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In this study, cadmium ions were effectively removed from domestic wastewaters using an adsorptive treatment strategy based on γ-AlOOH nanoflowers. A novel, rapid, and simple procedure was developed for the synthesis of the nanoflowers. Characterization studies were performed using X-ray powder diffraction patterns and scanning electron microscope images. The synthesized nanoflowers were utilized as adsorbent in the batch adsorption experiments. The influential parameters of the adsorption process were optimized, and a flame atomic absorption spectrophotometry (FAAS) system was used to determine maximum percent removal of cadmium ions. Matrix-matched calibration strategy, in which the calibration plot was developed in wastewater medium, was utilized for the accurate and precise quantification of cadmium in the effluent samples. The percentage removal efficiency values were calculated between 84 and 98% for different concentrations of cadmium ions in the wastewater samples. Equilibrium data was fitted to the four different linearization methods of the Langmuir isotherm model, as well as the Freundlich isotherm model and Elovich isotherm model. The best fitting was achieved for the Langmuir model with a high R 2 value of 0.9956 and maximum adsorption capacity was calculated as 6.23 mg/g., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Hypothesis: Multicore flower-like iron oxide nanoparticles (IONPs) are among the best candidates for magnetic hyperthermia applications against cancers. However, they are rarely investigated in physiological environments and their efficacy against cancer cells has been even less studied. The combination of magnetic hyperthermia, using multicore IONPs, with selected bioactive molecules should lead to an enhanced activity against cancer cells., Experiments: Multicore IONPs were synthesized by a seeded-growth thermal decomposition approach. Then, the cytotoxicity, cell uptake, and efficacy of the magnetic hyperthermia approach were studied with six cancer cell lines: PANC1 (pancreatic carcinoma), Mel202 (uveal melanoma), MCF7 (breast adenocarcinoma), MB231 (triple-negative breast cancer line), A549 (lung cancer), and HCT116 (colon cancer). Finally, IONPs were modified with a chemotherapeutic drug (SN38) and tumor suppressor microRNAs (miR-34a, miR-182, let-7b, and miR-137), to study their activity against cancer cells with and without combination with magnetic hyperthermia., Findings: Two types of multicore IONPs with very good heating abilities under magnetic stimulation have been prepared. Their concentration-dependent cytotoxicity and internalization have been established, showing a strong dependence on the cell line and the nanoparticle type. Magnetic hyperthermia causes significant cell death that is dramatically enhanced in combination with the bioactive molecules., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The present study focuses on the elaboration of magnetic nanocomposites by the in situ incorporation of magnetite (Fe 3 O 4 ) nanoparticles (NPs) with spherical and nanoflower-like morphologies in graphitic carbon nitride (g-C 3 N 4 ) sheets using two different synthetic routes. Nanomaterials are characterized by TEM, SEM, XRD, FTIR, BET, zetametry, vibrating sample magnetometry, and UV-vis absorption spectroscopy. The decoration of the carbon nitride matrix with the magnetic NPs enhanced optical and textural properties. The influence of the morphology of the magnetic NPs on the adsorptive and photocatalytic properties of the nanocomposites under different pH conditions (4.5, 6.9, and 10.6) was assessed from batch tests to remove methylene blue (MB) from aqueous solutions. In extreme pH conditions, the nanocomposites exhibited lower or equivalent MB removal capacity compared to the pure g-C 3 N 4 . However, at neutral medium, the nanocomposite with incorporated Fe 3 O 4 nanoflowers showed a significantly higher removal efficiency (80.7%) due to the combination of a high adsorption capacity and a good photocatalytic activity in this pH region. The proposed nanocomposite is a promising alternative to remove cationic dyes from water by magnetic assistance, since no pH adjustment of the polluted effluent is required, reducing costs and environmental impact in the dyeing industry., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Research in electrochemical detection in lateral flow assays (LFAs) has gained significant momentum in recent years. The primary impetus for this surge in interest is the pursuit of achieving lower limits of detection, especially given that LFAs are the most widely employed point-of-care biosensors. Conventionally, the strategy for merging electrochemistry and LFAs has centered on the superposition of screen-printed electrodes onto nitrocellulose substrates during LFA fabrication. Nevertheless, this approach poses substantial limitations regarding scalability. In response, we have developed a novel method for the complete integration of reduced graphene oxide (rGO) electrodes into LFA strips. We employed a CO 2 laser to concurrently reduce graphene oxide and pattern nitrocellulose, exposing its backing to create connection sites impervious to sample leakage. Subsequently, rGO and nitrocellulose were juxtaposed and introduced into a roll-to-roll system using a wax printer. The exerted pressure facilitated the transfer of rGO onto the nitrocellulose. We systematically evaluated several electrochemical strategies to harness the synergy between rGO and LFAs. While certain challenges persist, our rGO transfer technology presents compelling potential for setting a new standard in electrochemical LFA fabrication., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The use of organic-inorganic hybrid nanoflowers as a support material for enzyme immobilization has gained significant attention in recent years due to their high stability, ease of preparation, and enhanced catalytic activity. However, a major challenge in utilizing these hybrid nanoflowers for enzyme immobilization is the difficulty in handling and separating them due to their low density and high dispersion. To address this issue, magnetic nanoflowers have emerged as a promising alternative enzyme immobilization platform due to their easy separation, structural stability, and ability to enhance catalytic efficiency. This review focuses on different methods for designing magnetic nanoflowers, as well as future research directions. Additionally, it provides examples of enzymes immobilized in the form of magnetic nanoflowers and their applications in environmental remediation, biosensors, and food industries. Finally, the review discusses possible ways to improve the material for enhanced catalytic activity, structural stability, and scalability.

Facile synthesis of high-efficiency and stable bifunctional electrocatalyst is essential for producing clean hydrogen in energy storage systems. Herein, low Rh-doped flower-like Ni 3 S 2 /Co 3 S 4 heterostructures were facilely prepared on porous nickel foam (labeled Rh-Ni 3 S 2 /Co 3 S 4 /NF) by a hydrothermal method. The correlation of the precursors types with the morphological structures and catalytic properties were rigorously investigated for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in the control groups. The low Rh doping within the catalyst played important role in boosting the catalytic characteristics. The resulting catalyst showed the smaller overpotentials of 197 and 78 mV to drive a current density of 10 mA cm -2 for the OER and HER in alkaline electrolyte, respectively. And the potential only required 1.71 V to drive a current density of 100 mA cm -2 in a water splitting device. It reflects excellent overall water splitting of the home-made Rh-Ni 3 S 2 /Co 3 S 4 /NF. This strategy shed some constructive light for preparing transition metal sulfide-based electrocatalysts in water splitting devices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

