Excellent Adhesion Research Articles

PDA Nanoparticle-Induced Lubricating Film Formation in Marine Environments: An Active Approach

The low viscosity of water-lubricated films compromises their load-bearing capacity, posing challenges for practical application. Enhancing the lubrication stability of these films under load is critical for the successful use of seawater-lubricated bearings in engineering. Polydopamine (PDA) shows great potential to address this issue due to its strong bio-inspired adhesion and hydration lubrication properties. Thus, PDA nanoparticles and seawater suspensions were synthesized to promote adhesive lubricating film formation under dynamic friction. The lubrication properties of PDA suspensions were evaluated on Cu ball and ultra-high molecular weight polyethylene (UHMWPE) tribo-pairs, with a detailed comparison to seawater. The results show PDA nanoparticles provide excellent adhesion and lubrication, enhancing the formation of lubricating films during friction with seawater. Under identical conditions, PDA suspensions demonstrated the lowest friction coefficient and minimal wear. At 3 N, friction decreased by 56% and wear by 47% compared to distilled water. These findings suggest a novel strategy for using PDA as a lubricant in seawater for engineering applications.

Strong Bonding of Robust Lubricating Hydrogels to Porous Substrates for Joint Replacement.

Hydrogels with excellent mechanical and lubrication properties have been developed rapidly, laying the foundation for their application in cartilage replacement. However, the combination of robust hydrogels and substrates under different forms of movement is a great challenge. In addition, due to differences in modulus, the stress shielding effect caused by implantable artificial joint metal materials can lead to bone resorption. Here, we proposed to combine a 3D printed porous titanium alloy with a high-strength lubricating hydrogel to construct an integrated joint substitute material. The porous titanium alloy TC4 substrate constructed by 3D printing possesses a modulus similar to that of human bone. The strong bonding of the hydrogel and TC4 was achieved through two strategies: mechanical interlocking and chemical bonding. The combination of the alloy substrate and hydrogel realizes the construction of a bionic lubricating cartilage layer on the surface of traditional artificial joint materials. The hydrogel has excellent bonding properties with the porous substrate under different test conditions. Truly human-like joint sockets were prepared for the first time with soft-soft and soft-hard contact modes. Under conditions simulating human motion, the hydrogel maintains a low friction coefficient and still has excellent substrate adhesion after 100,000 cycles. This study further pushes the application of hydrogels in biolubrication into practice.

Densifying Conduction Networks of Vertically Aligned Carbon Fiber Arrays with Secondary Graphene Networks for Highly Thermally Conductive Polymer Composites

AbstractThermally conductive polymer composites hold great potential for thermal management applications in the electronics industry, but achieving metal‐like thermal conductivity (>200 W m−1 K−1) remains challenging due to the inevitable phonon scattering and the thermal resistance at filler‐filler and filler‐matrix interfaces. Herein, an efficient approach is presented to overcome this long‐standing barrier by designing a densified interconnecting filler framework, featuring a macro‐level carbon fiber (CF) array welded with a high‐quality, self‐assembled graphene network. In this framework, vertically aligned continuous CFs function as primary through‐plane thermal conduction paths, minimizing phonon scattering and thermal resistance. Meanwhile, the secondary graphene network interconnects the CFs into a more integrated and densified framework while introducing supplementary thermal conduction paths. Following polymer backfilling, the resulting epoxy nanocomposite exhibits an unprecedented through‐plane thermal conductivity of 262 W m−1 K−1 at a filler loading of 23.3 vol%, establishing a new benchmark among the thermally conducting polymer composites. When employed as a thermal interface material, this composite offers a 68.2% enhancement in cooling efficiency compared to standard commercial counterparts. Furthermore, the functional composite presents excellent Joule heating and interfacial adhesion properties, making it promising for thermal interface healing and multifunctional thermal management applications in complex environments.

Stem Cell Membrane-Camouflaged Biomimetic Nanoparticles Inhibiting Leptin Pathway for Intervertebral Disc Degeneration Therapy.

