Controlled Molecular Arrangement of Cinnamic Acid in Layered Double Hydroxide through pi-pi Interaction for Controlled Release

Cinnamic acid (CA) was successfully incorporated into Zn-Al layered double hydroxide (LDH) through coprecipitation. The CA moiety was stabilized in the interlayer space through not only electrostatic interaction but also intermolecular π-π interaction. It was noteworthy that the CA arrangement was fairly independent of the charge density of LDH, showing the important role of the layer-CA and CA-CA interactions in molecular stabilization. Computer simulations using the Monte Carlo method as well as analytical approaches including infrared, UV-vis spectroscopy, and differential scanning calorimetry showed the existence of intermolecular interaction. In order to reinforce molecular stabilization, a neutral derivative of CA, cinnamaldehyde (CAD), was additionally incorporated into LDH. It was clearly shown that CAD played a role as a π-π interaction mediator to enhance the stabilization of CA. The time-dependent release of CA from LDH was first governed by the layer charge density of LDH; however, the existence of CAD provided additional stabilization to the CA arrangement to slow down the release kinetics.

Comparison of blood loss between intra-articular microporous polysaccharide hemospheres powder and tranexamic acid following primary total knee arthroplasty

Total knee arthroplasty (TKA) is associated with substantial blood loss and tranexamic acid (TXA) effectively reduces postoperative bleeding. Although it is known that there is no difference between intravenous or intra-articular (IA) injection, the general interest is directed towards topical hemostatic agents regarding thromboembolic events in high-risk patients. This study aimed to compare the blood conservation effects of IA MPH powder and TXA in patients undergoing primary TKA. We retrospectively analyzed 103 patients who underwent primary TKA between June 2020 and December 2021. MPH powder was applied to the IA space before capsule closure (MPH group, n = 51). TXA (3 g) was injected via the drain after wound closure (TXA group, n = 52). All patients underwent drain clamping for three postoperative hours. The primary outcome was the drain output, and the secondary outcomes were the postoperative hemoglobin (Hb) levels during the hospitalization period and the perioperative blood transfusion rates. An independent Student's t-test was used to determine differences between the two groups. The drain output in the first 24 h after surgery was significantly higher in the MPH group than in the TXA group. The postoperative Hb levels were significantly lower in the MPH group than in the TXA group. In patients with simultaneous bilateral TKA, there was a significant difference in the blood transfusion volumes and the rates between groups. It is considered that IA MPH powder cannot replace IA TXA because of an inferior efficacy in reducing blood loss and maintaining postoperative Hb levels in the early postoperative period after primary TKA. Moreover, in the case of simultaneous bilateral TKA, we do not recommend the use of IA MPH powder because it was notably less effective in the field of transfusion volume and rate.

Controlled molecular arrangement of easily aggregated deoxycholate with layered double hydroxide

Deoxycholate (DA) is a natural emulsifying agent involved in the absorption of dietary lipids. Due to the facial distribution of hydrophobic-hydrophilic region, DA easily aggregates under ambient conditions, and this property hinders the practical application of DA in clinical applications. In this study, we found that the molecular arrangement of DA molecules could be controlled by using layered double hydroxide (LDH) under a specific reaction condition. The effect of reaction methods such as co-precipitation, ion exchange and reconstruction on the molecular arrangement of DA was investigated by X-ray diffraction, Fourier-transform infrared spectroscopy, high-resolution transmission electron microscopy and differential scanning calorimetry. It was demonstrated that the self-aggregation of DA molecules could be suppressed by the oriented arrangement of DA between the gallery space of LDH. The DA moiety was well stabilized in the LDH layers due to the electrostatic interaction between DA molecules and LDH layers. The most ordered arrangement of DA molecules was observed when DA was incorporated into LDH via a reconstruction method. The DA molecules arranged in LDH via reconstruction did not show significant exothermic or endothermic behaviour up to 400°C, showing that the DA moiety lost its intermolecular attraction in between LDH layers.

Blood Compatibility of Drug-Inorganic Hybrid in Human Blood: Red Blood Cell Hitchhiking and Soft Protein Corona

A drug-delivery system consisting of an inorganic host-layered double hydroxide (LDH)-and an anticancer drug-methotrexate (MTX)-was prepared via the intercalation route (MTX-LDH), and its hematocompatibility was investigated. Hemolysis, a red blood cell counting assay, and optical microscopy revealed that the MTX-LDH had no harmful toxic effect on blood cells. Both scanning electron microscopy and atomic force microscopy exhibited that the MTX-LDH particles softly landed on the concave part inred blood cells without serious morphological changes of the cells. The time-dependent change in the surface charge and hydrodynamic radius of MTX-LDH in the plasma condition demonstrated that the proteins can be gently adsorbed on the MTX-LDH particles, possibly through protein corona, giving rise to good colloidal stability. The fluorescence quenching assay was carried out to monitor the interaction between MTX-LDH and plasma protein, and the result showed that the MTX-LDH had less dynamic interaction with protein compared with MTX alone, due to the capsule moiety of the LDH host. It was verified by a quartz crystal microbalance assay that the surface interaction between MTX-LDH and protein was reversible and reproducible, and the type of protein corona was a soft one, having flexibility toward the biological environment.

Controlling the Surface Morphology of Two-Dimensional Nano-Materials upon Molecule-Mediated Crystal Growth

The surface morphology of Mg-Al-layered double hydroxide (LDH) was successfully controlled by reconstruction during systematic phase transformation from calcined LDH, which is referred to as layered double oxide (LDO). The LDH reconstructed its original phase by the hydration of LDO with expanded basal spacing when reacted with water, including carbonate or methyl orange molecules. During the reaction, the degree of crystal growth along the ab-plane and stacking along the c-axis was significantly influenced by the molecular size and the reaction conditions. The lower concentration of carbonate gave smaller particles on the surface of larger LDO (2000 nm), while the higher concentration induced a sand-rose structure. The reconstruction of smaller-sized LDH (350 nm) did not depend on the concentration of carbonate due to effective adsorption, and it gave a sand-rose structure and exfoliated the LDH layers. The higher the concentration of methyl orange and the longer the reaction time applied, the rougher the surface was obtained with a certain threshold point of the methyl orange concentration. The surface roughness generally increased with the loading mount of methyl orange. However, the degree of the surface roughness even increased after the methyl orange loading reached equilibrium. The result suggested that the surface roughening was mediated by not only the incorporation of guest molecules into the LDH but also a crystal arrangement after a sufficient amount of methyl orange was accommodated.