2-O-(α-d-glucopyranosyl)-sn-glycerol (2-αGG) has been applied in the food industry due to its numerous physiological benefits. The synthesis of 2-αGG can be achieved through a cascade catalytic reaction involving sucrose phosphorylase (SP) and 2-O-α-glucosylglycerol phosphorylase (GGP). However, the low substrate transfer rates between free enzymes have hindered the efficiency of 2-αGG synthesis. To address this issue, a novel technology was developed to prepare sequential multi-enzyme nanoflowers via chemical crosslinking and protein assembly, thus overcoming diffusion limitations. Specifically, spatially sequential co-immobilized enzymes, referred to as SP-GGP@Cap, were created through the targeted assembly of Bifidobacterium adolescentis SP and Marinobacter adhaerens GGP on Ca 2+ . This assembly was facilitated by the spontaneous protein reaction between SpyTag and SpyCatcher. Compared to free SP-GGP, SP-GGP@Cap demonstrated improved thermal and pH stability. Moreover, SP-GGP@Cap enhanced the biosynthesis of 2-αGG, achieving a relative concentration of 98 %. Additionally, it retained the ability to catalyze the substrate to yield 61 % relative concentration of 2-αGG even after ten cycles of recycling. This study presents a strategy for the spatially sequential co-immobilization of multiple enzymes in a confined environment and provides an exceptional biocatalyst for the potential industrial production of 2-αGG., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hybrid supercapacitors (HSCs) bridge the unique advantages of batteries and capacitors and are considered promising energy storage devices for hybrid vehicles and other electronic gadgets. Lithium-ion capacitors (LICs) have attained particular interest due to their higher energy and power density than traditional supercapacitor devices. The limited voltage window and the deterioration of anode materials upsurged the demand for efficient and stable electrode materials. Two-dimensional (2D) molybdenum sulfide (MoS 2 ) is a promising candidate for developing efficient and durable LICs due to its wide lithiation potential and unique layer structure, enhancing charge storage efficiency. Modifying the extrinsic features, such as the dimensions and shape at the nanoscale, serves as a potential path to overcome the sluggish kinetics observed in the LICs. Herein, the MoS 2 nanoflowers have been synthesized through a hydrothermal route. The developed LIC exhibited a specific capacitance of 202.4 F g -1 at 0.25 A g -1 and capacitance retention of >90 % over 5,000 cycles. Using an ether electrolyte improved the voltage window (2.0 V) and enhanced the stability performance. The ex-situ material characterization after the stability test reveals that the storage mechanism in MoS 2 -LICs is not diffusion-controlled. Instead, the fast surface redox reactions, especially intercalation/deintercalation of ions, are more prominent for charge storage., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

The current study presents the application of molybdenum diselenide nanoflowers (MoSe 2 -NFs) as an innovative substrate for immobilizing α-amylase by glutaraldehyde activation. This approach results in the development of a nanobiocatalyst that exhibits remarkable advantages compared to a standalone enzyme. Several physical methods, such as fluorescence microscopy, FT-IR, SEM, TEM, XRD, AFM, and Raman spectroscopy, were used to confirm that α-amylase was successfully attached to MoSe2-NFs. By employing the Box-Behnken design of the RSM, the parameters were optimized, resulting in an immobilization efficiency of roughly 87.33%. The immobilized variant of α-amylase demonstrated superior thermostability, pH stability, reusability, and storage stability in comparison to the soluble enzyme. The catalytic activity of α-amylase was highest when immobilized on MoSe 2 -NFs at the same pH and temperature as the soluble enzyme. However, there was an expansion in the range of parameters in which this activity was observed. Furthermore, the immobilized enzyme exhibited a retention of nearly 80% residual activity following 12 successive reuses. The immobilized enzyme exhibited around 82% residual activity after being stored for 120 days. It is possible that the immobilization process changed the Michaelis-Menten constant, which means that the substrate could no longer reach certain active sites on the enzyme because it had become longer. The study's findings suggest that the α-amylase-MoSe 2 -NFs system could be useful in industry because it can work in a wider range of temperature and pH conditions. Furthermore, the intrinsic non-toxic characteristics of the matrix, along with its ability to be kept for prolonged periods and recycled, render nano biocatalysts very well-suited for the effective synthesis of maltose in the food and pharmaceutical industries., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Although cobalt nitride (CoN)-based nanomaterials have been widely designed as advanced oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR) catalysts, the continuous consumption of lithium-ion batteries (LIBs) has led to a high price of cobalt metal. Therefore, in the future, recycling valuable Co elements from spent devices and boosting their service efficiency will inevitably promote the utilization of Co-based materials in water splitting and zinc-air batteries (ZABs). Herein, we realize the Co recycling from spent LIBs by a simple hydrometallurgy method. Under the assistance of hexamethylenetetramine and polystyrene spheres, after the hydrothermal and pyrolysis treatment in the NH 3 atmosphere, the as-reclaimed cobalt oxalates were successfully transformed into novel three-dimensional (3D) CoN nanoflowers (denoted as CoN NFs). Benefiting from the unique 3D flower-like architectures, intrinsic high conductivity, large surface area, uniformly dispersed CoN nanoparticles, and the synergistic effect between Co 3 N and CoO phases, the 3D flower-like CoN NFs exhibited excellent OER catalytic activity. The performance was much better than commercial RuO 2 in the 1.0 M KOH solution. Furthermore, the CoN NFs-based water splitting cell needed a voltage of 1.608 V to achieve the current density of 10 mA cm -2 , which is even 16 mV smaller than that of Pt/C||RuO 2 benchmark (1.624 V). Meanwhile, the CoN NFs-derived ZAB exhibited a high peak power density of 107.3 mW cm -2 (vs. 103.2 mW cm -2 of Pt/C-RuO 2 -based ZAB) and a low charge-discharge voltage gap (0.93 V vs. 1.43 V of Pt/C-RuO 2 -based ZAB). Due to the excellent structural and elemental stabilities, the corresponding water splitting cell and ZAB had outstanding durability. This work successfully explored an advanced industrial chain from recycling Co metal in spent devices to designing the high-efficiency HER/OER/ORR electrocatalysts for advanced water splitting devices and ZABs. This will further promote the value-added utilization of valuable Co metal in various energy storage or conversion devices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The development of efficient and low-cost catalysts for cathodic oxygen reduction reaction (ORR) in Zn-air battery (ZAB) is a key factor in reducing costs and achieving industrialization. Here, a novel segregated CoNiPt alloy embedded in N-doped porous carbon with a nanoflowers (NFs)-like hierarchy structure is synthesized through pyrolyzing Hofmann-type metal-organic frameworks (MOFs). The unique hierarchical NFs structure exposes more active sites and facilitates the transportation of reaction intermediates, thus accelerating the reaction kinetics. Impressively, the resulting 15% CoNiPt@C NFs catalyst exhibits outstanding alkaline ORR activity with a half-wave potential of 0.93 V, and its mass activity is 7.5 times higher than that of commercial Pt/C catalyst, surpassing state-of-the-art noble metal-based catalysts. Furthermore, the assembled CoNiPt@C+RuO2 ZAB demonstrates a maximum power density of 172 mW cm -2 , which is superior to that of commercial Pt/C+RuO2 ZAB. Experimental results reveal that the intrinsic ORR mass activity is attributed to the synergistic interaction between oxygen defects and pyrrolic/graphitic N species, which optimizes the adsorption energy of the intermediate species in the ORR process and greatly enhances catalytic activity. This work provides a practical and feasible strategy for synthesizing cost-effective alkaline ORR catalysts by optimizing the electronic structure of MOF-derived catalysts., (© 2023 Wiley-VCH GmbH.)

