Polydopamine Particles Research Articles

Dipolar-hollowed α-Fe2O3@Au/Polydopamine nanospindle for photothermal-photodynamic coupling antibacterial and drug-delivery

With the prevalence of drug-resistant bacteria and the waning effects of antibiotics, nanoplatform has become an effective strategy for fighting infections. This work reports a dipolar-hollowed α-Fe2O3@Au/Polydopamine (PDA) nanospindle which possesses both photothermal-photodynamic (PTT-PDT) coupling antibacterial and drug carrying performance. Firstly, the spindle type α-Fe2O3@Au/PDA particle was prepared by a simple one-step strategy and then the dipolar-hollow structure was obtained by controlling etching the inside α-Fe2O3 core with hydrochloric acid. After further loading the photosensitizer zinc phthalocyanine (ZnPc), the dipolar-hollowed α-Fe2O3@Au/PDA-ZnPc nanospindles were obtained. Owing to the dipolar-hollowed interior, the nanospindles are also effective in carrying antitumor drug doxorubicin (DOX) and shows a good drug loading-release behavior. The dipolar-hollowed α-Fe2O3@Au/PDA nanospindles exhibits a high antibacterial performance against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under near-infrared (NIR) and Xenon lamp irradiation. When α-Fe2O3@Au/PDA-ZnPc nanospindles concentration was increased to 100 μg/mL, the antibacterial rate was close to 100 %. In comparison to the original α-Fe2O3@Au/PDA nanospindles, the product achieved a lower effective antibacterial temperature. This triple-mode therapy (PTT/PDT/Drug) provides an interesting design idea for anisotropic therapeutic nanoplatform which can be applied in low-temperature antibacterial and drug delivery.

Gellan gum-based multifunctional hydrogel with enduring sterilization and ROS scavenging for infected wound healing

The progression of severe skin injury healing can be easily impeded by bacterial infections and the resultant overproduction of reactive oxygen species (ROS) within the wound microenvironment. In this study, we developed a multifunctional antibacterial hydrogel by integrating gallium ion-tannic acid and polydopamine particles into gellan gum via a facile heat-cooling process. By harnessing the synergistic effects of polydopamine for short-term photothermal therapy and gallium ion for long-term chemotherapy, the hydrogel obtained shows outstanding antibacterial activities. Sustained release of gallium ion and tannic acid ensures a prolonged sterilization along with ROS-scavenging benefits. Moreover, this hydrogel demonstrates superior cytocompatibility, hemostatic properties, as well as capabilities including promoting cell migration, and adsorption to bacterial cells and toxin. The therapeutic efficacy of the hydrogel was validated using a mouse model of MRSA-induced cutaneous infections. Overall, this work introduces a straightforward yet highly efficient multifunctional hydrogel platform that combines synergetic antibacterial actions, ROS scavenging, and hemostasis to enhance the healing of bacteria-associated wounds.

Mechanistic Insights into the Removal of Surfactant-Like Contaminants on Mesoporous Polydopamine Nanospheres from Complex Wastewater Matrices.

The detrimental environmental effects of surfactant-like contaminants (SLCs) with distinctive amphiphilic structures have garnered significant attention, particularly since perfluorooctanesulfonate was classified as a persistent organic pollutant. Despite the numerous absorbents developed for SLCs removal, the underlying interaction mechanisms remain speculative and lack experimental validation. To address this research gap, we elucidate the mechanistic insights into the selective removal of SLCs using mesoporous polydopamine nanospheres (MPDA) fabricated via a novel soft-template method. We employed low-field nuclear magnetic resonance to quantitatively characterize the hydrophilicity of the absorbents using water molecules as probes. The results demonstrated that MPDA with uniform mesopores exhibited a remarkable threefold enhancement in SLCs' adsorption capacity compared to conventional polydopamine particles via intraparticle diffusion. We further demonstrated the dominant effects of electrostatic and hydrophobic interactions on the selective removal of SLCs with MPDA by regulating the isoelectric pH value and performing a comparative analysis. The mechanism-inspired SLC-removal strategy achieved an average removal rate of 76.3% from highly contaminated wastewater. Our findings offer new avenues for applying MPDA as an efficient adsorbent and provide innovative and mechanistic insights for targeted SLC removal in complex wastewater matrices.