Effect of Tetrahedrally Coordinated Al on the Surface Acidity of Mg-Al Binary Mixed Oxides

Metal oxides (MOs) having Mg and Al with Mg/Al ratios of 1, 2, 3, and 4 were synthesized via calcination of the layered double hydroxides (LDH). The X-ray diffraction analysis revealed that all the MO consisted of periclase (MgO) crystallite with comparable crystallinity regardless of the metal ratio. According to the 27Al magic-angle spinning nuclear magnetic resonance, the phase transformation from LDH to MO upon calcination facilitated the evolution of the Al3+ ions with unsaturated coordination at the surface of MO. The specific surface area values of MOs were not significantly different from each other, ranging between 100 and 200 m2/g, suggesting that the metal ratio did not strongly influence the porous structure of MO. The temperature-dependent desorption of ammonia demonstrated that the Lewis acidity of the Al-rich MOs was the largest with an Mg/Al ratio of 1, attributed to the efficient exposure of the surface-active site Al3+-O2- pairs. The acidity of heterogenous Al-rich MOs significantly increased with the exposed tetrahedral Al site on the surface and dramatically diminished when the molar ratio (Mg/Al) was over two.

Time-Dependent Controlled Release of Ferulic Acid from Surface-Modified Hollow Nanoporous Silica Particles

Release of ferulic acid from surface-functionalized hollow nanoporous silica particles (HNSPs) was investigated in deionized water (DI water) and in ethanol. The host material, an HNSP, was synthesized in the presence of polymer and surfactant templates, and the pore as well as the surface were modified with either pentyltriethoxysilane (PTS) or octyltriethoxysilane (OTS) through silane coupling reactions. The inner hollow space occupied a volume of ~45% of the whole HNSP with a 2.54 nm pore channel in the wall. The pore size was estimated to decrease to 1.5 nm and 0.5 nm via the PTS and OTS functionalization, respectively. The encapsulation efficiencies of the HNSP (25 wt%), PTS-functionalized HNSP (PTS-HNSP, 22 wt%) and OTS-functionalized HNSP (OST-HNSP, 25 wt%) toward ferulic acid were similar, while the %release in DI water and ethanol varied following HNSP > PTS-HNSP > OTS-HNSP. Release kinetic analyses with Korsmeyer-Peppas fitting suggested a trade-off relationship between the solvent's ability to access the HNSP and the affinity of ferulic acid to the surface, allowing us to understand the solvent's controlled release rate and mechanism.

Biocompatible MgFeCO3 Layered Double Hydroxide (LDH) for Bone Regeneration-Low-Temperature Processing through Cold Sintering and Freeze-Casting

Layered Double Hydroxides (LDHs) are inorganic compounds of relevance to various domains, where their surface reactivity and/or intercalation capacities can be advantageously exploited for the retention/release of ionic and molecular species. In this study, we have explored specifically the applicability in the field of bone regeneration of one LDH composition, denoted "MgFeCO₃", of which components are already present in vivo, so as to convey a biocompatibility character. The propensity to be used as a bone substitute depends, however, on their ability to allow the fabrication of 3D constructs able to be implanted in bone sites. In this work, we display two appealing approaches for the processing of MgFeCO₃ LDH particles to prepare (i) porous 3D scaffolds by freeze-casting, involving an alginate biopolymeric matrix, and (ii) pure MgFeCO₃ LDH monoliths by Spark Plasma Sintering (SPS) at low temperature. We then explored the capacity of such LDH particles or monoliths to interact quantitatively with molecular moieties/drugs in view of their local release. The experimental data were complemented by computational chemistry calculations (Monte Carlo) to examine in more detail the mineral-organic interactions at play. Finally, preliminary in vitro tests on osteoblastic MG63 cells confirmed the high biocompatible character of this LDH composition. It was confirmed that (i) thermodynamically metastable LDH could be successfully consolidated into a monolith through SPS, (ii) the LDH particles could be incorporated into a polymer matrix through freeze casting, and (iii) the LDH in the consolidated monolith could incorporate and release drug molecules in a controlled manner. In other words, our results indicate that the MgFeCO₃ LDH (pyroaurite structure) may be seen as a new promising compound for the setup of bone substitute biomaterials with tailorable drug delivery capacity, including for personalized medicine.

Interconnected Vanadyl Pyrophosphate Nanonetworks as a Flexible Electrode for High-Voltage and Long-Life Li-Ion Supercapacitors

Engineering vanadium-based materials with high conductivity, superior redox performance, and high operating voltage has attracted widespread attention in energy storage devices. Herein, we demonstrated a simple and feasible phosphorization technique to design three-dimensional (3D) network-like vanadyl pyrophosphate ((VO)₂P₂O₇) nanowires on flexible carbon cloth (CC) (VP-CC). The phosphorization process enabled the VP-CC to increase the electronic conductivity, and the interconnected nano-network of VP-CC opens pathways for fast charge storage during the energy storage processes. Specifically, the 3D VP-CC electrodes and LiClO₄ electrolyte designed as a Li-ion supercapacitor (LSC) demonstrate a maximum operating window of 2.0 V with a superior energy density (E_d) of 96 μWh cm^-2, power density (P_d) of 10,028 μW cm^-2, and outstanding cycling retention (98%) even after 10,000 cycles. In addition, a flexible LSC assembled utilizing VP-CC electrodes with a PVA/Li-based solid-state gel electrolyte exhibits a high capacitance value of 137 mF cm^-2 and excellent cycling durability (86%) with a high E_d of 27 μWh cm^-2 and P_d of 7237 μW cm^-2. Considering excellent energy storage features, the highly conductive vanadium-based material has been utilized as an ideal electrode for various flexible/wearable energy storage devices with superior performance.

