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A series of La3(1−x)Ga5MO14:xSm3+ (M = Si or Ge) orange-red phosphors with high color purity, low correlated color temperature, and good thermal stability were successfully synthesized via a high-temperature solid-phase technique. The phase structure and morphology of La3Ga5SiO14(LGSi):xSm3+ and La3Ga5GeO14(LGGe):xSm3+ were investigated. Sm3+-doped LGSi and LGGe phosphors emitted orange-red light under an excitation of 403 nm, and the optimal doping concentrations were 3 mol% and 2 mol% with excellent color purities of 98.46% and 98.25%, respectively. The concentration quenching mechanism of both the samples was dominated by dipole–dipole interaction, and the effect of Si4+ and Ge4+ on luminescence performance was discussed. The internal quantum efficiencies of LGSi:0.03Sm3+ and LGGe:0.02Sm3+ were calculated to be 27.14% and 56.07%, respectively. The CIE and CCT values indicated that the luminescence of the prepared phosphors was in the orange-red region. Additionally, a white light-emitting diode (w-LED) was fabricated with LGGe:0.02Sm3+ phosphors, which was capable of emitting bright and warm white light and exhibiting a high color rendering index (CRI) of 87.17 and an appropriate correlated color temperature (CCT) of 6108 K. These results indicated that the prepared phosphors with excellent luminescent performances have potential application in indoor illumination. [ABSTRACT FROM AUTHOR]

Cascade alkyl migration of 2-alkynylanilines via an aromaticity destruction and reconstruction process is reported. The first alkyl migration is triggered by generation of a dearomatized arenium species via oxidation and cyclization, and the second is driven by the force to restore the aromaticity of rearrangement products. The reaction gave rise to a range of multi-functionalized indoles. [ABSTRACT FROM AUTHOR]

The development of photocatalysis is hindered, in part, by the quick recombination of photogenerated carriers and the instability of light sources. In this study, the problem of too-fast electron–hole pair compounding in photocatalysis is effectively regulated by the polarization field of pyroelectric materials using the pyroelectric method. Self-polarized pyroelectric materials that depend on temperature variations can generate usable electrical energy and polarized charge carriers to degrade organic pollutants. Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) is a relaxor ferroelectric material with spontaneous polarization characteristics. The PMN–0.30PT:1 mol%Sm3+ catalyst was prepared by applying the high-temperature solid-state reaction method. Under the dark condition and nine cold–hot cycles of 23 °C–68 °C, using H2O2-assisted PMN–0.30PT:1 mol%Sm3+ as a catalyst, the degradation rate of rhodamine 6G (10 mg L−1) was 94.3 ± 2.5%. In addition, the degradation rates of 88.52% and 64.32% were obtained for rhodamine B (10 mg L−1) and methylene blue (10 mg L−1), respectively. This study provides a new approach to the pyroelectric catalytic degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

New amphiphilic near-infrared fluorescent probes (λem = 710 nm) are reported for monitoring viscosity of cell membranes. The probes were found to be selective and sensitive to viscosity, and to quickly (within 2 minutes) and stably anchor onto the cell membrane. Moreover, the applicability of the probe MYN-BS (a superior representative) was demonstrated, revealing a reversible viscosity change with temperature change and an increase in viscosity during cell foaming. The proposed probes may serve as a reliable tool for studying viscosity-related processes of cell membranes. [ABSTRACT FROM AUTHOR]

Lipid droplets (LDs) have been known as a non-negligible cellular organelle for lipid storage and metabolism. Fluorescent probes for imaging LDs would be paramount for depicting their functions in cells. Although commercially available Nile Red and BODIPYtm 493/503 have been widely used for labelling LDs, they exhibit unsatisfactory specificity and spectroscopic properties. This feature article reviews the recent advances in organic fluorescent probes for imaging LDs. We first introduce the key points for probe design, including regulating hydrophobicity and enhancing fluorescence quantum yield in LDs. Then, we summarize the structural features and biological applications of some representative LD probes classified by their frameworks. In addition, the current challenges and future research trends for the fluorescent probes of LDs are discussed as well. [ABSTRACT FROM AUTHOR]

A nitroreductase (NTR)-activated NIR-II fluorescence probe for tumor imaging is reported. The probe can emit fluorescence in the range of 900–1300 nm, and target hypoxic tumors with NTR overexpression, thus allowing for accurate delineation of tumor margins through deep penetration. [ABSTRACT FROM AUTHOR]

