Thermo-assisted fabrication of a novel shape-memory hyaluronic acid sponge for non-compressible hemorrhage control.

Hyaluronic acid (HA), a major component of skin extracellular matrix, provides an excellent framework for hemostatic design; however, there still lacks HA materials tailored with superior mechanical properties to address non-compressible hemorrhages. Here, we present a solvent-free thermal approach for constructing a shape-memory HA sponge for this application. Following facile thermal incubation around 130 °C, HA underwent cross-linking via esterification with poly(acrylic acid) within the sponge pre-shaped through a prior freeze-drying process. The resulting sponge system exhibited extensively interconnected macropores with a high fluid absorption capacity, excellent shape-memory property, and robust mechanical elasticity. When introduced to whole blood in vitro, the HA sponges demonstrated remarkable hemostatic properties, yielding a shorter coagulation time and lower blood clotting index compared to the commercial gelatin sponge (GS). Furthermore, in vivo hemostatic studies involving two non-compressible hemorrhage models (rat liver volume defect injury or femoral artery injury) achieved a significant reduction of approximately 64% (or 56%) and 73% (or 70%) in bleeding time and blood loss, respectively, which also outperformed GS. Additionally, comprehensive in vitro and in vivo evaluations suggested the good biocompatibility and biodegradability of HA sponges. This study highlights the substantial potential for utilizing the designed HA sponges in massive bleeding management.

Fullerenol as a nano-molecular sieve additive enables stable zinc metal anodes.

Aqueous zinc batteries (AZBs) with the advantages of safety, low cost, and sustainability are promising candidates for large-scale energy storage devices. However, the issues of interface side reactions and dendrite growth at the zinc metal anode (ZMA) significantly harm the cycling lifespan of AZBs. In this study, we designed a nano-molecular sieve additive, fullerenol (C60(OH)n), which possesses a surface rich in hydroxyl groups that can be uniformly dispersed in the aqueous solution, and captures free water in the electrolyte, thereby suppressing the occurrence of interfacial corrosion. Besides, fullerenol can be further reduced to fullerene (C60) on the surface of ZMA, holding a unique self-smoothing effect that can inhibit the growth of dendritic Zn. With the synergistic action of these two effects, the fullerenol-contained electrolyte (FE) enables dendrite-free ZMAs. The Zn-Ti half-cell using FE exhibits stable cycling over 2500 times at 5 mA cm-2 with an average Coulombic efficiency as high as 99.8 %. Additionally, the Zn-NaV3O8 cell using this electrolyte displays a capacity retention rate of 100 % after 1000 cycles at -20 °C. This work provides important insights into the molecular design of multifunctional electrolyte additives.

Chitosan thermogelation and cascade mineralization via sequential CaCO3 incorporations for wound care.

Physically crosslinked hydrogels have shown great potential as excellent and eco-friendly matrices for wound management. Herein, we demonstrate the development of a thermosensitive chitosan hydrogel system using CaCO3 as a gelling agent, followed by CaCO3 mineralization to fine-tune its properties. The chitosan hydrogel effectively gelled at 37 °C and above after an incubation period of at least 2 h, facilitated by the CaCO3-mediated slow deprotonation of primary amine groups on chitosan polymers. Through synthesizing and characterizing various chitosan hydrogel compositions, we found that mineralization played a key role in enhancing the hydrogels' mechanical strength, viscosity, and thermal inertia. Moreover, thorough in vitro and in vivo assessments of the chitosan-based hydrogels, whether modified with mineralization or not, demonstrated their outstanding hemostatic activity (reducing coagulation time by >41 %), biocompatibility with minimal inflammation, and biodegradability. Importantly, in vivo evaluations using a rat burn wound model unveiled a clear wound healing promotion property of the chitosan hydrogels, and the mineralized form outperformed its precursor, with a reduction of >7 days in wound closure time. This study presents the first-time utilization of chitosan/CaCO3 as a thermogelation formulation, offering a promising prototype for a new family of thermosensitive hydrogels highly suited for wound care applications.

An injectable collagen peptide-based hydrogel with desirable antibacterial, self-healing and wound-healing properties based on multiple-dynamic crosslinking.

