Herein, ultrafast transient absorption spectroscopy is performed to probe the electron transfer studies between aqueous solution and gold nanorods (Au NRs). The seed-mediated growth method is used to synthesize crystalline cylindrical Au NRs having longitudinal plasmon resonance peak maximum at 825 nm. The as-synthesized Au NRs show average width and length of ∼10 ± 2 and ∼50 ± 2 nm, respectively, with an aspect ratio in the range of ∼5. The time-resolved decay profiles have been studied in a subpicosecond resolution range using pump wavelength at 410 nm excitation and probe wavelengths from visible to near-infrared region. The plasmon dynamics studies of Au NRs depend on the electron heating phenomena, coherent acoustic phonon vibration and electronic transient behavior, i.e., electron-phonon coupling, and homogenous dephasing processes. Thus, the obtained results highlighted that the ultrafast charge transfer dynamics studies in Au NRs could play an important role to elucidate their electronic, photothermal, and optical properties for molecular imaging, photothermal therapy, and optoelectronic and light-harvesting devices.

Perylenediimides (PDIs) have emerged as potential materials for optoelectronic applications. In the current work, four PDI derivatives, substituted at imide nitrogen with 2,6-diisopropyl phenyl, 2-nitrophenyl, diphenylmethylene, and pentafluorophenyl groups, have been synthesized from perylene 3,4,9,10-tetracarboxylic dianhydride using a facile imidization synthesis process. PDI derivatives have been spectroscopically characterized for their structure and optical properties. Temperature-variable absorption and emission spectroscopy study confirmed the H-aggregation property. H-aggregation along with strong emission suggests the slipped π-π stacking of PDI molecules. Electrochemical analysis was performed for their redox behavior and calculation of lowest unoccupied molecular orbital and highest occupied molecular orbital energy levels. Scanning electron microscopy showed the formation of ordered structures. The PDI derivatives showed excellent electron conductivity without doping and 5-10× higher electron mobility than that of state-of-the-art fullerene acceptor phenyl-C61-butyric acid methyl ester (PC61BM). Finally, the charge generation and charge transfer phenomenon was studied by transient absorption spectroscopy (TAS). TAS showed ultrafast charge transfer from the poly(3-hexyl)thiophene (P3HT) donor polymer to PDI and formation of long-lived charge-separated states similar to fullerene derivative PC61BM/P3HT blends. Such PDI derivatives with excellent solubility and photophysical and electronic properties are potential n-type materials to be used in organic electronic devices.

The generation of electricity by dissociating water into H3O+ and OH- ions through a hydroelectric cell (HEC) without liberating any toxic waste has achieved a groundbreaking feat. Nanoporous magnesium-doped SnO2 and cobalt-doped SnO2 materials have been prepared via a novel sol-gel method. The X-ray diffraction patterns of Mg-doped SnO2 and Co-doped SnO2 completely match with those of pure SnO2, which confirms the interstitial substitution of Mg and Co in the pristine SnO2. The results shown by Brunauer-Emmett-Teller theory curves illustrate the surface area of Mg-doped SnO2 and Co-doped SnO2 to be 46.22 and 46.81 m2/g, respectively, with their pore radii being ∼3 nm. The synthesized nanoparticles were pressed into square pellets of area 4.08 cm2. A zinc electrode was pasted on one side of each pellet and silver was painted on the other side to develop the HECs. The fabricated HECs of Mg-doped SnO2 and Co-doped SnO2 with 4.08 cm2 area deliver short-circuit current, open-circuit voltage, and off-load output power of 41.69 mA, 0.787 V, and 32.81 mW and 77.52 mA, 0.454 V, and 35.19 mW, respectively. Cyclic voltammetry of both materials exhibited cathodic and anodic peaks in relation to the redox reactions taking place at Zn and silver electrodes. Nyquist curves of both HECs in the wet state confirm the ionic diffusion of split H3O+ and OH- ions as compared to the dry state. An off-load output power of 35.19 mW delivered by the HEC of Co-doped SnO2 with 4.08 cm2 area is quite promising and has great potential to replace other green energy sources.