Leptin, a kind of adipokine, with its receptor in which the long isoform plays a crucial role in signal transduction, has been identified in intervertebral disc (IVD) tissues, especially showing an increased expression in degenerated discs. Initially identified as a metabolic sensor, leptin has recently been found able to regulate inflammation into imbalance, which favors catabolic degradative processes, thus contributing to progressive intervertebral disc degeneration (IDD). Therefore, efficiently inhibiting the leptin pathway may provide a new strategy to treat IDD. In this study, we introduced an innovative drug delivery system (DDS) that employs stem cell membranes (SCM) to encapsulate (Zeolitic imidazolate frameworks-8) ZIF-8 nanoparticles. These nanoparticles are used to transport a plasmid containing shRNA targeting the leptin receptor (LEPR), with the aim of facilitating repair in IDD. The regenerative performances of this DDS in IDD were verified through a combination of the in vitro western blot and immunofluorescence with the in vivo radiologic examination and histological staining. The DDS demonstrated excellent cell adhesion properties and gene transfection efficiency in vitro, along with impressive treatment outcomes in vivo. Both in vitro and in vivo studies revealed that the DDS effectively reduced leptin receptor expression and alleviated the inflammatory environment, thereby promoting regeneration in degenerated IVDs. We propose that the DDS represents a promising novel approach for treating IDD and may also be beneficial for other degenerative diseases linked to leptin pathway dysfunction.

Screening of bile salt hydrolase-producing lactic acid bacteria and evaluation of cholesterol-lowering activity in vitro

Hypercholesterolemia is a great threat to humans. Bile salt hydrolase (BSH)-producing lactic acid bacteria (LAB) may alleviate it, but current screening methods are inadequate. This study aimed to establish a more comprehensive in vitro method to screen BSH-producing LAB with greater potential for anti-hypercholesterolemia. Forty-one LAB were initially isolated from infant feces and 37 strains could produce BSH. Strains with BSH over 2 U/mg for sodium glycodeoxycholate and sodium taurodeoxycholate were used to analyse cholesterol degradation rate, hydrophobicity, self-aggregation, gastric fluid tolerance, and intestinal fluid tolerance. Based on the results of these indicators, Lactococcus lactis Y17, L. rhamnosus Q2, and L. fermentum Q11 with the top scores were considered anti-hypercholesterolemia candidates using a principal component analysis evaluation. Antioxidant and Caco-2 adhesion assays showed that these three strains exhibited excellent antioxidant ability and Caco-2 adhesion ability. Their total antioxidant capacity was above 0.99 μmol/L, while the Caco-2 adhesion rate was higher than 8.22%. Safety assessments, via antibiotic susceptibility and hemolysis tests, confirmed their safety. In the HepG2 cells assay, the total cholesterol content of the Y17, Q2, and Q11 groups was reduced by 0.525 mmol/L, 0.426 mmol/L, and 0.581 mmol/L, which verified the potential of the three LAB in anti-hypercholesterolemia. In addition, they could enhance cholesterol uptake and bile acid synthesis in HepG2 cells by upregulating the mRNA expression of bile acid synthase (CYP7A1 and CYP8B1) and cholesterol uptake receptors (NPC1L1 and LDLR). The results showed that the three LAB could be developed into anti-hypercholesterolemia foods with beneficial properties.

Stretchable, self-adhesive, and conductive hemicellulose-based hydrogels as wearable strain sensors

Conductive hydrogels have recently gained impressive attention in flexible sensing. However, their low sensing limit and poor interface matching have raised great concern during the practical application. Therefore, incorporating excellent stretchability and adhesiveness into conductive hydrogel is highly desirable but still be a huge challenge. In this study, we synthesized composite hydrogels with desired properties by utilizing the synergistic role of hemicellulose (HC) and conductive two-dimensional material MXene. As a result, the synthesized hydrogels showed good self-adhesion (3.12 KPa on the skin), great stretchability (>1700 %), and satisfactory electrical conductivity. These multifunctional hydrogels operated as adaptable sensors, adeptly capturing the nuanced signals emanating from an array of human motions. They exhibited an expansive strain tolerance, swift reactivity, and an enhanced acuity in detecting even the slightest deformations (GF = 2.1). Our research provides new insights for creating stretchable, self-adhesive, and functional hydrogels for sensing applications.