The present study highlights the treatment of industrial effluent, which is one of the most life-threatening factors. Herein, for the first time, two types of NiO (green and black) photocatalysts were prepared by facile chemical precipitation and thermal decomposition methods separately. The synthesized NiO materials were demonstrated with various instrumental techniques for finding their characteristics. The X-ray diffraction studies (XRD) and X-ray photoelectron spectroscopy (XPS) revealed the presence of Ni 2 O 3 in black NiO material. The transmission electron microscopic (TEM) images engrained the nanospherical shaped green NiO and nanoflower shaped black NiO/Ni 2 O 3 materials. Further, the band gap of black NiO nanoflower was 2.9 eV compared to green NiO having 3.8 eV obtained from UV-vis spectroscopy. Meanwhile, both NiO catalysts were employed for visible light degradation, which yields a 60.3% efficiency of black NiO comparable to a 4.3% efficiency of green NiO within 180 min of exposure. The higher degrading efficiency of black NiO was due to the presence of Ni 2 O 3 and the development of pores, which was evident from the Barrett-Joyner-Halenda (BJH) method. Type IV hysteresis was observed in black NiO nanoflowers with high surface area and pore size measurements. This black NiO/Ni 2 O 3 synthesized from the thermal decomposition method has promoted better photocatalytic degradation of 4-chlorophenol upon exposure to visible light and is applicable for other industrial pollutants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The natural biofilm on magnetosomes obtained from the biomineralization of magnetotactic bacteria, which replaced a complex chemical modification process on the surface of Fe 3 O 4 , can be used as the organic component and copper(II) ions as the inorganic component to form organic-inorganic nanoflowers in phosphate systems. Characterization by scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating-sample magnetometry proved that magnetic nanoflowers loaded with silver ions (Ag/MN-Cu×NFs) were successfully fabricated. In vitro antibacterial experiments demonstrated that Ag/MN-Cu×NFs displayed strong antibacterial effects against Escherichia coli and Staphylococcus aureus , with minimum inhibitory concentrations of 10 and 80 μg/mL, respectively. Ag/MN-Cu×NFs, which possessed good biocompatibility as confirmed by cytotoxicity and hemolysis tests, were able to promote wound healing in the face of bacterial infection in vivo without causing toxicity to major organs. Therefore, magnetosomes as a natural carrier have great application potential in the synthesis of multifunctional magnetosomes by direct hybridization with a target substance.

In this study, detection sensitivity of the conventional flame atomic absorption spectrophotometer (FAAS) for the determination of manganese (Mn 2+ ) was enhanced by employing a preconcentration method from wastewater samples. Flower-shaped Ni(OH) 2 nanomaterials were synthesized and used as sorbent material in preconcentration procedure. With the aim of attaining optimum experimental conditions, effective parameters of extraction method were optimized and these included pH of buffer solution, desorption solvent concentration and volume, mixing type and period, nanoflower amount, and sample volume. The detection limit of the optimized method was determined to be 2.2 μg L -1 , and this correlated to about 41-fold enhancement in detection power relative to direct FAAS measurement. Domestic wastewater was used to test the feasibility of the proposed method to real samples by performing spike recovery experiments. The wastewater sample was spiked at four different concentrations of manganese, and the percent recoveries determined were in the range of 95-120%., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Transition metal ions are served as disinfectant thousand years ago. However, the in vivo antibacterial application of metal ions is strongly restricted due to its high affinity with proteins and lack of appropriate bacterial targeting method. Herein, for the first time, Zn 2+ -gallic acid nanoflowers (ZGNFs) are synthesized by a facile one-pot method without additional stabilizing agents. ZGNFs are stable in aqueous solution while can be easily decomposed in acidic environments. Besides, ZGNFs can specifically adhere onto Gram-positive bacteria, which is mediated by the interaction of quinone from ZGNFs and amino groups from teichoic acid of Gram-positive bacteria. ZGNFs exhibit high bactericidal effect toward various Gram-positive bacteria in multiple environments, which can be ascribed to the in situ Zn 2+ release on bacterial surface. Transcriptome studies reveal that ZGNFs can disorder basic metabolic processes of Methicillin-resistant Staphylococcus aureus (MRSA). Moreover, in a MRSA-induced keratitis model, ZGNFs exhibit long-term retention in the infected corneal site and prominent MRSA elimination efficacy due to the self-targeting ability. This research not only reports an innovative method to prepare metal-polyphenol nanoparticles, but also provides a novel nanoplatform for targeted delivery of Zn 2+ in combating Gram-positive bacterial infections., (© 2023 Wiley-VCH GmbH.)

Designing anisotropic lignin-based particles and promoting the high-value utilization of lignin have nowadays drawn much attention from scientists. However, systematic studies addressing the self-assembly mechanisms of anisotropic lignin-based particles are scarce. In this work, an interaction including the electrostatic forces and chelating forces between lignin and Ag + was regulated via carboxymethylation modification. Subsequently, the aggregation morphology of carboxymethylated lignin in a Ag + solution was observed via SEM. The result showed that a large number of Ag + intercalated into the lignin molecules when the grafting degree of the carboxyl groups increased from 0.17 mmol/g to 0.53 mmol/g, which caused the lignin molecules to gradually transform from disordered blocks to ordered layers. Dynamics research indicated that the adsorption process of Ag + in carboxymethylated lignin conforms to the Pseudo-first-order kinetic model. The saturated adsorption amount of Ag + in the carboxymethylated lignin reached 1981.7 mg/g when the grafting rate of carboxyl groups increased to 0.53 mmol/g, which then fully intercalated into lignin molecules and formed a layered structure. The thermodynamic parameters showed that the thermal adsorption process conforms to the Langmuir model, which indicates that Ag + is monolayer-adsorbed and intercalated into lignin molecules. Meanwhile, the ΔH values are more than 0, which suggests that this adsorption process is a endothermic reaction and that a higher temperature is conducive to an adsorption reaction. Therefore, self-assembly of lignin in a Ag + solution under 70 °C is more conducive to the formation of a nanoflower structure, which is consistent with our experimental result. Finally, pH-responsive Pickering emulsions were successfully prepared using a lignin-based nanoflowers, which demonstrated their potential as a catalytic platform in the interface catalysis field. This work offers a deeper understanding into the formation mechanism of anisotropic lignin-based nanoflowers and hopes to be helpful for designing and preparing anisotropic lignin-based particles.

In the context of the proposed work, two different amino acids (Glycine, Phenylalanine) have interacted with copper ions in a phosphate buffer (PBS) in place of enzymes. This interaction resulted in the nucleation of copper phosphate crystals and the formation of flower-shaped amino acid-copper hybrid nanostructures (AA-hNFs), which grew through self-assembly. While Cu (II) ions in the structure of AA-hNFs were used as Fenton's agent for the catalytic activity. SEM, energy dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy measurements were used to define the AA-hNFs' characterisation. The peroxidase-like activities of AA-hNFs were investigated by UV/VIS spectrophotometer. Metal nanoparticles have peroxidase-like activity. A class of enzymes known as peroxidases is able to catalyze the conversion of hydrogen peroxide into hydroxyl radicals. These radicals also take part in electron transfers with substrates, which results in color during oxidation. When cupric oxide nanoparticles are added to the peroxidase substrate while H 2 O 2 is present, a blue color product with a maximum absorbance at=652 nm can result, demonstrating the catalytic activity of a peroxidase. The morphology and composition of AA-hNFs were carefully characterized and the synthesized parameters were optimized systematically. Results showed that the nanoparticles were dispersed with an average diameter of 7-9 μm and indicated a uniform flower shape. The results of the investigation are anticipated to significantly advance a number of technical and scientific sectors., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)

In this work, we report a low-cost and highly sensitive electrochemical sensor for detecting As(III) in water. The sensor uses a 3D microporous graphene electrode with nanoflowers, which enriches the reactive surface area and thus enhances its sensitivity. The detection range achieved was 1-50 ppb, meeting the US-EPA cutoff criteria of 10 ppb. The sensor works by trapping As(III) ions using the interlayer dipole between Ni and graphene, reducing As(III), and transferring electrons to the nanoflowers. The nanoflowers then exchange charges with the graphene layer, producing a measurable current. Interference by other ions, such as Pb(II) and Cd(II), was found to be negligible. The proposed method has potential for use as a portable field sensor for monitoring water quality to control hazardous As(III) in human life.

