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Ionic liquids (ILs) hold great promise in the fields of green chemistry, environmental science, and sustainable technology due to their unique properties, such as a tailorable structure, the various types available, and their environmentally friendly features. On the basis of multiscale simulations and experimental characterizations, two unique features of ILs are as follows: (1) strong coupling interactions between the electrostatic forces and hydrogen bonds, namely in the Z-bond, and (2) the unique semiordered structure and properties of ultrathin films, specifically regarding the quasi-liquid. In accordance with the aforementioned theoretical findings, many cutting-edge applications have been proposed: for example, CO 2 capture and conversion, biomass conversion and utilization, and energy storage materials. Although substantial progress has been made recently in the field of ILs, considerable challenges remain in understanding the nature of and devising applications for ILs, especially in terms of e.g. in situ /real-time observation and highly precise multiscale simulations of the Z-bond and quasi-liquid. In this Perspective, we review recent developments and challenges for the IL research community and provide insights into the nature and function of ILs, which will facilitate future applications., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Aqueous potassium-ion batteries are long-term pursued, due to their excellent performance and intrinsic superiority in safe, low-cost storage for portable and grid-scale applications. However, the notorious issues of K-ion battery chemistry are the inferior cycling stability and poor rate performance, due to the inevitably destabilization of the crystal structure caused by K-ions with pronouncedly large ionic radius. Here, we resolve such issues by reconstructing commercial vanadium oxide (α-V 2 O 5 ) into the bronze form, i.e. , δ-K 0.5 V 2 O 5 (KVO) nanobelts, as cathode materials with layered structure of enlarged space and anisotropic pathways for K-ion storage. Specifically, it can deliver a high capacity as 116 mAh g -1 at the 1 C-rate, an outstanding rate capacity of 65 mAh g -1 at 50 C, and a robust cyclic stability with 88.2% capacity retention after 1,000 cycles at 1 C. When coupled with organic anode in a full-cell configuration, the KVO electrodes can output 95 mAh g -1 at 1 C and cyclic stability with 77.3% capacity retention after 20,000 cycles at 10 C. According to experimental and calculational results, the ultradurable cyclic performance is assigned to the robust structural reversibility of the KVO electrode, and the ultrahigh-rate capability is attributed to the anisotropic pathways with improved electrical conductivity in KVO nanobelts. In addition, applying a 22 M KCF 3 SO 3 water-in-salt electrolyte can impede the dissolving issues of the KVO electrode and further stabilize the battery cyclic performance. Lastly, the as-designed AKIBs can operate with superior low-temperature adaptivity even at -30 °C. Overall, the KVO electrode can serve as a paradigm toward developing more suitable electrode materials for high-performance AKIBs.

The GPU-accelerated molecular dynamics simulations are performed to explore the dynamical inserting process of ionic liquids (ILs) into the lipid bilayer. We found that the free ions and clusters coexist in the system, but only the cation can insert into the lipid bilayer. In specific, after a microsecond-scale simulation (up to 1.16 μs), the inserting rate increases first and then decreases nonmonotonic as side chain of cation ( n chain ) elongates, peaking at n chain = 10. However, the inserting free energy decreases with n chain , indicating the inserting process is easier for the larger n chain . Such contrary originates from the formation of cluster, where the cluster dissociating energy shows that only cluster for n chain ≤ 10 can dissociate spontaneously. Hence, the inserting rate is determined by the balance between n chain and cluster stability. These quantitative competition mechanisms shed light to the rational design of the biocompatible ILs toward their applications in the biochemical-related fields.

Revealing the structure and behavior of confined ionic liquids (ILs) is essential for their applications in green chemical processes. Here, we explore the electroconductivity (σ) and ionic correlation of imidazole ILs confined in graphene nanochannels via joint molecular dynamics simulation and theoretical analysis. The ideal and actual σ of ILs are first calculated, showing a growing tendency and up to the bulk value as the nanochannel size ranges from 1 to 10 nm. To account for the ionic correlation, the ionicity was determined by the ratio of the actual to ideal σ, reflecting the average fraction of free ions in the confined ILs. Amazingly, the ionicity of all three ILs shows an abnormal changing tendency, which first increases and reaches the maximum at 2 nm and then decreases to the bulk value. The conformational analysis, pair dissociating energy, and residence time are further obtained, proving that the abnormal enhanced ionicity should be attributed to the structure reconstruction of ILs near the graphene wall. The analytical model of ionicity herein can guide the rational design of efficient IL-based nanoporous electrodes and solid catalysts.