Hybridization of Layered Titanium Oxides and Covalent Organic Nanosheets into Hollow Spheres for High-Performance Sodium-Ion Batteries with Boosted Electrical/Ionic Conductivity and Ultralong Cycle Life

While development of a sodium-ion battery (SIB) cathode has been approached by various routes, research on compatible anodes for advanced SIB systems has not been sufficiently addressed. The anode materials based on titanium oxide typically show low electrical performances in SIB systems primarily due to their low electrical/ionic conductivity. Thus, in this work, layered titanium oxides were hybridized with covalent organic nanosheets (CONs), which exhibited excellent electrical conductivity, to be used as anodes in SIBs. Moreover, to enlarge the accessible areas for sodium ions, the morphology of the hybrid was formulated in the form of a hollow sphere (HS), leading to the highly enhanced ionic conductivity. This synthesis method was based on the expectation of synergetic effects since titanium oxide provides direct electrostatic sodiation sites that shield organic components and CON supports high electrical and ionic conductivity with polarizable sodiation sites. Therefore, the hybrid shows enhanced and stable electrochemical performances as an anode for up to 2600 charge/discharge cycles compared to the HS without CONs. Furthermore, the best reversible capacities obtained from the hybrid were 426.2 and 108.5 mAh/g at current densities of 100 and 6000 mA/g, which are noteworthy results for the TiO₂-based material.

Hyaluronic acid-coated gold nanoparticles as a controlled drug delivery system for poorly water-soluble drugs

Hyaluronic acid (HA) is a natural linear polysaccharide which has been widely used in cosmetics and pharmaceuticals including drug delivery systems because of its excellent biocompatibility. In this study, we investigated the one-pot synthesis of HA-coated gold nanoparticles (AuNP-HA) as a drug delivery carrier. The HAs with different molecular weights were produced by e-beam irradiation and employed as coating materials for AuNPs. Sulfasalazine (SSZ), a poorly water-soluble drug, was used to demonstrate the efficiency of drug delivery and the controlled release behaviour of the AuNP-HA. As the molecular weight of the HA decreased, the drug encapsulation efficiency of the SSZ increased up to 94%, while drug loading capacity of the SSZ was maintained at the level of about 70%. The prepared AuNP-HA-SSZ exhibited slow release of the SSZ over a short time and excellent sensitivity to different pHs and physiological conditions. The SSZ release rate was the lowest in simulated gastric conditions and the highest in simulated intestinal conditions. In this case, the AuNP-HA protects the SSZ from release under the acidic pH conditions in the stomach; on the other hand, the drug release was facilitated in the basic environment of the small intestine and colon. The SSZ was released under simulated intestinal conditions through anomalous drug transport and followed the Korsmeyer-Peppas model. Therefore, this study suggests that AuNP-HA is a promising orally-administered and intestine-targeted drug delivery system with controlled release characteristics.

Enhanced Emulsifying Ability of Deoxycholate through Dynamic Interaction with Layered Double Hydroxide

The emulsifying ability of the naturally occurring surfactant deoxycholic acid (DCA) was improved by dynamic interaction with nanometric layered particles, layered double hydroxide (LDH). As DCA molecules are rigid due to the facial configuration of hydrophobic-hydrophilic groups, they tend to form molecular aggregation in an acidic condition or imbalanced water-lipid ratios. In this study, the homogeneous hybrids of DCA and LDH were obtained by the in situ growth of LDH at a DCA molecule. The DCA-LDH hybrid successfully prevented the molecular aggregation of DCA at an acidic pH and imbalanced water-to-oil ratio. The dynamic light scattering showed that the hydrodynamic radius of micelle in the emulsion made with DCA-LDH maintained its small size (<500 nm), while upon pH change and dilution with water, that made with DCA only uncontrollably increased up to ~3000 nm. The polydispersity index value of the DCA-LDH emulsion remained constant (<0.3) after the pH change and dilution with water, indicating the high stability of the formulation. Furthermore, time-dependent turbidity monitoring revealed that the DCA-only formulation suffered from serious coalescence and creaming compared with the DCA-LDH formulation. It is suggested that the dynamic interaction between LDH layers and DCA prevented molecular aggregation under unfavorable conditions for the oil-in-water emulsion.

Bio-Activation of HA/β-TCP Porous Scaffolds by High-Pressure CO2 Surface Remodeling: A Novel "Coating-from" Approach

Biphasic macroporous Hydroxyapatite/β-Tricalcium Phosphate (HA/β-TCP) scaffolds (BCPs) are widely used for bone repair. However, the high-temperature HA and β-TCP phases exhibit limited bioactivity (low solubility of HA, restricted surface area, low ion release). Strategies were developed to coat such BCPs with biomimetic apatite to enhance bioactivity. However, this can be associated with poor adhesion, and metastable solutions may prove difficult to handle at the industrial scale. Alternative strategies are thus desirable to generate a highly bioactive surface on commercial BCPs. In this work, we developed an innovative "coating from" approach for BCP surface remodeling via hydrothermal treatment under supercritical CO₂, used as a reversible pH modifier and with industrial scalability. Based on a set of complementary tools including FEG-SEM, solid state NMR and ion exchange tests, we demonstrate the remodeling of macroporous BCP surface with the occurrence of dissolution-reprecipitation phenomena involving biomimetic CaP phases. The newly precipitated compounds are identified as bone-like nanocrystalline apatite and octacalcium phosphate (OCP), both known for their high bioactivity character, favoring bone healing. We also explored the effects of key process parameters, and showed the possibility to dope the remodeled BCPs with antibacterial Cu²⁺ ions to convey additional functionality to the scaffolds, which was confirmed by in vitro tests. This new process could enhance the bioactivity of commercial BCP scaffolds via a simple and biocompatible approach.

Photochemical Consideration in the Interactions between Blood Proteins and Layered Inorganic Materials

Interactions between layered double hydroxide (LDH) nanomaterials and plasma proteins according to their particle size and surface charge were evaluated. The LDHs with different particle size (150, 350 and 2000 nm) were prepared by adjusting hydrothermal treatment and urea hydrolysis and subsequent organic coating with citrate, malite and serite was applied to control the surface charge (ζ-potential: −15, 6 and 36 mV). Adsorption isotherms and Stern–Volmer plots for fluorescence quenching indicated that the human blood plasma had weak interactions toward all the types of LDHs. The adsorption isotherms did not show significant differences in the size and surface charges, while the fluorescence quenching ratio increased with the increase in the surface charge, implying that electrostatic interaction played a major role in their interactions. The fluorescence quenching of three types of plasma proteins (human serum albumin, γ-globulin and fibrinogen) by the surface charge-controlled LDHs suggested that the proteins adsorbed on the LDHs with a single layer and additional proteins were weakly adsorbed to surround the LDHs with adsorbed proteins. It was concluded that the LDH nanomaterials are fairly compatible for blood components due to the protein corona while the electrostatic interaction can affect their interaction with the proteins.