Enzyme immobilization is used to improve the application of enzymes, allowing the reuse of biocatalysts and increasing their stability under reaction conditions. Immobilization of enzymes through structures, such as nanoflowers, is an innovative, simple, and low-cost method compared to other techniques. In this context, the main objective of this work is to synthesize hybrid biocatalytic nanostructures, similar to flowers, of lipases from Candida antarctica type B (CALB) and Thermomyces lanuginosus (TLL). The production of nanoflowers occurred by precipitation of lipases with CuCl 2 or CuSO 4 salts for 72 h. However, challenges and obstacles were faced in obtaining effective and practical nanoflowers, such as nanoflowers' low thermal stability and reusability. To overcome these challenges, two conditions were tested: nanoflowers cross-linked with glutaraldehyde and nanoflowers and nanoparticles cross-linked with glutaraldehyde. This last biocatalyst prepared by CuSO 4 precipitation showed better thermal stability (half-life about 230 and 233 min for CALB and TLL, respectively, under incubation at 60 °C and pH 7). The CALB biocatalyst retained 70 % of its initial activity (2.31 U) after 10 cycles of hydrolysis. Therefore, this work shows not only the problems and barriers of nanoflowers synthesis, but also the possibility of producing more stable and efficient biocatalysts using improved protocols., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Layered double hydroxides (LDHs) with high theoretical capacity have broad prospectsin energy storage applications. However, their slow charge transfer kinetics and easy agglomerate hinder their applications in high-performance supercapacitors. Herein, Co 2+ -doped nickel aluminum layered double hydroxides (NiAl-LDH-Co 2+ -x, x = 0, 0.3, 0.6, 0.9, 1.2, 1.5) have been designed and prepared by a convenient hydrothermal process. The multicomponent layer structure formed by cobalt doping facilitates sufficient penetration of the electrolyte and accelerates the charge transfer kinetics. Furthermore, the more open layer spacing and electronic interactions induced by Co 2+ doping are conducive to accelerating ion de-intercalation, thereby further improving the kinetic behavior of charge storage. Benefiting from the unique microstructure and Co 2+ doping effect, the prepared NiAl-LDH-Co 2+ -0.9 provides a superior specific capacity of 985 C g -1 at 1 A g -1 . In addition, the assembled hybrid supercapacitor with the NiAl-LDH-Co 2+ -0.9 as the positive electrode provides a remarkable energy density of 22.51 Wh kg -1 at a power density of 800 W kg -1 and exhibits an excellent cycle life with 80 % capacity retention after 20,000 cycles. This study demonstrates the great potential of efficient microstructure design and doping strategy in enhancing the charge storage of electrode materials., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

This article discusses the features of the synthesis and application of porous two-dimensional nanomaterials in developing conductometric gas sensors based on metal oxides. It is concluded that using porous 2D nanomaterials and 3D structures based on them is a promising approach to improving the parameters of gas sensors, such as sensitivity and the rate of response. The limitations that may arise when using 2D structures in gas sensors intended for the sensor market are considered.

The present study reported the synthesis of SnS 2 nanoparticles by using a thermal decomposition approach using tin chloride and thioacetamide in diphenyl ether at 200 °C over 60 min. SnS 2 nanoparticles with novel morphologies were prepared by the use of different alkylamines (namely, octylamine (OCA), dodecylamine (DDA), and oleylamine (OLA)), and their role during the synthesis was explored in detail. The synthesized SnS 2 nanostructures were characterized using an array of analytical techniques. The XRD results confirmed the formation of hexagonal SnS 2 , and the crystallite size varied from 6.1 nm to 19.0 nm and from 2.5 to 8.8 nm for (100) and (011) reflections, respectively. The functional group and thermal analysis confirmed the presence of organics on the surface of nanoparticles. The FE-SEM results revealed nanoparticles, nanoplates, and flakes assembled into flower-like morphologies when dodecylamine, octylamine, and oleylamine were used as capping agents, respectively. The analysis of optical properties showed the variation in the bandgap and the concentration of surface defects on the SnS 2 nanoparticles. The role of alkylamine as a capping agent was explored and discussed in detail in this paper and the mechanism for the evolution of different morphologies of SnS 2 nanoparticles was also proposed.

Immobilized enzymes are a significant technological approach to retain enzyme activity and reduce enzyme catalytic cost. In this work, trypsin-incorporated Zn 3 (PO 4 ) 2 hybrid nanoflowers were prepared via mild precipitation and coordination reactions. The controllable preparation of hybrid nanoflowers was achieved by systematically investigating the effects of the raw-material ratio, material concentration and reaction temperature on product morphology and physicochemical properties. The enzyme content of hybrid nanoflowers was about 6.5%, and the maximum specific surface area reached 68.35 m 2 /g. The hybrid nanoflowers exhibit excellent catalytic activity and environmental tolerance compared to free trypsin, which was attributed to the orderly accumulation of nanosheets and proper anchoring formation. Further, the enzyme activity retention rate was still higher than 80% after 12 repeated uses. Therefore, trypsin/Zn 3 (PO 4 ) 2 hybrid nanoflowers-which combine functionalities of excellent heat resistance, storage stability and reusability-exhibit potential industrial application prospects.

A green strategy for the synthesis of bimetallic core-shell Au@Pd nanoflowers (NFs) employing banana pseudo-stem-derived TEMPO-oxidized cellulose nanocrystals (TCNC) as both capping and shape-directing agent via seed-mediated method is presented. Flower-like nanostructures of Au@Pd bound to TEMPO-oxidized cellulose nanocrystals (TCNC-Au@Pd) were decorated on amino-functionalized graphene (NH 2 -RGO) without losing their unique structure, allowing them to be deployed as an efficient, reusable and a green alternative heterogeneous catalyst. The decisive role of TCNC in the structural metamorphosis of nanoparticle morphology were inferred from the structural and morphology analyses. According to our study, the presence of -OH rich TCNC appears to play a pivotal role in the structured evolution of intricate nanostructure morphology. The feasibility of the bio-supported catalyst has been investigated in two concurrently prevalent model catalytic reactions, namely the oxygen reduction reaction (ORR) and the reduction of 4-nitrophenol, the best model reactions in fuel cell and industrial catalytic applications, respectively., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Lipases from Thermomyces lanuginosus (TLL), Rhizomucor miehei (RML), Candida rugosa (CRL), forms A and B of lipase from Candida antarctica (CALA and CALB) and Eversa Transform 2.0 have been immobilized on octyl-agarose beads at two different loads (1 mg/g and saturated support) and treated with phosphate and/or some metallic salts (Zn 2+ , Co 2+ , Cu 2+ ). They have been also immobilized on the support modified by the metallic phosphate, usually driving to biocatalyst with lower stability or marginal improvements. The effects of the phosphate/metal modification on enzyme features depended on the loading of the support. Some enzymes (TLL, CRL or CALA), mainly using the highly loaded biocatalysts, showed very significant improvement on enzyme stability after the treatment with some of the metal phosphates (next to a 20-fold factor), improvements that were not justified by the presence of metallic or phosphate ions in solution, as they had negative effects on enzyme stabilities. In some other cases, a significant increase in enzyme activity was detected (e.g., CALB). This could be explained by the modification of the nucleation places of the enzymes by the metallic phosphate, and this could help to explain the good results obtained in the nanoflower immobilization of many enzymes., (Copyright © 2022. Published by Elsevier B.V.)

