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The antimicrobial and erythrocyte hemolysis activity of green arginine based cationic surfactants were studied for broadening the application field.

The GQDs-CS, oPPy and oPEDOT can serve as sensitizing elements to improve the sensing performance of a luteolin electrochemical sensor.

Au25 nanoclusters as a self-therapeutic nanodrug significantly modulated macrophage polarization from M1 to M2 and could act as an inhibitor of thioredoxin reductase (TrxR), which induced ROS-mediated FLS apoptosis by breaking redox homeostasis.

Electrocatalytic hydrogen evolution reaction (HER) holds promise in the renewable clean energy scheme. Crystalline Au and Ag are, however, poor in catalyzing HER, and the ligands on colloidal nanoparticles are generally another disadvantage. Herein, we report a thiolate (SR)-protected Au36Ag2(SR)18 nanocluster with low coverage of ligands and a core composed of three icosahedral (Ih) units for catalyzing HER efficiently. This trimeric structure, together with the monomeric Ih Au25(SR)18- and dimeric Ih Au38(SR)24, constitutes a unique series, providing an opportunity for revealing the correlation between the catalytic properties and the catalyst's structure. The Au36Ag2(SR)18 surprisingly exhibits high catalytic activity at lower overpotentials for HER due to its low ligand-to-metal ratio, low-coordinated Au atoms and unfilled superatomic orbitals. The current density of Au36Ag2(SR)18 at -0.3 V vs RHE is 3.8 and 5.1 times that of Au25(SR)18- and Au38(SR)24, respectively. Density functional theory (DFT) calculations reveal lower hydrogen binding energy and higher electron affinity of Au36Ag2(SR)18 for an energetically feasible HER pathway. Our findings provide a new strategy for constructing highly active catalysts from inert metals by pursuing atomically precise nanoclusters and controlling their geometrical and electronic structures.

Metallic-state gold nanorods are well known to exhibit strong longitudinal plasmon excitations in the near-infrared region (NIR) suitable for photothermal conversion. However, when the size decreases below ∼2 nm, Au nanostructures become nonmetallic, and whether the longitudinal excitation in plasmonic nanorods can be inherited is unknown. Here, we report atomically precise rod-shaped Au

The origin of photoluminescence in [Au25(SR)18]- nanoclusters remains elusive, and there is not a universal model that can well explain the experimental result. Here, we design Au25 nanoclusters protected by four different types of ligands for investigation of the photoluminescence mechanism by looking into the visible to near-infrared emissions. On the basis of time-resolved emission and nanosecond transient absorption spectroscopy analyses, we propose a model that can well explain the emission bands of Au25 nanoclusters. The visible and near-infrared emissions have different lifetimes and are found to arise from the core-shell charge transfer state and the Au13 core state, respectively. The obtained insight will help to understand how the excited state deactivates and to further engineer the photoluminescence of metal nanoclusters.

The excited state dynamics of small-sized metal nanoclusters are dependent on their crystal structures, while the effect of the charge state remains largely unknown. Here, we report the influence of single electrons on the excited-state dynamics of non-superatom Au clusters by comparing the transient absorption isotropy and anisotropy dynamics of two rod-shaped Au25 nanoclusters protected by organic ligands. Two decay lifetimes (0.9 ps and 2.3 μs) can be identified in the excited state relaxation of Au252+ rods, which are assigned to the internal conversion from a higher to lower excited state and the relaxation to the ground state, respectively. With the addition of one electron, an additional 660 ps decay is observed in Au25+, which should originate from the presence of a single electron occupied molecular orbital. Transient anisotropy measurements reveal a 500 ps rotational diffusion process in both the nanoclusters, while the initial dipole moment orientation is found to be highly dependent on the charge state. These results are of importance to understanding the effect of the charge state on the optical properties of metal nanoclusters.

The hierarchical assemblies of well-defined structural nanoclusters can help to better understand those of biologically important molecules such as DNA and proteins. Herein, we disclose the synthesis and characterization of a new silver nanocluster, that is Ag70(SR)42(PPh3)5 (Ag70-TPP). Directed by the ligands, Ag70-TPP nanoclusters undergo self-hierarchical assembly into a highly space-efficient complex secondary structure of a double helical 4H (DH4H) close packing pattern. The chirality of Ag70-TPP, and the van der Waals forces interactions between the ligands are believed to drive its DH4H arrangement, and the observed interlocking of the phosphine ligands of adjacent Ag70-TPP nanoclusters also contributed. Overall, this work has yielded important and unprecedented insights into the internal structure and crystallographic arrangement of nanoclusters.

