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Showing papers in "ACS Applied Materials & Interfaces in 2021"


Journal ArticleDOI
TL;DR: This Review aims to guide MOF design for novel biomedical applications by reviewing the historical application of MOFs for drug delivery, with a specific focus on the available options for designingMOFs for specific drug delivery applications.
Abstract: The use of metal-organic frameworks (MOFs) in biomedical applications has greatly expanded over the past decade due to the precision tunability, high surface areas, and high loading capacities of MOFs. Specifically, MOFs are being explored for a wide variety of drug delivery applications. Initially, MOFs were used for delivery of small-molecule pharmaceuticals; however, more recent work has focused on macromolecular cargos, such as proteins and nucleic acids. Here, we review the historical application of MOFs for drug delivery, with a specific focus on the available options for designing MOFs for specific drug delivery applications. These options include choices of MOF structure, synthetic method, and drug loading. Further considerations include tuning, modifications, biocompatibility, cellular targeting, and uptake. Altogether, this Review aims to guide MOF design for novel biomedical applications.

257 citations


Journal ArticleDOI
TL;DR: This Review demonstrates the emerging aptamer discovery technologies in developing advanced techniques for producing aptamers with high performance consistently and efficiently as well as requiring less cost and resources but offering a great chance of success.
Abstract: Aptamers are oligonucleotide sequences with a length of about 25-80 bases which have abilities to bind to specific target molecules that rival those of monoclonal antibodies. They are attracting great attention in diverse clinical translations on account of their various advantages, including prolonged storage life, little batch-to-batch differences, very low immunogenicity, and feasibility of chemical modifications for enhancing stability, prolonging the half-life in serum, and targeted delivery. In this Review, we demonstrate the emerging aptamer discovery technologies in developing advanced techniques for producing aptamers with high performance consistently and efficiently as well as requiring less cost and resources but offering a great chance of success. Further, the diverse modifications of aptamers for therapeutic applications including therapeutic agents, aptamer-drug conjugates, and targeted delivery materials are comprehensively summarized.

189 citations


Journal ArticleDOI
TL;DR: The preparation methods of high-performance electrospun air filTration membranes (EAFMs) and the typical surface structures and filtration principles of electrospinning nanofibers for air Filtration are reviewed.
Abstract: Air filtration materials (AFMs) have gradually become a research hotspot on account of the increasing attention paid to the global air quality problem. However, most AFMs cannot balance the contrad...

168 citations


Journal ArticleDOI
TL;DR: In this paper, BaSO4-acrylic paint is developed with a 60% volume concentration to enhance the reliability in outdoor applications, achieving a solar reflectance of 98.1% and a sky window emissivity of 0.95.
Abstract: Radiative cooling is a passive cooling technology that offers great promises to reduce space cooling cost, combat the urban island effect, and alleviate the global warming. To achieve passive daytime radiative cooling, current state-of-the-art solutions often utilize complicated multilayer structures or a reflective metal layer, limiting their applications in many fields. Attempts have been made to achieve passive daytime radiative cooling with single-layer paints, but they often require a thick coating or show partial daytime cooling. In this work, we experimentally demonstrate remarkable full-daytime subambient cooling performance with both BaSO4 nanoparticle films and BaSO4 nanocomposite paints. BaSO4 has a high electron band gap for low solar absorptance and phonon resonance at 9 μm for high sky window emissivity. With an appropriate particle size and a broad particle size distribution, the BaSO4 nanoparticle film reaches an ultrahigh solar reflectance of 97.6% and a high sky window emissivity of 0.96. During field tests, the BaSO4 film stays more than 4.5 °C below ambient temperature or achieves an average cooling power of 117 W/m2. The BaSO4-acrylic paint is developed with a 60% volume concentration to enhance the reliability in outdoor applications, achieving a solar reflectance of 98.1% and a sky window emissivity of 0.95. Field tests indicate similar cooling performance to the BaSO4 films. Overall, our BaSO4-acrylic paint shows a standard figure of merit of 0.77, which is among the highest of radiative cooling solutions while providing great reliability, convenient paint form, ease of use, and compatibility with the commercial paint fabrication process.

163 citations


Journal ArticleDOI
TL;DR: In this article, the authors present recent advances in hydrogel and organohydrogel-based stretchable sensors with four main sections: improved stability of hydrogels, fabrication and characterization of organhydrogel, working principles, and performance of different types of sensors.
Abstract: Conductive hydrogels have drawn significant attention in the field of stretchable/wearable sensors due to their intrinsic stretchability, tunable conductivity, biocompatibility, multistimuli sensitivity, and self-healing ability. Recent advancements in hydrogel- and organohydrogel-based sensors, including a novel sensing mechanism, outstanding performance, and broad application scenarios, suggest the great potential of hydrogels for stretchable electronics. However, a systematic summary of hydrogel- and organohydrogel-based sensors in terms of their working principles, unique properties, and promising applications is still lacking. In this spotlight, we present recent advances in hydrogel- and organohydrogel-based stretchable sensors with four main sections: improved stability of hydrogels, fabrication and characterization of organohydrogel, working principles, and performance of different types of sensors. We particularly highlight our recent work on ultrastretchable and high-performance strain, temperature, humidity, and gas sensors based on polyacrylamide/carrageenan double network hydrogel and ethylene glycol/glycerol modified organohydrogels obtained via a facile solvent displacement strategy. The organohydrogels display higher stability (drying and freezing tolerances) and sensing performances than corresponding hydrogels. The sensing mechanisms, key factors influencing the performance, and application prospects of these sensors are revealed. Especially, we find that the hindering effect of polymer networks on the ionic transport is one of the key mechanisms applicable for all four of these kinds of sensors.