As novel anodic materials for lithium-ion batteries (LIBs), transitional metal selenites can transform into metal oxide/selenide heterostructures in the first cycle, which helps to enhance the Li + storage performance, especially in terms of high discharge capacity. Herein, well-defined hierarchical CoSeO 3 ‧2H 2 O nanoflowers assembled using 10 nm-thick nanosheets are successfully synthesized via a facile one-step hydrothermal method. When used as anodic materials for LIBs, the CoSeO 3 ‧2H 2 O nanoflowers exhibit a considerably high discharge capacity of 1064.1 mAh g -1 at a current density of 0.1 A g -1 . In addition, the obtained anode possesses good rate capability and cycling stability. Owing to the superior electrochemical properties, the CoSeO 3 ‧2H 2 O nanoflowers would serve as promising anodic materials for high-performance LIBs.

Four commercial immobilized lipases biocatalysts have been submitted to modifications with different metal (zinc, cobalt or copper) phosphates to check the effects of this modification on enzyme features. The lipase preparations were Lipozyme ® TL (TLL-IM) (lipase from Thermomyces lanuginose ), Lipozyme ® 435 (L435) (lipase B from Candida antarctica ), Lipozyme ® RM (RML-IM), and LipuraSelect (LS-IM) (both from lipase from Rhizomucor miehei ). The modifications greatly altered enzyme specificity, increasing the activity versus some substrates (e.g., TLL-IM modified with zinc phosphate in hydrolysis of triacetin) while decreasing the activity versus other substrates (the same preparation in activity versus R - or S - methyl mandelate). Enantiospecificity was also drastically altered after these modifications, e.g., LS-IM increased the activity versus the R isomer while decreasing the activity versus the S isomer when treated with copper phosphate. Regarding the enzyme stability, it was significantly improved using octyl-agarose-lipases. Using all these commercial biocatalysts, no significant positive effects were found; in fact, a decrease in enzyme stability was usually detected. The results point towards the possibility of a battery of biocatalysts, including many different metal phosphates and immobilization protocols, being a good opportunity to tune enzyme features, increasing the possibilities of having biocatalysts that may be suitable for a specific process.

Self-assembling carrier-free nanodrugs are attractive agents because they accumulate at tumor by an enhanced permeability and retention (EPR) effect without introduction of inactive substances, and some nanodrugs can alter the immune environment. We synthesized a peptidyl arginine deiminase 4 (PAD4) molecular inhibitor, ZD-E-1M. It could self-assembled into nanodrug ZD-E-1. Using confocal laser scanning microscopy, we observed its cellular colocalization, PAD4 activity and neutrophil extracellular traps (NETs) formation. The populations of immune cells and expression of immune-related proteins were determined by single-cell mass cytometry. ZD-E-1 formed nanoflowers in an acidic environment, whereas it formed nanospheres at pH 7.4. Accumulation of ZD-E-1 at tumor was pH-responsive because of its pH-dependent differences in the size and shape. It could enter the nucleus and bind to PAD4 to prolong the intracellular retention time. In mice, ZD-E-1 inhibited tumor growth and metastasis by inhibiting PAD4 activity and NETs formation. Besides, ZD-E-1 could regulate the ratio of immune cells in LLC tumor-bearing mice. Immunosuppressive proteins like LAG3 were suppressed, while IFN- γ and TNF- α as stimulators of tumor immune response were upregulated. Overall, ZD-E-1 is a self-assembling carrier-free nanodrug that responds to pH, inhibits PAD4 activity, blocks neutrophil extracellular traps formation, and improves the tumor immune microenvironment., (© 2022 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.)

CRISPR-Cas9 as a powerful gene-editing tool has tremendous potential for the treatment of genetic diseases. Herein, a new mesoporous nanoflower (NF)-like delivery nanoplatform termed Cas9-NF is reported by crosslinking Cas9 and polymeric micelles that enables efficient intracellular delivery and controlled release of Cas9 in response to reductive microenvironment in tumor cells. The flower morphology is flexibly tunable by the protein concentration and different types of crosslinkers. Cas9 protein, embedded between polymeric micelles and protected by Cas9-NF, remains stable even under extreme pH conditions. Responsive cleavage of crosslinkers in tumor cells, leads to the traceless release of Cas9 for efficient gene knockout in nucleus. This crosslinked nanoparticle exhibits excellent capability of downregulating oncogene expression and inhibiting tumor growth in a murine tumor model. Taken together, these findings pave a new pathway toward the application of the protein-micelle crosslinked nanoflower for protein delivery, which warrants further investigations for gene regulation and cancer treatment., (© 2022 Wiley-VCH GmbH.)

Organic-inorganic hybrid nanoflowers (HNFs) of laccase@Zn 3 (PO 4 ) 2 were fabricated through a facile, simple, and rapid one-step strategy. In this process, laccase was involved in nucleation and fast anisotropic growth reactions with Zn (II) and phosphate ions. The average pore size of the prepared HNFs was 54.5 nm, and its BET-specific surface area was 59.5 m 2  g -1 . In comparison with the free laccase, the entrapped enzyme activity in the constructed HNFs was 86.4%. In addition, the hybrid biocatalyst displayed a maximum rate of reaction (V max ) of 1640.2 ± 3.6 μmol min -1 with respect to the native enzyme. The constructed HNFs maintained 45.1% and 60% of the original laccase activity after 12 successive reusability cycles and 30 days of storage at 4 °C, respectively. The as-obtained HNFs demonstrated a high bioremoval percentage of Direct blue-71 (94.1%) within a 10-h-treatment at 40 °C and 15 mg l -1 of the dye concentration. The pseudo-first order and second order were the best-fitted kinetic models for the dye removal using Zn 3 (PO 4 ) 2 nanoflakes and the fabricated HNFs, respectively. Besides, liquid chromatography-mass spectrometry (LC-MS) revealed biotransformation of the dye into less toxic metabolites as verified by testing on some bacterial strains., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The development of nanoplatforms prepared to perform both multimodal imaging and combined therapies in a single entity is a fast-growing field. These systems are able to improve diagnostic accuracy and therapy success. Multicomponent Nanoparticles (MCNPs), composed of iron oxide and gold, offer new opportunities for Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) diagnosis, as well as combined therapies based on Magnetic Hyperthermia (MH) and Photothermal Therapy (PT). In this work, we describe a new seed-assisted method for the synthesis of Au@Fe Nanoparticles (NPs) with a flower-like structure. For biomedical purposes, Au@Fe NPs were functionalized with a PEGylated ligand, leading to high colloidal stability. Moreover, the as-obtained Au@Fe-PEG NPs exhibited excellent features as both MRI and CT Contrast Agents (CAs), with high r 2 relaxivity (60.5 mM -1 ⋅s -1 ) and X-ray attenuation properties (8.8 HU mM -1 ⋅HU). In addition, these nanoflowers presented considerable energy-to-heat conversion under both Alternating Magnetic Fields (AMFs) (∆T ≈ 2.5 °C) and Near-Infrared (NIR) light (∆T ≈ 17 °C). Finally, Au@Fe-PEG NPs exhibited very low cytotoxicity, confirming their potential for theranostics applications.

