There is limited literature on the modulation of fat crystallization by natural waxes, which are underutilized and cost-effective food industry resources. In this study, the effects of two natural ...waxes (beeswax (BW) and carnauba wax (CW)) on the crystallization behavior of palm kernel stearin (PKS85) were systematically investigated by using differential scanning calorimetry (DSC), pulsed nuclear magnetic resonance (p-NMR), X-ray diffraction (XRD) and polarized light microscope (PLM). CW addition significantly promoted the isothermal crystallization process of PKS85, especially at 20 °C, while BW had no obvious effect on the crystallization rate. BW and CW addition changed the crystal growth mode at 20 °C. BW and CW could participate in the crystallization of TAGs in PKS85, induce the formation of a new hydrocarbon chain distances of 3.70 and 4.15 Å and decrease the lamellar distance (d(001)) and domain size (ξ) of the single crystallites, leading to a different morphology of fat crystals. Our findings indicated that BW and CW could modulate the fat crystal structure and possibly engineer the functional properties of fats and fat-structured materials, which also provided new application of natural waxes in the food industry.
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•CW addition promoted the isothermal crystallization process of PKS85.•BW and CW addition changed the crystal growth mode at 20 °C.•BW and CW induced a new hydrocarbon chain distances of 3.70 and 4.15 Å.•BW and CW decreased the lamellar distance and domain size of single crystallite.•BW and CW significantly changed the crystal morphology of PKS85.
Principle has it that even the most advanced super‐resolution microscope would be futile in providing biological insight into subcellular matrices without well‐designed fluorescent tags/probes. ...Developments in biology have increasingly been boosted by advances of chemistry, with one prominent example being small‐molecule fluorescent probes that not only allow cellular‐level imaging, but also subcellular imaging. A majority, if not all, of the chemical/biological events take place inside cellular organelles, and researchers have been shifting their attention towards these substructures with the help of fluorescence techniques. This Review summarizes the existing fluorescent probes that target chemical/biological events within a single organelle. More importantly, organelle‐anchoring strategies are described and emphasized to inspire the design of new generations of fluorescent probes, before concluding with future prospects on the possible further development of chemical biology.
See below the surface: Fluorescent probes that target individual organelles and elucidate their functionalities are systematically summarized in this Review. The design strategy towards organelle targeting will shed light on basic studies of cell biology.
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•Superhydrophobic POSS-GO was obtained by grafting reaction of POSS-NH2 and GO.•The dispersibility of GO was greatly improved by connecting POSS in many solvents.•The POSS-GO with ...special function was good for anticorrosion ability of coating.
Super-hydrophobicity polyhedral oligomeric silsesquioxane-modified graphene oxide (POSS-GO) was synthesized by one-step reaction between graphene oxide (GO) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS-NH2). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra indicated that the POSS were successfully connected to the edge and surface of GO nanosheets. Scanning probe microscope (SPM) and transmission electron microscope (TEM) images demonstrated that the POSS-GO with a thickness of 1.58 nm presented a stably dispersion in anhydrous ethanol. Results from electrochemical behaviors showed that the proper incorporation of POSS-GO could availably improve the anticorrosion ability of epoxy based coatings in simulate marine environment (3.5 wt% NaCl solution). The good dispersion of POSS-GO helped to fill the original defect and enhanced the complication of penetration path. The super-hydrophobicity of POSS-GO was beneficial to the reduction of actual contact zone. The synergistic effect of good dispersion and super-hydrophobicity promoted the enhancement of anticorrosion ability for composite coatings.
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•Sewage Treatment Plants are significant sources of microplastics (MPs).•Up to 99% of MPs’ can be removed during conventional wastewater (WW) treatment.•MPs accumulate to sludge, lack ...of data for possible changes during treatment.•Careful selection of advanced treatment process has positive impact on MPs removal.•A standardized protocol for MPs’ sampling, pretreatment and analysis is needed.
Microplastics are plastic fragments lower than 5 mm that are detected in the environment causing various effects on organisms. Several research articles have recognized Sewage Treatment Plants as important sources of polyethylene and polypropylene beads, polyester, polyamide and other types of microplastics. For their determination, techniques such as visual identification using microscope, Fourier-transform infrared and RAMAN spectroscopy are used, while chemical oxidation, enzymatic maceration and density separation are applied as pretreatment methods for the removal of the inorganic and organic content. Microplastics’ concentrations range up to 3160 particles L−1, 125 particles L−1 and 170.9 × 103 particles Kg-1 TS dw in raw, treated wastewater and sludge, respectively. Their removal during wastewater treatment ranges between 72% and 99.4%; the main processes that contribute to their removal are primary and secondary treatment, while the effect of tertiary treatment depends on the applied technology. Entrapment in suspended solids and accumulation to sludge are the major mechanisms governing their fate. A standardized protocol for samples’ collection and pretreatment as well as microplastics’ isolation and characterization is needed; future reseach should investigate the possible chemical and physical changes of microplastics during treatment, and their role as carriers for the transfer of emerging micropollutants.
In vivo quantitative measurement of biodistribution plays a critical role in the drug/probe development and diagnosis/treatment process monitoring. In this work, we report a probe, named ...AIE-SRS-Mito, for imaging mitochondria in live cells via fluorescence (FL) and stimulated Raman scattering (SRS) imaging. The probe features an aggregation-induced emission (AIE) characteristic and possesses an enhanced alkyne Raman peak at 2223 cm–1. The dual-mode imaging of AIE-SRS-Mito for selective mitochondrion-targeting was examined on a homemade FL–SRS microscope system. The detection limit of the probe in the SRS imaging was estimated to be 8.5 μM. Due to the linear concentration dependence of SRS and inertness of the alkyne Raman signal to environmental changes, the intracellular distribution of the probe was studied, showing a local concentration of >2.0 mM in the mitochondria matrix, which was >100-fold higher than the incubation concentration. To the best of our knowledge, this is the first time that the local concentration of AIE molecules inside cells has been measured noninvasively and directly. Also, the nonquenching effect of such AIE molecules in cell imaging has been verified by the positive correlation of FL and SRS signals. Our work will encourage the utilization of SRS microscopy for quantitative characterization of FL probes or other nonfluorescent compounds in living biological systems and the development of FL–SRS dual-mode probes for specific biotargets.