151 citations


Journal ArticleDOI
Li Zhao1, Zhijun Ren1, Xiong Liu1, Qiangjun Ling1, Zhengjun Li1, Haibin Gu1 
TL;DR: In this paper, a composite hydrogel network was built by borate ester bonds and hydrogen bonds, which exhibited pH and sugar-responsiveness, high stretchability (780% strain), and fast self-healing performance with healing efficiency (HE) as high as 93.56% without any external stimulus.
Abstract: Hydrogel-based wearable devices have attracted tremendous interest due to their potential applications in electronic skins, soft robotics, and sensors. However, it is still a challenge for hydrogel-based wearable devices to be integrated with high conductivity, a self-healing ability, remoldability, self-adhesiveness, good mechanical strength and high stretchability, good biocompatibility, and stimulus-responsiveness. Herein, multifunctional conductive composite hydrogels were fabricated by a simple one-pot method based on poly(vinyl alcohol) (PVA), sodium alginate (SA), and tannic acid (TA) using borax as a cross-linker. The composite hydrogel network was built by borate ester bonds and hydrogen bonds. The obtained hydrogel exhibited pH- and sugar-responsiveness, high stretchability (780% strain), and fast self-healing performance with healing efficiency (HE) as high as 93.56% without any external stimulus. Additionally, the hydrogel displayed considerable conductive behavior and stable changes of resistance with high sensitivity (gauge factor (GF) = 15.98 at a strain of 780%). The hydrogel was further applied as a strain sensor for monitoring large and tiny human motions with durable stability. Significantly, the healed hydrogel also showed good sensing behavior. This work broadens the avenue for the design and preparation of biocompatible polymer-based hydrogels to promote the application of hydrogel sensors with comfortable wearing feel and high sensitivity.

146 citations


Journal ArticleDOI
TL;DR: In this paper, an electrospun nanofiber-based TENG (EN-TENG) using a poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE)/MXene nanocomposite material with superior dielectric constant and high surface charge density is reported.
Abstract: Understanding of the triboelectric charge accumulation from the view of microcapacitor formation plays a critical role in boosting the output performance of the triboelectric nanogenerator (TENG). Here, an electrospun nanofiber-based TENG (EN-TENG) using a poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE)/MXene nanocomposite material with superior dielectric constant and high surface charge density is reported. The influence of dielectric properties on the output performance of the EN-TENG is investigated theoretically and experimentally. The fabricated EN-TENG exhibited a maximum power density of 4.02 W/m2 at a matching external load resistance of 4 MΩ. The PVDF-TrFE/MXene nanocomposite improved the output performance of the EN-TENG fourfold. The EN-TENG successfully powered an electronic stopwatch and thermo-hygrometer by harvesting energy from human finger tapping. Moreover, it was utilized in smart home applications as a self-powered switch for controlling electrical home appliances, including fire alarms, fans, and smart doors. This work presents an effective and innovative approach toward self-powered systems, human-machine interfaces, and smart home applications.

145 citations


Journal ArticleDOI
TL;DR: In this paper, the authors highlight the special wettable materials with intelligent functions, including photocatalytic, self-healing and switchable oil/water separation materials, which can achieve self-cleaning, selfhealing, and efficient oily wastewater treatment.
Abstract: Clean water resources are essential to our human society. Oil leakage has caused water contamination, which leads to serious shortage of clean water, environmental deterioration, and even increasing number of deaths. It is of great urgency to solve the oil-polluted water problems worldwide. Efficient oil/water separation, especially emulsified oil/water mixture separation, is widely used to mitigate water pollution issues. Recently, advanced materials with special wettability have been employed for oily wastewater remediation. Moreover, by endowing them with various intelligent functions, smart materials can effectively separate complex oil/water mixtures including extremely stable emulsions. In this review, oil/water separation mechanisms and various fabrication methods of special wettability separation materials are summarized. We highlight the special wettable materials with intelligent functions, including photocatalytic, self-healing, and switchable oil/water separation materials, which can achieve self-cleaning, self-healing, and efficient oily wastewater treatment. In each section, the acting mechanisms, fabricating technologies, representative studies, and separation efficiency are briefly introduced. Lastly, the challenges and outlook for oil/water separation based on the special wettability materials are discussed.