Access to detailed information on cells loaded with nanoparticles with nanoscale precision is of a long-standing interest in many areas of nanomedicine. In this context, designing a single experiment able to provide statistical mean data from a large number of living unsectioned cells concerning information on the nanoparticle size and aggregation inside cell endosomes and accurate nanoparticle cell up-take is of paramount importance. Small-angle X-ray scattering (SAXS) is presented here as a tool to achieve such relevant data. Experiments were carried out in cultures of B16F0 murine melanoma and A549 human lung adenocarcinoma cell lines loaded with various iron oxide nanostructures displaying distinctive structural characteristics. Five systems of water-dispersible magnetic nanoparticles (MNP) of different size, polydispersity and morphology were analyzed, namely, nearly monodisperse MNP with 11 and 13 nm mean size coated with meso-2,3-dimercaptosuccinic acid, more polydisperse 6 nm colloids coated with citric acid and two nanoflowers (NF) systems of 24 and 27 nm in size resulting from the aggregation of 8 nm MNP. Up-take was determined for each system using B16F0 cells. Here we show that SAXS pattern provides high resolution information on nanoparticles disposition inside endosomes of the cytoplasm through the structure factor analysis, on nanoparticles size and dispersity after their incorporation by the cell and on up-take quantification from the extrapolation of the intensity in absolute scale to null scattering vector. We also report on the cell culture preparation to reach sensitivity for the observation of MNP inside cell endosomes using high brightness SAXS synchrotron source. Our results show that SAXS can become a valuable tool for analyzing MNP in cells and tissues., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Magnetite and maghemite multicore nanoflowers (NFs) synthesized using the modified polyol-mediated routes are to date among the most effective nanoheaters in magnetic hyperthermia (MHT). Recently, magnetite NFs have also shown high photothermal (PT) performances in the most desired second near-infrared (NIR-II) biological window, making them attractive in the field of nanoparticle-activated thermal therapies. However, what makes magnetic NFs efficient heating agents in both modalities still remains an open question. In this work, we investigate the role of many parameters of the polyol synthesis on the final NFs' size, shape, chemical composition, number of cores, and crystallinity. These nanofeatures are later correlated to the magnetic, optical, and electronic properties of the NFs as well as their collective macroscopic thermal properties in MHT and PT to find relationships between their structure, properties, and function. We evidence the critical role of iron(III) and heating ramps on the elaboration of well-defined NFs with a high number of multicores. While MHT efficiency is found to be proportional to the average number of magnetic cores within the assemblies, the optical responses of the NFs and their collective photothermal properties depend directly on the mean volume of the NFs (as supported by optical cross sections numerical simulations) and strongly on the structural disorder in the NFs, rather than the stoichiometry. The concentration of defects in the nanostructures, evaluated by photoluminescence and Urbach energy ( E U ), evidence a switch in the optical behavior for a limit value of E U = 0.4 eV where a discontinuous transition from high to poor PT efficiency is also observed.

Compared to most of nano-sized particles, core-shell-structured nanoflowers have received great attention as bioactive materials because of their high surface area with the flower-like structures. In this study, core-shell-structured Si-based NiO nanoflowers, Si@NiO, were prepared by a modified chemical bath deposition method followed by thermal reduction. The crystal morphology and basic structure of the composites were characterized by powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) and porosity analysis (BJT), and inductively coupled plasma optical emission spectrometry (ICP-OES). The electrochemical properties of the Si@NiO nanoflowers were examined through the redox reaction of ascorbic acid with the metal ions present on the surface of the core-shell nanoflowers. This reaction favored the formation of reactive oxygen species. The Si@NiO nanoflowers showed excellent anticancer activity and low cytotoxicity toward the human breast cancer cell line (MCF-7) and mouse embryonic fibroblasts (MEFs), respectively, demonstrating that the anticancer activities of the Si@NiO nanoflowers were primarily derived from the oxidative capacity of the metal ions on the surface, rather than from the released metal ions. Thus, this proves that Si-based NiO nanoflowers can act as a promising candidate for therapeutic applications.

Herein, electrochemical synthesis of tungsten trioxide (WO 3 ) with globular clusters constructed of nanoplates is demonstrated. Under a breakdown anodization potential of 25 V at 50 °C, tungsten foil anode was efficiently electro-oxidized into WO 3 nanoplates-aggragated globular clusters powder, rather than a thin film structure as conventional anodization occurs. The WO 3 globular clusters were characterized by SEM, TEM, and XRD. Effects of electrolyte composition on the breakdown anodization of the W substrate has been discussed. It is suggested that the growth of the WO 3 nanoplates is initiated by localized anodic dielectric breakdown, and followed by an effective crystal growth in the electrolyte at high breakdown field., (© 2022 IOP Publishing Ltd.)

Micro- and nanoflowers are a class of materials composed of particles with high surface-to-volume ratio. They have been extensively studied in the last decade due to simple preparation protocols and promising applications in biosensing, as drug delivery agents, for water purification, and so on. Flowerlike objects, due to their highly irregular surface, may act also as plasmonic materials, providing resonant coupling between optical waves and surface plasmon excitations. This fact allows us to infer the possibility to use micro- and nanoflowers as effective surface-enhanced Raman scattering (SERS) substrate materials. Here, we report on the design and Raman enhancement properties of silver flowerlike structures, deposited on aluminum surface. A simple and cost-effective fabrication method is described, which leads to SERS substrates of high developed surface area. The morphology of the silver flowers on a nanoscale is characterized by self-organized quasiperiodic stacks of nanosheets, which act as plasmonic cavity resonators. The substrates were tested against rhodamine-6G (R6G) water solutions of concentration varying between 10 -3 M and 10 -7 M. Optimal SERS enhancement factors of up to 10 5 were established at R6G concentrations in the 10 -6 -10 -7 M range.

Many studies have found that gold nanoparticles with branched surfaces (nanoflowers) are markers for immunosensors that provide higher sensitivity gains than the commonly used spherical gold nanoparticles. Although the analytical characteristics of nanoparticle-using systems vary significantly depending on their size and shape, the question of choosing the best gold nanoflowers remains open. This work presents a comparative study of a panel of 33 preparations of gold nanoflowers formed by varying several parameters: the size of spherical nanoparticles-nuclei, the concentrations of nuclei, and tetrachloroauric acid during growth. The sizes of the resulting particles, their sorption capacity under antibody immobilization, mobility along membranes for lateral flow assays, and the effects of these parameters on the limits of detection of lateral flow immunoassay are characterized. The optimality of preparations obtained by growing a 0.2% v / v solution of nuclei with a diameter of 10 or 20 nm with tetrachloroauric acid at a concentration of 0.12 mM was shown. With their use, lateral flow immune tests were developed to determine markers of acute myocardial infarction-fatty acids binding protein and troponins I and T. The use of gold nanoflowers obtained under the proposed protocols led to significant gains in the limits of detection-3 to 10 times under visual detection and over 100 times under instrumental detection-compared to spherical gold nanoparticles. The significant increase under instrumental detection is due to the label's low nonspecific binding.