Topology dependent modification of layered double hydroxide for therapeutic and diagnostic platform

Layered double hydroxide is a family of two-dimensional materials with wide range of compositions. Recently, its ability to accommodate various chemical species and biocompatibility have been attracted in the biomedical applications to develop drug delivery system and nanodiagnostics. In this review, we categorized biomedical approaches of layered double hydroxide with respect to the three topologies of, namely, interlayer space, outer surface with particle edge, and the lattice points. There have been extensive researches on the intercalation of drug or tracing to make use of interlayer space of layered double hydroxide for drug stabilization, sustained release, cellular delivery and etc. Outer surface or edge has been utilized to immobilization of large therapeutic moieties and to attach tracing moiety. Lattice points consisting of various metal species could be utilized for the specific metal species like paramagnetic elements or radioisotopes. Based on these topologies in layered double hydroxide, both the synthetic routes and the achieved functionalities in terms of biomedical application will be discussed.

MXsorption of mercury: Exceptional reductive behavior of titanium carbide/carbonitride MXenes

Two-dimensional (2D) transition metal carbides and nitrides (MXenes) have drawn considerable attention for application in the field of environmental remediation. In this study, we report the simultaneous reductive-adsorption behavior of Ti₃CNT_x for toxic metal ion Hg²⁺ ion in the aqueous phase. 2D Ti₃CNT_x and Ti₃C₂T_x MXene nanosheets were synthesized by exfoliation of Ti₃AlCN and Ti₃AlC₂ MAX phases, respectively. Various characteristics analysis confirmed the successful fabrication of MAX phases and their exfoliation into MXenes. The fabricated MXene nanosheets were used to investigate their Hg²⁺ removal, Hg²⁺ intercalation, and surface interaction mechanism efficiencies. Both MXenes were found to adsorb and reduce a large amount of Hg²⁺. Analytical techniques such as X-ray powder diffraction, field emission transmission electron microscopy, zeta-potential analyses, and X-ray photoelectron spectroscopy were used to investigate the material characteristics and structural changes after uptake of Hg²⁺. The quantitative investigation confirmed the interaction of bimetal and hydroxyl groups with Hg²⁺ using electrostatic interactions and adsorption-coupled reduction. In addition, both MXenes exhibited extraordinary Hg ion removal capabilities in terms of fast kinetics with an excellent distribution coefficient (K_d^Hg) up to 1.36 × 10⁺⁹. Based on batch adsorption results, Ti₃C₂T_x and Ti₃CNT_x exhibited removal capacities of 5473.13 and 4606.04 mg/g, respectively, for Hg²⁺, which are higher than those of previous Hg adsorbents.

Periodic charge matching driven immobilization of gentamicin in nanoclays for stable and long-term antibacterial coating

Matching of charge periodicity between a guest and a host enabled effective immobilization of highly water-soluble antibiotic drug, gentamicin C, in a bentonite clay by cation exchange. X-ray diffraction, infrared spectroscopy and CHNS analysis revealed the immobilization manner of gentamicin C, which was immobilized between bentonite layers via periodic charge-charge interaction with tilted arrangement, as a trication. Both gentamicin alone and a gentamicin/bentonite hybrid were coated onto a polyurethane substrate using water-borne polyurethane binder. The antibiotic character of both films was investigated as prepared or after immersion in phosphate-buffered saline till 5 days against E. coli and B. subtilis bacteria. It was clearly shown that the gentamicin/bentonite hybrid-coated film showed sustained antibacterial efficacy even after exposure to phosphate-buffered saline, while gentamicin only-coated film gradually lost its performance under the same condition.

Two-Dimensional Organic/Inorganic Hybrid Nanosheet Electrodes for Enhanced Electrical Conductivity toward Stable and High-Performance Sodium-Ion Batteries

To investigate the effect of electrical conductivity on the energy-storage characteristics of anode materials in sodium-ion batteries, covalent organic nanosheets (CONs) are hybridized with highly conductive graphene nanosheets (GNs) via two different optimized synthesis routes, that is, reflux and solvothermal methods. The reflux-synthesized hybrid shows a well-overlapped 2D structure, whereas the solvothermally prepared hybrid forms a segregated phase in which the contact area between the CONs and GNs is reduced. These two hybrids synthesized by facile methods are fully characterized, and the results reveal that their energy-storage properties can be significantly improved by enhancing the electrical conductivity via the formation of a well-overlapped structure between CONs and GNs. The discharge capacity and rate capability of the reflux-synthesized hybrid was considerably larger than that of the bare CONs, highlighting that the improvement in the charge-carrier transport properties can improve the accessibility of Na ions to the surface of the hybrids. This synthetic methodology can be extended to the fabrication of high-performance anodes for Na-ion batteries.

Two-Dimensional Organic/Inorganic Hybrid Nanosheet Electrodes for Enhanced Electrical Conductivity toward Stable and High-Performance Sodium-Ion Batteries

Invited for this month's cover are the groups of Jae-Min Oh, Jin Kuen Park, and Seung-Min Paek at three different universities in South Korea. The image shows how the supramolecular interaction between two different two-dimensional materials can control the electrical storage properties for a sodium-ion battery. The Full Paper itself is available at 10.1002/cssc.202100545.

Development of polystyrene coated persulfate slow-release beads for the oxidation of targeted PAHs: Effects of sulfate and chloride ions

In this study, we synthesized polystyrene coated persulfate polyacrylonitrile beads (PC-PSPANBs) to control persulfate (PS) release for targeted PAHs' degradation in a batch reactor. Initially, the persulfate release rate (k_sr = 20.553 h^-1) from PSPANBs was fast, but coating the PSPANBs with polystyrene controlled PS release rate (k_sr= 2.841 h^-1), nearly ten times slower than without coating. When Fe(II) activated PC-PSPANBs applied for 12 h degradation of acenaphthene (ACE), 2-methlynaphthalene (2-MN) and dibenzofuran (DBF), the optimum percent removal efficiencies (% R.Es) were as ACE (82.12%) > DBF (68.57%) > 2-MN (58.80%) and the optimum degradation rate constants (k_obs) were found as ACE (11.348 h^-1) > 2-MN (3.441 h^-1) > DBF (1.101 h^-1). The effect of SO₄^2- and Cl^- on ACE degradation showed that % R.E and k_obs were enhanced with increasing anionic concentrations. The maximum % R.E was achieved for SO₄^2- (76.24%) > Cl^- (65.51%), but the highest k_obs was in case of Cl^- (1.536 h^-1) > SO₄^2- (0.510 h^-1). The effectiveness of PS release longevity was also found because net degradations of ACE and DBF after first spiking were 12 mg L^-1 and 16 mg L^-1, while after second spiking were 18 mg L^-1 and 10 mg L^-1, respectively.

