Hemicyanine-Phenothiazine Based Highly Selective Ratiometric Fluorescent Probes for Detecting Hypochlorite Ion in Fruits, Vegetables and Beverages.

Hypochloric acid (HClO) is a reactive oxygen species (ROS) that functions as a bacteriostatic and disinfectant in food production. Excessive levels of ClO-, however, have been linked to various health issues, including cardiovascular diseases (Halliwell and Gutteridge in Oxford University press, USA, 2015), arthritis, and neurodegenerative diseases (Heinzelmann and Bauer in Biol Chem. 391(6):675-693, 2010). Therefore, synthesizing highly selective and sensitive probes for rapidly detecting endogenous ClO- in daily foods is currently a popular research topic (Kalyanaraman et al. in Redox Biol. 15:347-362, 2018; Winterbourn in Nat Chem Biol. 4(5):278-286, 2008; Turrens in J Physiol. 552(2):335-344, 2003). Thus, we have developed two highly selective ratiometric fluorescent probes (Probe1 and Probe2) based on indole-phenothiazine to detect ClO- in common vegetables, fruits and beverages qualitatively and quantitatively. Moreover, Both Probe1 and Probe2 have shown good specificity and stability, with high fluorescence intensity and long duration (Feng et al. in Adv Sci. 5:1800397, 2018; Wei et al. in Angew Chem. 131(14):4595-4599, 2019; Baruah et al. in J Mater Chem B, 2022).

Design, Synthesis, Application and Research Progress of Fluorescent Probes.

Fluorescent probes are sensitive, selective, nontoxic in detection and thus provided a new solution in biomedical, environmental monitoring, and food safety. In order to expand the application of fluorescent probes in various fields, the paper discusses the design, synthesis, and characterization of fluorescent probes, explores new design and development trends of fluorescent probes in various fields, and improves the performance and applicability of fluorescent probes by using new materials and technologies to meet the evolving demands of molecular detection in various fields.

The Detection and Imaging of pH Values in Living Cells with Hemicyanine Based Colorimetric Mitochondria-Targeted Fluorescent Probe.

pH plays a crucial role in cells, especially mitochondria, an important organelle. Developing probes with well-performance for pH detection is still in great demand. Therefore, we first synthesized an indole-based probe (MC-ID-OL) to detect mitochondrial pH changes. The emission wavelength of MC-ID-OL is 649 nm, which does not reach the near-infrared region (650-900 nm). To further enlarge the emission wavelength, probe MC-BI-OL was developed by replacing indolenine with benzoindole. As expected, the emission wavelength changed from 649 to 656 nm. MC-BI-OL probes could also detect pH changes and mitochondria's highly reversible proportional fluorescence localization. In addition, the fluorescence imaging of the MC-BI-OL in HeLa cells demonstrated that this probe could sense changes in the pH of mitochondria in cells.

Rational Construction of a Ni/CoMoO4 Heterostructure with Strong Ni-O-Co Bonds for Improving Multifunctional Nanozyme Activity.

Due to the lack of a general descriptor to predict the activity of nanomaterials, the current exploration of nanozymes mainly depended on trial-and-error strategies, which hindered the effective design of nanozymes. Here, with the help of a large number of Ni-O-Co bonds at the interface of heterostructures, a prediction descriptor was successfully determined to reveal the double enzyme-like activity mechanisms for Ni/CoMoO4. Additionally, DFT calculations revealed that interface engineering could accelerate the catalytic kinetics of the enzyme-like activity. Ni-O-Co bonds were the main active sites for enzyme-like activity. Finally, the colorimetric signal and intelligent biosensor of Ni/CoMoO4 based on deep learning were used to detect organophosphorus and ziram sensitively. Meanwhile, the in situ FTIR results uncovered the detection mechanism: the target molecules could block Ni-O-Co active sites at the heterostructure interface leading to the signal peak decreasing. This study not only provided a well design strategy for the further development of nanozymes or other advanced catalysts, but it also designed a multifunctional intelligent biosensor platform. Furthermore, it also provided preferable ideas regarding the catalytic mechanism and detection mechanism of heterostructure nanozymes.

Arylboronic Acid Catalyzed Dehydrative Mono-/Dialkylation Reactions of ß-Ketoacids and Alcohols.