137 citations


Journal ArticleDOI
TL;DR: In this paper, a solar steam generation method has been widely investigated as a sustainable method to achieve seawater desalination and sewage treatment, however, oil pollutants are usually emitted in real seawa...
Abstract: A solar steam generation method has been widely investigated as a sustainable method to achieve seawater desalination and sewage treatment. However, oil pollutants are usually emitted in real seawa...

135 citations


Journal ArticleDOI
TL;DR: In this article, an antifreezing and antidrying organohydrogel with high transparency (over 85% transmittance), high stretchability, and robust adhesiveness to various substrates, which consist of polyacrylic acid, gelatin, AlCl3+, and tannic acid in a water/glycerin binary solvent as the dispersion medium.
Abstract: As a flexible wearable device, hydrogel-based sensors have attracted widespread attention in soft electronics. However, the application of traditional hydrogels at extreme temperatures or for a long-term stability still remain a challenge because of the existence of water. Herein, we reported an antifreezing and antidrying organohydrogel with high transparency (over 85% transmittance), high stretchability (up to 1200%), and robust adhesiveness to various substrates, which consist of polyacrylic acid, gelatin, AlCl3+, and tannic acid in a water/glycerin binary solvent as the dispersion medium. As the binary solvent easily forms strong hydrogen bonds with water molecules, organohydrogels exhibited excellent tolerance for drying and freezing. The organohydrogels maintained conductivity, adhesion, and stable sensitivity after a long-term storage or at subzero temperature (-14 °C). Moreover, the organohydrogel-based wearable sensors with a gauge factor of 2.5 (strain, 0-100%) could detect both large-scale movements and subtle motions. Therefore, the multifunctional organohydrogel-wearable sensors with antifreezing and antidrying properties have promising potential for human-machine interfaces and healthcare monitoring under a broad range of environmental conditions.

128 citations


Journal ArticleDOI
TL;DR: In this paper, a semi-solid-state battery-supercapacitor-hybrid (sss-BSH) device with two Fe-based metal-organic framework and one one-dimensional coordination polymer was proposed.
Abstract: One two-dimensional Fe-based metal-organic framework (FeSC1) and one one-dimensional coordination polymer (FeSC2) have been solvothermally prepared through the reaction among FeSO4·7H2O, the tripodal ligand 4,4',4″-s-triazine-2,4,6-triyl-tribenzoate (H3TATB), and flexible secondary building blocks p/m-bis((1H-imidazole-1-yl)methyl)benzene (bib). Given that their abundant interlayer spaces and different coordination modes, two compounds have been employed as battery-type electrodes to understand how void space and different coordination modes affect their performances in three-electrode electrochemical systems. Both materials exhibit outstanding but different electrochemical performances (including distinct capacities and charge-transfer abilities) under three-electrode configurations, where the charge storage for each electrode material is mainly dominated by the diffusion-controlled section (i ∝ v0.5) through power-law equations. Additionally, the partial phase transformations to more stable FeOOH are also detected in the long-term cycling loops. After coupling with the capacitive carbon-based electrode to assemble into the semi-solid-state battery-supercapacitor-hybrid (sss-BSH) devices, the sss-FeSC1//AC BSH device delivers excellent capacitance, superior energy and power density, and longstanding endurance as well as the potential practical property.

Journal ArticleDOI
TL;DR: In this paper, the authors found that the (Cu1/3Nb2/3)4+ substitution can effectively adjust the TCF (TCF) in microwave dielectric ceramics.
Abstract: Microwave dielectric ceramics are vital for filters, dielectric resonators, and dielectric antennas in the 5G era. It was found that the (Cu1/3Nb2/3)4+ substitution can effectively adjust the TCF (...

Journal ArticleDOI
TL;DR: In this paper, a universal strategy was proposed to prepare the dual superlyophobic surfaces in oil-water systems only via delicately controlling surface chemistry, that is, adjusting the ratios of superhydrophilic and super-hydrophobic counterparts in the spray solution.
Abstract: There are some methods to prepare superwetting surfaces with underwater superoleophobicity (UWSOB) or underoil superhydrophobicity (UOSHB), but it is still thorny to put forward a universal strategy for constructing dual superlyophobic surfaces in oil-water systems due to a thermodynamic contradiction. Herein, a universal strategy was proposed to prepare the dual superlyophobic surfaces in oil-water systems only via delicately controlling surface chemistry, that is, adjusting the ratios of superhydrophilic and superhydrophobic counterparts in the spray solution. Three types of materials, attapulgite (APT), TiO2, and loess, were chosen to prepare a diverse series of mixed coatings (mass gradient of superhydrophobic counterparts from 0 to 100 wt %). With the proportion of each superhydrophobic counterpart increasing, the underwater oil contact angle (θo/w*) of each mixed coating slightly decreased but still was more than 150°, that is, UWSOB. In contrast, the underoil water contact angle (θw/o*) was significantly improved, realizing the transformation from UOHL (or UOHB) to UOSHB. More importantly, the respective mass ratios of superhydrophobic counterparts in the resulting mixed coatings of APT, TiO2, and loess were finally determined to be 0.3, 0.4, and 0.2, respectively. Taking APT as a model, a train of mixed APT coatings with different superhydrophobic components were systematically characterized and analyzed. Finally, the prepared superlyophobic separation mesh in oil-water systems was applied to the separation of various surfactant-stabilized oil-water emulsions. We envision that this universal strategy we proposed will show a significant application potential in addressing scientific and technological challenges in the field of interfacial chemistry such as oil-water separation, microfluidics, microdroplet manipulation, antifogging/icing, cell engineering, drag reduction, and so forth.