Fluorescent sensors have been synthesized for organophosphate nerve agent detection. The resulting 4-pyridyl-5-hydroxyethyl structures react with organophosphate nerve agent simulants such as diethylchlorophosphate and diisopropylfluorophosphate and cyclize to form a dihydroquinolizinium ring that results in an increased fluorescence response to long-wave UV excitation. These sensors have been functionalized with monomeric substitutions that allow for covalent incorporation into a polymer matrix for organophosphate detection to develop a fieldable sensor. In addition, inclusion of silicon dioxide into the polymer matrix eliminated false-positive responses from mineral acids, greatly advancing this class of sensors.

Polymer nanocomposites (PNCs) have become an exciting field of current research and have attracted a huge interest among both academia and industry during the last few decades. However, the multifunctional single-nanocomposite film exhibiting the combination of desired structure and properties still remains a big challenge. Herein, we report a novel strategy to address these problems by using versatile polymer glycidyl methacrylate (GMA) as a bridging medium between the filler and the polymer matrix, resulting in high density of interfaces as well as strong interactions, which lead to generation of tunable thermal, mechanical, and electrical properties in the materials. The nanocomposites prepared by GMA bridging exhibit the remarkable combination of thermal (T d = 342.2 °C, T g = 150.1 °C ), mechanical (E = 7.6 Gpa and H = 0.45 Gpa ) and electrical (σ = 3.15 × 10-5 S/cm) properties. Hence, the conjugation approaches related to GMA bridging facilitate a new paradigm for producing multifunctional polymer nanocomposites having a unique combination of multifunctional properties, which can be potentially used in next-generation polymer-based advanced functional devices.

Using dielectric spectroscopy experiments performed at multiple temperatures and frequency ranges, we demonstrate how the chemotherapy drug paclitaxel changes the dynamic properties of water in a breast cancer cell line (MCF-7). From the measured data, we present evidence that treatment with paclitaxel leads to a slight increase in activation energy in a relaxation related to bulk-like water. More importantly, we also observe that paclitaxel changes the constraining imposed by the biological interfaces on hydration water, whose single-particle dynamics becomes slower and with higher activation energy. These variations are only observable after freezing the dynamics from other cellular components, such as proteins and DNAs, regardless of the state of the cells, that is, treated or not treated or even if the cells are no longer viable. Therefore, changes in water dynamics could be detected prior to those related to the global dynamics within the cellular environment.

Single-chain nanoparticles (SCNPs) are ultrasmall soft nanomaterials constructed via intrachain cross-linking of individual precursor polymer chains, with promising prospects for nanomedicine, catalysis, and sensing, among other different fields. SCNPs are versatile building blocks for the construction of new fluorescent probes with ultrasmall size, higher brightness, and better photostability than previous particle-based systems. Herein, we report on a new, fast, and efficient method to produce SCNPs with intense fluorescence emission in solution which is based on the photoactivation of appropriate aggregation-induced emission (AIE) cross-linking molecules containing azide functional groups. Remarkably, the presence of the azide moiety-that can be transformed to highly reactive nitrene species upon UV irradiation-was found to be essential for the SCNPs to display intense fluorescence emission. We attribute the fluorescence properties of the SCNPs to the immobilization of the initially nonfluorescent AIE molecules via intrachain cross-linking upon photoactivation. Such cross-linking-induced immobilization process activates the AIE mechanism and, hence, leads to fluorescent SCNPs in both solution and solid state.

Chemistry is among the last of the core natural sciences to embrace preprints, namely, the publication of non peer-reviewed scientific articles on the Internet. After a brief insight into the origins and the purpose of preprints in science, we conducted a concrete analysis of the concrete situation, aiming at providing an answer to several questions. Why has the chemistry community been late in embracing preprints? Is this in relation with the slow acceptance of open-access publishing by the same community? Will preprints become a common habit also for chemistry scholars?