Conventional collagen-based hydrogels as wound dressing materials are usually lack of antibacterial activity and easily broken when encountering external forces. In this work, we developed a collagen peptide-based hydrogel as a wound dressing, which was composed of adipic acid dihydrazide functionalized collagen peptide (Col-ADH), oxidized dextran (ODex), polyvinyl alcohol (PVA) and borax via multiple-dynamic reversible bonds (acylhydrazone, amine, borate ester and hydrogen bonds). The injectable hydrogel exhibited satisfactory self-healing ability, antibacterial activity, mechanical strength, as well as good biocompatibility and biodegradability. In vivo experiments demonstrated the rapid hemostasis, accelerated cell migration, and promoted wound healing capacities of the hydrogel. These results indicate that the multifunctional collagen peptide-based hydrogel has great potentials in the field of wound dressings.

Development of alginate macroporous hydrogels using sacrificial CaCO3 particles for enhanced hemostasis.

Polymeric hydrogels have increasingly garnered attention in the field of hemostasis. However, there remains a lack of targeted development and evaluation of non-dense polymeric hydrogels with physically incorporated pores to enhance hemostasis. Here, we present a facile route to macroporous alginate hydrogels using acid-induced CaCO3 dissolution to provide Ca2+ for alginate gelation and CO2 bubbles for subsequent macropore formation. The as-prepared pore structure in the hydrogels and its formation mechanisms were characterized through microscopic imaging and nitrogen adsorption/desorption tests. Functional analyses revealed that the macroporous hydrogels exhibited improved rheology, blood absorption, coagulation factor delivery, and platelet aggregation. Ultimately, the introduction of pores significantly enhanced the hemostatic effectiveness of alginate hydrogels in vivo, as demonstrated in rat tail amputation and liver injury models, leading to a reduction in blood loss of up to 77 % or a decrease in bleeding time of up to 88 %. Notably, hydrogels with higher porosity achieved with a CaCO3 to alginate ratio of 40 % outperformed those with lower porosity in the aforementioned properties. Furthermore, these improvements were found to be biocompatible and elicited minimal inflammation. Our findings underscore the potential of a simple porous hydrogel design to enhance hemostasis efficacy by physically incorporating macropores.

Robust Piezoelectric Biomolecular Membranes from Eggshell Protein for Wearable Sensors.

Flexible and wearable devices are drawing increasing attention due to their promising applications in energy harvesting and sensing. However, the application of wearable devices still faces great challenges, such as flexibility, repeatability, and biodegradability. Biopiezoelectric materials have been regarded as favorable energy-harvesting sources due to their nontoxicity and biocompatibility. Here, a wearable and biodegradable sensor is proposed to monitor human activities. The proposed sensor is fabricated via a low-cost, facile, and scalable electrospinning technology from nanofibers composed of eggshell membranes mixed with polyethylene oxide. It is shown that the sensor exhibits excellent flexibility, outstanding degradability, and mechanical stability over 3000 cycles under periodic stimulation. The device displays multiple potential applications, including the recognition of different objects, human motion monitoring, and active voice recognition. Finally, it is shown that the composite nanofiber membrane has good degradability and breathability. With excellent sensing performance, environmental friendliness, and ease of processing, the eggshell membrane-based sensor could be a promising candidate for greener and more environmentally friendly devices for application in implantable and wearable electronics.

Trojan-horse mineralization of trigger factor to impregnate non-woven alginate fabrics for enhanced hemostatic efficacy.

Uncontrolled hemorrhage remains a leading cause of mortality after trauma. This work describes a facile mineralization strategy for enhancing hemostatic efficacy of alginate non-woven fabrics, involving the precipitation of amorphous CaCO3 induced by alginate fibers, along with Trojan-horse-like tissue factor (TF) encapsulation. The amorphous CaCO3 served as a transient carrier, capable of releasing Ca2+ and TF upon contact with blood. Coagulation test and rat tail cut and hemorrhaging liver models all revealed superior hemostatic capability of mineralized TF-in-alginate fabrics compared to bare fabrics, solely mineralized form, or commercial zeolite-modified gauze, benefiting from the combined hemostatic properties of alginate matrix and released Ca2+ and TF. Meanwhile, comprehensive biocompatibility and mechanical stability evaluations demonstrate the ternary composite's good biosafety. These results along with the extension study with chitosan- and cellulose-based dressings underline the great potential and versatility of polysaccharide-hemostat-mediated CaCO3 mineralization with TF integration for achieving rapid hemorrhage control.