Journal ArticleDOI
TL;DR: It is confirmed that well-designed nanoarchitecture and porosity are required to allow efficient diffusion and maximum electrosorption of electrolyte ions in supercapacitor and capacitive deionization performance.
Abstract: Herein, the synergistic effects of hollow nanoarchitecture and high specific surface area of hollow activated carbons (HACs) are reported with the superior supercapacitor (SC) and capacitive deionization (CDI) performance. The center of zeolite imidazolate framework-8 (ZIF-8) is selectively etched to create a hollow cavity as a macropore, and the resulting hollow ZIF-8 (HZIF-8) is carbonized to obtain hollow carbon (HC). The distribution of nanopores is, subsequently, optimized by KOH activation to create more nanopores and significantly increase specific surface area. Indeed, as-prepared hollow activated carbons (HACs) show significant improvement not only in the maximum specific capacitance and desalination capacity but also capacitance retention and mean desalination rates in SC and CDI, respectively. As a result, it is confirmed that well-designed nanoarchitecture and porosity are required to allow efficient diffusion and maximum electrosorption of electrolyte ions.

Journal ArticleDOI
Yu Wang1, Ye Wu1, Linyu Long1, Li Yang1, Daihua Fu1, Cheng Hu1, Qingquan Kong1, Yunbing Wang1 
TL;DR: In this paper, a dual-responsive (pH and reactive oxygen species (ROS)) hydrogel was prepared to realize drug release properties under inflammatory stimulation by grafting 3-carboxy-phenylboronic acid to the gelatin molecular backbone and cross-linking with poly(vinyl alcohol).
Abstract: Stimuli-responsive hydrogels possess unique advantages in drug delivery due to their variable performance and status based on the external environment. In the present study, a dual-responsive (pH and reactive oxygen species (ROS)) hydrogel was prepared to realize drug release properties under inflammatory stimulation. By grafting 3-carboxy-phenylboronic acid to the gelatin molecular backbone and cross-linking with poly(vinyl alcohol), we successfully synthesized the inflammation-responsive drug-loaded hydrogels after encapsulation with vancomycin-conjugated silver nanoclusters (VAN-AgNCs) and pH-sensitive micelles loaded with nimesulide (NIM). This novel design not only retained the dynamic functions of hydrogels, such as injectability, self-healing, and remodeling, but also realized sequential and on-demand drug delivery at diabetic-infected wound sites. In this work, we found that the hydrogel exhibited excellent biocompatibility and hemostasis properties owing to the enhanced cell-adhesive property of the gelatin component. The significant antibacterial and anti-inflammatory effect of the hydrogel was demonstrated in an in vitro experiment. Moreover, in the in vivo experiment, the hydrogel was found to play a role in promoting infected wound healing through sequential hemostasis and antibacterial and anti-inflammatory processes. Collectively, this inflammation-responsive hydrogel design containing VAN-AgNCs and NIM-loaded micelles has great potential in the application of chronically infected diabetic wound treatment, as well as in other inflammatory diseases.

Journal ArticleDOI
TL;DR: In this paper, the use of a high-purity semiconducting (sc) single-walled carbon nanotube (SWCNT)-based field effect transistor (FET) decorated with specific binding chemistry to assess the presence of SARS-CoV-2 antigens in clinical nasopharyngeal samples was reported.
Abstract: Early diagnosis of SARS-CoV-2 infection is critical for facilitating proper containment procedures, and a rapid, sensitive antigen assay is a critical step in curbing the pandemic. In this work, we report the use of a high-purity semiconducting (sc) single-walled carbon nanotube (SWCNT)-based field-effect transistor (FET) decorated with specific binding chemistry to assess the presence of SARS-CoV-2 antigens in clinical nasopharyngeal samples. Our SWCNT FET sensors, with functionalization of the anti-SARS-CoV-2 spike protein antibody (SAb) and anti-nucleocapsid protein antibody, detected the S antigen (SAg) and N antigen (NAg), reaching a limit of detection of 0.55 fg/mL for SAg and 0.016 fg/mL for NAg in calibration samples. SAb-functionalized FET sensors also exhibited good sensing performance in discriminating positive and negative clinical samples, indicating a proof of principle for use as a rapid COVID-19 antigen diagnostic tool with high analytical sensitivity and specificity at low cost.