Deposition kinetics and adhesion behavior of polydopamine-based capsules on cellulose fibrous substrates

Polydopamine (PDA)-based capsules have been broadly used to functionalize cellulose-based fabrics owing to their enhanced adhesion properties. However, the deposition kinetics and adhesion behavior of PDA-based capsules on the fabrics remain understudied. In this work, the sizes, concentrations, and deposition time of PDA particles, as well as the electrostatic force between PDA particles and the fabrics were investigated to study the deposition kinetics and adhesion behavior of PDA particles on Lyocell fibers. The introduction of electrostatic interaction significantly enhanced both the deposition amount and the uniformity of PDA particles onto the fiber surface. The deposition kinetics of PDA particles on the fibers could be accurately described using a modified collision model, with the coverage of PDA particles conforming to a monolayer deposition pattern. The adhesion behavior of PDA particles was investigated by molecular dynamics simulation and isothermal titration calorimetry. The results indicated the driving forces during the deposition process were mainly hydrogen bonds, electrostatic force and van der Waals force. The van der Waals force was increased by around 106 %, and electrostatic force was even increased by approximately 201 % after the fiber cationization. This study provided a theoretical foundation for achieving controllable and quantitative surface functionalization of cellulose fibrous substrates.

Novel 4D-printing pellets with infrared-light responsive shape memory effect

Four-dimensional (4D)-printing technology is attractive to researchers since it combines 3D printing with smart materials to produce 3D structures with various shapes and change shapes under specific external stimuli. Herein, novel shape memory polymer (SMP) pellets with infrared-light responsive shape memory effect were developed for 4D printing applications. The structures, properties, and infrared-light responsive shape memory performances of the resulting (SMP) pellets were thoroughly investigated. The results showed PDA/SMP pellets prepared by direct loading of polydopamine (PDA) particles on SMP pellets displayed less influence on the basic properties of SMP while fluidity was enhanced. The obtained PDA/SMP pellets employed as feed materials for particle 3D printers revealed good thermal-induced shape memory performance and photo-responsive shape memory performance in printed 3D structures. Under infrared-light irradiation, the curled shape recovered to straight splines within 60 s due to the strong absorption and good photo-thermal conversion of the loaded PDA nanoparticles under infrared light. Overall, the as-prepared PDA/SMP pellets look promising for use in biomedical fields and smart devices, as well as remote control deformation with 4D printing technology.

Molecular Interaction Mechanisms Between Lubricant-Infused Slippery Surfaces and Mussel-Inspired Polydopamine Adhesive and DOPA Moiety.

Lubricant-infused slippery surfaces have recently emerged as promising antifouling coatings, showing potential against proteins, cells, and marine mussels. However, a comprehensive understanding of the molecular binding behaviors and interaction strength of foulants to these surfaces is lacking. In this work, mussel-inspired chemistry based on catechol-containing chemicals including 3,4-dihydroxyphenylalanine (DOPA) and polydopamine (PDA) is employed to investigate the antifouling performance and repellence mechanisms of fluorinated-based slippery surface, and the correlated interaction mechanisms are probed using atomic force microscopy (AFM). Intermolecular force measurements and deposition experiments between PDA and the surface reveal the ability of lubricant film to inhibit the contact of PDA particles with the substrate. Moreover, the binding mechanisms and bond dissociation energy between a single DOPA moiety and the lubricant-infused slippery surface are quantitatively investigated employing single-molecule force spectroscopy based on AFM (SM-AFM), which reveal that the infused lubricant layer can remarkably influence the dissociation forces and weaken the binding strength between DOPA and underneath per-fluorinated monolayer surface. This work provides new nanomechanical insights into the fundamental antifouling mechanisms of the lubricant-infused slippery surfaces against mussel-derived adhesive chemicals, with important implications for the design of lubricant-infused materials and other novel antifouling platforms for various bioengineering and engineering applications.

