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Fertiliser has been a vital part of agriculture due to it boosting crop productivity and preventing starvation throughout the world. Despite this huge contribution, the application of nitrogen (N) fertilisers results in N leaching and the formation of greenhouse gases, which threaten the environment and human health. To minimise the impacts, slow/controlled release fertilisers (S/CRFs) have been being developed since the beginning of the 20th century. Despite the efforts made over a century, the basic terminological and classification information of these fertilisers remains vague. The scientific knowledge published in S/CRF patents has also been overlooked since the beginning. This review focused on the information gaps, clarified the definitions, differentiation and classification methods that have been randomly used in previous literature. The objectives, formulations and technologies of 109 controlled release urea patents involving sulphur coated urea, polymer coated urea and urea matrix fertilisers published in the years since these products emerged were also reviewed to 1) highlight the overlooked scientific knowledge in the patents; 2) understand the evolutionary processes and current research states of the products; 3) clarify research preferences and challenges to date; 4) identify remaining gaps for the future direction. It is expected that the organised basic information and the patent knowledge highlighted in this paper can be new resources and foster the development of S/CRFs in the future.

Enzyme-linked immunosorbent assays (ELISA), as one of the most used immunoassays, have been conducted ubiquitously in hospitals, research laboratories, etc. However, the conventional ELISA procedure is usually laborious, occupies bulky instruments, consumes lengthy operation time, and relies considerably on the skills of technicians, and such limitations call for innovations to develop a fully automated ELISA platform. In this paper, we have presented a system incorporating a robotic-microfluidic interface (RoMI) and a modular hybrid microfluidic chip that embeds a highly sensitive nanofibrous membrane, referred to as Robotic ELISA, to achieve human-free sample-to-answer ELISA tests in a fully programmable and automated manner. It carries out multiple bioanalytical procedures to replace the manual steps involved in classic ELISA operations, including the pneumatically driven high-precision pipetting, efficient mixing and enrichment enabled by back-and-forth flows, washing, as well as integrated machine vision for colorimetric readout. The Robotic ELISA platform has achieved a low limit of detection (LOD) of 0.1 ng/mL in the detection of a low sample volume (15 μL) of chloramphenicol (CAP) within 20 min without human intervention, which is significantly faster than that of the conventional ELISA procedure. Benefiting from its modular design and automated operations, the Robotic ELISA platform has great potential to be deployed for a broad range of detections in various resource-limited settings or high-risk environments, where human involvement needs to be minimized, while the testing timeliness, consistency and sensitivity are all desired.

An ultrasensitive and portable colorimetric enzyme-linked immunosorbent assay (ELISA) sensor for antibiotics was fabricated by immobilizing antibodies inside the largely porous and highly hydrophilic nanofibrous membranes. Different from regular electrospun nanofibrous membranes where antibodies may frequently be blocked by the heterogeneous porous structure and sterically crowded loaded on the surface, the controlled microporous structure and increased hydrophilicity of nanofibrous membranes could improve the diffusion properties of antibodies, reduce the sterically crowding effect, and dramatically improve the sensitivity of the membrane-based ELISA. The limitation of detection (LOD) for chloramphenicol (CAP) reached 0.005 ng/mL, around 200 times lower than the conventional paper-based ELISA, making quantitative analysis and portable on-site detection achievable via the use of smartphones. The successful design and fabrication of the nanofibrous membrane-based ELISA with novel features overcome the structural drawbacks of regular electrospun nanofibrous membranes and provide new paths to develop highly sensitive on-site detection of hazardous chemical agents.

Hydroxyl radical is the main reactive species in hydrogen peroxide (H2O2) bleaching of cotton fabrics. Ultraviolet (UV) irradiation of the H2O2 bleaching system can efficiently produce hydroxyl radicals (HO·) under neutral or alkaline conditions, which were proven experimentally and theoretically by computational modeling. Various UV/H2O2 bleaching routes were screened to obtain desired whiteness index and acceptable bursting strength of the bleached fabrics. The optimal properties of the bleached cotton knitted fabric could be obtained at UV irradiation of 312 nm on the fabrics with a hydrogen peroxide solution under alkaline conditions.

