Eco-friendly chitosan@silver/plant fiber membranes for masks with thermal comfortability and self-sterilization.

The surgical masks have been essential consumables for public in the COVID-19 pandemic. However, long-time wearing masks will make wearers feel uncomfortable and massive discarded non-biodegradable masks lead to a heavy burden on our environment. In this paper, we adopt degradable chitosan@silver (CS@Ag) core-shell fibers and plant fibers to prepare an eco-friendly mask with excellent thermal comfort, self-sterilization, and antiviral effects. The thermal network of CS@Ag core-shell fibers highly improves the in-plane thermal conductivity of masks, which is 4.45 times higher than that of commercial masks. Because of the electrical conductivity of Ag, the fabricated mask can be electrically heated to warm the wearer in a cold environment and disinfect COVID-19 facilely at room temperature. Meanwhile, the in-situ reduced silver nanoparticles (AgNPs) endow the mask with superior antibacterial properties. Therefore, this mask shows a great potential to address the urgent need for a thermally comfortable, antibacterial, antiviral, and eco-friendly mask. Supplementary Information: The online version contains supplementary material available at 10.1007/s10570-022-04582-x.

Synthesis of micro-crosslinked adamantane-containing matrix resins designed for deep-UV lithography resists and their application in nanoimprint lithography.

A certain type of photoresist used for deep-UV lithography (DUVL) can also be used for other types of photolithography. Thus, to meet the requirements of two or more lithography technologies simultaneously, it is necessary to design a variety of corresponding functional groups in the molecules of materials and obtain the required properties. Herein, we designed four matrix resins based on acrylate for DUVL, employing alkyl sulfide, adamantane, methyladamantane, and hydroxyl as dangling groups and a microcrosslinking network by adding a small amount of crosslinker. These polymers were used in the thermal nanoimprint lithography (NIL) process, and distinct patterns with a resolution of 100 nm were observed. The acrylate copolymers designed for DUVL in this work can be used as thermal NIL resists and to obtain good patterns. It was found that ethylene dimethacrylate (EDMA) and adamantane endowed the matrix resins with good thermal stability and that PMMHM demonstrated the best patterning performance among the four resins. These polymers can be applied in the manufacturing of high-density integrated circuits, nano-transistors, optoelectronic devices and other components in the future.

Eco-Friendly Silver Nanoparticles/Chitosan/Poly(vinyl alcohol) Composites Exhibit Remarkable EMI Shielding Capabilities and Outstanding Thermal Conductivities.

The integration and miniaturization of contemporary electronics have led to significant challenges in dealing with electromagnetic (EM) radiation and heat accumulation. Despite these issues, achieving high thermal conductivity (TC) and electromagnetic interference (EMI) shielding effectiveness (SE) in polymer composite films remains an exceptionally difficult task. In this work, we used a straightforward in situ reduction process and a vacuum-drying method to successfully prepare a flexible Ag NPs/chitosan (CS)/PVA nanocomposite with three-dimensional (3D) conductive and thermally conductive network architectures. The 3D silver pathways formed by attaching to the chitosan fibers endow the material with simultaneous exceptional TC and EMI capabilities. At a silver concentration of 25 vol %, the TC of Ag NPs/CS/PVA nanocomposites reaches 5.18 W·m-1·K-1, exhibiting an approximately 25 times increase compared to CS/PVA composites. The electromagnetic shielding performance of 78.5 dB significantly outperforms the specifications of standard commercial EMI shielding applications by a significant margin. Additionally, Ag NPs/CS/PVA nanocomposites have greatly benefited from microwave absorption (SEA), effectively impeding the transmission of EM waves and reducing the reflected secondary EM wave pollution. Meanwhile, the composite material still maintains good mechanical properties and bendability. This endeavor helped develop malleable and durable composites that possess superior EMI shielding capabilities and intriguing heat dissipation properties using innovative design and fabrication methods.

Biomimetic redox-responsive smart coatings with resistance-release functions for reverse osmosis membranes.

Membrane fouling induces catastrophic loss of separation performance and seriously restricts the applications of reverse osmosis (RO) membranes. Inspired by the mussel structure, polydopamine (PDA) and cystamine molecules (CA) with excellent anti-fouling properties were used to prepare accessible, biocompatible, and redox-responsive coatings for RO membranes. The PDA/CA-coated RO membranes exhibit a superior water flux of 65 L m-2 h-1 with a favourable NaCl rejection exceeding 99%. The water permeability through the PDA/CA-coated membrane is much higher than that of most membranes with similar rejection rates. Due to the formed protective hydration layers by PDA/CA coatings, anti-fouling properties against proteins, polysaccharides and surfactants were evaluated separately, and ultralow fouling properties were demonstrated. Moreover, the disulfide linkages in CA molecules can cleave in a reducing environment, yielding the degradation of PDA/CA coatings, thereby removing the foulants deposited on the coatings. The degradation endows the coated membranes with satisfying longtime anti-fouling properties, where the flux recovery reaches up to 90%. The construction of redox-responsive smart coatings not only provided a promising route to alleviate membrane fouling but can also be upscaled for use in numerous practical applications like sensors, medical devices, and drug delivery.

Albumin-encapsulated HSP90-PROTAC BP3 nanoparticles not only retain protein degradation ability but also enhance the antitumour activity of BP3 in vivo.