Influence of step-by-step cerium-based conversion and polydopamine duplex coating on stir cast Al[sbnd]Cu[sbnd]Mg alloys mitigating saltwater corrosion

Intergranular corrosion (IGC) originates from secondary phases along the grain boundaries in AlCuMg-based alloys can dramatically compromises the tensile properties for structural applications. Insofar cerium-based conversion coating (CeCC) has been exploited to provide a cathodic barrier and mitigate intergranular crack propagation. However, CeCC-based coating deposited on secondary phases in AlCuMg alloys limits its potential use to improve corrosion resistance in the chlorinated environment. Herein, mussel-inspired polydopamine (PDA) coating has been explored on CeCC-treated AlCuMg alloy, providing both anodic and cathodic protection and significantly improving the corrosion resistance in 0.1 M NaCl solution. The micro-morphology of CeCC and CeCC/PDA duplex coating was investigated using X-ray diffraction, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), two and three-dimensional surface topography, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) reveal the formation of aluminum and/or cerium oxide/hydroxide-based complex coating [Ce2O3/CeO2/Al2O3/Al(OH)3] on the Cu-rich secondary phases [Al2Cu, Al2Cu(Mg), and Al5Si(CuMg)] providing cathodic protection. However, additional PDA treatment for 12 h provided uniform surface coverage of PDA particles along the grain boundaries as well as α-Al matrix owing to the formation of hydrogen bonding with hydroxy species [Al(OH)3/Ce(OH)4] and catechol and amine functional groups present in PDA. Potentiodynamic polarization (PDP) illustrates that the CeCC/PDA specimens can successfully retard the corrosion of AlCuMg alloy. In particular, CeCC-60 s/PDA specimen demonstrated the lowest corrosion current density (Icorr ∼ 0.16 μA/cm2), and the highest polarization resistance (Rp ∼ 119 kΩ·cm2) during electrochemical corrosion in 0.1 M NaCl solution. The corroded surface discloses accelerated IGC was evident on bare and CeCC specimens. On the contrary, CeCC-60 s/PDA specimen demonstrated a significant reduction in IGC and drastically improved corrosion rate.

Nanomedicine Targeting Cuproplasia in Cancer: Labile Copper Sequestration Using Polydopamine Particles Blocks Tumor Growth In Vivo through Altering Metabolism and Redox Homeostasis.

Copper plays critical roles as a metal active site cofactor and metalloallosteric signal for enzymes involved in cell proliferation and metabolism, making it an attractive target for cancer therapy. In this study, we investigated the efficacy of polydopamine nanoparticles (PDA NPs), classically applied for metal removal from water, as a therapeutic strategy for depleting intracellular labile copper pools in triple-negative breast cancer models through the metal-chelating groups present on the PDA surface. By using the activity-based sensing probe FCP-1, we could track the PDA-induced labile copper depletion while leaving total copper levels unchanged and link it to the selective MDA-MB-231 cell death. Further mechanistic investigations revealed that PDA NPs increased reactive oxygen species (ROS) levels, potentially through the inactivation of superoxide dismutase 1 (SOD1), a copper-dependent antioxidant enzyme. Additionally, PDA NPs were found to interact with the mitochondrial membrane, resulting in an increase in the mitochondrial membrane potential, which may contribute to enhanced ROS production. We employed an in vivo tumor model to validate the therapeutic efficacy of PDA NPs. Remarkably, in the absence of any additional treatment, the presence of PDA NPs alone led to a significant reduction in tumor volume by a factor of 1.66 after 22 days of tumor growth. Our findings highlight the potential of PDA NPs as a promising therapeutic approach for selectively targeting cancer by modulating copper levels and inducing oxidative stress, leading to tumor growth inhibition as shown in these triple-negative breast cancer models.

