Effect Of Zn2 Research Articles

Micromorphology evolution and properties of strontium-zinc-phosphate chemical conversion coatings on Ti:Effect of Zn2+ and Ca2+ in the reaction solution

Bioactive strontium zinc phosphate (SrZn2(PO4)2, SZP) coatings have attracted much attention in the surface modification of medical metal materials. And the micro-morphologies of that coating have an important influence on cellular function and osseointegration. This study prepared a variety of micro-morphology SrZn2(PO4)2 coatings on titanium (Ti) using the phosphate chemical conversion (PCC) method. The effect of Zn2+ concentration in the reaction solution on the micro-morphology and properties of the SZP coatings was studied. The results showed that the SZP crystal size increased with increasing concentration of Zn2+ in the reaction solution, which also led to a more regular morphology of the coatings on Ti. A corresponding increase in the thickness, hydrophilicity, and roughness of the SZP coatings was also observed because of the increase in Zn2+ concentration. The bond strength of the coatings showed an initial increase followed by a slight decline with rising Zn2+ concentration. Moreover, the addition of Ca2+ in the reaction solution also significantly affected the micro-morphology of the SZP coatings, changing the crystal morphology from rectangular blocky to shuttle-shaped lamellar. The wettability, bonding strength, porosity, and ion release rate of the coatings were also increased because of the addition of Ca2+. This study elucidated the mechanism of Zn2+ and Ca2+ ions in the reaction solution on the morphology and properties of SZP coatings. The findings provided a novel approach to controlling and optimizing the micro-morphology of phosphate coatings to enhance their osteogenic activity.

Effects of Zn2+/Si4+ co-doping on the cation distribution, crystal structure, and microwave dielectric characteristics of spinel-structured MgAl2O4 ceramics

Investigating the relationship between the structure and dielectric properties of cation-mixed spinel ceramics is crucial for overcoming the limitations of conventional microwave materials. In this study, MgAl2-x(Zn0.5Si0.5)xO4 (x = 0, 0.02, 0.04, 0.06, and 0.08) ceramics were prepared by a solid-state reaction method. The co-substitution for Al with Zn2+/Si4+ induces Al3+ cations for preferential occupation of the 8a site in the oxygen tetrahedra, forming a solid-solution ceramic at x ≤ 0.06. Enhanced ionic diffusion and compressive stress contribute to a dense microstructure (ρ > 95%) with uniform grain-size distribution after heating at 1650 °C for 4 h. Raman and 27Al NMR spectra reveal a relationship between cation distribution and covalency, consistent with the results of Rietveld refinement. The increases in cation disorder and degree of inversion are accompanied by an enhanced covalency of the Al–O bonds, which reduces intrinsic dielectric loss. In addition, the combination of Shannon ion polarizability and bond valence theory suggests that the increases in permittivity (εr) and the temperature coefficient of resonant frequency (τf) are related to the high polarizability of the dopant ions and the abnormal polarizability derived from the decreasing bond valence of the Al2–O site. The sample at x = 0.06 exhibits a low εr of 8.31, high Q × f of 194,159 GHz (at ∼11.35 GHz), and τf of -30.8 ppm/°C, indicating superior microwave application prospects as compared with traditional Mg-Al spinel ceramics.

The effect of Zn2+ on the positive electrolyte for all-vanadium redox flow battery

In this work, the effects of Zn2+ on the electrochemical activity of positive electrolyte were researched by cyclic voltammetry(CV), AC impedance. The results of CV showed that the positive electrolyte containing 2 wt% Zn2+ as additive had the best electrochemical activity. Compared with the electrolyte without any additive, the electrolyte with 2 wt% Zn2+ obviously enhanced electrochemical activity and reversibility of Farady reaction. In addition, the kinetic study of the mass transfer process indicated that the diffusion coefficient obviously increased. Besides, the results of electrochemical impedance spectroscopy implied that the internal charge transfer resistance of the electrolyte electrochemical system containing Zn2+ as an additive was significantly reduced. This indicated that the charge transfer was significantly accelerated, which was beneficial to the improvement of the electrochemical activity. Moreover, the study of the electrolyte stability showed that the electrolyte containing Zn2+ had superior stability yet after 30 cycles’ scanning.

