characterizations indicated the particle purity, size, and charge. The conjugate had a high thermal stability to steam sterilization conditions at 121°C (17 psi). After labeling the protein core with few different fluorescent dyes, they were strongly fluorescent with the corresponding colors independent of their size, unlike quantum dots. They are readily digested by proteases, and these water-soluble, non-toxic, highly stable, biocompatible, and biodegradable conjugates are suitable for cell imaging and drug delivery applications.

A highly selective fluorescent sensor with aggregation-induced emission for detection of H2S and its application in live cells imaging

Hydrogen sulfide (H2S) is traditionally considered as an ecologically toxic gas, has been proven to be the third endogenous signalling gasotransmitter and plays important roles in physiological and pathophysiological conditions. Herein, we designed and synthesized a novel “turn off” fluorescent probe for the detection of hydrogen sulfide(H2S) in vitro. Probe A could detect H2S in CH3CN/PBS system with significant fluorescence quenching. Probe A also showed obviously aggregation-induced emission (AIE) effects. Fluorescence titration experiments revealed probe A combine with H2S in a 1: 1 ratio with a detection limit of 6.54 μM. Cell imaging results demonstrated the potential applicability of probe A for H2S detection in living cells. The supramolecular assembly of probe A and β-cyclodextrin further revealed the interaction with H2S.

NCS-catalyzed synthesis of 2,4,5-triaryl-1H-imidazole and its selective detection of iron ions

In this study, an efficient synthesis of 2,4,5-trisubstituted imidazoles was developed via cyclocondensation starting from o-dione, substituted aromatic aldehyde and ammonium acetate using catalyst NCS, and was characterized by HR-MS, FT-IR, 1H and 13C NMR spectroscopy. A novel fluorescence sensor 4-(1H-phenanthro[9,10-d]imidazol-2-yl)-N, N-diphenylaniline (3bd) was discovered for the detection of Fe3+ ions. The probe 3bd exhibited strong blue radiation in solution. In the presence of Fe3+ ions, a significant fluorescence change of blue light to green light was observed in the EtOH/H2O (4/1, v/v) solution of 3bd (Ag+, Al3+, Ba2+, Ca2+, Cd2+, Co2+, Cr3+, Cu2+, Fe2+, Fe3+, Hg2+, Mg2+, Mn2+, Pb2+, Sr2+, Zn2+). The limits of detection of probe 3bd for Fe3+ ions was calculated to be as low as 0.70 μM, and it had excellent anti-interference ability. The probe 3bd complexed with Fe3+ ions at 1:1, and the complexation constant was 3.93 × 104 M−1. The probe 3bd realized the detection of Fe2+ oxidation to Fe3+, and the pH showed fine stability in the environment between 4.0–7.0, which ensured its potential application prospects. It also showed good reversibility upon addition of EDTA. Furthermore, the viability of 3bd to Fe3+ had practical application in live cell imaging.

An easily accessible probe for H2S based on AIE mechanism and its application in cell imaging

Hydrogen sulfide (H2S) is a crucial endogenous gas transmitter, maintaining the redox homeostasis in biological systems. Thus, a real-time and specific H2S detection approach is urgently necessary to study the attack and management of disorders linked to H2S. In this paper, a novel fluorescent probe HMP based on AIE property for the detection of H2S was elaborately conducted. In PBS buffer solution HMP exhibited high photostability, low detection limit (0.82 μM), significant anti-interference ability and fast response time and specificity to H2S. What’s more, it could be employed for the monitoring and luminescent imaging of H2S with Hela cells, thereby broadening the prospective capacity for diagnosing associated diseases.