The stable physicochemical properties of polyaniline/closo-[B12H12]2− (PA/B12) obtained by an ion exchange technique combined with polyaniline (PA) and closo-[B12H12]2− (B12) can realize rapid kinetic adsorption and complete removal of Cr(VI) and cationic dye pollutants at low concentrations. The reversible adsorption/desorption process of pollutants represents that PA/B12 has practical industrial use value. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinase-1 (MMP-1) is associated with many types of cancers, including oral, colorectal, and brain cancers. This paper describes the fabrication of an MMP-1 immunosensor based on a gold nanoparticle/polyethyleneimine/reduced graphene oxide (AuNP/PEI/rGO)-modified disposable screen-printed electrode (SPE). A microwave-assisted single-step method was employed for the simultaneous reduction of gold and graphene oxide in a PEI environment to avoid AuNP agglomeration. The crystal structure, chemical composition, optical properties, and interior morphology of the materials were probed by X-ray diffraction, Raman spectroscopy, UV-visible spectrometry, and transmission electron microscopy techniques. To assemble a label-free MMP-1 immunosensor layer-by-layer, 3-mercaptopropionic acid was utilized due to its strong sulfur-gold bonding ability, and its tail end was attached to a carboxyl group, allowing the MMP-1 antibody (anti-MMP-1) to be subsequently cross-linked using the traditional N-(3-dimethylaminopropyl) and N′ ethylcarbodiimide hydrochloride method. Differential pulse voltammetry analysis showed a linear relationship with MMP-1 concentration in the range of 1–50 ng ml−1 with an R2 value of ∼0.996 (n = 5, RSD < 5%). This immunosensor was successfully applied for MMP-1 detection in urine, saliva, bovine serum, and cell culture media (HSC-3 & C6) of oral and brain cancers showing results comparable to those of the credible ELISA method. [ABSTRACT FROM AUTHOR]

Nitroxyl (HNO) is a promising regulator for cancer therapy. Here, we develop a tumor-targeted near-infrared fluorescent probe for HNO and utilize it in the real-time imaging of HNO release in vivo. [ABSTRACT FROM AUTHOR]

Tyrosinase plays a pivotal role in the hyperpigmentation of wounds. Here, we develop a new fluorescent probe and with it, we reveal an increase of tyrosinase activity at the wound site in zebrafish. [ABSTRACT FROM AUTHOR]

The hydroxyl radical (˙OH) in the endoplasmic reticulum has not been studied thoroughly due to the lack of proper methods. Here, an endoplasmic reticulum-targeting fluorescent probe for detecting ˙OH is reported. With this probe, the action of ˙OH in the endoplasmic reticulum has been imaged in living cells. [ABSTRACT FROM AUTHOR]

A self-catalytic ampicillin–metal (Fe3+)-organic gels (AMP–MOGs (Fe))–H2O2 CL system, which is not influenced by transition metal ions, was studied. A method for CL detection of Staphylococcus aureus (S. aureus) based on the AMP–MOGs (Fe)–H2O2 CL system was achieved. A superior detection limit of 31 CFU mL−1 toward S. aureus was obtained with near-zero background noise. [ABSTRACT FROM AUTHOR]

Extraction of copper from sufidic ores, either by pyrometallurgy or hydrometallurgy, has various limitations. In this study, a solvometallurgical process for the extraction of copper from sulfidic ore minerals (chalcopyrite, bornite, chalcocite and digenite) was developed by using an organic lixiviant (FeCl3 as oxidizing agent and ethylene glycol (EG) as organic solvent). All the studied copper sulfide minerals could be leached efficiently with a FeCl3–EG solution. Other lixiviant systems, namely CuCl2–EG, FeCl3–ethanol and FeCl3–propylene glycol could also extract copper, but they did not perform as well as the FeCl3–EG solutions. The mechanistic study of chalcopyrite leaching in FeCl3–EG solutions confirmed that the leaching products of chalcopyrite were FeCl2, CuCl and solid elemental sulfur, where the Fe(II) and Cu(I) were quantified by UV-Vis absorption spectroscopy and solid sulfur was identified by powder XRD. A kinetic study showed that the leaching process was a surface chemical controlled process and the apparent activation energy was calculated to be 60.1 kJ mol−1. Subsequently, electrodeposition of copper from the pregnant leachate was investigated, and SEM-EDX analysis showed that uniform cubic crystalline deposits of pure copper were produced. Meanwhile, the Fe(III) was regenerated by oxidizing Fe(II) at the anode, with a Morgane membrane in between two electrode compartments to prevent the transfer of Fe(III) to the cathode. Finally, a closed-loop solvometallurgical process was designed with three operational steps: leaching, electrodeposition and removal of Fe(II). The regeneration of the FeCl3–EG solution and the use of EG contribute to the sustainability and the greenness of the process. [ABSTRACT FROM AUTHOR]