Effect of Zn2+–Ti4+ co-doping on the structural, infrared, surface, magnetic, electric and dielectric parameters of nanoscale CoFe2O4

Effect of Zn2+–Ti4+ co-doping on the structural, infrared, surface, magnetic, electric and dielectric parameters of nanoscale CoFe2O4

The Effect of Zn2(BDC)2 Metal Organic Framework on the Miscibility and Properties of Poly(Lactic Acid)/Poly(Butylene Adipate-co-Terephthalate) Biodegradable Blends

In our research described in this paper, the metal-organic framework MOF-2 [Zn2(BDC)2] was used to enhance the properties of a biodegradable blend based on poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT). PLA/PBAT/(1, 3, 5, and 7 wt%) MOF-2 blends were prepared using a melt blending technology with a twin-screw extruder. The phase morphology, rheological behavior and barrier properties of the blends were studied. X-ray diffraction (XRD) showed a slight increase in the crystalline content of the PLA/PBAT matrix with increasing MOF-2 content. Scanning electron microscopy (SEM) revealed that the PLA/PBAT blend was immiscible, and the phase morphology improved with MOF-2 by enhancing the interfacial compatibility, reducing the size of micro-domains and cavities, and promoting a transition to a co-continuous morphology, indicating better miscibility. The ternary nanocomposites with 5 and 7 wt% MOF-2 showed increased complex viscosity (η*) and storage modulus (G′) compared to those with 1 and 3% MOF-2, indicating stronger percolated networks. The thermal and barrier properties and water absorption capacity were also improved, confirming the rheological measurements. All the results showed that the PLA/PBAT/MOF-2 nanocomposites could be used in the field of packaging.

Effect of substituted cobalt–chromium–iron oxides’ dissolution kinetics in oxidizing formulation on decontamination process

Removing radioactive corrosion products from Cr-containing iron oxides require a multi-step and multi-cycle decontamination process. The present article brings out the effect of divalent metal ion substitution on the release rate of chromium in the oxidative pre-treatment step. The non-stoichiometric cobalt chromium ferrites were synthesized, characterized and effect of Zn2+/Ni2+ substitution on the dissolution behavior was probed. The dissolution rates decreased with increasing the degree of inclusion and showed minima at ~ 0.4–0.6 atom% which is explained on the basis of lattice structure. It is concluded that the dissolution kinetics of native nickel–chromium ferrites in reactors increases with metal ion inclusion.

Effect of Zn2+ doping on the structure and metal–insulator transition of La2CuO4 ceramics

The structure and electrical properties of layered perovskites La2Cu1-xZnxO4 have been investigated. The resistivity of these samples has been measured in the temperature range of 90–300 K. The Zn2+doping induces a shift of the metal–insulator transition temperature towards the high-temperature region. The d9 electronic configuration of Cu2+ in La2CuO4 leads to an uneven distribution of electron clouds, inducing axial stretching of the surrounding oxygen octahedra and resulting in Jahn-Teller distortion. After Zn2+ doping, the charge compensation induces a partial transformation of Cu2+ to Cu+. As a result, the positions occupied by Cu2+ are replaced by Zn2+ and Cu+ with perfectly symmetric electron clouds in the 3d10 outer electronic configuration, thus suppressing the Jahn-Teller effect. This shifts the phonon scattering, which is responsible for the emergence of the metal’s conductive properties, to higher temperatures.