Real-life wearable electronics with long-term stable sensing performance are of significant practical interest to public. Wearable pressure sensors with washable, comfortable, breathable, and stable sensing ability are a key requirement to meet the desire. However, effects of ubiquitous ambient moisture and intrinsic defects of current capacitive sensing materials are two factors leading to unstable sensing performance of current pressure sensors. Existing ionic liquid-based materials (i.e., ionic hydrogel, ionic film, or ionic/elastomers composite) have been used for efficient capacitive pressure sensing but are highly sensitive and especially affected by moisture. In this work, we introduce a washable capacitive pressure-sensing textile based on the use of a hydrophobic poly(ionic liquid) nanofibrous membrane (PILNM) with good mechanical properties and satisfactory moisture proof sensing performance. The PILNM membranes possessing rich ions and microporous structures are novel ideal polymeric dielectric materials for amplification of signals with negligible stimulations. Moreover, the PILNMs exhibit very high stable sensing signals under moisture interference (up to 70% relative humidity) and repeated washings (more than 10 washings), especially suitable for wearable electronics. Notably, the PILNM-based wearable pressure-sensing textiles offer high sensitivity for low pressure and bent chord length changes with a low-pressure detection limit even under harsh deformations. Owing to the superior performance, the PILNM-based wearable pressure-sensing textiles are comfortable to wear and suitable for monitoring different human motions and pulse vibrations at various body positions. Meanwhile, the assembled multiple wearable pressure-sensing array can spatially map the contact area of the pressure stimuli and synchronously reflect finger movements.

In this manuscript, a computerized systematic analysis system for identifying and selecting fluorescent dyes suitable for textile dyeing applications is discussed. Five representative fluorescent dyes are recommended for textile applications based on the overall evaluations. The analytical system includes rating fluorescent dyes based on their quantum yields, computational modeling of their structural features, estimation of their aquatic environmental toxicity, and calculation of their affinity to fibers. This system could significantly reduce and prevent negative consequences of applying fluorescent chemicals in textiles and consumer products.

Acupoint catgut embedding therapy (ACET) has become the most promising method for treatment of juvenile pseudomyopia due to its advantages of lasting effect, high efficiency, safety and no side effects. However, poor hydrophilicity and biocompatibility are the main disadvantages, preventing ACET materials from having wide applications. This work fabricated four types of polylactic acid (PLA) and polyglycolic acid (PGA) monofilaments from their polymer chips, and then the prepared monofilaments were treated ultrasonically by dipping them in a mixed solution composed of ethyl alcohol and H2O2(volume ratio 1:1) at 250 W ultrasonic power for 30 min. Afterwards, the PLA and PGA groups were fully characterized with respect to structure characterizations, mechanical properties and in vitro properties. The results showed that the surface roughness of the monofilaments had been greatly enhanced by ultrasonic modification. The PLA groups’ molecular structures changed little, while those of the PGA group emerged with some polar hydrophilic bonds. By deionized water measurement of contact angle values, the ultrasound modified PLA monofilaments (UMPLA1 = 87.2 ± 2.5°, UMPLA2 = 83.6 ± 3.5°) presented a decrease compared to that of untreated PLA ones (PLA1 =103.5 ± 3.4°, PLA2 = 108.4 ± 1.2°), while that of ultrasound modified PGA monofilaments (UMPGA1 = 75.6 ± 4.3°, UMPGA2 =70.5 ± 3.1°) was smaller than untreated PGA ones (PGA1 = 97.3 ± 1.7°, PGA2 = 95.8 ± 2.6°). Based on the measurement of the mechanical properties, the tensile properties and bending stiffness of the PLA and PGA groups changed little, and their swelling ratios were greatly improved after modification. All the prepared monofilaments presented non-toxicity with good cell viability (more than 75%), and samples UMPGA2 (81.4 ± 3.1%) and UMPLA2 (65.8 ± 0.8%) exhibited the largest cell attachment ratio values among their groups. In conclusion, these findings present important clinical implications regarding the ACET materials manufacturing process, which warrant further study.

Porous nanofibrous membranes have ultrahigh specific surface areas and could be broadly employed in protein purification, enzyme immobilization, and biosensors with enhanced selectivity, sensitivity, and efficiency. However, large biomolecules, such as proteins, have hindered diffusion behavior in the micro-porous media, significantly reducing the benefits provided by the nanofibrous membranes. The study of protein diffusion in polyacrylonitrile (PAN) nanofibrous membranes produced under varied humidity and polymer concentration of electrospinning revealed that heterogeneous structures of the nanofibrous membranes possess much smaller effective pore sizes than the measured pore sizes, which significantly affects the diffusion of large molecules through the system though sizes of proteins and pH conditions also have great impacts. Only when the measured membrane pore size is at least 1000 times higher than the protein size, the diffusion behavior of the protein is predictable in the system. The results provide insights into the design and applications of proper nanofibrous materials for improved applications in protein purification and immobilizations.