We have investigated adsorption-induced deformation in graphene oxide framework materials (GOFs) using neutron diffraction at sample pressures up to 140 bar. GOFs, made by the solvothermal reaction of graphite oxide and benzene-1,4-diboronic acid, are a suitable candidate for deformation studies due to their narrow (∼1 nm), monodispersed, slit-shaped pores whose width can be measured by diffraction techniques. We have observed, in situ, a monotonic expansion of the slit width with increasing pressure upon adsorption of xenon, methane, and hydrogen under supercritical conditions. The expansion of ∼4% observed for xenon at a pressure of 48 bar is the largest deformation yet reported for supercritical adsorption on a carbonaceous material. We find that the expansion of the three gases can be mapped onto a common curve based solely on their Lennard-Jones parameters, in a manner similar to a law of corresponding states.

The brown film (BF) of Lentinula edodes mycelium has been reported to exert biological activities during mushroom cultivation; however, to date, there is limited information on its chemical composition. In this study, untargeted metabolomics analysis was performed via liquid chromatography-mass spectrometry (LC-MS), and the results were used to screen the antimicrobial compounds. A total of 236 differential metabolites were found among the BF stages compared with the white hyphal stage. Among them, five important antimicrobial metabolites related to antimicrobial activities, namely, 6-deoxyerythronolide B, tanikolide, hydroxyanthraquinone, benzylideneacetone, and 9-OxooTrE, were present at high levels in the BF samples. The score plots of the principal component analysis indicated that the samples from four time points could be classified into two groups. This study provided a comprehensive profile of the antimicrobial compounds produced during BF formation and partly clarified the antibacterial and antifungal mechanism of the BF of L. edodes mycelium.

In this work, the structural and electronic properties of perylene tetracarboxylic diimide (PTCDI) derivative molecules have been calculated using density functional theory simulations. Here, we have obtained the equilibrium geometry for certain PTCDI derivatives and calculated their occupied and unoccupied density of states separately for molecular orbitals lying in-plane (σ type) and orthogonal to the plane (π type) of the molecules. We have also simulated the X-ray absorption spectroscopy (XAS) spectra for these molecules separately for π- and σ-type orbitals. A comparison between the unoccupied density of states and XAS data has been made because both provide a description of the molecular orbitals above the Fermi level. We have observed the presence of shallow-lying σ orbitals in twisted molecules and have obtained an almost linear relationship between the abundance of these orbitals and the degree of molecular twist. Additionally, we have shown the possibility of an experimentally viable stereoisomerism in PTCDI-C3.

In this work, a photoelectrochemical (PEC) sensing system was developed for chemical detection without any tags. The system is based on methylammonium lead iodide chloride perovskite as the photoelectrochemical signal-generating molecule, tin oxide nanoparticles (SnO2) as the electron transport layer, and ionic liquid of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) as the stabilizer and electrolyte. The photosensitizer film is formed through spin-coating followed by low-temperature sintering. Upon irradiation with 473 nm light, an anodic photocurrent is generated in a blank electrolyte and changed significantly after addition of hemin into the electrolyte. The change of photocurrent after addition of hemin suggested that the chemicals participated in a photoelectrochemical process. Our work paves the way to developing analytical methods with perovskite.

Near-critical mixtures of limited miscibility are significant for chemical physics, soft matter physics, and a variety of challenging applications. Their basic properties can be tuned by compressing or a systematic change of one of the components. This report addresses these issues, based on experimental studies in nitro-compound (nitrobenzene, o-nitrotoluene, and 1-nitropropane) and n-alkane (from pentane to eicosane) critical mixtures. Studies reveal new patterns for the evolution of the critical consolute temperature (T C) and concentration (x C, mole fraction) within the tested homologous series: T C(n) ∼ n 2 and x C(n) ∼ n 1/2. They also show two paths of the high-pressure impact: (i) dT C(P)/dP > 0 and overlapping of normalized T C(P) dependences and (ii) the crossover dT C(P)/dP < 0 → dT C(P)/dP > 0 with increasing n-alkane length. The consistent parameterization of all T C(P) dependencies is introduced. Supplementary nonlinear dielectric effect studies indicate a possible molecular origin of the phenomenon. The coexistence curve under high pressure is in the agreement with the isomorphism postulate for critical phenomena but with a surprisingly strong distortion from the Cailletet-Mathias law of the rectilinear diameter. The new and reliable method for estimating the critical concentration and temperature is proposed. It explores the analysis of relative volumes occupied by coexisting phases.