Facile Synthesis of Sodium Dodecyl Sulfate Intercalated Mg‐Al LDH and its Excellent Adsorption Performances for Cu2+ from Aqueous Solution

AbstractIn this study, the magnesium aluminum layered double hydroxide intercalated with sodium dodecyl sulfate (Mg‐Al S‐LDH) was synthesized by using a roasting–restoration method based on the Mg‐Al LDH precursor, and their effectiveness in removing Cu2+ from aqueous solutions was investigated. Detailed microstructural characterization of these adsorption materials involved employing X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption/desorption isotherms (N2 ad/desorption), and thermogravimetric‐differential thermal gravimetric analysis (TG‐DTG). The experimental results revealed that Mg‐Al S‐LDH displayed a plate‐like layered structure with a larger surface area and enhanced adsorption ability. Specifically, the maximum adsorption capacity, reaching 96.15 mg ⋅ g−1, was achieved at a temperature of 298 K, accompanied by a rapid adsorption rate. The adsorption kinetics adhered to the pseudo‐second‐order model, suggesting that chemisorption controlled the adsorption behavior. Furthermore, the adsorption of Cu2+ followed the Freundlich model, signifying a multi‐site adsorption mechanism onto the surface and layers of Mg‐Al S‐LDH. Thermodynamic investigations indicated that higher temperatures facilitated Cu2+ dissolution and strengthened the affinity with Mg‐Al S‐LDH, with a positive ΔHΘ value suggesting that the Cu2+ adsorption process was endothermic and temperature‐enhancing. Ion selectivity experiments demonstrated that Cd2+ and Pb2+ ions had a significant impact on Cu2+ adsorption, while the effects of Zn2+ and Fe2+ ions were less pronounced. The primary adsorption mechanisms of Cu2+ onto Mg‐Al S‐LDH encompassed precipitation, complexation on the surface and layers, and isomorphous substitution. This study sheds light on the promising potential of Mg‐Al S‐LDH as an effective adsorbent for heavy metal removal and provides valuable insights into its adsorption mechanisms and performance in different environmental conditions.

Zn2+ Binding Increases Parallel Structure in the Aβ(16-22) Oligomer by Disrupting Salt Bridge in Antiparallel Structure.

The aggregation of monomeric amyloid β protein (Aβ) into oligomers and amyloid plaque in the brain is associated with Alzheimer's disease. The hydrophobic central core Aβ16-22 has been widely studied due to its essential role in the fibrillization of full-length Aβ peptides. Compared to the homogeneous antiparallel structure of Aβ16-22 at the late stage, the early-stage prefibrillar aggregates contain varying proportions of different β structures. In this work, we studied the appearance probabilities of various self-assembly structures of Aβ16-22 and the effects of Zn2+ on these probabilities by replica exchange molecular dynamics simulations. It was found that at room temperature, Aβ16-22 can readily form assembled β-sheet structures in pure water, where a typical antiparallel arrangement dominates (24.8% of all sampled trimer structures). The addition of Zn2+ to the Aβ16-22 solution will dramatically decrease the appearance probability of antiparallel trimer structures to 12.5% by disrupting the formation of the Lys16-Glu22 salt bridge. Meanwhile, the probabilities of hybrid antiparallel/parallel structures increase. Our simulation results not only reveal the competition between antiparallel and parallel structures in the Aβ16-22 oligomers but also show that Zn2+ can affect the oligomer structures. The results also provide insights into the role of metal ions in the self-assembly of short peptides.

Development of CuO and CuO:Zn2+ nano-oxides for dye degradation and pharmaceutical studies

