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The solid phase microextraction (SPME) technique has been widely applied in the detection of trace compounds in food, environment, and medicine due to its advantages of easy quantification, simple operation, and greenness. Herein, a templating strategy with SiO 2 nanofibers (SiO 2 NFs) is reported to synthesize hierarchical covalent organic framework hollow nanofibers (COF HNFs)-coated stainless steel fiber for SPME application with dramatically enhanced enrichment performance for trace analytes. The construction of hierarchical porosity inside the microextraction coatings can not only increase the specific surface area of COF extraction materials for obtaining more abundant adsorption sites but also greatly improve the accessibility of internal COF micropores. Moreover, the thicknesses of the microextraction COF coatings can be facilely tailored by adjusting the amount of SiO 2 NFs pre-assembled on the SPME fibers. On the headspace solid phase microextraction (HS-SPME) of antimicrobial residues, the developed COF TpBD-Me 2 HNFs-12 fibers achieve enrichment factors of 2026 and 1823 for thymol and carvacrol respectively, which are significantly higher than those obtained from the counterpart COF TpBD-Me 2 -bonded fiber (8.5-8.2 times) and commercial CAR/PDMS fiber (3.3-4.4 times). Furthermore, the developed method was demonstrated to have wide linearity (0.1-50 μg L -1 ), low limits of detection (0.010 μg L -1 ), good thermal stability and excellent reusability (>60 recycles), demonstrating great application potential in the extraction of trace organic pollutants. The strategy developed in this work is applicable to preparing a variety of topological COF (e.g., TpBD, TpPa-1) HNFs-bonded fibers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this study, Pt nanoparticles-loaded nitrogen-doped mesoporous carbon nanotube (Pt/NMCT) was successfully synthesized through a polydopamine-mediated "one-pot" co-deposition strategy. The Pt source was introduced during the co-deposition of polydopamine and silica on the surface of SiO 2 nanowire (SiO 2 NW), and Pt atoms were fixed in the skeleton by the chelation of polydopamine. Thus, in the subsequent calcination process in nitrogen atmosphere, the growth and agglomeration of Pt nanoparticles were effectively restricted, achieving the in situ loading of uniformly dispersed, ultra-small (~2 nm) Pt nanoparticles. The method is mild, convenient, and does not require additional surfactants, reducing agents, or stabilizers. At the same time, the use of the dual silica templates (SiO 2 NW and the co-deposited silica nanoclusters) brought about a hierarchical pore structure with a high specific surface area (620 m 2 g -1 ) and a large pore volume (1.46 cm 3 g -1 ). The loading process of Pt was studied by analyzing the electron microscope and X-ray photoelectron spectroscopy of the intermediate products. The catalytic performance of Pt/NMCT was investigated in the reduction of 4-nitrophenol. The Pt/NMCT with a hierarchical pore structure had an apparent reaction rate constant of 0.184 min -1 , significantly higher than that of the sample, without the removal of the silica templates to generate the hierarchical porosity (0.017 min -1 ). This work provides an outstanding contribution to the design of supported noble metal catalysts and also highlights the importance of the hierarchical pore structure for catalytic activity.

Ti 3 C 2 T x MXene is a versatile two-dimensional material that exhibits exceptional properties, such as an abundance of surface functional groups that facilitate modifications. Additionally, Ti 3 C 2 T x MXene possesses remarkable photothermal effects. In this study, ultrathin Ti 3 C 2 T x nanosheets with dimensions (∼200 nm) suitable for biological applications were prepared by ultrasonication of larger pieces of Ti 3 C 2 T x MXene with a cell pulverizer operating at a specific power. The ultrathin nanosheets exhibited a significant photothermal conversion efficiency (47.1%) under an 808 nm infrared laser irradiation. In addition, they showed an excellent mass extinction coefficient of 15.7 L g -1 cm -1 . By exploiting the intermolecular force between these ultrathin nanosheets and doxorubicin (DOX), a drug loading efficiency of 72.8% was achieved. Through layer-by-layer surface modification of a sulfhydryl-modified polymethacrylic acid (PMAsh) shell and a transferrin (Tf) layer with targeting function, a multifunctional nanomedicine platform (Ti 3 C 2 T x -DOX-PMAsh-Tf) was constructed. Experiments executed in vitro with cells and in vivo to inhibit tumors manifested that Ti 3 C 2 T x is biocompatible. Furthermore, the results showed that the drug release behavior of Ti 3 C 2 T x -DOX-PMAsh-Tf is responsive to glutathione (GSH) stimulation. The synergistic treatment of photothermal therapy and the anticancer drug DOX effectively achieved the inhibition of human hypopharyngeal squamous cell carcinoma.