A peptide-engineered alginate aerogel with synergistic blood-absorbing and platelet-binding capabilities to rapidly stop bleeding.

Polysaccharide matrix infused with hemostasis-stimulating chemistry represents a critical medical need of bleeding management. Herein, we describe the development of a polysaccharide-peptide conjugate platform, an alginate engineered with fibrinogen-derived platelet-binding peptides (APE). The alginate backbone was found to allow for multivalent grafting of the peptides. Processing APE conjugate into crosslinked aerogels promoted platelet accumulation, leading to a significant reduction in the coagulation time of whole rabbit blood and improving the stability of the formed clot. The APE aerogels also exhibited a high porosity and fluid uptake capacity (>90 in weight ratio) as well as good biocompatibility in hemostasis. Furthermore, in vivo studies conducted in rat models of tail cut and hepatic hemorrhage showed that APE aerogels reduced bleeding time by >58 % and blood loss by >61 %. The platelet-enrichment capacity of the APE construct synergized by high absorbency in its aerogel form offers a prototype for customized polysaccharide hemostats.

Synthesis of Polyether Carboxylate and the Effect of Different Electrical Properties on Its Viscosity Reduction and Emulsification of Heavy Oil.

Heavy oil exploitation needs efficient viscosity reducers to reduce viscosity, and polyether carboxylate viscosity reducers have a significant viscosity reduction effect on heavy oil. Previous work has studied the effect of different side chain lengths on this viscosity reducer, and now a series of polyether carboxylate viscosity reducers, including APAD, APASD, APAS, APA, and AP5AD (the name of the viscosity reducer is determined by the name of the desired monomer), with different electrical properties have been synthesized to investigate the effect of their different electrical properties on viscosity reduction performance. Through the performance tests of surface tension, contact angle, emulsification, viscosity reduction, and foaming, it was found that APAD viscosity reducers had the best viscosity reduction performance, reducing the viscosity of heavy oil to 81 mPa·s with a viscosity reduction rate of 98.34%, and the worst viscosity reduction rate of other viscosity reducers also reached 97%. Additionally, APAD viscosity reducers have the highest emulsification rate, and the emulsion formed with heavy oil is also the most stable. The net charge of APAD was calculated from the molar ratio of the monomers and the total mass to minimize the net charge. While the net charge of other surfactants was higher. It shows that the amount of the surfactant's net charge affects the surfactant's viscosity reduction effect, and the smaller the net charge of the surfactant itself, the better the viscosity reduction effect.

Flexible Self-Powered Friction Piezoelectric Sensor Based on Structured PVDF-Based Composite Nanofiber Membranes.

With the rapid development of the economy and technology, intelligent wearable devices have gradually entered public life. Flexible sensors, as the main component of wearable devices, have been widely concerned. However, traditional flexible sensors need an external power supply, lacking flexibility and sustainable power supply. In this study, structured poly(vinylidene fluoride) (PVDF)-based composite nanofiber membranes doped with different mass fractions of MXene and zinc oxide (ZnO) were prepared by electrospinning and were then assembled to flexible self-powered friction piezoelectric sensors. The addition of MXene and ZnO endowed PVDF nanofiber membranes with better piezoelectric properties. The structured PVDF/MXene-PVDF/ZnO (PM/PZ) nanofiber membranes with a double-layer structure, interpenetrating structure, or core-shell structure could further enhance the piezoelectric properties of PVDF-based nanofiber membranes through the synergistic effects of filler doping and structural design. In particular, the output voltage of the self-powered friction piezoelectric sensor made of a core-shell PM/PZ nanofiber membrane showed a good linear relationship with the applied pressure and could produce a good piezoelectric response to the bending deformation caused by human motion.

Green-Solvent-Processable Composite Micro/Nanofiber Membrane with Gradient Asymmetric Structure for Efficient Microfiltration.