Imaging the transcriptome in situ with high accuracy has been a major challenge in single-cell biology, which is particularly hindered by the limits of optical resolution and the density of ...transcripts in single cells
. Here we demonstrate an evolution of sequential fluorescence in situ hybridization (seqFISH+). We show that seqFISH+ can image mRNAs for 10,000 genes in single cells-with high accuracy and sub-diffraction-limit resolution-in the cortex, subventricular zone and olfactory bulb of mouse brain, using a standard confocal microscope. The transcriptome-level profiling of seqFISH+ allows unbiased identification of cell classes and their spatial organization in tissues. In addition, seqFISH+ reveals subcellular mRNA localization patterns in cells and ligand-receptor pairs across neighbouring cells. This technology demonstrates the ability to generate spatial cell atlases and to perform discovery-driven studies of biological processes in situ.
The dynamics of enzymes are directly associated with their functions in various biological processes. Nevertheless, the ability to image motions of single enzymes in a highly parallel fashion remains ...a challenge. Here, we develop a DNA origami raft-based platform for in-situ real-time imaging of enzyme cascade at the single-molecule level. The motions of enzymes are rationally controlled via different tethering modes on a two-dimensional (2D) supported lipid bilayer (SLB). We construct an enzyme cascade by anchoring catalase on cholesterol-labeled double-stranded (ds) DNA and glucose oxidase on cholesterol-labeled origami rafts. DNA functionalized with cholesterol can be readily incorporated in SLB via the cholesterol–lipid interaction. By using a total internal reflection fluorescence microscope (TIRFM), we record the moving trajectory of fluorophore-labeled single enzymes on the 2D surface: the downstream catalase diffuses freely in SLB, whereas the upstream glucose oxidase is relatively immobile. By analyzing the trajectories of individual enzymes, we find that the lateral motion of enzymes increases in a substrate concentration-dependent manner and that the enhanced diffusion of enzymes can be transmitted via the cascade reaction. We expect that this platform sheds new light on studying dynamic interactions of proteins and even cellular interactions.
To understand the removal of particles from surfaces by water drops, we used an inverted laser scanning confocal microscope to image the collision between a water drop and a particle on a flat ...polydimethylsiloxane (PDMS) surface. The dynamic drop-particle contact line was monitored by fixing the drop directly above the objective lens while moving the sample stage at well-defined speeds (10-500 μm s
−1
). The lateral force acting on the drop during the collision was measured as a function of speed, using a force sensor mounted on the microscope. Depending on the collision speed, the particle either stays attached at the rear of the drop or detaches from it. We propose a criterion to determine whether the particle remains attached to the drop based on the capillary and resistive forces acting on the particle during the collision. The forces measured when the particle crosses the air-water interface are compared to existing models. We adapted these to account for rolling of the particle. By comparing our experimental measurements with an analytical model for the capillary torque acting on a particle rolling at an interface, we provide detailed insights on the origins of the resistive force acting on the particle when it is pushed or pulled by the drop. A low friction force between the surface and the particle increases the likelihood of particle removal.
Possible outcomes when a particle collides with a water drop on a hydrophobic surface.
The construction of atomically precise carbon nanostructures holds promise for developing materials for scientific study and nanotechnology applications. Here, we show that graphene origami is an ...efficient way to convert graphene into atomically precise, complex nanostructures. By scanning tunneling microscope manipulation at low temperature, we repeatedly fold and unfold graphene nanoislands (GNIs) along an arbitrarily chosen direction. A bilayer graphene stack featuring a tunable twist angle and a tubular edge connection between the layers is formed. Folding single-crystal GNIs creates tubular edges with specified chirality and one-dimensional electronic features similar to those of carbon nanotubes, whereas folding bicrystal GNIs creates well-defined intramolecular junctions. Both origami structural models and electronic band structures are computed to complement analysis of the experimental results. The present atomically precise graphene origami provides a platform for constructing carbon nanostructures with engineered quantum properties and, ultimately, quantum machines.
As a monolayered version of nanoscale metal–organic frameworks (nMOFs), nanoscale metal–organic layers (nMOLs) represent an emerging class of highly tunable two-dimensional materials for hierarchical ...functionalization and with facile access to analytes. Here we report the design of the first nMOL-based biosensor for ratiometric pH and oxygen sensing in mitochondria. Cationic Hf12-Ru nMOL was solvothermally synthesized by laterally connecting Hf12 secondary building units (SBUs) with oxygen-sensitive Ru(bpy)3 2+-derived DBB-Ru ligands (bpy = 2,2′-bipyridine). The Hf12-Ru nMOL was then covalently functionalized with pH-sensitive fluorescein isothiocyanate and pH/oxygen-independent Rhodamine-B isothiocyanate through thiourea linkages to afford Hf12-Ru-F/R as a mitochondria-targeted ratiometric sensor for pH and O2 in live cells. High-resolution confocal microscope imaging with Hf12-Ru-F/R revealed a positive correlation between pH and local O2 concentration in mitochondria. Our work shows the potential of nMOL-based ratiometric biosensors in sensing and imaging of biologically important analytes in live cells.
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