Advances in the Synthesis and Application of Anti-Fouling Membranes Using Two-Dimensional Nanomaterials

This article provides a comprehensive review of the recent progress in the application of advanced two-dimensional nanomaterials (2DNMs) in membranes fabrication and application for water purification. The membranes fouling, its types, and anti-fouling mechanisms of different 2DNMs containing membrane systems are also discussed. The developments in membrane synthesis and modification using 2DNMs, especially graphene and graphene family materials, carbon nanotubes (CNTs), MXenes, and others are critically reviewed. Further, the application potential of next-generation 2DNMs-based membranes in water/wastewater treatment systems is surveyed. Finally, the current problems and future opportunities of applying 2DNMs for anti-fouling membranes are also debated.

Mixed Metal Oxide by Calcination of Layered Double Hydroxide: Parameters Affecting Specific Surface Area

Mixed metal oxide (MMO) is one of the widely utilized ceramic materials in various industries. In order to obtain high performance, the specific surface area of MMO should be controlled. Calcination of layered double hydroxide (LDH) is a versatile way to prepare MMO with homogeneous metal distribution and well-developed porosity. Although researchers found that the specific surface area of LDH-originated MMO was relatively high, it had not been systematically investigated how the surface area is controlled under a certain parameter. In this review, we summarized LDH-originated MMO with various starting composition, calcination temperature, and pore developing agent in terms of specific surface area and porosity. Briefly, it was represented that MMOs with Mg-Al components generally had higher specific surface area than Mg-Fe or Zn-Al components. Calcination temperature in the range 300–600 °C resulted in the high specific surface area, while upper or lower temperature reduced the values. Pore developing agent did not result in dramatic increase in MMO; however, the pore size distribution became narrower in the presence of pore developing agents.

Controlled Growth of Silver Oxide Nanoparticles on the Surface of Citrate Anion Intercalated Layered Double Hydroxide

Silver oxide nanoparticles with controlled particle size were successfully obtained utilizing citrate-intercalated layered double hydroxide (LDH) as a substrate and Ag+ as a precursor. The lattice of LDH was partially dissolved during the reaction by Ag+. The released hydroxyl and citrate acted as a reactant in crystal growth and a size controlling capping agent, respectively. X-ray diffraction, X-ray photoelectron spectroscopy, and microscopic measurements clearly showed the development of nano-sized silver oxide particles on the LDH surface. The particle size, homogeneity and purity of silver oxide were influenced by the stoichiometric ratio of Ag/Al. At the lowest silver ratio, the particle size was the smallest, while the chemical purity was the highest. X-ray photoelectron spectroscopy and UV-vis spectroscopy results suggested that the high Ag/Al ratio tended to produce silver oxide with a complex silver environment. The small particle size and homogeneous distribution of silver oxide showed advantages in antibacterial efficacy compared with bulk silver oxide. LDH with an appropriate ratio could be utilized as a substrate to grow silver oxide nanoparticles with controlled size with effective antibacterial performance.

Porous Hybrids Structure between Silver Nanoparticle and Layered Double Hydroxide for Surface-Enhanced Raman Spectroscopy

Silver nanoparticle (AgNP), in terms of antibacterial, catalytic, electronic, and optical applications, is an attractive material. Especially, when prepared to furnish sharp edge and systematic particle orientation on the substrate, AgNPs can take advantage of surface-enhanced Raman spectroscopy (SERS). In this research, we suggested a synthetic method to immobilize the AgNP on metal oxide by utilizing Ag-thiolate and layered double hydroxide (LDH) as precursor and template, respectively. The layer-by-layer structure of LDH and Ag-thiolate transformed through reductive calcination to metal oxide and AgNP array. Physicochemical characterization, including powder X-ray diffraction, N₂ adsorption–desorption, microscopies, and X-ray photoelectron spectroscopy, revealed that the AgNP with sufficient crystallinity and particle gap was obtained at relatively high calcination temperature, ~600 °C. UV-vis diffusion reflectance spectroscopy showed that the calcination temperature affected particle size and electronic structure of AgNP. The prepared materials were subjected to SERS tests toward 4-nitrothiophenol (4-NTP). The sample obtained at 600 °C exhibited 50 times higher substrate enhancement factor (SEF) than the one obtained at 400 °C, suggesting that the calcination temperature was a determining parameter to enhance SERS activity in current synthetic condition.

Systematic utilization of layered double hydroxide nanosheets for effective removal of methyl orange from an aqueous system by π-π stacking-induced nanoconfinement

Systematic utilization of carbonated Mg-Al layered double hydroxide (LDH) nanosheets for methyl orange removal was investigated with respect to particle dimensions. LDHs with the smallest dimensions were carefully synthesized to have a small lateral size as well as high dispersibility. The other particles, with medium and large sizes, were prepared by hydrothermal treatment and urea hydrolysis to have larger sizes and higher crystallinity. According to kinetics and isotherm analyses, the smallest LDH showed efficient adsorption of methyl orange (1250 mg/g-LDH), which was remarkably higher than the adsorption by the other LDHs with larger lateral sizes. Unlike the larger lateral-sized LDHs, the small ones were shown to utilize all accessible adsorption sites on the nanosheets, generating nanoconfinement of methyl orange molecules. Transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD) patterns indicated that the LDHs with lateral dimensions of ~40 nm fully utilized interlayer nanospace. Monte Carlo simulation suggested that the intercalated methyl orange was stabilized not only through electrostatic interactions with the LDH layer but also by π-π stacking between the methyl orange molecules, which is thought to be the driving force for replacement of carbonate anions.