This paper reports synthesis, properties and gas sensing applications of ZnO nanoflowers and CdO-ZnO nanorices prepared by hydrothermal process. The morphological characterizations confirmed the formation of well-defined nanoflowers and nanorices structures for ZnO and CdO-ZnO nanomaterials, respectively. The structural properties revealed the wurtzite hexagonal phase of the synthesized materials. The sensor devices based on ZnO nanoflowers and CdO-ZnO nanorices were fabricated and tested towards various gases including ethanol, methanol, ammonia, carbon monoxide, methane and formaldehyde. The fabricated gas sensor based on CdO-ZnO nanorices exhibited a high response (34.5) towards 300 ppm formaldehyde gas at 350 °C compared to ZnO nanoflowers (14.5) under the same experimental conditions. The response and recovery times for ZnO nanoflowers-based sensor were~9.8 s and ~6 s while for CdO-ZnO based sensor, these were ~10s and ~6s, respectively. A rapid response (34.5) for CdO-ZnO nanorices based formaldehyde gas sensor was observed as compared to other gases such as ammonia (12.3), methanol (16.5), ethanol (20), carbon monoxide (16.3) and methane (12.4), which confirm the high-selectivity towards formaldehyde gas. Finally, a plausible formaldehyde gas sensing mechanism is proposed., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Herein, we have developed a novel sensing electrode to detect the eco-toxic 4-nitrophenol (4-NP). Ag-doped-ZnO nanoflowers were synthesized by facile hydrothermal method and examined by several characterization techniques in order to understand the morphology, crystal structure, composition, and surface properties. Morphological results were confirmed by the formation of Ag-doped ZnO nanoflowers decorated with nanosheets. Ag-doped ZnO/glassy carbon electrode (GCE) electrode-material-matrix was used for electrochemical sensing of toxic 4-NP. Under optimized conditions, Ag-doped ZnO/GCE modified electrode exhibits high-sensitivity and selectivity compared to the bare GCE electrode. The Ag-doped ZnO/GCE modified electrode exhibits high electrocatalytic oxidation towards 4-NP. Anodic peak current of 4-NP is increased linearly by increasing the concentration of nitrophenol. Additionally, Ag-doped ZnO/GCE shows a wide range of sensitivity from 10 µM to 500 µM, and a linear calibration plot with a good detection limit of 3 µM (S/N = 3). The proposed Ag-doped ZnO/GCE modified electrode showed high sensing stability. In addition, the oxidation mechanism was studied. The obtained results revealed that the Ag-ZnO/GCE electrode could be the promising sensing electrode for 4-NP sensing.

Enzyme-mimetic properties of nanomaterials can be efficiently tuned by controlling their size, composition, and structure. Here, ultrathin PdCu alloy nanosheet-assembled three-dimensional (3D) nanoflowers (Pd 1 Cu x NAFs) with tunable surface composition are obtained via a generalized strategy. In presence of H 2 O 2 , the as-synthesized Pd 1 Cu x NAFs can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to the oxidized form of TMB (oxTMB) with a characteristic absorption peak at 652 nm. Interestingly, Pd 1 Cu x NAFs show obviously composition-dependent peroxidase-like catalytic activities because of the synergistic interaction of nanoalloy. Additionally, different from 2D Pd nanosheets, the distinctive 3D superstructures are featured with rich approachable sites and proper layer spacing, which are in favor of fast mass transport and electron transfers during the catalytic process. Among the studied Pd 1 Cu x NAFs, the Pd 1 Cu 1.7 NAFs show the highest enzyme-like activities and can be successfully applied for the colorimetric detection of glucose with a low detection limit of 2.93 ± 0.53 μM. This work provides an efficient avenue to fabricate PdCu NAF nanozymes in biosensing toward glucose detection. Two-dimensional (2D) PdCu ultrathin nanosheet-assembled 3D nanoflowers (Pd 1 Cu x NAFs) with tunable surface composition exhibit substantially enhanced intrinsic peroxidase-like catalytic activities. The Pd 1 Cu 1.7 NAFs are successfully used as peroxidase mimic catalyst for the colorimetric detection of glucose with low detection limit of 2.93 μM.

Despite of broad range application, the cost effective, highly stable and reproduceable synthesis of ZnO is needed, especially which can make it biosafe as well. Here, a unique bioinspired synthesis of ZnO nanoflowers (NFs) has been introduced using Withania coagulans extract as reducing agent. Different molar concentrations were assessed to counter the effect of structural, morphological, antibacterial activity and high efficiency of algae harvesting. The UV-spectroscopy authenticates the synthesis of ZnO NFs having Wurtzite hexagonal structure with the size in the range of 360-550 nm. While surface analysis revealed the presence of stabilizing agent like phenolic, amine, etc. on surface of ZnO NFs. These perineum ZnO NFs exhibited a stronger antibacterial with Gram-positive bacteria Staphylococcus aureus as compare to Gram-negative bacteria Pseudomonas aeruginosa and greater harvesting efficiency up to 94% on the account of greater surface area and unique surface chemistry, thus leading a new horizon of more efficient and effective applications for ethanol production., (Copyright © 2020. Published by Elsevier B.V.)

Thrombosis formation and bacterial infection are key challenges for blood-contacting medical devices. When blood components encounter a device's surface, proteins are adsorbed, followed by the adhesion and activation of platelets as well as an immune response. This culminates in clot formation via the trapping of red blood cells in a fibrin matrix, which can block the device's function and cause severe complications for the patient. In addition, bacteria may adhere to a device's surface. This can lead to the formation of a biofilm, a protective layer for bacteria that significantly increases resistance to antibiotics. Despite years of research, no long-term solutions have been discovered to combat these issues. To impede thrombosis, patients often take antiplatelet drugs for the life of their device, which can cause excess bleeding and other complications. Patients can take antibiotics to fight bacterial infection, but these are often ineffective if biofilms are formed. Superhydrophobic surfaces show promise in reducing both thrombosis and bacterial infection on devices by impeding contact between biological components and the biomaterial. In this study, superhydrophobic titania nanoflower surfaces were successfully fabricated on a titanium alloy Ti-6Al-4V substrate with hydrothermal synthesis and vapor-phase silanization. The surface topography, surface wettability, surface chemistry, and surface crystallography of the surfaces was subsequently characterized. Surface hemocompatibility was investigated through lactate dehydrogenase (LDH) cytotoxicity analysis, blood-plasma protein adsorption, platelet and leukocyte adhesion and activation, and whole blood clotting analysis. Surface bacterial infection was characterized through Gram-positive and Gram-negative bacterial adhesion and biofilm morphology. The results indicated a reduction of protein adsorption, platelet and leukocyte adhesion and activation, bacterial adhesion, and biofilm formation as well as improved contact angle stability compared to control surfaces., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Potassium-ion batteries (PIBs) are prospective for energy storage systems owing to their low price and high operating voltage. Antimony-based electrode materials have the advantage of high capacity for PIBs, while suffering from huge volume expansion and inferior stability because of the large radius of K + . Therefore, developing suitable antimony-based electrode materials with high performance is highly challenging. Herein, self-assembled Sb 2 S 3 nanoflowers on the surfaces of MXene (Ti 3 C 2 ) flakes are synthesized through a solvothermal reaction along with a calcination method. The highly conductive two-dimensional Ti 3 C 2 soft substrate could not only boost the charge transfer kinetics but also buffer the volumetric expansion of Sb 2 S 3 effectively. In addition, the structural stability is enhanced because the Sb 2 S 3 nanoflowers are in situ grown on Ti 3 C 2 flakes through the strong interfacial coupling. Consequently, the Ti 3 C 2 -Sb 2 S 3 anode exhibits a high reversible capacity of 461 mAh g -1 at 100 mA g -1 , long cycling life (capacity retention of 79% for 500 cycles), and superior rate performance (102 at 2000 mA g -1 ). This work may provide a pathway for designing advanced materials for PIBs.