A simple, sensitive, and enantioselective HPLC-MS/MS method has been developed for the determination of orphenadrine (ORP) enantiomers in rat plasma for the first time. The method used diphenhydramine as the internal standard (IS), and plasma samples were extracted by liquid–liquid extraction with satisfactory recovery. Chiral separation of the ORP enantiomers was obtained on a Chiralcel OD-RH column (150 mm × 4.6 mm, 5 μm). The mobile phase consists of acetonitrile–ammonium bicarbonate buffer (30 mM, pH 9.0) (80 : 20, v/v). Sufficient resolution (Rs = 3.562) was achieved in a short analysis time (7 min). The multiple reaction monitoring (MRM) mode was used for the detection of ORP enantiomers and IS. The transitions of m/z 270.0 → 181.1 and 256.2 → 167.1 were chosen for monitoring the ORP enantiomers and IS, respectively. Linearity was confirmed in the range of 0.1–50.0 ng mL−1 with the lower limit of quantification of 0.1 ng mL−1 for both ORP enantiomers in plasma. After validation, the method was applied to the enantioselective pharmacokinetic study of ORP enantiomers in rat plasma following oral administration of 10 mg kg−1 racemic ORP. Significant differences (P < 0.05) of ORP enantiomers were observed in pharmacokinetic parameters including Cmax, AUC, t1/2, CL, Vd, MRT, and VRT, which indicated that enantioselective pharmacokinetic behavior of ORP enantiomers was present in rats.

Atom-by-atom manipulation on metal nanoclusters (NCs) has long been desired, as the resulting series of NCs can provide insightful understanding of how a single atom affects the structure and properties as well as the evolution with size. Here, we report crystallizations of Au22(SAdm)16 and Au22Cd1(SAdm)16 (SAdm = adamantanethiolate) which link up with Au21(SAdm)15 and Au24(SAdm)16 NCs and form an atom-by-atom evolving series protected by the same ligand. Structurally, Au22(SAdm)16 has an Au3(SAdm)4 surface motif which is longer than the Au2(SAdm)3 on Au21(SAdm)15, whereas Au22Cd1(SAdm)16 lacks one staple Au atom compared to Au24(SAdm)16 and thus the surface structure is reconstructed. A single Cd atom triggers the structural transition from Au22 with a 10-atom bioctahedral kernel to Au22Cd1 with a 13-atom cuboctahedral kernel, and correspondingly, the optical properties are dramatically changed. The photoexcited carrier lifetime demonstrates that the optical properties and excited state relaxation are highly sensitive at the single atom level. By contrast, little change in both ionization potential and electron affinity is found in this series of NCs by theoretical calculations, indicating the electronic properties are independent of adding a single atom in this series. The work provides a paradigm that the NCs with continuous metal atom numbers are accessible and crystallizable when meticulously designed, and the optical properties are more affected at the single atom level than the electronic properties.

Precise atomic structure of metal nanoclusters (NCs) is fundamental for elucidating the structure-property relationships and the inherent size-evolution principles. Reported here is the largest known FCC-based (FCC=face centered cubic) silver nanocluster, [Ag100 (SC6 H3 3,4 F2 )48 (PPh3 )8 ]- : the first all-octahedral symmetric nesting Ag nanocluster with a four-layered Ag6 @Ag38 @Ag48 S24 @Ag8 S24 P8 structure, consistent symmetry elements, and a unique rhombicuboctahedral morphology distinct from theoretical predictions and previously reported FCC-based Ag clusters. DFT studies revealed extensive interlayer interactions and degenerate frontier orbitals. The FCC-based Russian nesting doll model constitutes a new platform for the study of the size-evolution principles of Ag NCs.

Cloperastine is a central antitussive used to reduce the frequency and intensity of coughing on a short-term basis. In this study, a reliable chiral LC-MS/MS technology has been developed for the quantification of cloperastine enantiomers in the rat plasma. Carbinoxamine was selected as the internal standard. The enantioseparation of cloperastine was performed on a Chiralpak IA column with a mobile phase composed of acetonitrile-water-ammonium hydroxide (80:20:0.1, v/v/v) at a flow rate of 0.6 mL/min. Cloperastine enantiomers were detected by mass spectrometry in multiple reaction monitoring mode with a positive electrospray ionization source. The method was validated over the linear concentration range of 0.05 to 10.0 ng/mL (5.0 × 10-4 ng to 0.10 ng) for both enantiomers. The lower limit of quantification (LLOQ) for each analyte was determined as 0.05 ng/mL. The relative standard deviations (RSDs) of intraday and interday precision was less than 13.9%, and the relative error (RE) of accuracy ranged from -5.4% to 6.1%, which were within the acceptance criteria. Finally, an application to the stereoselective pharmacokinetics of cloperastine in rats was successfully realized in our assay. The developed method on a commercially available Chiralpak IA column under isocratic mobile phase is advantageous to analyze cloperastine enantiomers in plasma samples collected for enantioselective metabolism or drug interaction studies.

