Water pollution is a growing concern for mankind due to its harmful effects on humans, animals and plants. Usually, several pollutants are present in wastewater. For example, dyes and antibiotics are found in wastewater because of their widespread use in factories and hospitals. However, one single technique, e.g. either adsorption or photocatalysis, cannot easily remove more than one kind of pollutant, especially by using one single material in water. For this reason, here multifunctional iron(ii,iii) oxide/poly(N-isopropylacrylamide-co-methacrylic acid)/silver-titanium dioxide (Fe3O4/P(NIPAM-co-MAA)/Ag-TiO2) nanocomposites were used to remove a mixture of pollutants from water. Specifically, three types of experiments were performed to evaluate the adsorption capacity and photodegradation activity of the nanocomposites towards the dye basic fuchsin (BF) and the antibiotic ciprofloxacin (CIP), which were added sequentially to the nanocomposites dispersion or were concurrently present as a mixture. The results demonstrated that the nanocomposites could adsorb BF, and subsequently photodegrade CIP under visible-light irradiation, if BF was the first added pollutant. As well, the nanocomposites could first degrade CIP under visible-light irradiation, and then adsorb BF if they were initially put in contact with CIP. Finally, the ability of adsorbing BF and photodegrading CIP was confirmed in the co-presence of the two pollutants.

Controlling site-selectivity and reactivity in chemical reactions continues to be a key challenge in modern synthetic chemistry. Here, we demonstrate the discovery of site-selective chemical reactions on the water surface via a sequential assembly approach. A negatively charged surfactant monolayer on the water surface guides the electrostatically driven, epitaxial, and aligned assembly of reagent amino-substituted porphyrin molecules, resulting in a well-defined J-aggregated structure. This constrained geometry of the porphyrin molecules prompts the subsequent directional alignment of the perylenetetracarboxylic dianhydride reagent, enabling the selective formation of a one-sided imide bond between porphyrin and reagent. Surface-specific in-situ spectroscopies reveal the underlying mechanism of the dynamic interface that promotes multilayer growth of the site-selective imide product. The site-selective reaction on the water surface is further demonstrated by three reversible and irreversible chemical reactions, such as imide-, imine-, and 1, 3-diazole (imidazole)- bonds involving porphyrin molecules. This unique sequential assembly approach enables site-selective chemical reactions that can bring on-water surface synthesis to the forefront of modern organic chemistry.

The van der Waals heterostructures have evolved as novel materials for complementing the Si-based semiconductor technologies. Group-10 noble metal dichalcogenides (e.g., PtS2, PtSe2, PdS2, and PdSe2) have been listed into two-dimensional (2D) materials toolkit to assemble van der Waals heterostructures. Among them, PdSe2 demonstrates advantages of high stability in air, high mobility, and wide tunable bandgap. However, the regulation of p-type doping of PdSe2 remains unsolved problem prior to fabricating p–n junction as a fundamental platform of semiconductor physics. Besides, a quantitative method for the controllable doping of PdSe2 is yet to be reported. In this study, the doping level of PdSe2 was correlated with the concentration of Lewis acids, for example, SnCl4, used for soaking. Considering the transfer characteristics, the threshold voltage (the gate voltage corresponding to the minimum drain current) increased after SnCl4 soaking treatment. PdSe2 transistors were soaked in SnCl4 solutions with five different concentrations. The threshold voltages from the as-obtained transfer curves were extracted for linear fitting to the threshold voltage versus doping concentration correlation equation. This study provides in-depth insights into the controllable p-type doping of PdSe2. It may also push forward the research of the regulation of conductivity behaviors of 2D materials.

In recent years, neuromorphic computing has gained attention as a promising approach to enhance computing efficiency. Among existing approaches, neurotransistors have emerged as a particularly promising option as they accurately represent neuron structure, integrating the plasticity of synapses along with that of the neuronal membrane. An ambipolar character could offer designers more flexibility in customizing the charge flow to construct circuits of higher complexity. We propose a novel design for an ambipolar neuromorphic transistor, utilizing carbon nanotubes as the semiconducting channel and an ion-doped sol–gel as the polarizable gate dielectric. Due to its tunability and high dielectric constant, the sol–gel effectively modulates the conductivity of nanotubes, leading to efficient and controllable short-term potentiation and depression. Experimental results indicate that the proposed design achieves reliable and tunable synaptic responses with low power consumption. Our findings suggest that the method can potentially provide an efficient solution for realizing more adaptable cognitive computing systems.Impact statementThe huge amount of data generated by the current society makes it necessary to explore new computing methods with higher efficiency to overcome the bottleneck formed between data storage and processing tasks. Neuromorphic computing aims at emulating the functioning of our brain, which performs both tasks utilizing the same hardware. Here, we propose ambipolar field-effect transistors based on carbon nanotubes with a polarizable gate dielectric, capable of providing memory functions reminiscent of neuronal synapses, at both polarities of the device. The ambipolar characteristic doubles the possibilities of previously demonstrated neurotransistors. The short-term and ambipolar behavior of the device can find its place in novel applications in the future. Machine learning-enabled gas sensing is an excellent example, where real-time processing of large amounts of data is beneficial. In addition, interaction with oxidative and reductive gases will result in dual responses due to the ambipolarity of the transistor, along with the possibility of storing the sensing data.Graphical abstract