Powdered Medical Adhesive with Long Lasting Adhesion in Water Environment.

Medical adhesives have been used under surgical conditions. However, it is always a big challenge to maintain long-term adhesion in a water environment. Besides, it usually takes a long time to complete the adhesion, and the operation might be complicated. In this study, tannic acid and gelatin solution under acidic conditions were mixed, flocculated, lyophilized, and crushed; thus, a powdered medical adhesive (POWDER) was prepared with long-lasting adhesion in a water environment, convenience, and low price. Tannic acid bound gelatin and maintained adhesive force primarily through hydrogen bonding and reacted with amino sulfhydryl and other amino acid residues after oxidation into aldehyde, exhibiting excellent underwater adhesion. Oxidized dextran (ODex) powder rich in an aldehyde group was introduced to provide covalent binding in the adhesive. In vitro and in vivo studies showed that POWDER could quickly adhere to various tissues in the water environment. In vitro skin adhesion experiments demonstrated that it could achieve effective adhesion in a water environment for up to 60 days. Its blood compatibility, low cytotoxicity, and biodegradability were also verified. The POWDER developed in this study is of great significance for patients who need rapid wound treatments.

Chitosan and gelatin based sprayable hydrogels incorporating photothermal and long-acting antibiotic sterilization for infected wound management with shape adaptability

Severe skin damage resulting from acute trauma is often accompanied by uncontrolled bleeding, microbial infections, and delayed wound healing. Herein, multifunctional sprayable hydrogels (CT-CS-ZIF@CIP Gel) were developed for wound management by incorporating antibacterial nanoplatforms (CT-CS-ZIF@CIP) into photocurable gels consisting of chitosan methacrylate and gallic acid grafted gelatin. The nanoplatform was initially constructed by sequentially loading Cu2Se (CS) and ciprofloxacin-decorated zeolitic imidazolate framework-8 (ZIF@CIP) onto Cu-doped Ti MOF (CT), in which CS served as a photothermal agent, ZIF enabled pH-responsive release of CIP, and CT acted as carriers for CS and ZIF@CIP. The hydrogel precursor can be sprayed onto wound surface and photocured quickly, allowing hydrogel to fit the wound shape and form a protective barrier onsite. The resultant hydrogel exhibited excellent hemostatic ability, adhesion properties, cytocompatibility and toxin adsorption capacity. By integrating CS for short-term photothermal therapy with CIP for long-acting chemotherapy, the CT-CS-ZIF@CIP Gel demonstrated 100 % sterilization of three bacterial strains. Furthermore, moderate release of zinc and copper ions promoted wound healing. The therapeutic efficacy of hydrogel was validated in an infected cutaneous mouse model. Overall, this work presents a versatile sprayable hydrogel that can be flexibly applied to irregular dynamic wounds for safe and effective wound management.

Experimental study of the in-situ fabrication of strain sensor with conductive adhesive to monitor the concrete structure

Conventional strain sensors typically had a limited detection area and the fragility of the sensor-concrete interface. This study proposed an in-situ sensor fabrication technique using conductive epoxy adhesive to fabricate strain sensors in the concrete. The performance of the strain sensors was systematically evaluated, resulting in the conductive adhesive strain sensor exhibiting excellent linearity, sensitivity, low zero drift, and minimal hysteresis. There was a positive impact on strain sensor linearity and sensitivity through the increase in the length of the conductive adhesive. The resistance change rate in the sensors accelerated with increasing temperature, establishing a functional relationship between resistance change rate and temperature. The sensors exhibited excellent linearity and sensitivity with strain, and all the fitted data points were within the 95 % confidence interval. Furthermore, the microscopic characterization revealed that the in-situ fabricated sensors exhibited excellent adhesion to the cement composite, demonstrating favorable working performance in the cement-based environment.