In this work, a new Cu(I) cluster is synthesized and structurally characterized: [Cu11(TBBT)9(PPh3)6](SbF6)2 (where TBBT = 4-tert-butylbenzenethiol). This Cu(I) cluster exhibits good stability and a bright-red emission both in solution (685 nm) and in the solid state (675 nm) with a large Stokes shift (∼280 nm) under ambient conditions. Its absolute quantum yield is 0.22 in the solid state. Temperature-dependent emissions and theoretical calculations suggest that the origin of this cluster luminescence mainly results from a mixture of the metal-ligand charge transfer and the cluster-centered triplet excited states. This work not only opens new opportunities for functional applications of copper clusters but also sheds light on the structure-luminescence relationship.

Dipole moment (μ) is a critical parameter for molecules and nanomaterials as it affects many properties. In metal–thiolate (SR) nanoclusters (NCs), μ is commonly low (0–5 D) compared to quantum dot...

An understanding of the response of nanomaterials to specific environmental parameters is an essential prerequisite for their practical use, especially in living systems. Herein, we disclose the preparation of a water-soluble nanocluster Au16(SR)12 (SR denotes deprotonated captopril) and its characterization by a combination of theoretical (e.g., density functional theory calculations) and experimental (UV-vis, electrospray ionization mass spectrometry, etc.) methods. Interestingly, Au16(SR)12 was found to convert to Au18(SR)14 under acidic conditions, while the reverse conversion from Au18(SR)14 to Au16(SR)12 occurred upon the addition of base. A mechanistic investigation determined this pH regulation to originate from the distinct steric and electrostatic properties of these two clusters. This study is the first to report the susceptibility of Au18(SR)14 and Au16(SR)12 to pH, and the distinct pH stability unambiguously reveals the importance of size-tracking of nanomaterials in living systems for future clinical applications.

Mixtu res of the anionic surfactant AEC7-Na (branched alcohol ether carboxylate) and the cationic surfactant didecylmethylhydroxyethylammonium chloride (DEQ) were systematically investigated. The results showed that the mixtures possess synergisms. The DEQ-AEC7-Na mixture with a mass ratio of 1:1 showed the best result in terms of surface activity, wettability and emulsifying performance. However, when the mass ratio m(DEQ):m(AEC7-Na) = 8:2, the foaming ability and foam stability of the individual surfactants are better. Vesicles smaller than 100 nm coexist with worm-like micelles as soon as a small amount of AEC7- Na is added to DEQ (m(DEQ):m(AEC7-Na) = 8:2). At m(DEQ):m(AEC7-Na) = 4:6 and 2:8, vesicles of approximate ly 80 nm were observed.

A quaternary ammonium salt gemini surfactant (C12N)2O with diethyl ether as the spacer group was synthesized by dodecyl dimethyl amine and 2-chloroethyl ether. The structure of the product was confirmed by Fourier transform infrared spectra (FT-IR) and proton nuclear magnetic resonance spectra (1H NMR), which showed that the structure of the synthesized product was consistent with the theoretical structure. We tested the surface tension of (C12N)2O at 25°C and found the critical micelle concentration (CMC) was roughly 2 orders of magnitude lower than that of dodecyl trimethylamine chloride (DTAC). Gemini structure and the unique diethyl ether spacer group endowed the novel amphiphile excellent properties including low contact angle and high antistatic property. (C1 2N)2O showed good compatibility with alcohol ether sulfate (AES) and dodecylbenzene sulfonate (LAS) in surfactant mixed systems. When the ratio of (C12N)2O:AES was 1:4 and (C12N)2O:LAS 1:9, the emulsifying properties were preferable to single surfactant.

A novel geometric structure of an Ag30Cu14(TPP)4(SR)28 nanocluster with an irregular kernel is reported; furthermore, both the Ag27 core and Ag3Cu14(TPP)4(SR)28 shell show C2 symmetry which contributes to the chirality of the structure.