The effect of Zn2+ doping on photocatalytic and biomedical properties of CuO synthesized by the simple hydrothermal method was analyzed in this study. The phase structure, morphology, and surface chemistry of synthesized CuO and CuO:Zn2+ samples were analyzed. XRD analysis revealed the monoclinic phase of synthesized CuO. Due to the concentration of precursors and optimization of processing conditions, the morphology of CuO appears to be like pine needles. It is transformed from pine needles to blocks by incorporating Zn into the CuO matrix. In this study, CuO and CuO:Zn2+ photocatalysts were used for the degradation of Methylene Blue (MB) dye under UV light irradiation. The photocatalytic degradation process was studied under different conditions, including time-based study, pH, and catalyst concentration. Results showed that both CuO and CuO:Zn2+ photocatalysts were effective in degrading MB dye under UV light irradiation. The rate of dye degradation increased with increasing irradiation time. Moreover, the MTT approach was employed to evaluate the cell viability of MCF-7 cancer cells both in the absence and presence of UV radiation. The proportion of MCF-7 cells destroyed was elevated due to the easy diffusion of CuO and CuO:Zn2+ nano-oxides into cancer cells in anticancer activity without UV light. The anticancer activity under UV light was augmented, which was attributed to an increase in ROS generation caused by the increased dose of these CuO and CuO:Zn2+ compounds. As a result, these CuO and CuO:Zn2+ can potentially be used as drug delivery systems, and their low toxicity and therapeutic properties make them suitable for use as photosensitizers on MCF-7 cells when exposed to UV radiation.

Effect of Zn2+, S2−, Mo4+ and V5+ single doped BiTa7O19:Er3+/Yb3+ on upconversion luminescence intensity under 980 nm laser excitation

On the basis of BiTa7O19 (BTO):0.1Er3+/0.4 Yb3+, Zn2+, S2−, Mo4+ and V5+ single doped upconversion phosphors (UCP) were successfully prepared by solid phase sintering. The lattice structure, particle size and diffuse reflectance spectra were measured by X-ray diffraction, scanning electron microscope and spectrophotometer. Upconversion luminescence (UCL) spectra of these UCP were investigated under 980 nm laser excitation with power density from 1.82 to 124.99 W/cm2. Zn2+ doped UCP can obtain the highest UCL intensity when excitation power density is less than 56.91 W/cm2, and Mo4+ doped UCP can obtain the highest UCL intensity when excitation power density is from 56.91 to 124.99 W/cm2. The UCL intensity of all samples increases first and then decreases with the increase of excitation power. By measuring UCL intensity changes with the excitation power of the UCP mixing with BN and UCP in vacuum and atmosphere, the experimental results show that the increase of temperature caused by laser excitation is the reason for the decrease of UCL intensity under high power excitation. Utilizing LIR technology, it is proven that at high power 90.95 W/cm2, Mo4+ and Zn2+ single doped can decrease and increase the UCP temperature under the same power density excitation compared with BTO:0.1Er3+/0.4 Yb3+, respectively. The maximum relative temperature sensitivity of all UCP is calculated in the range of 0.00767–0.00854 K−1 at 303 K. All experiments show that Zn2+ and Mo4+ single-doped UCP are suitable for temperature sensing and luminescence imaging under low and high-power excitation, respectively.

Zn2+ Differentially Influences the Neutralisation of Heparins by HRG, Fibrinogen, and Fibronectin.

For coagulation to be initiated, anticoagulant glycosaminoglycans (GAGs) such as heparins need to be neutralised to allow fibrin clot formation. Platelet activation triggers the release of several proteins that bind GAGs, including histidine-rich glycoprotein (HRG), fibrinogen, and fibronectin. Zn2+ ions are also released and have been shown to enhance the binding of HRG to heparins of a high molecular weight (HMWH) but not to those of low molecular weight (LMWH). The effect of Zn2+ on fibrinogen and fibronectin binding to GAGs is unknown. Here, chromogenic assays were used to measure the anti-factor Xa and anti-thrombin activities of heparins of different molecular weights and to assess the effects of HRG, fibrinogen, fibronectin, and Zn2+. Surface plasmon resonance was also used to examine the influence of Zn2+ on the binding of fibrinogen to heparins of different molecular weights. Zn2+ had no effect on the neutralisation of anti-factor Xa (FXa) or anti-thrombin activities of heparin by fibronectin, whereas it enhanced the neutralisation of unfractionated heparin (UFH) and HMWH by both fibrinogen and HRG. Zn2+ also increased neutralisation of the anti-FXa activity of LMWH by fibrinogen but not HRG. SPR showed that Zn2+ increased fibrinogen binding to both UFH and LMWH in a concentration-dependent manner. The presented results reveal that an increase in Zn2+ concentration has differential effects upon anticoagulant GAG neutralisation by HRG and fibrinogen, with implications for modulating anti-coagulant activity in plasma.