The fabrication of hybrid protein-Cu 3 (PO 4 ) 2 nanoflowers (NFs) via an intermediate toroidal structure is dramatically accelerated under shear using a vortex fluidic device (VFD), which possesses a rapidly rotating angled tube. As-prepared laccase NFs (LNFs) exhibit ≈1.8-fold increase in catalytic activity compared to free laccase under diffusion control, which is further enhanced by ≈ 2.9-fold for the catalysis under shear in the VFD. A new LNF immobilization platform, LNF@silica incorporated in a VFD tube, was subsequently developed by mixing the LNFs for 15 min with silica hydrogel resulting in gelation along the VFD tube surface. The resulting LNFs@silica coating is highly stable and reusable, which allows a dramatic 16-fold enhancement in catalytic rates relative to LNF@silica inside glass vials. Ultraviolet-visible spectroscopy-based real-time monitoring within the LNFs@silica-coated tube reveals good stability of the coating in continuous flow processing. The results demonstrate the utility of the VFD microfluidic platform, further highlighting its ability to control chemical and enzymatic processes.

A new composite, AgPW@PDA@Nisin, with shell-core structure was successfully synthesized by a polydopamine (PDA) surfaced conjugated nisin (an antibacterial 34 amino acid polycyclic peptide) as shell and polyoxometalates (Ag 3 PW 12 O 40  = AgPW) as core. The composite was characterized by the zeta potential, scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction analysis (XRD), fourier transform infrared (FT-IR). The AgPW@PDA@Nisin showed flower hierarchical structure and potential antibacterial activity against S. aureus ATCC29213. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of it were 4 and 32 μg/mL. AgPW@PDA@Nisin nanoflowers-induced bacterial death bears the characteristic of cell morphology, membrane integrity and permeability changing, nucleotide leakage. It indicated that the AgPW@PDA@Nisin interfere with the cell membrane, resulting in antibacterial activity against S. aureus. The cytotoxicity of the nanoflowers was low on HDF-a (human dermal fibroblasts) cells. A new class of hybrid inorganic-organic nanoflowers based on polyoxometalates and nisin with enhanced antibacterial properties can be developed for food preservation., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Improving conductivity of electron and ion was considered to be the significant tendency on pseudocapacitive materials. In this work, a flower-like P-NiAl LDHs electrode materials have been successfully fabricated by hydrothermal synthesis and subsequent phosphatized treatment. Owing to the presence of phosphide, the resulting P-NiAl LDHs electrode showed a high specific capacitance of 2159F g -1 at 1 A g -1 and a good capacitance retention of 85.6% at 20 A g -1 , which more excellent than NiAl LDHs electrode. Besides, the P-NiAl LDHs//AC asymmetric supercapacitor exhibited a high energy density of 79.3 Wh kg -1 under a power density of 1033.6 W kg -1 and an acceptable stability of 73.6% specific capacitance retention after 2400 charge-discharge cycles. Consequently, the P-NiAl LDHs nanoflower is one of the better candidates for assembling supercapacitor, and this phosphatized method is a kind of facile and desirable strategies to improve the electrochemical characteristics of LDH-based supercapacitor materials., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Ligand-induced chirality in asymmetric CdSe/CdS core-shell nanocrystals (NCs) has been extensively applied in chiral biosensors, regioselective syntheses and assemblies, circularly polarized luminescence (CPL), and chiroptic-based devices due to their excellent physiochemical properties, such as the tunable quantum confinement effects, surface functionality, and chemical stability. Herein, we present CdSe/CdS NCs with various morphologies such as nanoflowers, tadpoles, and dot/rods (DRs) with chirality induced by surface chiral ligands. The observed circular dichroism (CD) and CPL activities are closely associated with the geometrical characteristics of the nanostructures, such as the shell thickness and the aspect ratio of the CdSe/CdS NCs. Furthermore, in situ observations of the growth of tadpoles with a single tail indicate that the CD response is mainly attributed to the CdS shell, which has a maximum tail length of ∼45 nm (approximately λ/10 of the incident light wavelength). On the other hand, the CPL activity is only related to the CdSe core, and the activity benefits from a thin CdS shell with a relatively high photoluminescence quantum yield (QY). Further theoretical models demonstrated the aspect-ratio-dependent g -factor and QY variations in these asymmetric nanostructures. These findings provide insights into not only the asymmetric synthesis of CdSe/CdS NCs, but also the rational design of CdSe/CdS nanostructures with tunable CD and CPL activities.

Recently, composites of MXenes and two-dimensional transition metal dichalcogenides have emerged as promising materials for energy storage applications. In this study, W 2 C/WS 2 alloy nanoflowers (NFs) were prepared by a facile hydrothermal method. The alloy NFs showed a particle size of 200 nm-1 μm, which could be controlled. The electrochemical performance of the as-prepared alloy NFs was investigated to evaluate their potential for application as lithium-ion battery (LIB) anodes. The incorporation of W 2 C in the WS 2 NFs improved their electronic properties. Among them, the W 2 C/WS 2 _4h NF electrode showed the best electrochemical performance with an initial discharge capacity of 1040 mAh g -1 and excellent cyclability corresponding to a reversible capacity of 500 mAh g -1 after 100 cycles compared to that of the pure WS 2 NF electrode. Therefore, the incorporation of W 2 C is a promising approach to improve the performance of LIB anode materials.

In this work, flower-like ZnO nanorods (NRs) were successfully prepared using microwave-assisted techniques at a low temperature. The synthesized NRs exhibited a smooth surface and good crystal structure phase of ZnO. The sharp peak of the XRD and Raman spectrum confirmed the high crystallinity of these ZnO NRs with a pure wurtzite structure. The nanorods were ~2 μm in length and ~150 nm in diameter, respectively. The electron diffraction pattern confirmed that the single crystal ZnO nanorods aligned along the [001] plane. The NRs were applied to fabricate a gas sensor for reducing gases such as CH 4 , CO, and H 2 . The sensor showed a good performance and sensitivity toward the target gases. However, its response toward CH 4 and CO was higher compared to H 2 gas. Although the operating temperature was varied from room temperature (RT) up to 350°C, the sensor did not show a response toward any of the target gases in the range of RT-150°C, but dramatic enhancement of the sensor response was observed at 200°C, and up to higher temperatures. This behavior was ascribed to the activity of the smooth surface and the reactivity of surface oxygen species with the targeted gases. The sensor response was measured at various gas concentrations, where the calibration curve was shown. The gas sensing mechanism was described in terms of the reaction of the gases with the transformed oxygen species on the surface of the oxides., (Copyright © 2020 Aljaafari, Ahmed, Awada and Shaalan.)