A new dual-function fluorescent probe is developed for detecting nitroreductase (NTR) and adenosine triphosphate (ATP) with different responses. Imaging application of the probe reveals that intracellular NTR and ATP display an adverse changing trend during a hypoxic process and ATP can serve as a new sign for cell hypoxia. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) with trichloride anions ([Cl3]−) combined with different cations were synthesised by bringing chlorine gas into contact with the corresponding chloride (Cl−) ILs at room temperature. These trichloride ILs safely store chlorine and are useful as oxidising agents for dissolution of various metals and alloys under mild conditions. [ABSTRACT FROM AUTHOR]

We have, for the first time, developed a near-infrared fluorescent probe for aminopeptidase N by combining a hemicyanine and an alanyl residue. The probe exhibits high selectivity and sensitivity with a detection limit of 0.8 ng mL−1. With the probe, aminopeptidase N has been imaged in both cells and mice in vivo, indicating a promising tool for studying the function of the enzyme. [ABSTRACT FROM AUTHOR]

A resorufin-based highly sensitive and selective fluorescence off–on probe with a new recognition moiety for tyrosinase is developed, and applied to detect and image endogenous tyrosinase activity in different living cells. [ABSTRACT FROM AUTHOR]

A novel method for sensitive detection of liver cancer cells using anti-CD155 and anti-CD112 monoclonal antibodies conjugated to ultrabright fluorescent mesoporous silica nanoparticles (FMSNs) encapsulating Rhodamine 6G and fluorescein was developed. The diameter of the obtained nanoparticles was 90 nm, and the quantum yield was 69%. Because the emission of fluorescein has a high degree of overlap with the excitation of Rhodamine 6G, and these two dyes were sufficiently close to each other on the nanoparticles, fluorescence resonance energy transfer can occur between these two dyes. This transfer not only maintains the original feature of the nanochannels and the skeletal network of the silica weakening the inner filtering of the dye, but also makes the excitation peak of the nanoparticles wider and increases the useful load amount of the dye. Because the wider Stokes shifts weaken the interference of excitation, the detection sensitivity is enhanced at the same time. The NaIO4 oxidation method does not use a cross-linker but rather uses covalent immobilization of the monoclonal antibodies on the FMSNs. This method can maintain the activity of the monoclonal antibodies more easily than the glutaraldehyde method. These advantages ensure that the nanosensor has high sensitivity and specificity for detecting liver cancer SMMC-7721 and HHCC cells. The in vivo imaging experiment also ensured that the biosensor can target tumor tissue in mice. [ABSTRACT FROM AUTHOR]

Correction for 'Recent advances in fluorescent probes for lipid droplets' by Yanyan Zhao et al., Chem. Commun., 2022, 58, 1495–1509, DOI: 10.1039/D1CC05717K. [ABSTRACT FROM AUTHOR]

Qualitative and quantitative studies of glycosylation patterns of various biologically important proteins represent a key field for the understanding of their complex structure–function relationships. However, the analysis of glycoprotein glycans is usually undermined by tedious sample processing steps prior to detection, including deproteination, desalting and removal of some other non-glycan impurities, which results in considerable sample loss and increased difficulty of quantitative analysis. Herein we report a facile and versatile method for the quantitative isolation of reducing glycans from complex samples using sulfonyl hydrazine-functionalized polystyrene (SHPS) beads, namely the SHPS-based glycan capturing procedure. This method allows the chemoselective and efficient condensation of the aldehyde group of reducing glycans with the active sulfonyl hydrazine group of SHPS beads under anhydrous conditions, resulting in the formation of sulfonyl hydrazone conjugates. The non-glycan components in samples, such as proteins, salts and some other impurities, can be completely removed by washing the sulfonyl hydrazone conjugates. Regeneration of the reducing glycans can be performed via mild hydrolysis of the washed sulfonyl hydrazone conjugates. This procedure is compatible with almost all the current techniques for the derivatization or detection of reducing glycans. We have obtained essential data for this method, including optimized reaction conditions, linearity and reproducibility for glycan quantitation, as well as a final glycan recovery ratio. Moreover, mass spectrometric analysis of the glycans from some complex biological samples, including milk, human blood plasma and fetal bovine serum, was achieved, demonstrating good applicability of this novel procedure. [ABSTRACT FROM AUTHOR]