Zn2+/Poly(2‐Hydroxyethyl Acrylate/Itaconic Acid) Hydrogels as Potential Antibacterial Wound Dressings

AbstractAntibacterial hydrogels, as an advanced approach, can create optimal conditions for wound healing, even in the fight against stubborn and difficult‐to‐treat wound infections. Interestingly, pH is an often neglected clinical parameter, although it has a significant impact on the wound healing process. At different stages of wound healing, the pH in the wound bed changes from slightly alkaline to neutral to acidic. To develop novel pH‐sensitive antibacterial hydrogel dressings, Zn2+‐loaded poly(2‐hydroxyethyl acrylate/itaconic acid) hydrogels are synthesized. The hydrogels exhibit pH‐sensitive swelling in the physiologically relevant pH range, with a pronounced swelling ability at neutral pH. The controlled release of Zn2+ occurs in a buffer of pH 7.40 at 37 °C. The liquid transport mechanism and release kinetics are evaluated using the specific kinetic models of Ritger‐Peppas and Peppas‐Sahlin. The effect of Zn2+ on structural, thermal, swelling, cytocompatibility, and antibacterial properties is evaluated by Fourier transform infrared spectroscopy, differential scanning calorimetry, swelling studies, MTT, and antibacterial tests. The hydrogels show excellent antibacterial activity against Escherichia coli. The research opens new perspectives for efficient wound healing management, and the extension of the study will be orchestrated by optimising the hydrogel composition to achieve improved performance.

Effect of Zn2+ ion substitution in Al3+-substituted rare-earth free Sr-hexaferrite for different permanent magnet applications

Effect of Zn2+ ion substitution in Al3+-substituted rare-earth free Sr-hexaferrite for different permanent magnet applications

First-Principles Simulations for the Effect of Zinc Ions on MnO2/water system

The aqueous zinc-ion battery (AZIB), with its excellent power density, high energy density, safety, and sustainability, is a potential energy storage device. Manganese dioxide (MnO2), as the cathode material of AZIB, has shown exceptional electrochemical performance due to its multiple valence states and outstanding ion storage performance. Nevertheless, the energy storage process of MnO2 remains controversial. In order to explain the energy storage process of MnO2 in AZIB, it is necessary to explore the effect of Zinc ions (Zn2+) on the structure of the MnO2/water interface at the atomic scale. The effect of Zn2+ on the structure of MnO2/water interface systems was examined in this work using molecular dynamics simulation. Two representative crystal phases of MnO2, including α-MnO2 and δ-MnO2, were considered. The results revealed that Zn2+ will affect the structural stability of the MnO2/water interface system, and the degree of structural deformation in MnO2 varies with its crystal phase. Moreover, Zn2+ for both the α-MnO2/water and δ-MnO2/water systems prefer to be stabilized at the interface near MnO2 and the water, forming a spinel-like product. These results offer a fresh understanding of the MnO2 energy storage process in AZIBs and can help in the development of high-performance cathode materials.

Cathodic Polarization Behavior of Steel in Aqueous MgCl2 Solutions Containing Zn2+