Self-adhesive, mechanically strong, and conductive organogel for flexible/wearable electronics and underwater electronic skin

Due to their flexibility, self-healing ability, and biocompatibility, conductive hydrogels have become excellent candidates for flexible electronics. However, challenges remain, such as water evaporation when exposed to air, resulting in a loss of flexibility and conductivity. Additionally, traditional hydrogels quickly swell underwater, which causes irreversible damage to their structure and electrical properties. As a promising alternative, organogels have gained attention for overcoming these drawbacks. Here, we report a transparent, multifunctional organogel using ultraviolet-initiated polymerization, which exhibits excellent adhesion, robustness, electrical and interfacial stability, and super stretchability. By adjusting the concentration of the lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the conductivity of organogel could be easily regulated from non-conductive to conductive, obtaining non-conducting elastomer (NCE, without LiTFSI) and ion-conducting elastomer (ICE, with LiTFSI) with identical mechanical properties and superior adhesion due to the same composing polymer chains. This unique characteristic overcomes the interface mismatch problem of traditional flexible electronic devices. Moreover, a high-performance triboelectric nanogenerator (TENG) was designed (ICE-TENG) to achieve a maximum power density of 151.3 μW cm−2, which was utilized to power small electronics. Additionally, a strain sensor was constructed using the ICE, realizing underwater sensing and communication with high stability. This multifunctional organogel is promising for multi-functional human–machine interaction.

Bioadhesive supramolecular polymer/hyaluronic acid hydrogel with zinc ion and dexamethasone slow release for diabetic wound healing

Diabetic patients often struggle with wound healing and are at higher risk of infections, necessitating the development of a stretchable, adhesive hydrogel dressing with antibacterial and angiogenesis-promoting properties. In this study, we synthesized a series of adhesive, antibacterial and anti-inflammatory hydrogels using free radical polymerization with materials including methacrylated hyaluronic acid (HAMA), N-[tris(hydroxymethyl)methyl]acrylamide (THMA), and 3-(bis(pyridin-2-ylmethyl)amino)propyl methacrylate (DPAMA). By leveraging the strong affinity of zinc(II)-dipicolylamine coordination complexes for the phosphorylated groups in dexamethasone sodium phosphate (DMSP), Zn2+ and DMSP were successfully incorporated into the hydrogel. The results demonstrated that the hydrogels possessed excellent adhesiveness and mechanical properties, enabling them to adhere closely to the skin while remaining easily removable without causing trauma. Antibacterial tests demonstrated significant inhibitory effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), attributed to the slow release of Zn2+, which effectively suppressed bacterial growth. Additionally, the slow release of DMSP provided strong anti-inflammatory effects. The DHTDZ2 hydrogel, containing 1.5 mg/mL Zn2+ and 4 mg/mL DMSP, significantly accelerated the healing of full-thickness skin wounds. In vitro angiogenesis, immunofluorescence, and immuno-histochemical results further confirmed that the DHTDZ2 hydrogel promoted angiogenesis and reduced the expression of pro-inflammatory factors. In summary, the hydrogel is an effective wound healing dressing that can reduce wound infections and inflammation.

Bio-inspired chitosan/polyvinyl alcohol/tannic acid hydrogels as plant grafting wood adhesives

Recently, there has been growing interest in plant-inspired materials for various biological, medical, and industrial applications. Notably, tannic acid-based materials exhibit remarkable adhesive properties and can be used in a variety of applications, particularly biomedical applications. In addition, mixtures composed of tannic acid and polymers (e.g., polyvinyl alcohol) exhibit excellent adhesion to various substrates. In this study, we developed gallol-containing chitosan (G-CS), polyvinyl alcohol (PVA), and tannic acid (TA) composite (G-CPT) hydrogels as wood adhesive materials. G-CPT hydrogels were immediately formed by mixing the G-CS/PVA solution with the TA solution. Rheological analysis revealed an increase in the elastic modulus (G′) with the addition of small amounts of G-CS. In addition, the detachment stress of wood sticks attached using G-CPT hydrogels was 142.2 ± 7.2 MPa, which was substantially higher than that of G-CS (5.3 ± 1.4 kPa), PVA (2.2 ± 0.2 kPa), TA (0.4 ± 0.1 kPa), and PVA/TA hydrogels (106.5 ± 2.5 MPa). Furthermore, G-CPT hydrogels can be used as wood adhesives for scion grafting into the rootstock of English ivy. These findings highlight the importance of G-CPT hydrogels as eco-friendly wood adhesives with enormous potential for various industrial and agricultural applications.