Physicochemical Properties and Hematocompatibility of Layered Double Hydroxide-Based Anticancer Drug Methotrexate Delivery System

A layered double hydroxide (LDH)-based anticancer delivery system was investigated in terms of crystalline phase, particle size, hydrodynamic radius, zeta potential, etc. through in vitro and in vivo study. Size controlled LDH with anticancer drug methotrexate (MTX) incorporation was successfully prepared through step-by-step hydrothermal reaction and ion-exchange reaction. The MTX-LDH was determined to have a neutral surface charge and strong agglomeration in the neutral aqueous condition due to the surface adsorbed MTX; however, the existence of proteins in the media dramatically reduced agglomeration, resulting in the hydrodynamic radius of MTX-LDH being similar to the primary particle size. The protein fluorescence quenching assay exhibited that MTX readily reduced the fluorescence of proteins, suggesting that the interaction between MTX and proteins was strong. On the other hand, MTX-LDH showed much less binding constant to proteins compared with MTX, implying that the protein interaction of MTX was effectively blocked by the LDH carrier. The in vivo hemolysis assay after intravenous injection of MTX-LDH showed neither significant reduction in red blood cell number nor membrane damage. Furthermore, the morphology of red blood cells in a mouse model did not change upon MTX-LDH injection. Scanning electron microscopy showed that the MTX-LDH particles were attached on the blood cells without serious denaturation of cellular morphology, taking advantage of the cell hitchhiking property.

Automated Detection of TMJ Osteoarthritis Based on Artificial Intelligence

The purpose of this study was to develop a diagnostic tool to automatically detect temporomandibular joint osteoarthritis (TMJOA) from cone beam computed tomography (CBCT) images with artificial intelligence. CBCT images of patients diagnosed with temporomandibular disorder were included for image preparation. Single-shot detection, an object detection model, was trained with 3,514 sagittal CBCT images of the temporomandibular joint that showed signs of osseous changes in the mandibular condyle. The region of interest (condylar head) was defined and classified into 2 categories-indeterminate for TMJOA and TMJOA-according to image analysis criteria for the diagnosis of temporomandibular disorder. The model was tested with 2 sets of 300 images in total. The average accuracy, precision, recall, and F1 score over the 2 test sets were 0.86, 0.85, 0.84, and 0.84, respectively. Automated detection of TMJOA from sagittal CBCT images is possible by using a deep neural networks model. It may be used to support clinicians with diagnosis and decision making for treatments of TMJOA.

Determination of the fate and biological responses of food additive silica particles in commercial foods

Synthetic amorphous silica (SAS) is widely added to commercial foods as an anticaking agent. Concern about the potential application of nanosized silica in foods has increased as nanomaterials are not intended for use as food additives. This study evaluated the particle size distributions and biological responses of food additive SAS. An accurate, sensitive, and cost-effective analytical method for probing SAS was established, and quantitative analysis of its presence in commercial foods was performed. The results demonstrate that food additive SAS is an aggregated material composed of nanosized particles with nanosized aggregates of silica particles identified in commercial foods. Food additive SAS did not exhibit acute cytotoxicity compared to both general-grade nano (G-nano) and bulk (G-bulk) silica. Moreover, intestinal transport amounts of food additive SAS were significantly lower than for G-nano. Taken together, we find that food additive SAS does not exhibit acute toxicity resulting from nanosized materials.

Random array of inorganic nanoparticles on polymer surface for anti-biofouling property through cost-effective and high-performance dip-coating

Anti-biofouling treatment is required in various fields such as biomedical application, construction, civil engineering, and so on. Currently available techniques such as lithography and replica methods have several limitations in application and accessibility. We introduced a simple, biocompatible, and cost-effective anti-biofouling dip-coating method with polyurethane-inorganic (anisotropic montmorillonite and spherical TiO₂) hybrid coating agent. Layer thickness of coating was as thin as 5 μm. It was cross-confirmed with thickness gauge and cross-section scanning electron microscopy. Through atomic force microscopy, inorganic nanoparticles were observed to be randomly arrayed with particles partially embedded in the polyurethane network. The calculated surface roughness of inorganic-polyurethane hybrid coating was five times larger than the neat substrate film and three times larger than coating without inorganic nanoparticles. Surface energy of the inorganic-polyurethane film decreased with increasing surface roughness as random pattern of inorganic particle reduced van der Waals interaction. Biofouling efficacy was evaluated by mucin adsorption and consecutive alcian blue assay. Results showed that coated film decreased biofouling 81% compared to bare film.

Facile Synthetic Route To Prepare Ultrathin Silver Nanosheets by Reducing Silver Thiolates in Interlayer Surface of Layered Double Hydroxides

Silver metal nanostructures have gained much interest, due to their utility in various fields, based on their unique properties at nanosize. Tremendous research efforts have been made to establish synthetic methods to manipulate their shape and size. The most challenging synthesis in silver nanostructures has been known as a plate-like shape having a few nanometers size thickness and high aspect ratio. Here, we demonstrate a novel and facile synthetic route for ultrathin (≤1 nm) silver nanosheets using silver carboxylthiolate as precursor. Such silver thiolate formed single-layered colloid in aqueous basic solution, due to the electrostatic repulsion between carboxylate groups. These single layers of silver thiolates were stabilized within the interlayer space of layered double hydroxide (LDH). When silver thiolates confined in LDHs were calcined under reductive atmosphere, the LDHs effectively suppressed the vertical growth of silver crystals.

Finely crafted quasi-core–shell gadolinium/layered double hydroxide hybrids for switching on/off bimodal CT/MRI contrasting nanodiagnostic platforms

Quasi core–shell structure of LDH platetes and Gd(OH)₃ nanorods were synthesized to control water approach to Gd(OH)₃ depending on pH.

Substrate templated synthesis of single-phase and uniform Zr-porphyrin-based metal–organic frameworks

We successfully demonstrate that the chemical bath deposition (CBD) method is a versatile method for synthesizing phase-pure and uniform MOFs by controlling their nucleation stages and pore structures.