There is a critical need for new efficient solutions to purify and disinfect water from source to point-of-use, especially for the water contaminated by pathogenic microbes. Traditional disinfection technologies are chemically intensive and limited, either by biofouling or by the irreversible consumption of disinfectants. Herein, we present a scalable methodology to create biocidal and rechargeable nanofibrous membranes (BNF membranes) by combining

Polyglycolic acid (PGA) monofilament has been regarded as an excellent acupoint catgut embedding therapy (ACET) material because it offers numerous advantages, including easy accessibility and good forming and degradable properties. However, the poor hydrophilicity and cytocompatibility are the main disadvantages preventing it from having wider applications. In this communication, two types of PGA monofilaments were first fabricated from their polymer chips, followed by ultrasound/H2O2 combined surface modification at 1:1 (V/V), and different ultrasound frequencies (45, 60 and 75 KHz) were explored. The modified PGA monofilaments were fully characterized with respect to structure characterizations (surface morphology, weights and diameters, Fourier transform infrared spectroscopy (FT-IR) analysis and hydrophilicity), mechanical properties (tensile property, swelling behavior and flexibility) and in vitro properties (cytotoxicity, cell attachment and cell morphology). The results showed that the PGA monofilaments after modification would become coarser, with larger weights and diameters. Samples 1-PGA 75 and 2-PGA 75 exhibited the smallest contact angles at 70.51° ± 3.27° and 62.84° ± 2.53°, respectively. The FT-IR analysis results confirmed that some polar groups emerged, promoting the hydrophilicity of PGA monofilaments. The swelling behavior of monofilaments was enhanced, while tensile and bending stiffness values slightly decreased. All the prepared samples presented no toxicity, and the cell attachment ratio (cultured for 48 h) of PGA monofilaments had been greatly improved after modification. These findings present important clinical implications in the ACET materials manufacturing process and warrant further study to develop new PGA embedding materials with outstanding clinical efficacy.

An ultrasensitive label-free amperometric immunosensor for the detection of chloramphenicol (CAP) residues in milk has been developed by using a screen-printed carbon electrode laminated with a layer of poly (vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane that is covalently immobilized with a CAP antibody (anti-CAP). The performance of the PVA-co-PE nanofiber membrane (PVA-co-PE NFM) on the electrode was compared with a PVA-co-PE casted membrane (PVA-co-PE CM), necessary fabrication steps and performance of the sensors were investigated by electrochemical impedance spectroscopy (EIS). The application of the PVA-co-PE NFM decreased the electron-transfer-resistance by about 4 times compared with a conventional PVA-co-PE casted membrane. Under the optimal conditions, the established immunosensor exhibited high sensitivity for determination of CAP in a range 0.01–10 ng mL−1, with a limit of detection of 0.0047 ng mL−1. In addition to the good selectivity, reusability and stability over time, the prepared immunosensor was successfully used in the detection of CAP in milk samples without any pretreatment.

Enzyme-linked immunoassay (ELISA) is highly specific and selective towards target molecules and is convenient for on-site detection. However, in many cases, lack of high sensitivity makes it hard to reveal a significant colorimetric signal for detecting a trace amount of target molecules. Thus, analytical instruments are required for detection, which limits the application of ELISA for on-site detection. In the present study, a highly sensitive and naked-eyed detectable colorimetric biosensor for chloramphenicol (CAP) was prepared by incorporating ELISA onto surfaces of microporous and nanofibrous membranes. The high specific surface areas of the nanofibers significantly increased the number of antibodies covalently linked onto the fiber surfaces and binding capacity of the sensor with antigens present in a sample. With such an integration, the sensitivity of the ELISA sensor was dramatically increased, and a trace number of targets could reveal a naked-eye detectable color. The immunoassay sensor exhibited a significant naked-eye distinguishable color to chloramphenicol (CAP) at 0.3ng/mL. The successful design and fabrication of the nanofibrous membrane immunoassay sensor provide new paths towards the development of on-site inspection sensors without the assistance from any instrument.

Fabricating adsorptive materials for fast and high efficient adsorption of enzymes is critical to match the great demands for separation and recovery of enzymes used as biocatalysts. However, it has proven extremely challenging. Here, we report a cost-effective strategy to construct the sulfated group surface-functionalized silk fibroin nanofibrous membranes (SS-SFNM) under mild conditions for positively charged Candida rugosa lipase adsorption. The naturally abundant silk is thus reconstructed into nanofibrous membranes with tunable surface functions. Thereby, the resultant SS-SFNM exhibited excellent adsorption performance towards lipase, including a superior adsorption capacity of 148 mg g−1, fast adsorption equilibrium within 3 h and good reversibility. The fabrication of such fascinating silk-based materials may provide new chance into the design and development of multi-functional membranes for various separated applications.