Enhancing molecular interaction is critical for improving the immobilization and stability of proteins on TiO 2 surfaces. In this work, mesoporous TiO 2 materials with varied pore geometries were decorated with phenyl phosphoric acid (PPA), followed by a thermal treatment to obtain chemically heterogeneous C-TiO 2 samples without changing the geometry and crystalline structure, which can keep the advantages of both carbon and TiO 2 . The molecular interaction force between the protein and the surfaces was measured using atomic force microscopy by decomposing from the total adhesion forces, showing that the surface chemistry determines the interaction strength and depends on the amount of partial carbon coverage on the TiO 2 surface (∼40-80%). Samples with 58.3% carbon coverage provide the strongest molecular interaction force, consistent with the observation from the detected friction force. Surface-enhanced Raman scattering and electrochemical biosensor measurements for these C-TiO 2 materials were further conducted to illustrate their practical implications, implying their promising applications such as in protein detection and biosensing.

Photochemical vapor generation (PVG) is emerging as a promising analytical tool for Te determination, thanks to its efficient matrix separation, and simple and green procedure. However, the low PVG generation efficiency of Te is the bottleneck for its wide application in environmental samples containing trace Te. Herein, we reported a high efficient PVG for Te determination by synergistic effect of ferric ion and nano-TiO 2 . The analytical sensitivity was enhanced approximately 15-fold for Te(IV) in the presence of both ferric ions and nano-TiO 2 , comparing to conventional PVG. Besides, the use of nano-TiO 2 can provide Te(VI) and Te(IV) an equal and high PVG efficiency in the presence of ferric ions, owned to the high photocatalytic performance of TiO 2 under short-wavelength UV irradiation (254 and 185 nm). Under the optimized experimental conditions, a detection limit of 1.0 ng L -1 was obtained. The precision of replicate measurements was 2.3% (RSD, n = 7) at 0.5 μg L -1 for Te(IV). The methodology was validated by successful determination of Te in surface waters and two standard reference sediment samples. To our best knowledge, this is the first report of the synergistic enhancement of transitional metal ions and nano-TiO 2 in PVG, which possesses potential for highly sensitive determination of vapor-forming elements.

The addition of highly polar and aprotic cosolvents to ionic liquids has proven to considerably decrease the viscosity of the solution and improve mass transfer in many chemical reactions. In this work, the interactions between a representative pyridinium-based ionic liquid, N -butylpyridinium dicyanamide ([Bpy][DCA]), and a cosolvent, dimethylsulfoxide (DMSO), were studied in detail by the combined use of attenuated total reflection Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance ( 1 H NMR), and density functional theory calculations. Several species in the [Bpy][DCA]-DMSO mixtures have been identified, that is, ion clusters can translate into ion pairs during the dilution process. DMSO formed hydrogen bonds (H bonds) simultaneously with [Bpy] + cations and [DCA] - anions but stronger hydrogen-bonding interactions with the [Bpy] + cations than the [DCA] - anions, and the intrinsic hydrogen-bond networks of IL were difficult to interrupt at low DMSO concentrations. Interestingly, hydrogen-bonding interactions reach the strongest when the molar fraction of DMSO is 0.4-0.5. Hydrogen-bonding interactions are prominent in the chemical shifts of hydrogen atoms in [Bpy] + cations, and anisotropy is the main reason for the upfield shifts of DMSO in the presence of [Bpy][DCA]. The theoretical calculations offer in-depth studies of the structural evolution and NMR calculation., Competing Interests: The authors declare no competing financial interest.

This study proposes an effective melanoma small interfering RNA (siRNA), named siMB3, which targets the mRNA of mutant BRAF protein. We found that Bis-pep-siMB3, with peptide KALLAL-conjugated siMB3 at the 3'-termini of both strands, inhibited translation of the target genes and expression of the related protein as effectively as siMB3, but for substantially longer, and the conjugates could alleviate off-target effects. Further studies on the mechanisms of action showed that the stability of Bis-pep-siMB3 in fetal bovine serum improved and the half-life period of Bis-pep-siMB3 was increased 21-fold over that of siMB3. Peptide conjugation could improve the combination of siRNA and cationic lipid vectors. Bis-pep-siMB3 is likely to reach the lysosome earlier and stay longer, and appears to increase the release of siRNA from the endosome. At the animal level, application of Bis-pep-siMB3 showed good therapeutic potential, inhibiting the growth of xenograft tumors in athymic mice slightly better than siMB3 and greatly prolonging the circulating time in vivo. Moreover, it distributed widely in mice. These results show the promising potential of Bis-pep-siRNA conjugates as therapeutic siRNAs for cancer treatment.