High-performance proton exchange membrane employing water-insoluble hybrid formed by chemically bonding phosphotungstic acid with polydopamine

Heteropolyacids can retain water in a proton exchange membrane to increase proton conductivity at high temperatures and low humidity; however, their high solubility in water leads to leaching, which limits their further application. Herein, we used phosphotungstic acid (HPW) and polydopamine (PDA) particles to prepare a water-insoluble PDA/HPW hybrid (PDW) via hydrothermal reaction. The amino groups of PDA in PDW chemically bonded to HPW and acted as an anchor for HPW. The proton conductivity of the sulfonated poly(ether ether ketone) (SPEEK) composite membrane containing 15wt% PDW (SPEEK/PDW-15) in liquid water was 0.052 S⸱cm–1 at 25 ℃, which was 63% higher than that of the SPEEK control membrane (0.032 S⸱cm–1). The SPEEK/PDW-15 composite membrane also showed stable proton conductivity during 80 days of testing while immersed in water.

Biomimicking trilayer scaffolds with controlled estradiol release for uterine tissue regeneration.

Scaffold-based tissue engineering provides an efficient approach for repairing uterine tissue defects and restoring fertility. In the current study, a novel trilayer tissue engineering scaffold with high similarity to the uterine tissue in structure was designed and fabricated via 4D printing, electrospinning and 3D bioprinting for uterine regeneration. Highly stretchable poly(l-lactide-co-trimethylene carbonate) (PLLA-co-TMC, "PTMC" in short)/thermoplastic polyurethane (TPU) polymer blend scaffolds were firstly made via 4D printing. To improve the biocompatibility, porous poly(lactic acid-co-glycolic acid) (PLGA)/gelatin methacryloyl (GelMA) fibers incorporated with polydopamine (PDA) particles were produced on PTMC/TPU scaffolds via electrospinning. Importantly, estradiol (E2) was encapsulated in PDA particles. The bilayer scaffolds thus produced could provide controlled and sustained release of E2. Subsequently, bone marrow derived mesenchymal stem cells (BMSCs) were mixed with gelatin methacryloyl (GelMA)-based inks and the formulated bioinks were used to fabricate a cell-laden hydrogel layer on the bilayer scaffolds via 3D bioprinting, forming ultimately biomimicking trilayer scaffolds for uterine tissue regeneration. The trilayer tissue engineering scaffolds thus formed exhibited a shape morphing ability by transforming from the planar shape to tubular structures when immersed in the culture medium at 37°C. The trilayer tissue engineering scaffolds under development would provide new insights for uterine tissue regeneration.

Two-electron oxidized polyphenol chemistry-inspired superhydrophilic drug-carrying coatings for the construction of multifunctional nasolacrimal duct stents.

Nasolacrimal duct obstruction due to infection, inflammation, or excessive fibroblast proliferation may result in persistent tearing, intraocular inflammation, or even blindness. In this study, surface engineering techniques are applied to nasolacrimal duct stents for the first time. Based on the functioning of marine mussels, "one-pot" and "stepwise" methods were employed to construct a novel multifunctional superhydrophilic PDA/RAP coating using dopamine and rapamycin. Micron-sized rapamycin crystals combined with nano-sized polydopamine particles form a micro-nano topographical structure. Therefore, acting synergistically with in situ-generated hydrophilic groups (amino, carboxyl, and phenolic hydroxyl), they impart excellent and long-lasting superhydrophilicity to the nasolacrimal duct stent. The PDA/RAP coating effectively maintained the stability of the initial microenvironment during stent implantation by inhibiting the onset of acute inflammation and infection during the early stages of implantation. Meanwhile, the rapamycin crystals, supported by the superhydrophilic platform, exhibited a sustained-release capability that helped them to better exert their anti-inflammatory, antibacterial, and anti-fibroblast proliferative properties, ensuring conducive conditions for the rapid repair of nasolacrimal duct epithelial cells, verified by a series of experiments. In conclusion, the PDA/RAP hydrophilic coating has anti-inflammatory, antifibrotic, antibacterial, and antithrombotic properties, offering a new strategy to address restenosis following clinical nasolacrimal duct stent implantation.

Injectable, pH-responsive hybrid hydrogels for the treatment of periodontitis.