Electrospinning technology has attracted extensive attention in recent decades and is widely used to prepare nanofiber membranes from hundreds of polymers. Polyvinyl formal acetal (PVFA), as a polymer with excellent properties such as high strength and heat resistance, is not reported on the electrospun water treatment membrane. In this paper, the preparation process of electrospun PVFA nanofiber membrane is optimized, and the effect of sodium chloride (NaCl) addition on the physical and mechanical properties and microfiltration performance of nanofiber membrane is also explored. And the hydrophobic PVFA nanofiber filter layer is then combined with a hydrophilic nonwoven support layer to construct a composite micro/nanofiber membrane with a pore-size gradient structure and a hydrophilic/hydrophobic asymmetric structure. Finally, unidirectional water transport and water treatment performance are further investigated. The results show that the tensile breaking strength of the composite membrane can reach up to 37.8 MPa, the retention rate for particles with the size of 0.1-0.3 µm is 99.7%, and the water flux is 513.4 L m-2 h-1 under the hydrostatic pressure. Moreover, it still has a retention of more than 98% after three repeated uses. Therefore, the electrospun PVFA composite membrane has a great potential in microfiltration.

Armoring a liposome-integrated tissue factor with sacrificial CaCO3 to form potent self-propelled hemostats.

The development of hemostatic materials suitable for diverse emergency scenarios is of paramount significance, and there is growing interest in wound-site delivery of hemostasis-enhancing agents that can leverage the body's inherent mechanisms. Herein we report the design and performance of a biomimetic nanoparticle system enclosing tissue factor (TF), the most potent known blood coagulation trigger, which was reconstituted into liposomes and shielded by the liposome-templated CaCO3 mineralization. The mineral coatings, which mainly comprised water-soluble amorphous and vateritic phases, synergized with the lipidated TF to improve blood coagulation in vitro. These coatings served as sacrificial masks capable of releasing Ca2+ coagulation factors or propelling the TF-liposomes via acid-aided generation of CO2 bubbles while endowing them with high thermostability under dry conditions. In comparison to commercially available hemostatic particles, CaCO3 mineralized TF-liposomes yielded significantly shorter hemostasis times and less blood loss in vivo. When mixed with organic acids, the CO2-generating formulation further improved hemostasis by delivering TF-liposomes deep into actively bleeding wounds with good biocompatibility, as observed in a rat hepatic injury model. Therefore, the designed composite mimicry of coagulatory components exhibited strong hemostatic efficacy, which in combination with the propulsion mechanism would serve as a versatile approach to treating a variety of severe hemorrhages.

Driving factors and emission reduction scenarios analysis of CO2 emissions in Guangdong-Hong Kong-Macao Greater Bay Area and surrounding cities based on LMDI and system dynamics.

As one of the most open and economically dynamic regions in China, the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) is at the forefront of low-carbon development and has an exemplary and leading role for other regions. This study provides a research framework based on the Logarithmic Mean Divisia Index (LMDI) and system dynamics (SD) by first compiling an inventory of CO2 emissions in the GBA and surrounding cities from 2000 to 2019 and then systematically and comprehensively analyzing the driving factors, future trends and policy implications of CO2 emissions in the GBA and surrounding cities. The results show that (a) CO2 emissions in the GBA and surrounding cities grew from 253.39 Mt in 2000 to 627.86 Mt in 2019, with an average annual growth rate of 4.89 %. The per capita CO2 emissions showed a continuous decreasing trend, and the overall carbon intensity of each sector showed a decreasing trend. (b) GDP per capita growth has the greatest effect on CO2 emissions, followed by the number of transport vehicles and population. The negative effects are energy intensity, average output of transportation vehicles, and residential energy intensity, with energy intensity being the most critical. (c) In the baseline scenario, regional CO2 emissions in 2030 are 1.25 times higher than those in 2019 and continue to grow. (d) Technological innovation measures are the most effective among individual emission reduction policies, followed by optimization of industrial structure. Furthermore, energy structure adjustment, vehicle licensing restrictions, and residents' green living are less effective. (e) Under comprehensive emission reduction measures, the region can achieve carbon emissions peaking in 2026 and reduce the regional carbon intensity by 66.24 % in 2030 compared with 2005. This study provides effective data support for the GBA and surrounding cities to formulate low carbon policies, promote carbon emission reduction and achieve carbon emissions peaking early.

