Plasmonic photoelectrochemical reactions on noble metal electrodes of nanostructures

Plasmonic noble metal nanostructures have been targeted due to their strong surface plasmon resonance at photoelectrochemical interfaces. Recently, it has been concluded that, the plasmonic noble metal nanostructures on photoexcitation permit the transfer of effective hot carriers (hot electron/hole pair) to nearby adsorbed molecules where, the transformed hot carriers can efficiently decrease the activation barrier of a reaction. In this review, our recent achievements in the plasmon-mediated chemical reactions of organic molecules such as para-aminothiophenol, substituted para-aminothiophenol and para-nitrothiophenol at nanostructures modified noble metal electrodes using surface enhanced Raman spectroscopy, electrochemical methods, and theoretical calculations will be discussed.     

Gold-Catalyzed One-Pot Synthesis of Polyfluoroalkylated Oxazoles from N-Propargylamides Under Visible-Light Irradiation

A gold-catalyzed synthesis of polyfluoroalkylated oxazoles from N-propargylamides under visible-light irradiation has been developed. These reactions display excellent compatibility of radicals and gold catalysts under visible-light irradiation. Mechanistic experiments indicate that polyfluoroalkyl iodides play a dual role in enhanced compatibility of radicals and gold catalysts through assisted protodeauration of vinyl gold and reactivated the gold catalyst. In addition, PPh₃AuNTf₂ not only activates N-propargylamide to generate vinyl gold intermediate, but also greatly promotes homolysis of polyfluoroalkyl iodides under blue light irradiation.     

In Vitro Anticancer Activity of Nanoformulated Mono- and Di-nuclear Pt Compounds

Nanoformulations of mononuclear Pt complexes cis-PtCl₂(PPh₃)₂ ( 1 ), [Pt(PPh₃)₂(L−Cys)] ⋅ H₂O ( 3 , L−Cys=L-cysteinate), trans-PtCl₂(PPh₂PhNMe₂)₂ ( 4 ; PPh₂PhNMe₂=4-(dimethylamine)triphenylphosphine), trans-PtI₂(PPh₂PhNMe₂)₂ ( 5 ) and dinuclear Pt cluster Pt₂(μ-S)₂(PPh₃)₄ ( 2 ) have comparable cytotoxicity to cisplatin against murine melanoma cell line B16F10. Masking of these discrete molecular entities within the hydrophobic core of Pluronic® F-127 significantly boosted their solubility and stability, ensuring efficient cellular uptake, giving in vitro IC₅₀ values in the range of 0.87–11.23 μM. These results highlight the potential therapeutic value of Pt complexes featuring stable Pt−P bonds in nanocomposite formulations with biocompatible amphiphilic polymers.     

Electrodeposition of Se on carbon-supported Pt nanoparticles by cyclic voltammetry

Cyclic voltammetry (CV) is a powerful and popular electrochemical technique widely used to study the surface structure of materials through the electrochemical behaviors. Herein CV is utilized to study the electrochemical deposition of selenium (Se) on carbon black-supported Pt nanostructures. We synthesized carbon-loaded platinum nanoparticles (Pt/C) by microwave method and studied the electrochemical behavior of selenium on them. Through the experiment of changing the reverse potential, the corresponding relationship between the Se deposition peak and stripping peak was clarified and the deposition and stripping process of Se was proposed. Meanwhile, we synthesized cubic and octahedral nanocrystals of Pt, and used CV to study the Se deposition on these nanosctructures supported by carbon. It was found that the relative intensity of UPD peaks on Pt is different, as Pt_cube@C is dominated by (100) and Pt_oct@C electrode is dominated by (111) while Pt@C falls in between.

     

Biocomputing Based on DNA Strand Displacement Reactions

The high sequence specificity and precise base complementary pairing principle of DNA provides a rich orthogonal molecular library for molecular programming, making it one of the most promising materials for developing bio-compatible intelligence. In recent years, DNA has been extensively studied and applied in the field of biological computing. Among them, the toehold-mediated strand displacement reaction (SDR) with properties including enzyme free, flexible design and precise control, have been extensively used to construct biological computing circuits. This review provides a systemic overview of SDR design principles and the applications. Strategies for designing DNA-only, enzymes-assisted, other molecules-involved and external stimuli-controlled SDRs are described. The recently realized computing functions and the application of DNA computing in other fields are introduced. Finally, the advantages and challenges of SDR-based computing are discussed.     

Functional Group Modification and Bonding Characteristics of Ti3C2 MXene-Organic Composites from First-Principles Calculations

The unique physical structure and abundant surface functional groups of MXene make the grafted organic molecules exhibit specific electrical and optical properties. This work reports the results of first-principles calculations to investigate the composite systems formed by different organic molecular monomers, namely acrylic acid (AA), acrylamide (AM), 1-aziridineethanol (1-AD) and glucose, and Ti₃C₂ MXene saturated with different functional groups, namely −OH, −O and −F. The results show that the interaction between organic molecules and the MXene surface depends on the type of functional groups of the organic molecules, while the strength of the interaction is determined by the type of surface functional groups and the number of hydrogen bonds. The bare Ti₃C₂ and Ti₃C₂(OH)₂ can readily form strong chemical and hydrogen bonds with AA and AM molecules, leading to strong adsorption energy and a large amount of charge transfer, while the interaction between organic molecules and MXene saturated by −F or −O groups mainly exhibits physical interactions, accompanied by low adsorption energy and a small amount of charge transfer. This research provides theoretical guidance for the synthesis of high-performance MXene organic composite systems.     