Journal ArticleDOI
Xiong Liu1, Zhijun Ren1, Fangfei Liu1, Li Zhao1, Qiangjun Ling1, Haibin Gu1 
TL;DR: In this paper, a multifunctional dual network (DN) composite hydrogel was used as flexible strain sensors to detect different human motions to track the respiratory movement of a pig lung in vitro.
Abstract: Hydrogel-based flexible strain sensors have shown great potential in body movement tracking, early disease diagnosis, noninvasive treatment, electronic skins, and soft robotics. The good self-healing, biocompatible, sensitive and stretchable properties are the focus of hydrogel-based flexible strain sensors. Dual network (DN) hydrogels are hopeful to fabricate self-healing hydrogels with the above properties. Here, multifunctional DN hydrogels are prepared via a combination of host-guest interaction of β-cyclodextrin and ferrocene with dynamic borate ester bonds of poly(vinyl alcohol) and borax. Carbon nanotubes are used to endow the DN hydrogels with good conductivity. The obtained DN composite hydrogels possess good biocompatibility, stretchability (436%), fracture strength (41.0 KPa), self-healing property (healing efficiency of 95%), and high tensile strain sensitivity (gauge factor of 5.9). The DN composite hydrogels are used as flexible strain sensors to detect different human motions. After cutting, the healed hydrogels also can monitor human motions and have good stability. In addition, the hydrogel sensors may track the respiratory movement of a pig lung in vitro. This work exhibits new ideas and approaches to develop multifunctional self-healing hydrogels for constructing flexible strain sensors.

Journal ArticleDOI
TL;DR: In this article, an antifreezing, safe, and nontoxic gel electrolyte based on the polyvinyl alcohol (PVA)/Zn/ethylene glycol system was reported.
Abstract: Zn-ion energy storage devices employing hydrogel electrolytes are considered as promising candidates for flexible and wearable electronics applications. This is because of their safe nature, low cost, and good mechanical characteristics. However, conventional hydrogel electrolytes face limitation at subzero temperatures. Herein, we report an antifreezing, safe, and nontoxic gel electrolyte based on the poly(vinyl alcohol) (PVA)/Zn/ethylene glycol system. The optimal gel electrolyte membrane exhibits a high ionic conductivity (15.03 mS cm-1 at room temperature) and promising antifreezing performance (9.05 mS cm-1 at -20 °C and 3.53 mS cm-1 at -40 °C). Moreover, the antifreezing gel electrolyte can suppress the growth of Zn dendrites to display a uniform Zn plating/stripping behavior. Also, a flexible antifreezing Zn-ion hybrid supercapacitor fabricated with the optimum antifreezing gel electrolyte membrane exhibits excellent electrochemical properties. The supercapacitor possesses a high specific capacity of 247.7 F g-1 at room temperature under a high working voltage of 2 V. It also displays an outstanding cyclic stability at room temperature. Moreover, the supercapacitor shows an extraordinary electrochemical behavior and cyclic stability over up to 30 000 cycles at -20 °C under a current load of 5 A g-1, demonstrating its outstanding low-temperature electrochemical performance. Besides, the antifreezing supercapacitor device also offers high flexibility under different deformation conditions. Therefore, it is believed that this work provides a simplistic method of realizing the application of flexible antifreezing Zn-ion energy storage devices in a subzero-temperature environment.

Journal ArticleDOI
TL;DR: In this article, an efficient approach is demonstrated to fabricate conductive and lightweight Ti3C2Tx carbon nanotube anisotropic aerogels (MCAs) with superelasticity and high thermal insulation.
Abstract: Although hydrophilic and electrically conductive transition-metal carbon/nitride (MXenes) nanosheets hold great promise for electrically conductive and electromagnetic interference (EMI) shielding applications, the weak interaction among MXene nanosheets makes them difficult to form compressible three-dimensional architectures with high conductivity. Herein, inspired by the plant "Parthenocissus tricuspidata", an efficient approach is demonstrated to fabricate conductive and lightweight Ti3C2Tx MXene/acidified carbon nanotube anisotropic aerogels (MCAs) with superelasticity and high thermal insulation. The MXene nanosheets construct the anisotropic and porous skeleton, while the acidified carbon nanotubes reinforce the pore walls of MXene nanosheets, making the MCAs superelastic and compressible. The superelastic MCA with only 5 wt % of the acidified carbon nanotubes is structurally stable during cyclic compressions at both high and ultralow temperatures. Its high conductivity (447.2 S m-1) and ultralow density (9.1 mg cm-3) endow its paraffin composite with a high EMI shielding efficiency of ∼51 dB at an ultralow filler content of 0.3 vol %. When the density of MCA increases to 18.2 mg cm-3, its EMI shielding effectiveness reaches 90 dB. Additionally, the porous and ultralight MCAs exhibit better thermal insulation performances as compared to commercial melamine and polystyrene foams. Therefore, the superelastic, electrically conductive, lightweight, and thermally insulating MCAs would be promising for EMI shielding applications in space equipment and portable wearable devices.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the potential of using multifunctional electrospun poly(methyl methacrylate) (PMMA) nanofibers decorated with ZnO nanorods and Ag nanoparticles in protective mats.
Abstract: The COVID-19 pandemic has clearly shown the importance of developments in fabrication of advanced protective equipment. This study investigates the potential of using multifunctional electrospun poly(methyl methacrylate) (PMMA) nanofibers decorated with ZnO nanorods and Ag nanoparticles (PMMA/ZnO-Ag NFs) in protective mats. Herein, the PMMA/ZnO-Ag NFs with an average diameter of 450 nm were simply prepared on a nonwoven fabric by directly electrospinning from solutions containing PMMA, ZnO nanorods, and Ag nanoparticles. The novel material showed high performance with four functionalities (i) antibacterial agent for killing of Gram-negative and Gram-positive bacteria, (ii) antiviral agent for inhibition of corona and influenza viruses, (iii) photocatalyst for degradation of organic pollutants, enabling a self-cleaning protective mat, and (iv) reusable surface-enhanced Raman scattering substrate for quantitative analysis of trace pollutants on the nanofiber. This multi-functional material has high potential for use in protective clothing applications by providing passive and active protection pathways together with sensing capabilities.