Enzyme-immobilized nanoparticles that are both catalysis effective and recyclable would have wide applications ranging from bioengineering and food industry to environmental fields; however, creating such materials has proven extremely challenging. Herein, we present a scalable methodology to create Candida rugosa lipase-immobilized magnetic nanoparticles (L-MNPs) by the combination of nonionic reverse micelle method and Fe3O4 nanoparticles. Our approach causes the naturally abundant and sustainable Candida rugose lipase to ordered-assemble into nanoparticles with high catalytic activity and durability. The resultant L-MNPs exhibit the integrated properties of high porosity, large surface area, fractal dimension, robust enzymatic activity, good durability, and high magnetic saturation (59 emu g−1), which can effectively catalyze pentyl valerate esterification and be easily separated by an external magnet in 60 second. The fabrication of such fascinating L-MNPs may provide new insights for developing functional enzyme-immobilized materials towards various applications.

There is a critical need for new efficient solutions to purify and disinfect water from source to point-of-use, especially for the water contaminated by pathogenic microbes. Traditional disinfection technologies are chemically intensive and limited, either by biofouling or by the irreversible consumption of disinfectants. Herein, we present a scalable methodology to create biocidal and rechargeable nanofibrous membranes (BNF membranes) by combining N-halamine antimicrobial agent with electrospun nanofibers. Our method allows intrinsically rechargeable N-halamine moieties to covalently incorporate into nanofibers with high biocidal activity and durability. The resulting BNF membranes exhibit integrated properties of high porosity, large surface area, robust mechanical strength, super hydrophilicity, rechargeable chlorination capability (>3000 ppm), and high bactericidal efficacy (99.9999% contact-killing), which enabled the BNF membranes effectively disinfect bacteria-contained water by direct filtration, ...

In recent years, fluorescent carbon dots have attracted great attention due to their good luminescence and low toxicity. Here, blue fluorescent core-shell structured carbon polymer dots (CPDs) with high stability under a wide range of pH values, long storage time and excellent fluorescence in various solvents and even in solid state were prepared by hydrothermal synthesis of dendritic tris(2-aminoethyl)amine (TAEA) and citric acid. The CPDs core structure provides strong fluorescent luminescence, a shell structure of the core possesses high amount of dendritic primary amino groups connected by ethylene groups to the core. This unique structure prevents aggregation of the cores and self-quenching effect of CPDs. As a result, the CPDs have high fluorescence in both aqueous and hydrophobic solutions and even as pure solid-state powder. In addition, the CPDs are also insensitive to pH of solutions, and the fluorescence intensity of the solution was stable in the pH range of 4-14. The CPDs embedded polymer films and fibers revealed excellent fluorescent properties.

5-(Carbonyloxy succinic)-benzene-1,2,4-tricarboxylic acid (BSTA) was synthesized and applied as an effective cross-linking agent for cotton fabrics. In this study, BSTA was analyzed and compared with two other extensively investigated poly(carboxylic acid)s, 1,2,3,4-butanetetracarboxylic acid (BTCA) and 3,3′4,4′- benzophenone tetracarboxylic acid (BPTCA), in cross-linking cellulose. Possessing both aromatic and aliphatic carboxylic acid groups and respective properties, BSTA can cross-link cellulose as efficiently as BTCA without causing significant loss of tensile strength of the products. In addition, BSTA exhibits better hydrophilicity and higher affinity to cellulose than the aromatic acid. BSTA is able to produce anhydride under high temperature but it is not a rate-determining step in the esterification process. The kinetic data of BTCA, BPTCA, and BSTA with cellulose were calculated by measuring the concentrations of the carboxylic acids on the fabric, showing an order of BPTCA< BSTA< BTCA in react...

Poly (vinyl alcohol-co-ethylene) nanofibrous membranes (PVA-co-PE NFM) were successfully modified by sodium-3-sulfobenzoate to become negatively charged with sulfonate groups, and the sulfonated (PVA-co-PE) nanofiber membrane SS (PVA-co-PE NFM) was used in non-covalent adsorption of cellulases via electrostatic attraction. The modified NFM showed excellent adsorption to the enzyme molecules due to the incorporated static charge interaction with the fibers, high open-porosity and ultrahigh surface areas of the nanofibers. Such unique morphology and chemical structures lead to the adsorption capacity of 130 mg g−1 and reusability for 5 cycles without significant change in catalytic functions. The morphology changes of the nanofibrous membranes were observed by using a scanning electron microscopy, and chemical structures of the membranes were characterized by using FTIR and water contact angle measurements. SS (PVA-co-PE NFM) is a promising solid support media for enzyme immobilization, and the immobilized enzymes can be applied in industrial applications.