So far, we have revealed that the dissolution rate of zinc is accelerated in relative high concentrations of MgCl2 in the corrosion process of galvanic couples consisting of zinc and steel. In this study, we investigated the cathodic polarization behavior of steel in MgCl2 solution containing Zn2+ and the effect of Zn2+ dissolved in the solution on the oxygen reduction reaction and hydrogen evolution reaction.The specimens used in the experiments were carbon steel SS400 (Fe-0.12C-0.60Mn-0.011P-0.019S) machined into a 1.5×1.5×0.3 cm3. One side of the specimen was polished with SiC abrasive paper up to #2000 grit and degreased in acetone before being used for the experiment. The test solution was mixtures of 0.25 M MgCl2 + x mM ZnCl2 (x = 2.5, 5 mM, Mg/Zn molar ratio: 100, 50) at room temperature under a naturally aerated condition. As a comparison solution, 0.5 M NaCl + y mM ZnCl2 (x = 5, 10 mM, molar ratio of Na/Zn: 100, 50) with the same chloride ion concentrations were used. Cathodic polarization curves of steel were measured using a three-electrode method with a platinum wire as the counter electrode and an Ag/AgCl electrode (saturated KCl, SSE) as the reference electrode. The potential sweep rate was 0.5 mV/s. After the polarization test, the specimen surfaces were observed with a scanning electron microscope and analyzed for corrosion products formed during cathodic polarization with XRD and laser Raman spectroscopy.The cathodic polarization behavior of steel in MgCl2 solution without Zn2+ was investigated and compared with that of NaCl solution without Zn2+. Diffusion-limited currents of dissolved oxygen reduction (ORR) were observed at -0.6 V to -0.8 V in MgCl2 and NaCl solutions. Furthermore, cathodic polarization in MgCl2 and NaCl solutions showed an increase in current due to hydrogen evolution reaction (HER), and the cathodic current due to HER on steel was larger in the MgCl2 solution than in the NaCl solution. To investigate the difference in HER in both solutions, the steel surface was observed after constant polarization at -1.0 V for 20 min. Mg(OH)2 deposition was observed on the steel surface in the MgCl2 solution, but not in the NaCl solution. This indicates that the increase in pH due to ORR and HER is mitigated by the formation of Mg(OH)2 during cathodic polarization. Therefore, due to the pH buffering action of Mg2+ associated with the formation of Mg(OH)2, it can be considered that a larger HER current flowed in the MgCl2 solution than in the NaCl solution when compared at the same potential.On the other hand, cathodic polarization curves for steel in MgCl2 and NaCl solution containing Zn2+ were investigated. As a result, ORR and HER were observed at potentials down to -1 V in the MgCl2 and NaCl solutions containing Zn2+; the cathodic current due to ORR and HER in the MgCl2 and NaCl solutions containing Zn2+ was reduced compared to the solutions without Zn2+. The inhibition of ORR and HER can be attributed to the precipitation of Zn corrosion products.These results suggest that in solution environments containing Mg2+ and Zn2+, the promotion of HER by the effect of Mg2+ and the inhibition of HER and ORR by Zn corrosion products occur simultaneously.

Fabrication of p-ZnCo2O4/n-Si spinel heterojunction devices for self-powered ultraviolet photodetectors: Effect of Zn2+ concentration

Pure and zinc-doped cobalt oxide heterojunction devices on n-type silicon substrates have been fabricated via sol-gel spin coating deposition. The fabricated devices have been characterized by XRD, Raman spectroscopy, FESEM, and EDS elemental mapping. The fabricated heterojunction devices show non-linear I-V characteristics, which suggests their diodic behavior. A blend of mathematical and physical methods that are based on the Lambert W function and the modified Shockley equation has been used to examine the performances of the devices. The UV sensing measurements were conducted on the devices under zero bias conditions while they were subjected to UV light with wavelengths of 365 and 254 nm. The study has indicated that Co3O4 in its pure form does not exhibit activity towards either UV wavelength. However, the introduction of Zn2+ into Co3O4 results in a notably substantial photoresponse of approximately 978 %, 1393 %, and 2400 % for Zn2+ concentrations of 5 %, 15 %, and 30 %, respectively, when exposed to 365 nm UV radiation. The responsivity value of the fabricated devices was found to increase from 0.026 mA/W to 15.82 mA/W with an increase in Zn2+ from 5 % to 30 %. Detectivity and EQE values of the devices also demonstrate remarkable increase from 7.50 × 108 cmHz1/2/W (5 % Zn2+) to 2.86 × 1010 cmHz1/2/W (30 % Zn2+) and from 0.009 % (5 % Zn2+) to 5.39 % (30 % Zn2+) respectively. The increase in Zn2+ concentration also increases the linear dynamic range (LDR) value from 20.65 dB to 27.96 dB.