Grazing incidence X-ray diffraction (GIXD) studies of monolayers of biomolecules at an air-water interface give quantitative information of in-plane packing, coherence length of crystalline domains, etc. Rheo-GIXD measurements can reveal quantitative changes in the nanocrystalline domains of a monolayer under shear. Here, we report GIXD studies of monolayers of alamethicin peptide, DPPC lipid, and their mixtures at an air-water interface under steady shear stress. The alamethicin monolayer and the mixed monolayer show a flow jamming transition. On the other hand, the pure 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer under constant stress flows steadily with a notable enhancement of the area/molecule and coherence lengths, suggesting the fusion of nanocrystallites during flow. The DPPC-alamethicin mixed monolayer shows no significant change in the area/DPPC molecule, but the coherence lengths of the individual phases (DPPC and alamethicin) increase, suggesting that the crystallites of individual phases grow bigger by merging of domains. More phase separation occurs in the system during flow. Our results show that rheo-GIXD has the potential to explore in situ molecular structural changes under rheological conditions for a diverse range of confined biomolecules at interfaces.

Isolation of circulating tumor cells (CTCs) is of great significance for the diagnosis, prognosis, and treatment of metastatic cancer. Among CTC capture methods independent of antibodies, membrane filtration-based methods have the advantages of simplicity, rapidity, and high throughput but usually have problems such as clogging, high pressure drop, and impaired cell viability. In this study, we designed and tested a reusable device that used horizontal rotor and fluid-assisted separation to capture CTCs by centrifugal membrane filtration, achieving simple, fast, highly efficient, and viable cell capture on traditional centrifuge. The average capture efficiency was 95.8% for different types of cancer cells with >90% survival, and the removal of white blood cells can reach 99.72% under four times cleaning of the membrane after filtration. A further clinic demo was performed using the device to detect residual leukemic cells in patients; the results showed a 10-fold enrichment of the leukemic cells in peripheral blood samples. Taken together, the simple, robust, and efficient CTC capture device may have the potential for clinic routine detection and analysis of circulating tumor cells.

Rational design and informed development of nontoxic antifouling coatings requires a thorough understanding of the interactions between surfaces and fouling species. With more complex antifouling materials, such as composites or zwitterionic polymers, there follows also a need for better characterization of the materials as such. To further the understanding of the antifouling properties of charge-balanced polymers, we explore the properties of layered polyelectrolytes and their interactions with charged surfaces. These polymers were prepared via self-initiated photografting and photopolymerization (SIPGP); on top of a uniform bottom layer of anionic poly(methacrylic acid) (PMAA), a cationic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) thickness gradient was formed. Infrared microscopy and imaging spectroscopic ellipsometry were used to characterize chemical composition and swelling of the combined layer. Direct force measurements by colloidal probe atomic force microscopy were performed to investigate the forces between the polymer gradients and charged probes. The swelling of PMAA and PDMAEMA are very different, with steric and electrostatic forces varying in a nontrivial manner along the gradient. The gradients can be tuned to form a protein-resistant charge-neutral region, and we demonstrate that this region, where both electrostatic and steric forces are small, is highly compressed and the origin of the protein resistance of this region is most likely an effect of strong hydration of charged residues at the surface, rather than swelling or bulk hydration of the polymer. In the highly swollen regions far from charge-neutrality, steric forces dominate the interactions between the probe and the polymer. In these regions, the SIPGP polymer has qualitative similarities with brushes, but we were unable to quantitatively describe the polymer as a brush, supporting previous data suggesting that these polymers are cross-linked.