Chromium oxide (Cr2O3) nanoparticles were found to greatly enhance the chemiluminescence (CL) of the luminol–hydrogen peroxide (H2O2) system. A novel microarray CL method was originally developed for the detection of triacetone triperoxide (TATP). The novel CL method was based on the outstanding catalytic effect of a Cr2O3 nanoparticle array on the CL reaction between lower concentrations of luminol and H2O2, which come from hydrolysis of TATP vapor. The calibration curve of H2O2 was linear over a range of 1.0 × 10−8 to 3.0 × 10−5 M with a detection limit of 1.6 × 10−9 M (R2 = 0.9992, n = 12). The CL method has the advantages of being sensitive, selective, simple, time-saving, high-throughput, and shows good reproducibility. Therefore, these merits would make it easily popular. [ABSTRACT FROM AUTHOR]

Development of efficient, cheap and recyclable catalysts for a reaction under green reaction conditions is still a very attractive topic. In this work, the cycloaddition reactions of CO2 with various epoxides to form five-membered cyclic carbonates catalyzed by chitosan functionalized 1-ethyl-3-methyl imidazolium halides (CS-EMImX, X = Cl, Br) without additional solvent and metal co-catalyst were achieved in high yield and selectivity. The catalyst could be easily recovered and reused five times with high catalytic activity and selectivity. Besides, a possible catalytic cycle for the hydrogen bond assisted ring-opening of epoxide and activation of CO2 induced by the nucleophilic tertiary nitrogen of the chitosan was also proposed. The process represents a simple, ecologically safe and cost-effective route to synthesize cyclic carbonates with high product yield, as well as easy catalyst recycling. [ABSTRACT FROM AUTHOR]

A simple and stable fluorescent off–on probe for discrimination of cysteine (Cys) from glutathione (GSH) has been developed by combining resorufin with 7-nitrobenzofurazan. The probe, displaying distinct emission patterns for Cys and GSH at just one excitation wavelength, can be used for simultaneous determination of Cys and GSH in human plasma. [ABSTRACT FROM AUTHOR]

A new spectroscopic off–on probe, 7-((5-nitrothiophen-2-yl)methoxy)-3H-phenoxazin-3-one, is developed and applied to real-time detection of nitroreductase produced by Escherichia coli. [ABSTRACT FROM AUTHOR]

A new method with high simplicity, rapidity and sensitivity has been developed for visual detection of phosgene based on the distinct color change of cysteine-modified gold nanoparticles. [ABSTRACT FROM AUTHOR]

Development of efficient, cheap and recyclable catalysts for a reaction under green reaction conditions is still a very attractive topic. In this work, the cycloaddition reactions of CO2 with various epoxides to form five-membered cyclic carbonates catalyzed by chitosan functionalized 1-ethyl-3-methyl imidazolium halides (CS-EMImX, X = Cl, Br) without additional solvent and metal co-catalyst were achieved in high yield and selectivity. The catalyst could be easily recovered and reused five times with high catalytic activity and selectivity. Besides, a possible catalytic cycle for the hydrogen bond assisted ring-opening of epoxide and activation of CO2 induced by the nucleophilic tertiary nitrogen of the chitosan was also proposed. The process represents a simple, ecologically safe and cost-effective route to synthesize cyclic carbonates with high product yield, as well as easy catalyst recycling. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are essential for electric vehicles and energy storage devices. With the increasing demand for their production and the concomitant surge in waste generation, the need for an efficient and environmentally friendly recycling process has become imperative. This work presents a new approach for recycling of metals from the LiFePO 4 (LFP) cathode material. The cathode material was first leached by a HCl solution without an oxidizing agent. Subsequently, an ionic-liquid-based aqueous biphasic system (IL-based ABS) was used for the separation of lithium and iron from leachate solutions, followed by a precipitation process. The influence of the acid concentration, solid-to-liquid ratio and leaching time on the leaching yield was investigated. UV-vis absorption spectra revealed the presence of mixed-valent iron in the leachate, with 83 ± 1% Fe(ii) and 17 ± 1% Fe(iii). The ABS systems comprised tributyltetradecylphosphonium chloride [P 44414 ]Cl and a salting-out agent (HCl or NaCl). The extraction percentage of iron reached 90% and less than 1% of lithium was extracted under the studied optimal conditions. Further enhancement of iron extraction, reaching 98%, was achieved via a two-stage cross-current extraction process. Iron was precipitated from the loaded IL phase with an efficiency of 97% as Fe(OH) 2 and Fe(OH) 3 , using an aqueous ammonia solution. Lithium was precipitated as Li 3 PO 4 with a lithium purity of 99.5% by adding K 3 PO 4 solution. The ionic liquid used in the process was efficiently regenerated and used in four extraction cycles with no activity decline, with an extraction percentage of 90% of iron in each cycle., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