In this study, carboxymethyl-6-(4-methoxybenzylamino)-β-cyclodextrin (CMCDPN) was synthesized for the first time and managed to be used as a chiral selector to enantioseparate 13 kinds of chiral drugs (chlorpheniramine, brompheniramine, pheniramine, homatropine, homatropine methyl, clorprenaline, terbutaline, procaterol, tulobuterol, cycloclenbuterol, propranolol, pindolol and ofloxacin) by capillary electrophoresis (CE). The analysis was carried out by CE using a fused-silica capillary (50 cm × 50 μm i.d., 40 cm effective length) with 30 mmol L−1 phosphate buffer under an applied voltage of 20 kV. The effect of analysis conditions such as buffer concentration, buffer pH, applied voltage and concentration of the chiral selector on the enantioseparation results was systematically investigated. By the method established by us, eleven of the analytes reached baseline separation and the other two reached partial separation. The molecular dockings were applied to further demonstrate the mechanisms of chiral recognition. The docking results showed good agreement with our experimental results.

Understanding the critical roles of ligands (e.g. thiolates, SR) in the formation of metal nanoclusters of specific sizes has long been an intriguing task since the report of ligand exchange-induced transformation of Au38(SR)24 into Au36(SR′)24. Herein, we conduct a systematic study of ligand exchange on Au38(SC2H4Ph)24 with 21 incoming thiols and reveal that the size/structure preference is dependent on the substituent site. Specifically, ortho-substituted benzenethiols preserve the structure of Au38(SR)24, while para- or non-substituted benzenethiols cause its transformation into Au36(SR)24. Strong electron-donating or -withdrawing groups do not make a difference, but they will inhibit full ligand exchange. Moreover, the crystal structure of Au38(SR)24 (SR = 2,4-dimethylbenzenethiolate) exhibits distinctive π⋯π stacking and “anagostic” interactions (indicated by substantially short Au⋯H distances). Theoretical calculations reveal the increased energies of frontier orbitals for aromatic ligand-protected Au38, indicating decreased electronic stability. However, this adverse effect could be compensated for by the Au⋯H–C interactions, which improve the geometric stability when ortho-substituted benzenethiols are used. Overall, this work reveals the substituent site effects based on the Au38 model, and highlights the long-neglected “anagostic” interactions on the surface of Au-SR NCs which improve the structural stability.

Despite the widespread use of bimetallic nanomaterial catalysts, a molecular-level understanding of the synergistic effects is unclear, limiting our ability to pre-design “tailor-made” bimetallic catalysts. We chose bimetallic Au1Ag24(SR)18 and Au25−xAgx(SR)18 (x = 2–6) nanoclusters (NCs) as models to investigate the relationship between microstructure and performance, comparing them with the corresponding monometallic NCs. Experimental and theoretical analyses demonstrated that the Au@Ag kernel was the essential structural feature for high activity and super stability of Au1Ag24(SR)18 catalyst in the alkynylation of CF3-ketone. This structure-activity relationship was successfully extended to other bimetallic systems bearing an Au@Ag kernel, such as Au12Ag32(SR)30 NC, and is thought to constitute a guiding principle for the intelligent design of high-performance bimetallic catalysts in the future.

BmK DKK13 (DKK13) is a mutated recombinant peptide, which has a significant antinociception in a rat model of the inflammatory pain. The purpose of this study was to evaluate the antinociceptive effect of DKK13 on trigeminal neuralgia (TN) in rats. Male Sprague-Dawley (SD) rats were treated with the chronic constriction injury of the infraorbital nerve (IoN-CCI) model to induce stable symptoms of TN. DKK13 (1.0 mg/kg, 2.0 mg/kg and 4.0 mg/kg, i.v.) or morphine (4.0 mg/kg, i.v.) was administered by tail vein once on day 14 after IoN-CCI injury. Behavioral tests, electrophysiology and western blotting were performed to investigate the role and underlying mechanisms of DKK13 on IoN-CCI model. Behavioral test results showed that DKK13 could significantly increase the mechanical pain and thermal radiation pain thresholds of IoN-CCI rats and inhibit the asymmetric spontaneous pain scratching behavior. Electrophysiological results showed that DKK13 could significantly reduce the current density of Nav1.8 in the ipsilateral side of trigeminal ganglion (TG) neurons in IoN-CCI rats, and the steady-state activation and inactivation curves of Nav1.8 shifted, respectively, to the direction of hyperpolarization and depolarization. Western blotting results showed that DKK13 significantly reduced the expression of Nav1.8 and the phosphorylation levels of key proteins of MAPKs/CREB pathway in TG tissues of IoN-CCI rats. In brief, DKK13 has a significant antinociceptive effect on IoN-CCI rats, which may be achieved by changing the dynamic characteristics of Nav1.8 channel and regulating the protein phosphorylation in MAPKs/CREB pathway.