Effects of zinc ion concentrations on the performance of SBR treating livestock wastewater and analysis of microbial community

Zinc ion (Zn2+) is a frequently occurring heavy metal in livestock wastewater. The effects of Zn2+ on the physicochemical properties and the microbial distribution of activated sludge are essential to controlling nitrogen removal performance. Nevertheless, there are raw studies on the effects of Zn2+ on nitrogen removal. This study investigated the effect of Zn2+ on the treatment performance of livestock wastewater in a sequencing batch reactor (SBR). The results indicated the low Zn2+ concentrations could improve nitrogen removal performance. However, as the Zn2+ concentration increased, the total nitrogen (TN) removal performance of the reactor gradually deteriorated. When the Zn2+ concentration was 90.00 mg/L, the TN removal efficiency was the lowest, only 2.40%. The contents of the Extracellular polymeric substance (EPS) presented a trend of first increasing and then decreasing with the increase of Zn2+ concentration, and the main reason was the decrease of protein-like and tryptophan-like. The 16SrRNA analysis indicated that Zn2+ within a specific concentration could increase the operational taxonomic units (OTUs) number, microbial richness, and diversity of microorganisms in the SBR. However, with Zn2+ concentration exceeding 10.00 mg/L, the relative abundance of denitrification functional bacteria (Dechloromonas, Nitrospira, and Thauera) decreased.

A pH-sensitive fluorescent probe based on hemicyanine dyes for responding microenvironment changes of cardiomyocytes induced by Zn2+

The physiological state of myocardium is closely related to human health. Adverse physiological processes will lead to significant fluctuations in cardiomyocytes microenvironment, and even myocardial damage. So, it is particularly necessary to achieve the goal that monitoring cardiomyocytes microenvironment changes. Herein, we developed a new pH-sensitive fluorescent probe (3-ethyl-2-(4-hydroxy-3,5-dimethoxystyryl) benzo[d]thiazol-3-ium hemicyanine, named ETHC). The probe could respond to the pH in solution via both single fluorescence channel and ratio fluorescence as the output signal with great stability and biocompatibility. Then, the effect of Zn2+ on cardiomyocyte microenvironment was successfully monitored by ETHC through the significant changes of red channel fluorescence, which proved that Zn2+, just as resveratrol (Res), had excellent synergistic effect on cardiomyocyte protection. The subsequent carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and ionomycin/Ca2+ treatment confirmed that the decrease of red channel fluorescence was indeed attributed to the acidification of mitochondria in cardiomyocytes. ETHC achieves the monitoring and biological imaging of cardiomyocyte microenvironment changes, which provides a valuable tool for the study of related life event models.

Zn2+ decoration of microtubules arrests axonal transport and displaces tau, doublecortin, and MAP2C.

Intracellular Zn2+ concentrations increase via depolarization-mediated influx or intracellular release, but the immediate effects of Zn2+ signals on neuron function are not fully understood. By simultaneous recording of cytosolic Zn2+ and organelle motility, we find that elevated Zn2+ (IC50 ≈ 5-10 nM) reduces both lysosomal and mitochondrial motility in primary rat hippocampal neurons and HeLa cells. Using live-cell confocal microscopy and in vitro single-molecule TIRF imaging, we reveal that Zn2+ inhibits activity of motor proteins (kinesin and dynein) without disrupting their microtubule binding. Instead, Zn2+ directly binds to microtubules and selectively promotes detachment of tau, DCX, and MAP2C, but not MAP1B, MAP4, MAP7, MAP9, or p150glued. Bioinformatic predictions and structural modeling show that the Zn2+ binding sites on microtubules partially overlap with the microtubule binding sites of tau, DCX, dynein, and kinesin. Our results reveal that intraneuronal Zn2+ regulates axonal transport and microtubule-based processes by interacting with microtubules.