Proteolysis-targeting chimaera (PROTAC) has received extensive attention in industry. However, there are still some limitations that hinder its further development. In a previous study, our group first demonstrated that the HSP90 degrader BP3 synthesised by the principle of PROTACs showed therapeutic potential for cancer. However, its application was hindered by its high molecular weight and water insolubility. Herein, we aimed to improve these properties of HSP90-PROTAC BP3 by encapsulating it into human serum albumin nanoparticles (BP3@HSA NPs). The results demonstrated that BP3@HSA NPs showed a uniform spherical shape with a size of 141.01 ± 1.07 nm and polydispersity index < 0.2; moreover, BP3@HSA NPs were more readily taken up by breast cancer cells and had a stronger inhibitory effect in vitro than free BP3. BP3@HSA NPs also demonstrated the ability to degrade HSP90. Mechanistically, the improved inhibitory effect of BP3@HSA NPs on breast cancer cells was related to its stronger ability to induce cell cycle arrest and apoptosis. Furthermore, BP3@HSA NPs improved PK properties and showed stronger tumour suppression in mice. Taken together, this study demonstrated that hydrophobic HSP90-PROTAC BP3 nanoparticles encapsulated by human serum albumin could improve the safety and antitumour efficacy of BP3.

Donnan Effect-Engineered Covalent Organic Framework Membranes toward Size- and Charge-Based Precise Molecular Sieving.

Covalent organic frameworks (COFs), with ordered pores and well-defined topology, are ideal materials for nanofiltration (NF) membranes because of their capacity of transcending the permeance/selectivity trade-off predicament. However, most reported COF-based membranes are focused on separating molecules with different sizes, resulting in low selectivity to similar molecules with different charges. Here, the negatively charged COF layer was fabricated in situ on a microporous support for the separation of molecules with different sizes and charges. Ultrahigh water permeance (216.56 L m-2 h-1 bar-1) was obtained because of the ordered pores and excellent hydrophilicity, which exceeds that of most membranes with similar rejections. For the first time, we used multifarious dyes with different sizes and charges, for the investigation of the selectivity behavior caused by the Donnan effect and size exclusion. The obtained membranes represent superior rejections to negatively and neutrally charged dyes larger than 1.3 nm, while positively charged dyes with a size of 1.6 nm can pass through the membrane, resulting in the separation of negative/positive mixed dyes with similar molecular sizes. This strategy of combining the Donnan effect and size exclusion in nanoporous materials may evolve into a generic platform for sophisticated separation.

A spectrophotometric method for measuring permanganate index (CODMn) by N,N-diethyl-p-phenylenediamine (DPD).

A new spectrophotometric method for measuring permanganate index (chemical oxygen demand using potassium permanganate (KMnO4) as oxidant, CODMn) in water was established. The method was based on the rapid oxidation of N,N-diethyl-p-phenylenediamine (DPD) by residual KMnO4 in digestion solution under neutral pH condition to form the stable pink radical (DPD●+). Only 20 s were enough to form the pink DPD●+. The generated DPD●+ could be quantitatively measured by a visible spectrophotometer at 551 nm. Stoichiometric coefficient of the reaction between KMnO4 and DPD was close to 1:5 (1:5.07). There was a well linear relationship (R2 = 0.999) between the change of the absorbance of DPD●+ at 551 nm and the concentration of CODMn in the range of 0-4.46 mg L-1. Limit of detection of the DPD method was as low as 0.02 mg L-1 CODMn. The DPD method was highly accurate for measuring CODMn in standard solutions with well recovery rates of 99.17%-102.22%, and was well tolerant to the interference of coexistent Cl- and Fe3+. The DPD method was successfully applied for measuring CODMn in real water samples, including surface water, underground water and drinking water. In comparison to the traditional titration method, the proposed DPD method was more convenient to operate, required less samples and digestion reagents (i.e., KMnO4 and H2SO4) and could be employed for online monitor.

Fabrication of Multifocal Microlens Array by One Step Exposure Process.

Microlenses can be widely used in integrated micro-optical systems. However, in some special applications, such as light field imaging systems, multifocal microlens arrays (MLA) are expected to improve imaging resolution. For the fabrication of multifocal MLA, the traditional fabrication method is no longer applicable. To solve this problem, a fabrication method of multifocal MLA by a one step exposure process is proposed. Through the analyses and research of photoresist AZ9260, the nonlinear relationship between exposure dose and exposure depth is established. In the design of the mask, the mask pattern is corrected according to the nonlinear relationship to obtain the final mask. The continuous surface of the multifocal MLA is fabricated by the mask moving exposure. The experimental results show that the prepared multifocal MLA has high filling factor and surface fidelity. What is more, this method is simple and efficient to use in practical applications.

Electrochemical sensing performance of Eu-BTC and Er-BTC frameworks toward Sunset Yellow.

Two lanthanide metal-organic frameworks (Ln-MOFs) using 1,3,5-benzenetricarboxylic acid (H3BTC) and Ln(III) nitrate hydrate (Ln = Eu, Er) as precursors have been prepared through a one-step solvothermal approach. The as-synthesized compounds were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy, confirming that the targeted Ln-MOFs were successfully synthesised, with a straw-sheaf appearance. Their sensing properties were studied using cyclic voltammetry and electrochemical impedance spectroscopy, and the results showed that the prepared Ln-BTCs possessed larger electrochemical-response areas and stronger electron-transport capability, especially the Er-BTC. The oxidation behaviour of Sunset Yellow was investigated, and it was found that the Er-BTC exhibited a superior enhancement effect. Chronocoulometry was used to prove that Er-BTC more strongly adsorbs Sunset Yellow, resulting in a larger electrochemical response signal. The novel Sunset Yellow sensor exhibited a linear response in the range of 0.2-100 nM with a low limit of detection (0.05 nM, S/N = 3), and was applied in drink samples. The results were validated by high-performance liquid chromatography, indicating this sensor is a promising tool for Sunset Yellow detection.