Anti-inflammatory hydrogels have demonstrated great potential in the treatment of periodontitis. However, intelligent removal of reactive oxygen species (ROS) remains significantly challenging. In this study, a novel pH-responsive anti-inflammatory hydrogel was designed to treat periodontitis. We synthesized methacrylated alginate modified with a unique pH-sensitive phenylboronic acid through a one-step synthesis and then incorporated polydopamine particles loaded with minocycline to obtain a novel hydrogel under ultraviolet irradiation. Infrared and ultraviolet tests confirmed the successful preparation of the hydrogel. In environments with low pH, drug release rates significantly increased. In addition, in vitro cell experiments demonstrated excellent biocompatibility of the hydrogels. Furthermore, ROS detection revealed that the hydrogel effectively reduced cellular ROS levels and displayed excellent anti-inflammatory properties. These results strongly suggest that this novel pH-responsive anti-inflammatory hydrogel platform has tremendous potential for the treatment of periodontitis.

Response surface methodology and machine learning based tensile strength prediction in ultrasonic assisted coating of poly lactic acid bone plates manufactured using fused deposition modeling

Poly Lactic Acid (PLA) based bone plates fabricated using Fused Deposition Modeling have poor mechanical strength which can be improved by biocompatible polydopamine (PDM) coating. However, PDM particles, being heavy in nature, settle at the container bottom with increase in coating solution concentration at the time of bone plate coating using dip coating technique. Thus, the present work aims to witness the effect of ultrasonic assisted coating parameters on tensile strength of coated bone plates. The coating parameters involving power of ultrasonic vibrations, coating solution concentration and immersion time were varied. The standard Response Surface Methodology (RSM) was applied and experimental trials were performed for obtaining tensile strength of bone plates under varied coating parameters. The objective of the present study was to compare the values of tensile strength predicted using RSM and machine learning (ML) models. Based on the obtained experimental values, gradient boosting regression (GBReg), linear regression (LReg) and random forest regression (RFReg) were trained and tested for predicting tensile strength of bone plates. The accuracy and prediction errors corresponding to RSM and ML based models were compared with respect to R2, Mean Squared Error (MSE), Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE). The findings revealed that GBReg exhibited R2, MSE, RMSE and MAE values as 0.9312, 1.7142, 1.2877 and 1.0861 respectively, while RSM showed R2, MSE, RMSE and MAE values as 0.882, 2.13, 1.4595 and 1.258 respectively. RSM model has shown minimum accuracy with high prediction errors amongst the four models. GBReg has outperformed other ML models in terms of their accuracy and error metrics. The present study therefore suggests the application of GBReg based ML model for predicting tensile strength of PDM coated bone plates in response to its accurate and robust prediction performance.

Hybrid assembly based on nanomaterial reinforcement for multifunctionalized skin-like flexible sensors

Currently, the inferior mechanical strength, weak environmental adaptability, and limited functionality of conductive hydrogel significantly impede its potential application in wearable sensors. Here, ''hard'' acrylic bentonite (AABT) intercalated nanostructures and silver-modified polydopamine (PDA@Ag) particles are encapsulated in a ''soft'' polyacrylic acid matrix in a water/glycerol binary solvent system. This strategy successfully realized the high matched skin modulus (58 kPa), high stress (371 kPa) and strain (1025 %). The PDA@Ag particles retains rich phenolic hydroxyl groups imitating mussel to provide strong adhesion (29.12 kPa). These particles also give the hydrogel long time antibacterial properties (3 days), while demonstrating excellent biosafety. The introduction of a binary system of water/glycerol effectively suppresses the evaporation and crystallization of water, thereby maintaining sensing performance above 82 % even under extreme conditions. This hydrogel achieves integrated applications of multifunctionality and multi-environmental adaptability, providing a new idea for the development of next-generation skin-like hydrogel sensors.