Journal ArticleDOI
TL;DR: In this article, a triple-scale micro/nanostructured super-hydrophobic surface with both excellent anti-icing and icephobic properties has been designed via a hybrid method, combining ultrafast laser ablation and chemical oxidation.
Abstract: Passive anti-icing or icephobic superhydrophobic surfaces have attracted great interest due to their potential multifaceted implications for the prevention and/or easy removal of undesired ice in many applications. However, a superhydrophobic surface with both excellent anti-icing and icephobic performances has rarely been reported due to difficulties in sustaining a good Cassie state stability. This is the case especially under high humidity and freezing environment conditions. In the present study, a new triple-scale micro/nanostructured superhydrophobic surface with both excellent anti-icing and icephobic properties has been designed via a hybrid method, combining ultrafast laser ablation and chemical oxidation. The novel surface structure is composed of periodical microcone arrays covered with densely grown nanograsses and dispersedly distributed microflowers. This surface exhibits an excellent Cassie state stability with its critical Laplace pressure reaching up to 1450 Pa, which is essential for good anti-icing and icephobic performances. The anti-icing feature of the prepared superhydrophobic surface is achieved by a rapid rolling-off of the impacting droplets. Moreover, an excellent resistance to the impact of high humidity has been achieved via hierarchical condensation, coalescence-induced jumping, and upward moving. A good delay of the heterogeneous nucleation at the solid-liquid interface under freezing condition has been registered as well, due to the presence of stable air pockets within the surface structures. In addition, the ice adhesion strength of the prepared superhydrophobic surface can be as low as 1.7 kPa, which is the lowest value when compared with the state-of-the-art superhydrophobic surfaces. Such a low ice adhesion strength allows the ice to be easily removed by its own weight and demonstrates an excellent icephobic performance. The repeated icing-deicing tests indicate a decent deicing robustness of the synthesized superhydrophobic surface. Thus, this triple-scale superhydrophobic surface exhibits a good anti-icing and icephobic performance with an excellent Cassie state stability, high humidity resistance, and good deicing durability. We hypothesize that the proposed fabrication strategy and associated basic findings will shed new light on the design of robust ice-resistant superhydrophobic surfaces and contribute to a better understanding of the relationship between superhydrophobicity and ice resistance.

Journal ArticleDOI
TL;DR: Aqueous zinc-ion batteries (ZIBs) are considered as a promising energy storage system due to their low cost and high safety merits as mentioned in this paper, however, they suffer from the challenge of uncontrollable dendrit.
Abstract: Aqueous zinc-ion batteries (ZIBs) are considered as a promising energy storage system due to their low cost and high safety merits. However, they suffer from the challenge of uncontrollable dendrit...

Journal ArticleDOI
TL;DR: A review of the recent progress in the development of TMP HER electrocatalysts is presented in this paper, focusing on the strategies that have been recently explored to tune the activity in acidic, neutral, and basic media.
Abstract: Hydrogen is a fuel with a potentially zero-carbon footprint viewed as a viable alternative to fossil fuels. It can be produced in a large scale via electrochemical water splitting using electricity derived from renewable sources, but this would require highly active, inexpensive, and stable hydrogen evolution reaction (HER) catalysts to replace the Pt benchmark. Transition-metal phosphides (TMPs) are potential Pt replacements owing to their generally high activity as well as versatility as HER catalysts for different pH media. This review summarizes the recent progress in the development of TMP HER electrocatalysts, focusing on the strategies that have been recently explored to tune the activity in acidic, neutral, and basic media. These strategies are the doping of TMPs with metal and nonmetal elements, fabrication of multimetallic phosphide phases, and construction of multicomponent heterostructures comprising TMPs and another component such as a different TMP or a metal oxide/hydroxide. The synthetic methods utilized to design the catalysts are also presented. Finally, the challenges still remaining and future research directions are discussed.