A series of La 3(1- x ) Ga 5 MO 14 : x Sm 3+ (M = Si or Ge) orange-red phosphors with high color purity, low correlated color temperature, and good thermal stability were successfully synthesized via a high-temperature solid-phase technique. The phase structure and morphology of La 3 Ga 5 SiO 14 (LGSi): x Sm 3+ and La 3 Ga 5 GeO 14 (LGGe): x Sm 3+ were investigated. Sm 3+ -doped LGSi and LGGe phosphors emitted orange-red light under an excitation of 403 nm, and the optimal doping concentrations were 3 mol% and 2 mol% with excellent color purities of 98.46% and 98.25%, respectively. The concentration quenching mechanism of both the samples was dominated by dipole-dipole interaction, and the effect of Si 4+ and Ge 4+ on luminescence performance was discussed. The internal quantum efficiencies of LGSi:0.03Sm 3+ and LGGe:0.02Sm 3+ were calculated to be 27.14% and 56.07%, respectively. The CIE and CCT values indicated that the luminescence of the prepared phosphors was in the orange-red region. Additionally, a white light-emitting diode (w-LED) was fabricated with LGGe:0.02Sm 3+ phosphors, which was capable of emitting bright and warm white light and exhibiting a high color rendering index (CRI) of 87.17 and an appropriate correlated color temperature (CCT) of 6108 K. These results indicated that the prepared phosphors with excellent luminescent performances have potential application in indoor illumination.

Cascade alkyl migration of 2-alkynylanilines via an aromaticity destruction and reconstruction process is reported. The first alkyl migration is triggered by generation of a dearomatized arenium species via oxidation and cyclization, and the second is driven by the force to restore the aromaticity of rearrangement products. The reaction gave rise to a range of multi-functionalized indoles.

The development of photocatalysis is hindered, in part, by the quick recombination of photogenerated carriers and the instability of light sources. In this study, the problem of too-fast electron-hole pair compounding in photocatalysis is effectively regulated by the polarization field of pyroelectric materials using the pyroelectric method. Self-polarized pyroelectric materials that depend on temperature variations can generate usable electrical energy and polarized charge carriers to degrade organic pollutants. Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) is a relaxor ferroelectric material with spontaneous polarization characteristics. The PMN-0.30PT:1 mol%Sm 3+ catalyst was prepared by applying the high-temperature solid-state reaction method. Under the dark condition and nine cold-hot cycles of 23 °C-68 °C, using H 2 O 2 -assisted PMN-0.30PT:1 mol%Sm 3+ as a catalyst, the degradation rate of rhodamine 6G (10 mg L -1 ) was 94.3 ± 2.5%. In addition, the degradation rates of 88.52% and 64.32% were obtained for rhodamine B (10 mg L -1 ) and methylene blue (10 mg L -1 ), respectively. This study provides a new approach to the pyroelectric catalytic degradation of organic pollutants.

A self-catalytic ampicillin-metal (Fe 3+ )-organic gels (AMP-MOGs (Fe))-H 2 O 2 CL system, which is not influenced by transition metal ions, was studied. A method for CL detection of Staphylococcus aureus (S. aureus) based on the AMP-MOGs (Fe)-H 2 O 2 CL system was achieved. A superior detection limit of 31 CFU mL -1 toward S. aureus was obtained with near-zero background noise.

Mitophagy is a selective form of autophagy by which dysfunctional and damaged mitochondria are degraded in autolysosomes. Since defective mitophagy is closely related to various pathological processes, investigation on the detailed mitophagy process is of great importance. In this respect, disclosing the alterations of mitochondrial microenvironments is expected to be a promising way. However, an appropriate method for monitoring the fluctuations of mitochondrial polarity during mitophagy is still lacking. Here, we report a near-infrared hydroxyl-hemicyanine fluorescent probe that responds to polarity exclusively. Both the shift of emission maxima and the fluorescence intensity ratios at two different wavelengths of the probe can be applied to quantifying the polarity accurately. With ratiometric fluorescence imaging, the polarity differences of normal and cancer cells are clearly discriminated. Most importantly, the mitochondrial polarity variations during starvation and drug-induced mitophagy are determined for the first time. The observed decrease of mitochondrial polarity during mitophagy, together with the rationally designed probe, may facilitate the study on the vital role of mitophagy in physiological and pathological bioprocesses., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Gold nanoparticles are functionalized as a nanoprobe with cresyl violet and porphyrin via hyaluronic acid. The nanoprobe becomes highly fluorescent in the presence of hyaluronidase or under ultraviolet irradiation, and can be used to target cancer cells via the overexpressed CD44 receptor for fluorescence imaging and phototherapy.