The dehydrative mono-/dialkylation reactions of alcohols and ß-ketoacids were realized under arylboronic acid catalysis, furnishing a series of ß-aryl ketones and ß-ketoesters in yields of 15-99%, with CO2 and H2O being the byproducts. In this context, the decarboxylative alkylation reaction occurred to give ß-aryl ketones at 50 °C, while the decarboxylation was suppressed to generate dialkylated ester products at 0 °C. A possible catalytic cycle was proposed based on control experiments.

Fabrication of a three-dimensional porous Z-scheme silver/silver bromide/graphitic carbon nitride@nitrogen-doped graphene aerogel with enhanced visible-light photocatalytic and antibacterial activities.

A novel three-dimensional (3D) porous Z-scheme silver/silver bromide/graphitic carbon nitride@nitrogen-doped graphene aerogel (Ag/AgBr/g-C3N4@NGA) photocatalyst was successfully fabricated by a facile hydrothermal and freeze-drying method, and its photocatalytic degradation performance and inactivation effects were also evaluated. The series of characterization results certified that the obtained Ag/AgBr/g-C3N4@NGA synergistically integrates the structural and functional advantages of the Ag/AgBr species and g-C3N4 into the 3D macroscopic porous nitrogen-doped graphene aerogel (NGA) with high conductivity. Benefiting from a unique composition and structure, the obtained Ag/AgBr/g-C3N4@NGA exhibited excellent photocatalytic degradation efficiency for methyl orange (MO), approximately 96% after 30 min of visible-light illumination, which was approximately 1.7 times higher than that of a graphitic carbon nitride@nitrogen-doped graphene aerogel (g-C3N4@NGA). Meanwhile, Ag/AgBr/g-C3N4@NGA possessed high photodegradation efficiency for bisphenol A (BPA), approximately 92% within 120 min. Based on the underlying premise of maintaining the original morphology, the mass loss of Ag/AgBr/g-C3N4@NGA is below 5%, and its excellent photocatalytic performance was also well maintained after eight cycles. Moreover, Ag/AgBr/g-C3N4@NGA has a disinfection effect on E. coli (approximately 6 log inactivation) and S. aureus (approximately 1.2 log inactivation) in 60 min of visible-light illumination, and an excellent disinfection effect on E. coli was maintained after five applications.

Kinetics and thermodynamics studies on the BMP-2 adsorption onto hydroxyapatite surface with different multi-morphological features.

The effect of the surface topography on protein adsorption process is of great significance for designing hydroxyapatite (HA) ceramic material surfaces. In this work, three different topographies of HA materials HA-sheet, HA-rod, and HA-whisker were synthesized and testified by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Brunauer-Emmett-Teller (BET) and a field emission scanning electron microscopy (FE-SEM). We have systematically investigated the adsorption kinetics and thermodynamics of bone morphogenetic proteins (BMP-2) on the three different topography surfaces of HA, respectively. The results showed that the maximum adsorption capacities of HA-sheet, HA-rod and HA-whisker were (219.96 ± 10.18), (247.13 ± 12.35), and (354.67 ± 17.73) µg · g(-1), respectively. Kinetic parameters, rate constants, equilibrium adsorption capacities and related correlation coefficients, for each kinetic model were calculated as well as discussed. It demonstrated that the adsorption of BMP-2 onto HA could be described by the pseudo second-order equation. Adsorption of BMP-2 onto HA followed the Langmuir isotherm. It confirmed that compared with other samples HA-whisker had more adsorption sites for its high specific surface area which could provide more opportunities for protein molecules. The adsorption processes were endothermic (ΔH > 0), spontaneous (ΔG < 0) and entropy increasing (ΔS > 0). A possible adsorption mechanism has been proposed. In addition, the BMP-2 could be adsorbed to the surface which existed slight conformational changes by FT-IR.

A second ortho-rhom-bic polymorph of 4-(Pyridin-4-ylmethoxy)phenol [corrected].

The crystal structure of the title compound, C(12)H(11)NO(2), represents a new ortho-rhom-bic polymorph II of the previously reported ortho-rhom-bic form I [Zhang et al. (2009 ▶) Acta Cryst. E65, o3160]. In polymorph II, the six-membered rings form a dihedral angle of 13.8 (1)° [71.6 (1)° in I], and O-H⋯N hydrogen bonds link mol-ecules into chains along [100], whereas the crystal structure of I features hydrogen-bonded centrosymmetric dimers.