Chinese ink-coated elastic PU/PET fibers as multifunctional flexible wearable sensors

Textiles as conductive substrates are widely used in sensing applications due to their good elasticity, high stretchability and recoverable deformation. Here, the mask rope (polyurethane/polyester blended fibers) was selected as flexible substrate to load of conductive Chinese ink using surface swelling technique in N, N-dimethylformamide. The presence of carbon nanoparticles in the ink imparts electrical conductivity to the elastic fiber while maintaining the mechanical properties and extensibility of the fiber. This simple and low-cost method allows excellent interfacial adhesion between the conductivity ink layer and the elastic fibers, and the carbon particles do not fall off even when the modified fiber was treated by sonication in water. The ink coated elastic fiber as strain sensor shows excellent stability and sensitive responsiveness after 500 stretch-release cycles. The response and recovery times during the sensitivity experiment of the flexible fiber sensor are 133.79 and 134.76 ms. The sensor exhibits physiological motion detection and quality monitoring capabilities, which can accurately monitor human movements such as walking, wrist movement, throat swallowing and articulation. The sensor also has a good Joule heating effect, and the temperature of the conductive fiber can increase 88.9°C in the 60 s under 15 V voltage. This work develops a simple and efficient, low-cost, mass-producible flexible sensor with potential for physiological activity, temperature, and humidity detection.

Concrete-Inspired Bionic Bone Glue Repairs Osteoporotic Bone Defects by Gluing and Remodeling Aging Macrophages.

Osteoporotic fractures are characterized by abnormal inflammation, deterioration of the bone microenvironment, weakened mechanical properties, and difficulties in osteogenic differentiation. The chronic inflammatory state characterized by aging macrophages leads to delayed or non-healing of the fracture or even the formation of bone defects. The current bottleneck in clinical treatment is to achieve strong fixation of the comminuted bone fragments and effective regulation of the complex microenvironment of aging macrophages. Inspired by cement and gravel in concrete infrastructure, a biomimetic bone glue with poly(lactic-co-glycolic acid) microspheres is developed and levodopa/oxidized chitosan hydrogel stabilized on an organic-inorganic framework of nanohydroxyapatite, named DOPM. DOPM is characterized via morphological and mechanical characterization techniques, in vitro experiments with bone marrow mesenchymal stromal cells, and in vivo experiments with an aged SD rat model exhibiting osteoporotic bone defects. DOPM exhibited excellent adhesion properties, good biocompatibility, and significant osteogenic differentiation. Transcriptomic analysis revealed that DOPM improved the inflammatory microenvironment by inhibiting the NF-κB signaling pathway and promoting aging macrophage polarization toward M2 macrophages, thus significantly accelerating bone defect repair and regeneration. This biomimetic bone glue, which enhances osteointegration and reestablishes the homeostasis of aging macrophages, has potential applications in the treatment of osteoporotic bone defects.

A clean and novel drying method for bamboo colorization and in-situ surface wax utilization