Research Progress of Water Treatment Technology Based on Nanofiber Membranes.

In the field of water purification, membrane separation technology plays a significant role. Electrospinning has emerged as a primary method to produce nanofiber membranes due to its straightforward, low cost, functional diversity, and process controllability. It is possible to flexibly control the structural characteristics of electrospun nanofiber membranes as well as carry out various membrane material combinations to make full use of their various properties, including high porosity, high selectivity, and microporous permeability to obtain high-performance water treatment membranes. These water separation membranes can satisfy the fast and efficient purification requirements in different water purification applications due to their high filtration efficiency. The current research on water treatment membranes is still focused on creating high-permeability membranes with outstanding selectivity, remarkable antifouling performance, superior physical and chemical performance, and long-term stability. This paper reviewed the preparation methods and properties of electrospun nanofiber membranes for water treatment in various fields, including microfiltration, ultrafiltration, nanofiltration, reverse osmosis, forward osmosis, and other special applications. Lastly, various antifouling technologies and research progress of water treatment membranes were discussed, and the future development direction of electrospun nanofiber membranes for water treatment was also presented.

Electrospun PVDF-based piezoelectric nanofibers: materials, structures, and applications.

Polyvinylidene fluoride (PVDF) has been considered as a promising piezoelectric material for advanced sensing and energy storage systems because of its high dielectric constant and good electroactive response. Electrospinning is a straightforward, low cost, and scalable technology that can be used to create PVDF-based nanofibers with outstanding piezoelectric characteristics. Herein, we summarize the state-of-the-art progress on the use of filler doping and structural design to enhance the output performance of electrospun PVDF-based piezoelectric fiber films. We divide the fillers into single filler and double fillers and make comments on the effects of various dopant materials on the performance and the underlying mechanism of the PVDF-based piezoelectric fiber film. The effects of highly oriented structures, core-shell structures, and multilayer composite structures on the output properties of PVDF-based piezoelectric nanofibers are discussed in detail. Furthermore, the perspectives and opportunities for PVDF piezoelectric nanofibers in the fields of health care, environmental monitoring, and energy collection are also discussed.

Sprayable surface-adaptive biocompatible membranes for efficient hemostasis via assembly of chitosan and polyphosphate.

This work describes a hemostatic membrane system (or surface coating) based on spray-assisted layer-by-layer electrostatic assemblies of oppositely charged polyphosphate (polyP) and chitosan (Cs). The as-prepared membrane formed a robust micro-stratified porous structure with high flexibility. Both blood clotting test and rodent hepatic severe hemorrhage model revealed the excellent hemostatic performance of the membrane system, benefitting from the robust assembly and synergistic effect of polyP/Cs as well as membrane surface chemistry. Compared to Cs-topped membrane surface, polyP-sprayed one exhibited further improved hemostatic effect via promoting fibrin formation. Besides, comprehensive in vitro and in vivo evaluations demonstrated good biocompatibility and biodegradability of the membrane. The present approach that integrated the hemostasis-stimulating capability of polyP/Cs with facile spraying method is highly scalable and flexible, which is envisioned to be adapted readily for other hemostatic polyelectrolytes and surface functionalization of diverse existing hemostatic products on demand.

Injectable thermogelling bioadhesive chitosan-based hydrogels for efficient hemostasis.

Development of an injectable hemostatic for treating noncompressible or irregularly shaped bleeding wounds remains a pressing medical need. Herein, we report an injectable thermogelling chitosan/glycerophosphate formulation that enhances gel-forming capacity and wet tissue adherence by incorporation of dihydrocaffeic acid (DHCA). This was found to decrease gelation time by >2 times around 37 °C while increasing hydrogel internal network structure, with its tissue adhesive strength >2 times greater than that of the non-composite hydrogel or previously reported. The thermosensitive hydrogels significantly reduce whole blood coagulation time in vitro and both hemostasis time and blood loss in vivo using rat hepatic hemorrhage and tail amputation models. These improvements are biocompatible, without adversely affecting cell viability, blood components, biodegradability, or introducing notable inflammation, thus enabling injury healing. Moreover, our results displayed the potential of a facile approach to enhance thermogelling and bioadhesion of chitosan-based hydrogels via noncovalent supramolecular mechanisms.