Maximizing the benefits of combining fibroin and sericin: Functionalized obsoleted silk cocoon shell for purifying oily wastewater containing Pb2+

Based on the durability of fibroin and the biocompatibility of sericin, researchers are exploring ways to maximize their advantages by combining them in the biomedical field. Fortunately, silk cocoon shell (SC) offers a natural composite material of fibroin and sericin. However, the inherent hydrophobicity of SC, the random arrangement connection of fibers, and the protection provided by the outer sericin limit its application in purifying oil wastewater. In this work, a cost-effective method was developed to improve the hydrophilicity of SC and the mechanical properties of SC by utilizing obsoleted SC as a matrix as well as by dissolving portions of sericin proteins. The polydopamine particle (PDP) was utilized as the intermediate modification layer and a supramolecular gel (SMG) was introduced to the surface of SC, further improving the surface's hydrophilicity of SC. The study indicated that SC@P-SMG has excellent mechanical properties, favorable anti-fouling properties, and superior self-cleaning ability. Furthermore, when the SC@P-SMG was applied in water purification, it could achieve multifunctional applications such as purifying wastewater containing emulsified oil and Pb2+ ions, methylene blue (MB), and oil-water mixture separation. This work provided innovative ideas to maximize the benefits of combining fibroin and sericin.

Interfacial bonding property of SR/CF composites enhanced by secondary modification

In this work, anilino-methyl-triethoxysilane (AMTS) was used as a modifier to secondary modified carbon fiber (CF). Firstly, the CF was pretreated by immersing it in a dopamine (DA) solution so that a certain amount of polydopamine (PDA) particles were attached to its surface to obtain modified carbon fiber (m-CF). Next, m-CF was immersed in a solution of ethanol with AMTS. m-CF@AMTS was obtained by hydrolytic bonding of AMTS to the surface of m-CF. Finally, a silicone rubber/carbon fiber composite (SR/m-CF@AMTS) was prepared from m-CF@AMTS and silicone rubber (SR) matrix. Meanwhile, γ-Aminopropyltriethoxysilane (KH550), 3-Glycidoxypropyltrimethoxysilane (KH560), and 3-(Trimethoxysily)proply methacrylate (KH570) were used as controls for the AMTS secondary modified carbon fiber. The resultant of transverse fiber bundle tests (TFBT) shows that the SR/m-CF@AMTS compared with untreated silicone rubber/carbon fiber (SR/CF) and dopamine (DA) modified silicone rubber/carbon fiber (SR/m-CF) composites, the TFBT strength of SR/m-CF@AMTS was improved by 135.5 % and 51.6 %, and the elongation at break was improved by 177.9 % and 63.8 %, respectively. The above results show that secondary modification of CF by AMTS is a successful and efficient method. Secondary modification of CF by AMTS was first proposed and applied to the experiment.

A cell-free tissue-engineered tracheal substitute with sequential cytokine release maintained airway opening in a rabbit tracheal full circumferential defect model

In this study, a cell-free tissue-engineered tracheal substitute was developed, which is based on a 3D-printed polycaprolactone scaffold coated with a gelatin-methacryloyl (GelMA) hydrogel, with transforming growth factor-β1 (TGF-β) and stromal cell-derived factor-1α (SDF-1) sequentially embedded, to facilitate cell recruitment and differentiation toward chondrocyte-phenotype. TGF-β was loaded onto polydopamine particles, and then encapsulated into the GelMA together with SDF-1, and called G/S/P@T, which was used to coat 3D-printed PCL scaffold to form the tracheal substitute. A rapid release of SDF-1 was observed during the first week, followed by a slow and sustained release of TGF-β for approximately four weeks. The tracheal substitute significantly promoted the recruitment of mesenchymal stromal cells (MSCs) or human bronchial epithelial cells in vitro, and enhanced the ability of MSCs to differentiate towards chondrocyte phenotype. Implantation of the tissue-engineered tracheal substitute with a rabbit tracheal anterior defect model improved regeneration of airway epithelium, recruitment of endogenous MSCs and expression of markers of chondrocytes at the tracheal defect site. Moreover, the tracheal substitute maintained airway opening for 4 weeks in a tracheal full circumferential defect model with airway epithelium coverage at the defect sites without granulation tissue accumulation in the tracheal lumen or underneath. The promising results suggest that this simple, cell-free tissue-engineered tracheal substitute can be used directly after tracheal defect removal and should be further developed towards clinical application.