Journal ArticleDOI
TL;DR: In this paper, the recent targeting strategies of different organelles and the corresponding design principles of molecular and nanostructured photosensitizers are summarized and discussed, and the current challenges and opportunities in organelle-targeted photodynamic therapy (PDT) are also presented.
Abstract: Subcellular organelles are the cornerstones of cells, and destroying them will cause cell dysfunction and even death. Therefore, realizing precise organelle targeting of photosensitizers (PSs) can help reduce PS dosage, minimize side effects, avoid drug resistance, and enhance therapeutic efficacy in photodynamic therapy (PDT). Organelle-targeted PSs provide a new paradigm for the construction of the next generation of PSs and may provide implementable strategies for future precision medicine. In this Review, the recent targeting strategies of different organelles and the corresponding design principles of molecular and nanostructured PSs are summarized and discussed. The current challenges and opportunities in organelle-targeted PDT are also presented.

Journal ArticleDOI
TL;DR: In this paper, a bio-inspired hydrogel with multiple conductive capabilities was designed by incorporating carbon nanotubes into a chelate of calcium ions with polyacrylic acid and sodium alginate.
Abstract: Bioinspired hydrogels have promising prospects in applications such as wearable devices, human health monitoring equipment, and soft robots due to their multifunctional sensing properties resembling natural skin. However, the preparation of intelligent hydrogels that provide feedback on multiple electronic signals simultaneously, such as human skin receptors, when stimulated by external contact pressure remains a substantial challenge. In this study, we designed a bioinspired hydrogel with multiple conductive capabilities by incorporating carbon nanotubes into a chelate of calcium ions with polyacrylic acid and sodium alginate. The bioinspired hydrogel consolidates self-healing ability, stretchability, 3D printability, and multiple conductivities. It can be fabricated as an integrated strain sensor with simultaneous piezoresistive and piezocapacitive performances, exhibiting sensitive (gauge factor of 6.29 in resistance mode and 1.25 kPa-1 in capacitance mode) responses to subtle pressure changes in the human body, such as finger flexion, knee flexion, and respiration. Furthermore, the bioinspired strain sensor sensitively and discriminatively recognizes the signatures written on it. Hence, we expect our ideas to provide inspiration for studies exploring the use of advanced hydrogels in multifunctional skin-like smart wearable devices.

Journal ArticleDOI
TL;DR: Li et al. as discussed by the authors designed a stretchable and transparent temperature sensor based on a novel thin-film sandwich structure (TFSS), which display unprecedented thermal sensitivity (24.54%/°C), fast response time (0.19 s) and recovery time ( 0.08 s), a broad detection range (from -28 to 95.8 °C), and high stability.
Abstract: Conductive hydrogels can be used in wearable electronics integrated with skin, but the bulk structure of existing hydrogel-based temperature sensors limits the wearing comfort, response/recovery speeds, and sensitivity. Here, stretchable and transparent temperature sensors based on a novel thin-film sandwich structure (TFSS) are designed, which display unprecedented thermal sensitivity (24.54%/°C), fast response time (0.19 s) and recovery time (0.08 s), a broad detection range (from -28 to 95.3 °C), high resolution (0.8 °C), and high stability. The thin hydrogel layer (12.15 μm) is encapsulated by two thin elastomer layers, which prevent the water evaporation and enhance the heat transfer, leading to the boosted stability and accelerated response/recovery speeds. The nondrying and antifreezing capabilities are further promoted by the hydratable lithium bromide (LiBr) incorporated in the hydrogel, enabling it to avoid dehydration in an extremely arid environment and freeze below subzero temperatures (freezing point below -120 °C). A comparative study reveals that the thermal sensitivity displayed by the TFSS sensor in capacitance mode is several times higher than that in conventional conductance/resistance mode above room temperature. Importantly, a new mechanism based on a horizontal plate capacitance model is proposed to understand the high sensitivity by considering the permittivity and geometry variations of TFSS. The thin TFSS, stretchability and transparency enable the sensor to be conformally and comfortably attached to human skin for real-time and reliable monitoring of various human motions, physical states, skin temperature, etc., without affecting the appearance.

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TL;DR: In this paper, an ultrasmall copper phosphosulfide (us-Cu3P|S) nanocrystals anchored on 2D g-C3N4 nanosheets were used for photocatalytic CO2 reduction.
Abstract: Transition metal phosphosulfides (TMPSs) have gained much interest due to their highly enhanced photocatalytic activities compared to their corresponding phosphides and sulfides. However, the application of TMPSs on photocatalytic CO2 reduction remains a challenge due to their inappropriate band positions and rapid recombination of photogenerated electron-hole pairs. Herein, we report ultrasmall copper phosphosulfide (us-Cu3P|S) nanocrystals anchored on 2D g-C3N4 nanosheets. Systematic studies on the interaction between us-Cu3P|S and g-C3N4 indicate the formation of an S-scheme heterojunction via interfacial P-N chemical bonds, which acts as an electron transfer channel and facilitates the separation and migration of photogenerated charge carriers. Upon the composite formation, the band structures of us-Cu3P|S and g-C3N4 are altered to enable the enhanced photocatalytic CO generation rate of 137 μmol g-1 h-1, which is eight times higher than that of pristine g-C3N4. The unique phosphosulfide structure is also beneficial for the enhanced electron transfer rate and provides abundant active sites. This first application of Cu3P|S to photocatalytic CO2 reduction marks an important step toward the development of TMPSs for photocatalytic applications.