We present a complete toolbox to use responsive ionic liquid (IL) emulsions for extraction purposes. IL emulsions stabilized by responsive microgels are shown to allow rapid extraction and reversible breaking and re-emulsification. Moreover, by using a paramagnetic ionic liquid, droplets can be easily collected in low magnetic fields.

This paper presents a novel sensor to detect proteolytically active prostate-specific antigen (PSA) by assembling a purpose-designed FITC-labeled peptide with graphene oxide (GO). The fluorescence of the dye-labeled peptide was quenched in the presence of GO. Reaction of the sensor with PSA cleaves the peptide, leading to the release of the dye moiety and a great increase in fluorescence intensity in a dose- and time-dependent manner, and PSA can be quantified accordingly. This approach is simple compared to existing methods since the GO-peptide-based sensor is easily assembled and detection can be achieved without the involvement of complicated procedures. Moreover, the applicability of the method has been demonstrated by detecting PSA in spiked urine samples.

A new resorufin-based spectroscopic probe, 7-(p-acetoxyphenylmethyloxy)-3H-phenoxazin-3-one (1), has been developed for detecting carboxylesterase activity. The probe is designed by introducing p-acetoxyphenylmethyloxy as a bifunctional moiety to resorufin. The p-acetoxyphenylmethyloxy moiety not only quenches the spectroscopic signal of resorufin, but also serves as a recognition unit for carboxylesterase. As a result, the prepared latent spectroscopic probe 1 shows very low background signal, which is rather desired for achieving sensitive detection. The specific cleavage of the carboxylic ester bond by carboxylesterase induces the hydrolysis of the probe, resulting in the release of resorufin and thereby the recovery of both color and fluorescence signal. This behaviour leads to the development of a simple and sensitive fluorescent method for assaying carboxylesterase activity, with a detection limit of 8.6 × 10(-5) U mL(-1), which is much more sensitive than the existing fluorescence approaches. Moreover, experimental results showed that the probe 1 is cell membrane permeable, and its applicability has been demonstrated for monitoring carboxylesterase activity in HeLa cells.

A graphene oxide-peptide based fluorescence sensor has been developed for matrix metalloproteinase 2 (MMP2), and its applicability has been demonstrated by monitoring the concentration of MMP2 secreted by HeLa cells, revealing that HeLa cells with a density of 5.48 × 10(5) cells per mL can produce 22 nM in cell culture media in 24 h., (This journal is © The Royal Society of Chemistry 2011)

A new cyanine-based near-infrared fluorescent probe has been developed for monitoring tyrosinase activity.

The synthesis of a set of new clickable fluorophores that virtually cover the whole visible spectrum reaching the near infra-red regime is presented herein. Besides dyes that are capable of participating in classical copper catalyzed 1,3-dipolar cycloaddition reactions with the counterparting function we have also prepared dyes containing a cyclooctyne moiety, an alkyne derivative that enables copper free clicking to azides. The suitability of these dyes for fluorescent labeling of biomolecules is presented by examples on model frameworks representing major biopolymer building blocks. The versatility of these dyes is presented in cell labeling experiments as well as by labeling the azide modified surface glycans of CHO-cells either by copper catalyzed or copper-free click reaction. These dyes are expected to have a large variety of applications in (bio)orthogonal labeling schemes both in vivo and in vitro.

Dihydroxyalkenes or their monoprotected alcohol derivatives are transformed to 5,5- and 5,6-spiroketals through a sequence involving an initial iodocyclization, followed by a silver triflate mediated spiroketalization step on the derived hydroxy-iodoether.

4,4'(5')-Bis[2-(9-anthryloxy)ethylthio]tetrathiafulvalene bearing an electron-rich tetrathiafulvalene unit and a luminophore of anthracene shows a highly selective and sensitive chemiluminescence response to singlet oxygen., (Copyright 2004 The Royal Society of Chemistry)