Aromatic polycarboxylic acids can directly react with cellulose to form ester cross-linking structures and provide wrinkle resistance functions to cotton fabrics, different from aliphatic polycarboxylic acids, which will form anhydrides as intermediates. Sodium hypophosphite is a catalyst proven effective in the reactions of both acids. In order to find alternative catalysts, the mechanism of the direct esterification and the role of the catalyst in the reaction were investigated in this study. Several sodium salts of phosphorous acid and dichloroacetic acid with varied pKa values were employed in the treatment of cotton fabric with 3,3′,4,4′-benzophenone tetracarboxylic acid (BPTCA). The results confirmed that the overall reaction follows the Fischer esterification mechanism, an acid catalyzed reaction. The acid anions also play an important role in the reaction. Results of wrinkle recovery angles, FTIR band ratios of ester bonds, and thermogravimetric analyses of the treated fabrics consistently support...

1,2,3,4-Butanetetracarboxylic acid (BTCA) can efficiently esterify cellulose with pyrophosphoric acid (PPA) as a catalyst to remove protons of reaction intermediates. However, valence and relative concentration ratio (RCR) of catalyst anions correlating to pH of finishing bath played a critical role in the reactions. Results here indicated that wrinkle recovery angle, tensile strength retention and ester absorbance of fabrics treated at pH of 2.8 showed higher values. It was a competing reaction for BTCA molecules to esterify or depolymerize cellulose. Importantly, divalent PPA anions were more efficient than monovalent ones in catalyzing the esterification between anhydrides and cellulose, which was confirmed by FTIR results and two-dimensional correlation spectroscopy analyses and by the RCRs of PPA anions and their changing rates versus pH. Furthermore, the higher catalytic efficiency of divalent anions was proved by the selected model catalysts. Meaningfully, the fabrics treated at pH≤3.2 presented good durability.

In this study, polyanionic alginate gel beads crosslinked by Ca2 + and glutaraldehyde have demonstrated a strong electrostatic interaction with specific proteins. Due to the naturally abundant carboxyl groups, the prepared alginate gel beads exhibited a relatively superior integrated adsorption performance toward lysozyme, including a superior adsorption capacity of 213 mg g− 1, fast adsorption equilibrium within 12 h, good selectivity, and good reversibility. Compared with other protein adsorbents, the as-prepared adsorptive beads have the advantages of excellent adsorption performance, easy to prepare, convenient, efficient, reliable and environment-friendly to apply, which can serve as a more sustainable material in protein separation and purification.

Antimicrobial polymeric films that are both mechanically robust and function renewable would have broad technological implications for areas ranging from medical safety and bioengineering to foods industry; however, creating such materials has proven extremely challenging. Here, a novel strategy is reported to create high-strength N-halamine incorporated poly(vinyl alcohol-co-ethylene) films (HAF films) with renewable antimicrobial activity by combining melt radical graft polymerization and reactive extrusion technique. The approach allows here the intrinsically rechargeable N-halamine moieties to be covalently incorporated into polymeric films with high biocidal activity and durability. The resulting HAF films exhibit integrated properties of robust mechanical strength, high transparency, rechargeable chlorination capability (>300 ppm), and long-term durability, which can effectively offer 3–5 logs CFU reduction against typical pathogenic bacterium Escherichia coli within a short contact time of 1 h, even at high organism conditions. The successful synthesis of HAF films also provides a versatile platform for exploring the applications of antimicrobial N-halamine moieties in a self-supporting, structurally adaptive, and function renewable form.

1,2,3,4-Butanetetracarboxylic acid (BTCA) imparts good anti-wrinkle property to cotton fabrics and results in significant strength loss due to cross-linking and acid degradation of cellulose simultaneously. However, benzophenone-3,3',4,4'- tetracarboxylic acid (BPTCA), an aromatic acid, crosslinks cellulose effectively but causes less strength loss to the products under similar conditions. The difference in damages to cellulose fibers was analyzed by using diffusibility and corresponding affinity of the acids to cellulose fibers, which were estimated by their molecular sizes and Hansen solubility parameters (HSP). Both experimental results and theoretical speculations revealed consistent agreement, indicating that smaller acid molecules could diffuse into cellulose fiber more rapidly and deeply, resulting in more acid degradation. Besides, the aliphatic acid such as BTCA has higher molecular affinity than BPTCA to cellulose, causing additional more degradation of cellulose. Both factors are potential reasons of the observed more severe tensile strength loss of the BTCA treated cotton fabrics.