Incorporation of tissue factor-integrated liposome and silica nanoparticle into collagen hydrogel as a promising hemostatic system.

Bleeding complications are associated with substantial tissue morbidities and mortalities. Biomimetic composite materials that possess the ability to sufficiently stimulate and augment different physiological mechanisms of hemostasis are highly desirable to reduce bleeding-related casualties, which, however, are still largely under-explored. This study aims to develop a composite hemostatic system by combining collagen hydrogel with tissue factor (TF)-integrated liposome and silica nanoparticle, which could integrate the platelet plug-promoting capacity of collagen with the abilities of the latter two components to activate the extrinsic and intrinsic pathways of coagulation respectively. Several hydrogel compositions were synthesized and characterized. We show that lipidated TF and silica were evenly distributed in the collagen-based hydrogels, while exhibiting tunable release kinetics in simulated body fluid. Time-to-coagulation test revealed that each component in the TF-liposome/silica/collagen ternary hydrogels was hemostasis-active, and their combination showed enhanced and potent procoagulant performance, without detectable cytotoxicity against NIH/3T3 model cells. These results suggest that collagen hydrogels with embedded TF-liposome and silica nanoparticle may serve as a platform for an effective hemostatic composite that incorporates all the basic known pathways of coagulation.

Recent Advances in Wearable Biosensors for Non-Invasive Detection of Human Lactate.

Lactate, a crucial product of the anaerobic metabolism of carbohydrates in the human body, is of enormous significance in the diagnosis and treatment of diseases and scientific exercise management. The level of lactate in the bio-fluid is a crucial health indicator because it is related to diseases, such as hypoxia, metabolic disorders, renal failure, heart failure, and respiratory failure. For critically ill patients and those who need to regularly control lactate levels, it is vital to develop a non-invasive wearable sensor to detect lactate levels in matrices other than blood. Due to its high sensitivity, high selectivity, low detection limit, simplicity of use, and ability to identify target molecules in the presence of interfering chemicals, biosensing is a potential analytical approach for lactate detection that has received increasing attention. Various types of wearable lactate biosensors are reviewed in this paper, along with their preparation, key properties, and commonly used flexible substrate materials including polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), paper, and textiles. Key performance indicators, including sensitivity, linear detection range, and detection limit, are also compared. The challenges for future development are also summarized, along with some recommendations for the future development of lactate biosensors.

Experimental Evaluation of Sensor Fusion of Low-Cost UWB and IMU for Localization under Indoor Dynamic Testing Conditions.

Autonomous systems usually require accurate localization methods for them to navigate safely in indoor environments. Most localization methods are expensive and difficult to set up. In this work, we built a low-cost and portable indoor location tracking system by using Raspberry Pi 4 computer, ultra-wideband (UWB) sensors, and inertial measurement unit(s) (IMU). We also developed the data logging software and the Kalman filter (KF) sensor fusion algorithm to process the data from a low-power UWB transceiver (Decawave, model DWM1001) module and IMU device (Bosch, model BNO055). Autonomous systems move with different velocities and accelerations, which requires its localization performance to be evaluated under diverse motion conditions. We built a dynamic testing platform to generate not only the ground truth trajectory but also the ground truth acceleration and velocity. In this way, our tracking system's localization performance can be evaluated under dynamic testing conditions. The novel contributions in this work are a low-cost, low-power, tracking system hardware-software design, and an experimental setup to observe the tracking system's localization performance under different dynamic testing conditions. The testing platform has a 1 m translation length and 80 µm of bidirectional repeatability. The tracking system's localization performance was evaluated under dynamic conditions with eight different combinations of acceleration and velocity. The ground truth accelerations varied from 0.6 to 1.6 m/s2 and the ground truth velocities varied from 0.6 to 0.8 m/s. Our experimental results show that the location error can reach up to 50 cm under dynamic testing conditions when only relying on the UWB sensor, with the KF sensor fusion of UWB and IMU, the location error decreases to 13.7 cm.