Round bamboo is considered an environmentally friendly product, with surface color crucial to its value. Surface wax is crucial for the growth and development of bamboo, but can alter the color of round bamboo and easily detach under the influence of heat and humidity, leading to uneven colorization. By controlling the drying temperature at 90 ℃, the surface wax can be uniformly levelled on the bamboo’s surface, enhancing its color to a consistent deep red. Chromaticity measurements show L* values between 29.58 and 34.68 and a* values from 5.58 to 6.04 at 90 ℃. DSC test shows that the wax completely melted and levelled evenly at 90 ℃, solidifying uniformly on the bamboo surface upon drying, thus realising in-situ utilization of the wax. FTIR, GC-MS and XPS analyses reveal that drying at 90 ℃ leads to an increase in chromogenic substances within the wax and bamboo green, along with heightened intensity of unsaturated functional groups, and deepening of surface color, ultimately achieving the colorization of the round bamboo. Furthermore, the prepared round bamboo exhibits excellent pencil hardness (5 H), adhesion, and glossiness (5.38 GU), while maintaining its mechanical properties. This innovative method integrates drying, colorization, and wax utilization in one step, offering a novel strategy for enhancing round bamboo’s quality.

Copper hydrogen phosphate nanosheets functionalized hydrogel with tissue adhesive, antibacterial, and angiogenic capabilities for tracheal mucosal regeneration

Timely and effective interventions after tracheal mucosal injury are lack in clinical practices, which elevate the risks of airway infection, tracheal cartilage deterioration, and even asphyxiated death. Herein, we proposed a biomaterial-based strategy for the repair of injured tracheal mucosal based on a copper hydrogen phosphate nanosheets (CuHP NSs) functionalized commercial hydrogel (polyethylene glycol disuccinimidyl succinate-human serum albumin, PH). Such CuHP/PH hydrogel achieved favorable injectability, stable gelation, and excellent adhesiveness within the tracheal lumen. Moreover, CuHP NSs within the CuHP/PH hydrogel effectively stimulate the proliferation and migration of endothelial/epithelial cells, enhancing angiogenesis and demonstrating excellent tissue regenerative potential. Additionally, it exhibited significant inhibitory effects on both bacteria and bacterial biofilms. More importantly, when injected injured site of tracheal mucosa under fiberoptic bronchoscopy guidance, our results demonstrated CuHP/PH hydrogel adhered tightly to the tracheal mucosa. The therapeutic effects of the CuHP/PH hydrogel were further confirmed, which significantly improved survival rates, vascular and mucosal regeneration, reduced occurrences of intraluminal infections, tracheal stenosis, and cartilage damage complications. This research presents an initial proposition outlining a strategy employing biomaterials to mitigate tracheal mucosal injury, offering novel perspectives on the treatment of mucosal injuries and other tracheal diseases.

Synthesis and evaluation of bio-based Poly(oxime-urethane) with intrinsic antimicrobial properties

Intrinsic antimicrobial properties can give polyurethanes a wider range of applications. In this work, the bio-based chain extender, 2,5-diformylfuran dioxime (DFFD) possessing antimicrobial characteristic, is used to synthesize the intrinsical antimicrobial poly(oxime-urethane) (Dx-PU) with isophorone diisocyanate (IPDI) and poly(tetramethylene glycol) (PTMG-1000), and its properties are investigated. The results show that the tensile strength is 19.12 ± 0.49 MPa, the Young’s modulus of the poly(oxime-urethane) is 118.70 ± 11.40 MPa. The elongation at break and Shore A hardness were 292 ± 11 % and 93 ± 2, respectively. Additionally, the Dx-PU demonstrated a high thermal decomposition temperature of over 250 °C and a low glass transition temperature of the soft segments at approximately −60 °C. Meanwhile, research on Dx-PU coating has demonstrated that Dx-PU coating is 100 % antimicrobial against E. coli and S. aureus, and is suitable for use on a wide range of substrates, including glass, engineering plastics, metal and leather with excellent adhesion (ISO 0), pencil hardness (2H), impact resistance (0.5 m·kg) and flexibility (2 mm). The Dx-PU coating also has significant antibacterial performance in everyday environments. The outstanding flexibility, moderate Young’s modulus, high elongation at break, good thermal resistance, and excellent antimicrobial performance of Dx-PU make it highly suitable for applications on high-contact surfaces such as hospital walls, public sanitation facilities, countertops, and door handles. As a bio-based chain extender from renewable sources, DFFD offers new solutions for the synthesis of bio-based antimicrobial polyurethane and its coatings.