Conducting polymers are routinely used in optoelectronic biomaterials, but large polymer polydispersity and poor aqueous compatibility complicate integration with biomolecular templates and development of discrete and defined supramolecular complexes. Herein, we report on a chiro-optical hybrid material generated by the self-assembly of an anionic peptide and a chemically defined cationic pentameric thiophene in aqueous environment. The peptide acts as a stereochemical template for the thiophene and adopts an α-helical conformation upon association, inducing optical activity in the thiophene π-π* transition region. Theoretical calculations confirm the experimentally observed induced structural changes and indicate the importance of electrostatic interactions in the complex. The association process is also probed at the substrate-solvent interface using peptide-functionalized gold nanoparticles, indicating that the peptide can also act as a scaffold when immobilized, resulting in structurally well-defined supramolecular complexes. The hybrid complex could rapidly be assembled, and the kinetics of the formation could be monitored by utilizing the local surface plasmon resonance originating from the gold nanoparticles. We foresee that these findings will aid in designing novel hybrid materials and provide a possible route for the development of functional optoelectronic interfaces for both biomaterials and energy harvesting applications.

Solution-based indium-gallium-zinc oxide (IGZO) nanoparticles deposited by spin coating have been investigated as a resistive switching layer in metal-insulator-metal structures for nonvolatile memory applications. Optimized devices show a bipolar resistive switching behavior, low programming voltages of ±1 V, on/off ratios higher than 10, high endurance, and a retention time of up to 104 s. The better performing devices were achieved with annealing temperatures of 200 °C and using asymmetric electrode materials of titanium and silver. The physics behind the improved switching properties of the devices is discussed in terms of the oxygen deficiency of IGZO. Temperature analysis of the conductance states revealed a nonmetallic filamentary conduction. The presented devices are potential candidates for the integration of memory functionality into low-cost System-on-Panel technology.

G-Quadruplex DNA structure has been proven to be a binding target for small molecular organic compounds and hence regarded as a promising pharmacological target. Cisplatin is a widely used chemotherapy drug that targets duplex DNA and was recently shown to react also with G-quadruplex, implying that cisplatin actually may also target G-quadruplex. In this work, we employed magnetic tweezers to investigate the influence of cisplatin on the folding kinetics of single human telomeric G-quadruplex. It was revealed that cisplatin and G-quadruplex interact in two different and competitive ways that depend on cisplatin concentration.

The polymer electrolyte films (poly((vinylidene fluoride)-co-hexafluoropropylene)/LiClO4@90:10 w/w, PHL10) were prepared by solution-casting technique and the effect of various dosages of electron beam (EB) irradiation on structure, morphology, thermal, dielectric, and conductivity properties at various dosages. The atomic force microscope topography image shows substantial change in surface morphology due to irradiation and the modification of chemical bonds through chain scission process with increased EB dose was confirmed by Fourier transform infrared spectroscopy studies. NMR studies confirm the change in structural properties due to irradiation. The X-ray diffractometer confirms the decreased crystallinity from 50.10 for unirradiated film to 40.96 at 120 kGy doses; hence, increase in amorphousity due to a decrease in melting temperature from 460 to 418 °C leads to the degradation of the polymer, and the differential scanning calorimetry study reveals the decreased crystallinity with increased irradiation dose. The dielectric and modulus parameters are observed to decrease with increasing frequency as well as temperature. The conductivity increases with frequency and EB dose due to the increased segmental motion of charged ions by chain scission/cross-linking process. The high conductivity of 1.81 × 10-3 S/cm with the corresponding relaxation time of 1.697 × 10-6 at 120 kGy dose was observed. The conduction mechanism reveals an Ohmic behavior and the I-V plot exhibits a gradual increase in current with applied voltage as well as irradiation dose. The electrochemical performance of the irradiated polymer electrolyte was improved significantly and hence the polymer electrolytes can be used in solid-state batteries and storage applications after altering the properties by the influence of irradiation.