Solar-driven photocatalysis is of great interest in terms of a sustainable use of energy and its application in wastewater treatment. The UV light-driven photogeneration of H2O2 by solar irradiation is an advanced strategy for the treatment of bacteria and recalcitrant pollutants in wastewater, but suffers from low efficiencies. In this work, a solar-driven multifunctional nanocomposite consisting of Tm3+ upconverting nanoparticles, poly(vinyl alcohol), poly(acrylic acid) and hydroxylated sulfonated poly(ether ether ketone) was prepared. The components were crosslinked via a heating treatment at 170 °C, resulting in a non-leaching porous material. This nanocomposite exhibited excellent adsorption ability (89 % in 150 min) toward a 100 mg/L ciprofloxacin aqueous solution and proved to photodegrade it (50 %) upon 4 h artificial solar irradiation, exploiting photon upconversion processes. Moreover, an 80 % bactericidal effect against E. coli was registered upon sunlight irradiation. Altogether, these results suggest the feasibility of a solar-driven wastewater treatment based on upconverting nanoparticles.

This proof-of-concept study demonstrates for the first time the fabrication of a multifunctional reinforcing grid-building material within a thermoelectric element generator (TEG) configuration. Commercially available carbon fiber yarns, which possess inherent Seebeck coefficient (S) values of −2.5 μV/K (n-type) and +7.4 μV/K (p-type), were thoroughly investigated prior to their impregnation with a geopolymer (GP)-based suspension. The resulting hardened mineral-impregnated carbon-fiber (MCF) reinforcements were subsequently tested regarding their physicochemical and mechanical properties. Afterward, individual MCFs were employed as n-/p-type thermoelements to assemble a grid-like TEG consisting of five serially interconnected junctions. The TEG-enabled reinforcing grid exhibited a voltage output of 1.8 mV, corresponding to a generated power of 22.3 nW upon exposure to an in-plane temperature difference (ΔT) of 50 K. Multifunctional building materials are envisaged to exploit thermal gradients on a large-scale during their service lifetime, contributing towards zero energy consumption constructions.

The SARS-CoV-2 pandemic has increased the demand for low-cost, portable, and rapid biosensors, driving huge research efforts toward new nanomaterial-based approaches with high sensitivity. Many of them employ antibodies as bioreceptors, which have a costly development process that requires animal facilities. Recently, sybodies emerged as a new alternative class of synthetic binders and receptors with high antigen binding efficiency, improved chemical stability, and lower production costs via animal-free methods. Their smaller size is an important asset to consider in combination with ultrasensitive field-effect transistors (FETs) as transducers, which respond more intensely when biorecognition occurs near their surface. This work demonstrates the immobilization of sybodies against the spike protein of the virus on silicon surfaces, which are often integral parts of the semiconducting channel of FETs. Immobilized sybodies maintain the capability to capture antigens, even at low concentrations in the femtomolar range, as observed by fluorescence microscopy. Finally, the first proof of concept of sybody-modified FET sensing is provided using a nanoscopic silicon net as the sensitive area where the sybodies are immobilized. The future development of further sybodies against other biomarkers and their generalization in biosensors could be critical to decrease the cost of biodetection platforms in future pandemics.

In light of the recent pandemic, several COVID-19 vaccines were developed, tested and approved in a very short time, a process that otherwise takes many years. Above all, these efforts have also unmistakably revealed the capacity limits and potential for improvement in vaccine production. This review aims to emphasize recent approaches for the targeted rapid adaptation and production of vaccines from an interdisciplinary, multifaceted perspective. Using research from the literature, stakeholder analysis and a value proposition canvas, we reviewed technological innovations on the pharmacological level, formulation, validation and resilient vaccine production to supply bottlenecks and logistic networks. We identified four main drivers to accelerate the vaccine product life cycle: computerized candidate screening, modular production, digitized quality management and a resilient business model with corresponding transparent supply chains. In summary, the results presented here can serve as a guide and implementation tool for flexible, scalable vaccine production to swiftly respond to pandemic situations in the future.

In this research, we explore sequence-dependent chiral-induced spin selectivity (CISS) in double-stranded (ds)-DNA using time-correlated single-photon counting and electrochemical impedance spectroscopy supplemented by tight-binding calculations of the phenomenon for the first time. The average lifetime of the photo-excited electrons in a Quantum Dot-DNA system is influenced by the CISS effect generated by the DNA molecule, and the difference in average time decay of electrons was found to be 345ps for opposite polarity ("UP" and "DOWN") of spins due to the CISS effect. Moreover, the yield of spin-polarized electrons due to the CISS effect was reduced by more than 35% from perfect DNA to DNA with point mutations. Remarkably, by employing a tight binding method combined with Green's function formalism for transport, simulations of the process support the observed experimental trends. Our results provide a basic understanding of the sequence-specific spin-dependent electron transfer through ds-DNA. These results would help to build spin-based next-generation DNA sensors.

We address the electron-spin-phonon coupling in an effective model Hamiltonian for DNA to assess its role in spin transfer involved in the Chiral-Induced Spin Selectivity (CISS) effect. The envelope function approach is used to describe semiclassical electron transfer in a tight-binding model of DNA at half filling in the presence of intrinsic spin-orbit coupling. Spin-phonon coupling arises from the orbital-configuration dependence of the spin-orbit interaction. We find spin-phonon coupling only for the acoustic modes, while the optical modes exhibit electron-phonon interaction without coupling to spin. We derive an effective Hamiltonian whose eigenstates carry spin currents that are protected by spin-inactive stretching optical modes. As optical phonons interact more strongly than acoustic phonons, side buckling and tilting optical base modes will be more strongly associated with decoherence, which allows for the two terminal spin filtering effects found in CISS.