Zingiber officinale Extract (ZOE) Incorporated with Layered Double Hydroxide Hybrid through Reconstruction to Preserve Antioxidant Activity of ZOE against Ultrasound and Microwave Irradiation

We prepared Zingiber officinale extract (ZOE) incorporated in a layered double hydroxide (LDH) hybrid through a reconstruction method in order to preserve the antioxidant activity of ZOE from ultrasound and microwave irradiation. X-ray patterns, infrared spectroscopy, and scanning electron microscopy suggested that ZOE moieties were encapsulated in the interparticle space of reconstructed LDH, thus preserving its intact structure. Dynamic light scattering and zeta-potential measurement also supported the hypothesis that ZOE moieties were located in the interparticle pore of LDH rather than at the surface of LDH particles. Thermogravimetry analysis revealed that thermal stability of encapsulated ZOE could be enhanced by LDH encapsulation. Radical scavenging assay showed that antioxidant activity of ZOE-LDH hybrid was increased after ultrasound and microwave irradiation, while ZOE itself dramatically lost its antioxidant activity upon ultrasound and microwave treatment.

Incorporation of Glycine max Merrill Extract into Layered Double Hydroxide through Ion-Exchange and Reconstruction

We incorporated extract of Glycine max Merrill (GM), which is generally known as soybean, into a layered double hydroxide (LDH) nanostructure through two different methods, ion-exchange and reconstruction. Through X-ray diffraction, field-emission scanning electron microscopy, and zeta-potential measurement, GM moiety seemed to be simply attached on the surface of LDH by ion-exchange process, while the extract could be incorporated in the inter-particle pore of LDHs by reconstruction reaction. The quantification exhibited that both incorporation method showed comparable extract loading capacity of 15.6 wt/wt% for GM-LDH hybrid prepared by ion-exchange (GML-I) and 18.6 wt/wt% for GM-LDH hybrid by reconstruction (GML-R). On the other hand, bioactive substance in both GM-LDH hybrids, revealed that GML-R has higher daidzein content (0.0286 wt/wt%) compared with GML-I (0.0108 wt/wt%). According to time-dependent daidzein release, we confirmed that GML-R showed pH dependent daidzein release; a higher amount of daidzein was released in pH 4.5 physiological condition than in pH 7.4, suggesting the drug delivery potential of GML-R. Furthermore, alkaline phosphatase activity and collagen fiber formation on human osteoblast-like MG-63 cells displayed that GML-R had superior possibility of osteoblast differentiation than GML-I. From these results, we concluded that reconstruction method was more effective for extract incorporation than ion-exchange reaction, due to its pH dependent release property and alkaline phosphatase activity.

Food Additive Titanium Dioxide and Its Fate in Commercial Foods

Titanium dioxide (TiO2) is one of the most extensively utilized food additives (E171) in the food industry. Along with nanotechnology development, the concern about the presence of nanostructured particles in E171 TiO2 and commercial food products is growing. In the present study, the physicochemical properties of commercially available E171 TiO2 particles, including particle size distribution, were investigated, followed by their cytotoxicity and intestinal transport evaluation. The fate determination and quantification of E171 TiO2 in commercial foods were carried out based on the analytical procedure developed using simulated foods. The results demonstrated that TiO2 is a material mainly composed of particles larger than 100 nm, but present as an agglomerated or aggregated particle in commercial foods with amounts of less than 1% (wt/wt). Titanium dioxide particles generated reactive oxygen species and inhibited long-term colony formation, but the cytotoxicity was not related to particle size distribution or particle type (food- or general-grade). All TiO2 particles were mainly transported by microfold (M) cells, but also by intestinal tight junction. These findings will be useful for TiO2 application in the food industry and predicting its potential toxicity.

Hierarchical Ag Nanostructures Fabricated from Silver Coordination Polymers for Antibacterial Surface

A hierarchical silver nanostructure with improved antibacterial property was fabricated utilizing silver coordination polymer. Octadecanethiolate⁻silver polymer was synthesized to have a layered structure and was coated on silicon wafer by drop-casting method utilizing hydrophobic⁻hydrophobic interaction. Thus, the silver coordination polymer was calcined under reductive condition to produce zero-valent silver with a hierarchical nanostructure. X-ray diffraction patterns revealed that layered silver coordination polymer successfully transformed to hexagonal silver upon calcination. According to scanning electron and atomic force microscopy, silver coordination polymer with ~145.5 nm size was homogeneously coated on the surface before calcination, and it evolved micrometer-sized lumps and grooves which were composed of ~58.8 nm sized Ag nanoparticles. The hierarchical structure-micrometer lump/groove consisting of Ag nanoparticles-would be advantageous to kill bacteria; micrometer-grooves provide physical condition (pocket for bacteria capture) and the Ag nanoparticles from the neighboring lump endow chemical condition (antibacterial property of released Ag⁺). The antibacterial activity test on Escherichia coli via colony forming inhibitory assay indeed exhibited an improved antibacterial activity of hierarchical Ag nanostructure compared with the surface simply coated with Ag nanoparticles. From the line profile of atomic force microscopy, the bacterium trapped in the hierarchical Ag nanostructure was shown to interact intimately with Ag surface.

Immunotoxicity of titanium dioxide nanoparticles via simultaneous induction of apoptosis and multiple toll-like receptors signaling through ROS-dependent SAPK/JNK and p38 MAPK activation

BACKGROUND

Titanium dioxide nanoparticles (TiO2 NPs) represent a scientific breakthrough in the areas of biological and medicinal applications. Interaction of TiO2 NPs with components of innate immune system remains elusive.

AIM

This study explored in vitro immunotoxicity of murine macrophage RAW 264.7 to TiO2 NPs (20 nm, negative charge) and its underlying molecular mechanism by way of immunoredox profiling.

MATERIALS AND METHODS

In this study, chemically synthesized BSA-functionalized TiO2 NPs (20 nm, negative charge) were characterized and immunotoxicity was investigated on RAW 264.7 cells.

RESULTS

We found that reactive oxygen species levels significantly increased with increasing nitric oxide production, whereas depleting endogenous antioxidant super oxide dismutase as well as nuclear factor erythroid 2-related factor 2 (Nrf2) protein levels. Furthermore, NPs exposure increased the expression of apoptotic factors such as BAX, BIM, and PUMA with disruption of mitochondrial membrane potential (Δψm) that lead to decrease in immunocytes. Molecular immune profiling revealed the activation of multiple toll-like receptors (TLRs) 4/9/12/13 simultaneously with the phosphorylation of p-p38MAPK and p-SAPK/c-Jun N-terminal kinase (JNK) compared to untreated control.