A series of novel nucleotide phosphoramidites were rationally designed and synthesized and were then site-specifically incorporated in DNA oligonucleotide probes with pyrene-modified phosphate. These oligodeoxynucleotide (ODN) probes almost have no inherent fluorescence emission with pyrene modification at 3' phosphate of corresponding nucleotides as a result of the photoinduced electron-transfer quenching effect of nucleobases (thymidine ∼ cytidine > guanosine ≫ adenosine). However, strong fluorescence emission was observed only with the perfectly matched duplex for the probes with pyrene modified at 3' phosphate of thymidine and cytidine. These rationally designed ODN probes successfully worked as "turn on" fluorescence oligonucleotide sensors for single-nucleotide polymorphism (SNP) and were used for detecting a single BRAF mutation site (V600E) of human melanoma.

A novel and facile approach has been developed to create thermoresponsive surfaces with macroscale patterns together with microscale features. The surface patterns were formed by applying macroscale nucleation agent patterns onto saturated N-isopropylacrylamide monomer solution membranes to induce the divergent growth of needlelike monomer crystals; the patterned monomer crystals were then photopolymerized to form patterned thermoresponsive films. A series of analytical tools (i.e., scanning electron microscopy, profilometry, and contact angle measurement) were used to characterize the properties of the patterned films. Cell coculture on this patterned thermoresponsive films enables cell separation and sorting by modulating temperature- and topography-dependent cell-substrate interactions and cell morphology, respectively. This versatile technique allows the formation of various macroscale patterns with microscale features over large areas, and on most solid substrates, within minutes, all of this without the need for expensive equipment and facilities. Such patterned surfaces can act as both in vitro tumor models and separation platforms for cancer studies. This method can also be applied to other cell-based biological studies and clinical applications.

Surface molecular imprinting, in particular over nanosized support materials, is very suitable for a template of bulky structure like protein. Inspired by the surface template immobilization method reported previously, we herein demonstrate an alternative strategy for enhancing specific recognition of core-shell protein-imprinted nanoparticles through prefunctionalizing the cores with noncovalent template sorption groups. For proof of this concept, silica nanoparticles chosen as the core materials were modified consecutively with 3-aminopropyltrimethoxysilane and maleic anhydride to introduce polymerizable double bonds and terminal carboxyl groups, hence capable of physically adsorbing the print protein. With lysozyme as a template, thin protein-imprinted shells were fabricated according to our newly developed approach for surface protein imprinting over nanoparticles. The rebinding experiments confirmed that the introduction of the carboxyl groups could remarkably improve the imprinting effect in relation to a significantly increased imprinting factor and specific rebinding capacity. Moreover, in contrast to the harsh template removal conditions required for the covalent template coupling approach, the template removal during the imprinted particle synthesis as well as desorption after rebinding could be mildly achieved via washing with salt solution.

An all-atom force field was set up for a new class of ionic liquids (ILs), tetrabutylphosphonium amino acid, on the basis of the AMBER force field with determining parameters related to the phosphorus atom and modifying several parameters. Ab initio quantum chemical calculations were employed to obtain molecular geometries, infrared frequencies, and torsion energy profiles. Atom partial charges were obtained by using the one-conformation, two-step restraint electrostatic potential approach. Molecular dynamics simulation was carried out in the isothermal-isobaric ensemble for 14 tetrabutylphosphonium amino acid ILs at two temperatures to validate the force field against the experimental densities and heat capacities at constant pressure. Computed thermodynamic properties are in good agreement with available experimental values. Moreover, radial distribution functions were investigated to depict the microscopic structures of these ILs.

This letter describes the fabrication of three-dimensional particulate-like hydrogel microstructures using a combination of soft lithography and volume expansion induced self-folding. Bilayer structures are produced by solvent casting and photocuring of liquid resins. They curl into three-dimensional (3D) structures upon contacting with water due to differential swelling of the two layers. The curvature can be controlled by adjusting the polymer composition of the primary swelling layer. A simple semiempirical mathematical model is used to predict this self-folding behavior. By designing the two-dimensional (2D) shapes of the bilayers, this technique can lead to complicated 3D microstructures.