Polydopamine particle in-situ assisted carbon fiber/CNTs brush with dynamic imine bonds for enhancing the interface properties of its polyamide 6 composites

Fabricating carbon fiber/carbon nanotubes (CF/CNTs) brush is regarded as an effective way to improve its composite interfacial and mechanical properties. Different from other reports, a novel fabrication method was developed in this work. Based on Schiff base reaction, polydopamine (PDA) particle with moderate size could in-situ assist CNTs hairs to be grafted onto carbon fibers surface under agitation condition. This method can guarantee thermal stability of modified layers and facilitate the interfacial compatibility of CF/PA6 due to dynamic imine bond exchanges under high temperature (240 °C) during the injection molding. The contact angle of modified CF with PA6 decreased to 34.2° from 53.6° of the untreated-CF. The results also showed both the interfacial and mechanical properties of the composites were improved. Compared with that of the untreated-CF/PA6 composites, the interfacial shear strength, tensile strength and tensile modulus of modified-CF/PA6 were increased by nearly 64.39%, 22.14% and 21.67%, respectively. This simple modification method would provide the premise to expand it to scale-up industry production of CF reinforced thermoplastic composites.

Versatile synthesis of hollow PDA motors by interfacial protection

Micro/nanomotors (MNMs) are miniaturized devices capable of autonomous motion and on-demand task execution, which have broad application prospects in environmental remediation and biomedicine. However, miniaturization makes it difficult for chemically driven MNMs to integrate functional parts to perform tasks in a simple way. Here, we present a novel approach to manufacture asymmetric, hollow, modifiable and catalytic micromotors by the interfacial protection of polystyrene (PS) and inherent property of polydopamine (PDA). The hollow PDA microparticle with a single hole on its surface, as the main structure of the micromotors, is fabricated by swelling-induced symmetry breaking. Due to interfacial protection of PS, the functional component platinum nanoparticle (PtNP) can be selectively assembled on the outer or inner of the hollow PDA particle, respectively. Benefiting from the geometric shape and composition characteristics, PtNP-modified PDA motors can perform self-propulsion and catalyze the decomposition of methylene blue (MB) during motion. Moreover, the successful loading of nanoparticles with different functions (AuNP, Fe3O4 and MnO2) enables it to fabricate different functional MNMs as required. In short, the strategy is a versatile, general for designing asymmetric hollow MNMs with adjustable function by virtue of interfacial protection and functionalized PDA.

Mussel inspired stable underwater superoleophobic cotton fabric combined with carbon nanotubes for efficient oil/water separation and dye adsorption

Currently reported biobased superwetting cotton fabrics (CF) for wastewater purification were limited because they can only separate oil/water mixtures but cannot remove other pollutants such as dyes from wastewater. In this study, we reported a superhydrophilic and underwater superoleophobic cotton fabric (SUSCF) which was fabricated via a facile two-step method, i.e., dip-coating in poly(sodium 4-styrenesulfonate) (PSS) wrapped carbon nanotube (CNT) dispersion and subsequent in-situ deposition of polydopamine (PDA). The deposited PDA particles and coated CNT endowed CF with superhydrophilicity and underwater superoleophobicity by improving surface roughness and hydrophilicity. The obtained SUSCF showed an underwater oil contact angle of 160°, which made it an attractive water-removing material for oil/water separation with separation efficiency and water flux of higher than 99.8% and 10,834 L m-2h−1, respectively. The combination of CNT, PSS, and PDA endowed the SUSCF with outstanding cationic dye adsorption capacity, especially leading to a maximum removal ratio of 97% toward methylene blue. In addition, the SUSCF exhibited excellent stability to survive after exposure to sandpaper abrasion, boiling water, organic solvents, salt solution, and acidic/alkali erosion, due to the strong hydrogen bonds and mussel-inspired adhesion between coated components and fabric surface. The stable biobased underwater superoleophobic cotton fabric with integrated excellent oil/water separation performance and dye adsorption capacity shows great potential in wastewater purification even under some harsh conditions.