From borophosphate to fluoroborophosphate: a rational design of fluorine-induced birefringence enhancement

The introduction of oxofluoride anion into anionic group assists to tune optical properties owing to the change of coordination,electronegativity,and according anionic framework.Here,we proposed a rational design of new compounds by fluorine-driven structure and optical property evolution.A new borophosphate Ba_2BP_3O_(11)with the monoclinic space group P2_1/c has been synthesized in the sealed system.Ba_2BP_3O_(11)exhibits a rare P–O–P bridge formation,which is the first example in alkaline-earth metal borophosphates.By further substituting[BO_4]~(3-)with[BO_3F]~(4-),the first alkaline-earth metal/lead fluoroborophosphates M_2BP_2O_8F (M=Ba and Pb) with the same space group were designed.Since the scissors effect of fluorine,in M_2BP_2O_8F (M=Ba and Pb),a BO_3F tetrahedron corner-sharing with three PO_4tetrahedra forms 1D chains along the b-axial direction,which are filled by MO_n(M=Ba/Pb,n=5,6,8) distorted polyhedra.The first principles calculation shows that the borophosphate Ba_2BP_3O_(11)has a birefringence about 0.013@1,064 nm,while the fluoroborophosphates M_2BP_2O_8F (M=Ba and Pb) have the values of 0.035 and 0.043@1,064 nm,respectively.Such an apparent enhancement in birefringence is derived from synergies of the oxyfluoride and cation.The introduction of fluorine-containing heteroanionic groups provides a feasible strategy to design novel promising optical materials.     

Synthesis of Fluorescent Carbon Dots and Their Application in Ascorbic Acid Detection

Water-soluble fluorescent carbon dots (CDs) were synthesized by a hydrothermal method using citric acid as the carbon source and ethylenediamine as the nitrogen source. The repeated and scale-up synthetic experiments were carried out to explore the feasibility of macroscopic preparation of CDs. The CDs/Fe³⁺ composite was prepared by the interaction of the CDs solution and Fe³⁺ solution. The optical properties, pH dependence and stability behavior of CDs or the CDs/Fe³⁺ composite were studied by ultraviolet spectroscopy and fluorescence spectroscopy. Following the principles of fluorescence quenching after the addition of Fe³⁺ and then the fluorescence recovery after the addition of asorbic acid, the fluorescence intensity of the carbon dots was measured at λex = 360 nm, λem = 460 nm. The content of ascorbic acid was calculated by quantitative analysis of the changing fluorescence intensity. The CDs/Fe³⁺ composite was applied to the determination of different active molecules, and it was found that the composite had specific recognition of ascorbic acid and showed an excellent linear relationship in 5.0–350.0 μmol·L⁻¹. Moreover, the detection limit was 3.11 μmol·L⁻¹. Satisfactory results were achieved when the method was applied to the ascorbic acid determination in jujube fruit. The fluorescent carbon dots composites prepared in this study may have broad application prospects in a rapid, sensitive and trace determination of ascorbic acid content during food processing.     

The Effect of Hispidulin,a Flavonoid from Salvia plebeia,on Human Nasopharyngeal Carcinoma CNE-2Z Cell Proliferation,Migration, Invasion,and Apoptosis

Nasopharyngeal carcinoma (NPC) is a common malignant head and neck tumor. Drug resistance and distant metastasis are the predominant cause of treatment failure in NPC patients. Hispidulin is a flavonoid extracted from the bioassay-guided separation of the EtOH extract of Salvia plebeia with strong anti-proliferative activity in nasopharyngeal carcinoma cells (CNE-2Z). In this study, the effects of hispidulin on proliferation, invasion, migration, and apoptosis were investigated in CNE-2Z cells. The [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay and the colony formation assay revealed that hispidulin could inhibit CNE-2Z cell proliferation. Hispidulin (25, 50, 100 μM) also induced apoptosis in a dose-dependent manner in CNE-2Z cells. The expression of Akt was reduced, and the expression of the ratio of Bax/Bcl-2 was increased. In addition, scratch wound and transwell assays proved that hispidulin (6.25, 12.5, 25 μM) could inhibited the migration and invasion in CNE-2Z cells. The expressions of HIF-1α, MMP-9, and MMP-2 were decreased, while the MMPs inhibitor TIMP1 was enhanced by hispidulin. Moreover, hispidulin exhibited potent suppression tumor growth and low toxicity in CNE-2Z cancer-bearing mice at a dosage of 20 mg/kg/day. Thus, hispidulin appears to be a potentially effective agent for NPC treatment.     

Rapid Preparation of Mesoporous Methylsilsesquioxane Aerogels by Microwave Heating Technology

Microwave heating technology is known as an alternative to traditional gas and electric heating sources. In this work, mesoporous methylsilsesquioxane (MSQ) aerogels were prepared via a sol–gel process accompanied by microwave heating technology, and microwave heating was used in the gelation of sol and the drying of wet gels, respectively. The effects of hexadecyltrimethylammonium chloride (CTAC) as a surfactant and template, hydrochloric acid (HCl) as a catalyst, ethanol as a solvent, sodium hydroxide (NaOH) as a gelation agent, and microwave power on the pore structure of as-prepared MSQ aerogels were investigated in detail. Microwave heating at low power results in the acceleration of sol–gel transition and achieves the gelation within a few minutes. Appropriate amounts of chemical reagents and microwave heating at high power allow the preparation of mesoporous MSQ aerogels with a BET-specific surface area of 681.6 m²·g⁻¹ and a mesopore size of 19 nm, and the resultant MSQ aerogel still has a BET specific surface area as high as 134 m²·g⁻¹ after heat treatment at 600 °C for 2 h, showing high thermal stability. The MSQ aerogels/fibre composite possesses a low thermal conductivity of 0.039 W/(m·k)⁻¹, displaying good thermal insulation. Microwave heating technology is a promising heating method for the preparation of other aerogels.