The excited state dynamics of small-sized metal nanoclusters are dependent on their crystal structures, while the effect of the charge state remains largely unknown. Here, we report the influence of single electrons on the excited-state dynamics of non-superatom Au clusters by comparing the transient absorption isotropy and anisotropy dynamics of two rod-shaped Au

The hierarchical assemblies of well-defined structural nanoclusters can help to better understand those of biologically important molecules such as DNA and proteins. Herein, we disclose the synthesis and characterization of a new silver nanocluster, that is Ag

Alloying is one of the most effective strategies to change the properties of inorganic–organic hybrid materials, but there are few reports of the alloying of one-dimensional nanowires with precise atomic structure due to the difficulties in obtaining the single crystals of nanowires themselves. Herein, we describe the synthesis and characterization of an alloyed one-dimensional Ag–Cu nanowire [Ag2.5Cu1.5(S-Adm)4]n. Compared with the unalloyed [Ag4(S-Adm)4]n, our novel alloyed nanowire exhibits good conductivity, and its resistivity (as a powder) was determined to be 107 Ω m by impedance analysis–consistent with that of a semiconductor. Accordingly, based on these properties combined with its excellent thermal stability and high-yielding, gram-scale synthesis, [Ag2.5Cu1.5(S-Adm)4]n is proposed for electronic-device applications.

Buthus martensii Karsch (BmK), is a kind of traditional Chinese medicine, which has been used for a long history for the treatment of many diseases, such as inflammation, pain and cancer. In this study, DKK-SP1/2/3 genes were screened and extracted from the cDNA library of BmK. The DKK-SP1/2/3 were expressed by using plasmid pSYPU-1b in E. coli BL21, and recombinant proteins were obtained by column chromatography. In the xylene-induced mouse ear swelling and carrageenan-induced rat paw swelling model, DKK-SP1 exerted a significant anti-inflammatory effect by inhibiting the expression of Nav1.8 channel. Meanwhile, the release of pro-inflammatory cytokines (COX-2, IL-6) was decreased significantly and the release of anti-inflammatory cytokines (IL-10) were elevated significantly. Moreover, DKK-SP1 could significantly decrease the Nav1.8 current in acutely isolated rat DRG neurons. In the acetic acid-writhing and ION-CCI model, DKK-SP2 displayed significant analgesic activity by inhibiting the expression of the Nav1.7 channel. Moreover, DKK-SP2 could significantly inhibit the Nav1.7 current in the hNav1.7-CHO cells.

Glutamic acid modified Pluronic P123 (P123-G) was synthesized to coat hydrophobic mesoporous silica nanoparticles (PGMSN) aiming to target large amino acid transporter 1 (LAT1) overexpressed cancer cells. We discovered that, once internalized, PGMSN could be transported out of the cells with their cargo, and the exported nanoparticles were then taken up by neighboring cells. This intercellular delivery of particles led to a deeper tumor penetration, presumably through tandem cycles of LAT1 mediated endocytosis and exocytosis. Taking advantage of high drug loading capability of MSN, a kind of cyanine dye Cypate acting as a photothermal converting agent was loaded into MSN along with the chemotherapeutic drug doxorubicin hydrochloride (DOX) to improve the anti-cancer effect by the combination of chemotherapy and photothermal therapy (PTT). Both DOX and Cypate stably dispersed in the pores of MSN, and the coating of P123-G serving as diffusion barrier blocked drug preleakage. The system possessed pH and near-infrared (NIR) light dual-responsive DOX release property. Additionally, PGMSN exhibited targeted PTT effect which strengthened cytotoxic activity of the system due to the enhanced endocytosis. So the deep tumor penetration and targeted PTT effect made PGMSN especially suitable for cancers overexpressing LAT1 receptors.

Herein, a Au–Cu bimetal nanocluster (bi-MNC) with strong emission (13.2% quantum yield) was synthesized and structurally determined. Its structure features a sandwich construction: a ring-like Au7C...