1D carbon nanotubes have been widely applied in many fields, such as catalysis, sensing and energy storage. However, the long tunnel-like pores and relatively low specific surface area of carbon nanotubes often restrict their performance in certain applications. Herein, a dual-silica template-mediated method to prepare nitrogen-doped mesoporous carbon nanotubes (NMCTs) through co-depositing polydopamine (both carbon and nitrogen precursors) and silica nanoparticles (the porogen for mesopore formation) on a silica nanowire template is proposed. The obtained NMCTs have a hierarchical pore structure of large open mesopores and tubular macropores, a high specific surface area (1037 m 2 g -1 ), and homogeneous nitrogen doping. The NMCT-45 (prepared at an interval time of 45 min) shows excellent performance in supercapacitor applications with a high capacitance (373.6 F g -1 at 1.0 A g- 1 ), excellent rate capability, high energy density (11.6 W h kg -1 at a power density of 313 W kg -1 ), and outstanding cycling stability (98.2% capacity retention after 10 000 cycles at 10 A g -1 ). Owing to the unique tubular morphology, hierarchical porosity and homogeneous N-doping, the NMCT also has tremendous potential in electrochemical catalysis and sensing applications., (© 2022 Wiley-VCH GmbH.)

Electric field-based noncontact flexible electronics (EF-NFEs) allow people to communicate with intelligent devices through noncontact human-machine interactions, but current EF-NFEs with limited detections (usually <20 cm) distance often lack a high spatial resolution. Here, we report a versatile material for preparing EF-NFE devices with a high spatial resolution to realize everyday human activity detection. Eutectic gallium-indium alloy (EGaIn) was introduced into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) chains to fabricate this material, named Ga-PP. The introduction of EGaIn successfully regulates the intra- and interchain interactions of PEDOT chains and thus increases the π-electron accumulation on Ga-PP chains, which facilitates improvement of the electron storage of Ga-PP and its noncontact sensing ability. The water solubility of the obtained Ga-PP can reach approximately 15 mg/mL, comparable to that of commercial PEDOT:PSS, thus making Ga-PP suitable for various design strategies to prepare EF-NFE devices. We demonstrate that a conductive textile with a noncontact sensing ability can be achieved by immersing a commercial silk fabric into a Ga-PP solution for 5 min. With a detection distance exceeding 1 m, the prepared Ga-PP-based conductive textile (Ga-PP-CT) possesses outstanding noncontact sensing sensitivity, showing advantages in tracing the locations of signal sources and distinguishing motion states. Surprisingly, even when placed in water, Ga-PP-CT can be used to monitor the movement signals of athletes in different sporting events and output specific noncontact response signals for different sports. Intriguingly, the Ga-PP solution itself can be used to construct noncontact sensing conductive circuits, displaying the potential to be incorporated into smart electronics.

Covalent organic frameworks (COF), a class of emerging microporous polymers, have been restrained for drug delivery applications due to their limited controllability over particle sizes and degradability. Herein, a dendritic mesoporous silica nanosphere (DMSN)-mediated growth strategy is proposed to fabricate hierarchical DMSN@COF hybrids through in situ growing of 1,3,5-tris(4-aminophenyl)benzene and 2,5-dimethoxyterephthaldehyde connected COF with acid cleavable C=N bonds. After the removal of the DMSN template, COF hierarchical particles (COF HP) with tailored particle sizes and degradability were obtained. Notably, the COF HP could be degraded by 55% after 24 h of incubation at pH 5.5, whereas the counterpart bulk COF only showed 15% of degradation in the same conditions. Due to the improved porosity and surface area, the COF HP can be utilized to load the chemotherapeutic drug, doxorubicin (DOX), with a high loading (46.8 wt%), outperforming the bulk COF (32.1 wt%). Moreover, around 90% of the loaded DOX can be discharged from the COF HP within 8 h of incubation at pH 5.5, whereas, only ~55% of the loaded DOX was released from the bulk COF. Cell experiments demonstrated that the IC 50 value of the DOX loaded in COF HP was 2-3 times lower than that of the DOX loaded in the bulk COF and the hybrid DMSN@COF. Attributed to the high loading capacity and more pH-labile particle deconstruction properties, COF HP shows great potential in the application as vehicles for drug delivery.