CONCLUSION

Collectively, this study shows that the molecular nature of TiO2 SA20(-) NP-induced immunotoxicity in RAW 264.7 macrophage is simultaneous induction of immunocyte apoptosis and multiple TLRs signaling through oxidative stress-dependent SAPK/JNK and p38 mitogen-associated protein kinase activation. This is the first study to address newer molecular mechanism of TiO2 SA20(-) NP-induced immunotoxicity.

Layered Double Hydroxide Nanomaterials Encapsulating Angelica gigas Nakai Extract for Potential Anticancer Nanomedicine

We prepared hybrids consisting of Angelica gigas Nakai (AGN) root or flower extract and layered double hydroxide (LDH) for potential anticancer nanomedicine, as decursin species (DS) in AGN are known to have anticancer activity. Dimethylsulfoxide solvent was determined hybridization reaction media, as it has affinity to both AGN and LDH moiety. In order to develop inter-particle spaces in LDH, a reversible dehydration-rehydration, so-called reconstruction route, was applied in AGN-LDH hybridization. Quantitative analyses on AGN-LDH hybrids indicated that the content of DS was two times more concentrated in the hybrids than in extract itself. Using X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy, and zeta-potential measurement, we found that AGN extract moiety was incorporated into inter-particle spaces of LDH nanoparticles during the reconstruction reaction. Time-dependent DS release from hybrids at pH 7.4 (physiological condition) and pH 4.5 (lysosomal condition) exhibited a pH-dependent release of extract-incorporated LDH hybrids. An anticancer activity test using HeLa, A549, and HEK293T cells showed that the AGN-LDH hybrid, regardless of extract type, showed enhanced anticancer activity compared with extract alone at an equivalent amount of DS, suggesting a nanomedicine effect of AGN-LDH hybrids.

Development and clinical application of an evidence-based pharmaceutical care service algorithm in acute coronary syndrome

WHAT IS KNOWN AND OBJECTIVE

Drug therapies are critical for preventing secondary complications in acute coronary syndrome (ACS). The purpose of this study was to develop and apply a pharmaceutical care service (PCS) algorithm for ACS and confirm that it is applicable through a prospective clinical trial.

METHODS

The ACS-PCS algorithm was developed according to extant evidence-based treatment and pharmaceutical care guidelines. Quality assurance was conducted through two methods: literature comparison and expert panel evaluation. The literature comparison was used to compare the content of the algorithm with the referenced guidelines. Expert evaluations were conducted by nine experts for 75 questionnaire items. A trial was conducted to confirm its effectiveness. Seventy-nine patients were assigned to either the pharmacist-included multidisciplinary team care (MTC) group or the usual care (UC) group. The endpoints of the trial were the prescription rate of two important drugs, readmission, emergency room (ER) visit and mortality.

RESULTS AND DISCUSSION

The main frame of the algorithm was structured with three tasks: medication reconciliation, medication optimization and transition of care. The contents and context of the algorithm were compliant with class I recommendations and the main service items from the evidence-based guidelines. Opinions from the expert panel were mostly positive. There were significant differences in beta-blocker prescription rates in the overall period (P = .013) and ER visits (four cases, 9.76%, P = .016) in the MTC group compared to the UC group, respectively.

WHAT IS NEW AND CONCLUSION

We developed a PCS algorithm for ACS based on the contents of evidence-based drug therapy and the core concept of pharmacist services.

Dietary total, animal, vegetable calcium and type 2 diabetes incidence among Korean adults: The Korean Multi-Rural Communities Cohort (MRCohort)

BACKGROUND AND AIMS

Although a possible mechanism for developing type 2 diabetes in relation to calcium intake has been suggested, there is currently little epidemiological evidence on the association between dietary calcium and type 2 diabetes (T2D). This study aimed to evaluate the prospective association between dietary calcium and T2D incidence among adults 40 years of age or over, from the Multi-rural Communities Cohort (MRCohort), South Korea.

METHODS AND RESULTS

In total, 8313 participants (3033 men and 5280 women) who did not have diabetes at baseline were recruited between 2005 and 2013. The incidence rate ratio (IRR) was estimated using a modified Poisson regression model with a robust error estimator. During follow-up (31,570 person-years), 322 T2D cases were newly diagnosed. Dietary calcium (total and vegetable calcium) were inversely associated with the risk of T2D incidence among women (IRR = 0.61, 95% CI = 0.43-0.86, P for trend = 0.007 in third tertile of baseline total calcium intake comparing to the first tertile; IRR = 0.57, 95% CI = 0.39-0.84, P for trend = 0.006 for baseline vegetable calcium intake), not for men. The tendency of those inverse associations remained in both the normal fasting blood glucose group and the impaired fasting blood glucose group and were independent of obesity, smoking, and magnesium intake.

CONCLUSIONS

Total and vegetable calcium may be inversely associated with T2D incidence among women, regardless of impaired fasting blood glucose group or normal group. The associations may be potentially dose-responsive. Moderate dietary calcium may be related to lower risk of T2D incidence comparing to low intake group among women.

Cytotoxicity, Intestinal Transport, and Bioavailability of Dispersible Iron and Zinc Supplements

Iron or zinc deficiency is one of the most important nutritional disorders which causes health problem. However, food fortification with minerals often induces unacceptable organoleptic changes during preparation process and storage, has low bioavailability and solubility, and is expensive. Nanotechnology surface modification to obtain novel characteristics can be a useful tool to overcome these problems. In this study, the efficacy and potential toxicity of dispersible Fe or Zn supplement coated in dextrin and glycerides (SunActive Fe^TM and SunActive Zn^TM) were evaluated in terms of cytotoxicity, intestinal transport, and bioavailability, as compared with each counterpart without coating, ferric pyrophosphate (FePP) and zinc oxide (ZnO) nanoparticles (NPs), respectively. The results demonstrate that the cytotoxicity of FePP was not significantly affected by surface modification (SunActive Fe^TM), while SunActive Zn^TM was more cytotoxic than ZnO-NPs. Cellular uptake and intestinal transport efficiency of SunActive Fe^TM were significantly higher than those of its counterpart material, which was in good agreement with enhanced oral absorption efficacy after a single-dose oral administration to rats. These results seem to be related to dissolution, particle dispersibility, and coating stability of materials depending on suspending media. Both SunActive^TM products and their counterpart materials were determined to be primarily transported by microfold (M) cells through the intestinal epithelium. It was, therefore, concluded that surface modification of food fortification will be a useful strategy to enhance oral absorption efficiency at safe levels.