Potential probiotic Lactiplantibacillus plantarum DS1800 extends lifespan and enhances stress resistance in Caenorhabditis elegans model.

Probiotics are live microorganisms that provide health benefits when administered in appropriate amounts by improving or restoring the balance of intestinal microbiota. Various functional probiotic products have been developed due to the growing interest in the health-promoting and anti-aging effects of enhancing the gut microbiome. Lactiplantibacillus plantarum species are known for their potential to extend lifespan. However, this activity is strain or isolation source specific, necessitating the identification of individual strain functionalities. This study used the C. elegans model to screen probiotics for life-extension effects and analyze their functions. The 43 lactic-acid bacteria strains isolated from fermented foods, breast milk, and human feces were subjected to longevity assays, and L. plantarum DS1800 was selected to demonstrate the most effective lifespan extension. The average lifespan of Caenorhabditis elegans fed DS1800 increased by 17.36% compared with those fed Escherichia coli OP50. Further analysis of the expression of key genes related to longevity revealed the high expression of the skinhead-1 (skn-1), antibacterial, and heat stress resistance genes via the p38 MAPK pathway. These expression patterns suggest that DS1800 extends the lifespan of C. elegans by enhancing its stress resistance and protecting it against pathogens. Additionally, DS1800 exhibited excellent intestinal adhesion, with 7.56% adhesion to HT-29 cells. Therefore, L. plantarum DS1800 is effective in extending the lifespan of C. elegans and can be used as a functional probiotic.

Synthesis of highly transparent and fast-responding photochromic coating by template method with space-limited domains

The persistent global high-temperature weather warns us that improving energy efficiency and reducing CO2 emissions are urgent. Controlling the solar energy input in buildings using photochromic smart coating can effectively reduce the energy consumption required for cooling. However, it remains a challenge to achieve high transparency and fast photoresponse in organic–inorganic hybrid photochromic smart coating. Herein, we utilize space-limited domains to design a template polymer that facilitates the formation of amorphous WO3 nanodots, thereby enhancing the polymer network structure through hydrogen bonding and dipole–dipole interactions, which endow the smart coating with excellent adhesion strength up to 13 MPa. Notably, the photochromic smart coating with amorphous WO3 nanodots exhibits higher transparency (96.8 %) than conventional glass (91 %), and a wide visible light modulation range of 96.8 %-4.8 %. Based on this, the cooling efficacy of the smart photochromic coating was assessed within a model residence under actual environmental conditions. The inner temperature of the model house was reduced by up to 13 °C, which decreased indoor heat absorption by 25.8 %, significantly improving energy efficiency. This work provides an important and attractive strategy for achieving energy-efficient building materials and addressing global climate warming.

Chitosan-melanin complex microsphere: A potential colonic delivery system for protein drugs

The characteristics and performance of chitosan-based colon delivery systems are significantly influenced by the method of preparation. Insect chitosan-melanin complex (CMC) may offer superior attributes over traditional shrimp and crab chitosan (CS) for colon-targeted administration. This study used dung beetle CMC as the carrier matrix and comprehensively examined the impact of various crosslinking techniques on the colonic drug delivery efficacy of microspheres, encompassing drug loading, swelling, drug release behavior, adhesion, enzymatic degradation, and absorption enhancement. The results indicate that F-TPPLC microspheres, crosslinked with a combination of formaldehyde and sodium tripolyphosphate, exhibit superior drug loading capabilities, optimal swelling behavior, and controlled in vitro drug release profiles in the colonic environment, along with excellent adhesion and enzymatic degradation properties within intestinal tract. Notably, these F-TPPLC microspheres increase paracellular permeability, possibly by disrupting the calcium-dependent adhesion junctions. In comparison to commercial CS, CMC demonstrates superior drug encapsulation efficiency, enhanced colonic drug release, adhesion, and absorption promotion, rendering it a favorable candidate as a carrier in colon-targeted drug delivery systems. Consequently, F-TPPLC microspheres derived from CMC are highly suitable for colon drug delivery applications and show promising potential for the oral delivery of peptide and protein-based therapeutics to the colon.