Mesoporous silica materials have attracted great research interest for various applications ranging from (bio)catalysis and sensing to drug delivery. It remains challenging to prepare hollow mesoporous silica nanoparticles (HMSN) with large center-radial mesopores that could provide a more efficient transport channel through the cell for guest molecules. Here, we propose a novel strategy for the preparation of HMSN with large dendritic mesopores to achieve higher enzyme loading capacity and more efficient bioreactors. The materials were prepared by combining barium sulfate nanoparticles (BaSO 4 NP) as a hard template and the in situ-formed 3-aminophenol/formaldehyde resin as a porogen for directing the dendritic mesopores' formation. HMSNs with different particle sizes, shell thicknesses, and pore structures have been prepared by choosing BaSO 4 NP of various sizes and adjusting the amount of tetraethyl orthosilicate added in synthesis. The obtained HMSN-1.1 possesses a high pore volume (1.07 cm 3 g -1 ), a large average pore size (10.9 nm), and dendritic mesopores that penetrated through the shell. The advantages of HMSNs are also demonstrated for enzyme (catalase) immobilization and subsequent use of catalase-loaded HMSNs as bioreactors for catalyzing the H 2 O 2 degradation reaction. The hollow and dendritic mesoporous shell features of HMSNs provide abundant tunnels for molecular transport and more accessible surfaces for molecular adsorption, showing great promise in developing efficient nanoreactors and drug delivery vehicles.

Designing electronic skin (e-skin) with proteins is a critical way to endow e-skin with biocompatibility, but engineering protein structures to achieve controllable mechanical properties and self-healing ability remains a challenge. Here, we develop a hybrid gluten network through the incorporation of a eutectic gallium indium alloy (EGaIn) to design a self-healable e-skin with improved mechanical properties. The intrinsic reversible disulfide bond/sulfhydryl group reconfiguration of gluten networks is explored as a driving force to introduce EGaIn as a chemical cross-linker, thus inducing secondary structure rearrangement of gluten to form additional β-sheets as physical cross-linkers. Remarkably, the obtained gluten-based material is self-healing, achieves synthetic material-like stretchability (>1600%) and possesses the ability to promote skin cell proliferation. The final e-skin is biocompatible and biodegradable and can sense strain changes from human motions of different scales. The protein network microregulation method paves the way for future skin-like protein-based e-skin., (© 2022. The Author(s).)

Two-dimensional (2D) nanoreactors with cascade catalytic activity for glucose oxidation and hydrogen peroxide decomposition are prepared via immobilizing glucose oxidase (GOx) on Ti 3 C 2 MXene nanosheets. Amino-rich polypeptide, poly-l-lysine (PLL), is applied to modify the ultra-thin Ti 3 C 2 MXene nanosheets with a compatible surface for GOx immobilization. The PLL-modified Ti 3 C 2 nanosheets possess a positively charged surface and show an excellent GOx loading capacity as high as 50 wt% of the Ti 3 C 2 nanosheets. The physically adsorbed enzymes are then cross-linked with the amine groups in the PLL chains to form a robust GOx-PLL network covered on the MXene nanosheets. The GOx-conjugated Ti 3 C 2 -PLL (Ti 3 C 2 -PLL-GOx) nanosheets showed superior enzymatic activities than the activities of GOx immobilized on an inert porous silica substrate, largely because that the Ti 3 C 2 nanosheets can catalyze the decomposition of the toxic intermediate H 2 O 2 generated from the glucose oxidation. Given the excellent electrical conductivity of Ti 3 C 2 MXene, the Ti 3 C 2 -PLL-GOx nanosheets are further deposited on glassy carbon electrode to construct a high-performance biosensor with a glucose detection limit of 2.6 μM., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)