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TL;DR: This work develops a multimaterial printing technology for the complex structural integration of MSMs and M-SMPs to explore their enhanced multimodal shape transformation and tunable properties and demonstrates multiple deformation modes with distinct shape configurations that further enable active metamaterials with tunable physical properties such as sign-change Poisson's ratio.
Abstract: Magnetic soft materials (MSMs) have shown potential in soft robotics, actuators, metamaterials, and biomedical devices because they are capable of untethered, fast, and reversible shape reconfigurations as well as controllable dynamic motions under applied magnetic fields. Recently, magnetic shape memory polymers (M-SMPs) that incorporate hard magnetic particles in shape memory polymers demonstrated superior shape manipulation performance by realizing reprogrammable, untethered, fast, and reversible shape transformation and shape locking in one material system. In this work, we develop a multimaterial printing technology for the complex structural integration of MSMs and M-SMPs to explore their enhanced multimodal shape transformation and tunable properties. By cooperative thermal and magnetic actuation, we demonstrate multiple deformation modes with distinct shape configurations, which further enable active metamaterials with tunable physical properties such as sign-change Poisson's ratio. Because of the multiphysics response of the M-MSP/MSM metamaterials, one distinct feature is their capability of shifting between various global mechanical behaviors such as expansion, contraction, shear, and bending. We anticipate that the multimaterial printing technique opens new avenues for the fabrication of multifunctional magnetic materials.

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Zhen Chen1, Jing Liu1, Yujie Chen1, Xu Zheng1, Hezhou Liu1, Hua Li1 
TL;DR: In this paper, a multistimulus-responsive and multifunctional hydrogel system (carboxymethyl cellulose/poly acrylic-acrylamide) with good elasticity, superior flexibility, and stable conductivity was prepared.
Abstract: Stimulus-responsive hydrogels, such as conductive hydrogels and thermoresponsive hydrogels, have been explored extensively and are considered promising candidates for smart materials such as wearable devices and artificial muscles. However, most of the existing studies on stimulus-responsive hydrogels have mainly focused on their single stimulus-responsive property and have not explored multistimulus-responsive or multifunction properties. Although some works involved multifunctionality, the prepared hydrogels were incompatible. In this work, a multistimulus-responsive and multifunctional hydrogel system (carboxymethyl cellulose/poly acrylic-acrylamide) with good elasticity, superior flexibility, and stable conductivity was prepared. The prepared hydrogel not only showed excellent human motion detection and physiological signal response but also possessed the ability to respond to environmental temperature changes. By integrating a conductive hydrogel with a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel to form a bilayer hydrogel, the prepared bilayer also functioned as two kinds of actuators owing to the different degrees of swelling and shrinking under different thermal stimuli. Furthermore, the different thermochromic properties of each layer in the bilayer hydrogel endowed the hydrogel with a thermoresponsive "smart" feature, the ability to display and conceal information. Therefore, the prepared hydrogel system has excellent prospects as a smart material in different applications, such as ionic skin, smart info-window, and soft robotics.

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TL;DR: In this article, hollow porphyrinic metal-organic framework (H-PMOF) nanoparticles with a mesoporous spherical shell have been fabricated via a facile self-sacrificial ZIF-8 nanoparticle template strategy.
Abstract: Hollow nanostructures have attracted significant research interest in drug delivery systems due to their high capacities for drug loading and unique physicochemical properties, showing great potential in specific biomedical applications. Herein, hollow porphyrinic metal-organic framework (H-PMOF) nanoparticles with a mesoporous spherical shell have been fabricated via a facile self-sacrificial ZIF-8 nanoparticle template strategy. The H-PMOF nanoplatform not only demonstrates a greatly enhanced photodynamic therapy efficacy compared with nonhollow porphyrinic MOF nanoparticles but also can be used as a superior drug carrier to co-load doxorubicin (DOX) and indocyanine green (ICG) with an ultrahigh drug-loading capacity of 635%. Furthermore, cancer cell membrane camouflage of the (DOX and ICG)@H-PMOF composite nanoparticles affords a biomimetic nanoplatform, that is, (DOX and ICG)@H-PMOF@mem (DIHPm for short), with an outstanding homologous tumor-targeting and immune-escaping ability. Interestingly, DIHPm shows both pH-controlled and near-infrared laser-triggered DOX release. Both in vitro and in vivo studies of DIHPm demonstrate an excellent imaging-guided synergistic photodynamic/photothermal/chemotherapy anticancer activity with negligible systemic toxicity. The development of the high-performance H-PMOF nanoplatform provides new insights into the design of MOF-based multifunctional nanomedicines for combination cancer therapy and precise theranostics.