Search Results (156)

Reducing hospital-acquired infections, especially those related to medical devices, is essential not only to improve patients’ well-being but also to reduce healthcare costs. Among various antibacterial approaches, creating bactericidal device surfaces has been advocated as it reduces the likelihood of antibiotic-resistant strains emerging when antibiotics are used. Functionalizing the device surface with cationic groups, such as quaternary ammonium terminal groups, has been considered an effective approach for killing microbes upon contact. Nonetheless, multiple steps, some of which may require harsh chemical reactions and toxic solvents, are generally required to attach the cationic quaternary ammonium functionalities to the surface. Inspired by the mussel’s capability to bind to various substrates, various novel biomimetic cationic catechol-terminated small molecules having the quaternary ammonium functionality with different alkyl chain lengths were synthesized for the first time. These compounds were used for surface modification of medical-grade titanium using simple immersion approaches: a single-layer procedure or a two-layer approach, in which the first layer was prepared by dopamine immersion, followed by a second immersion in the compound of interest. The surface characteristics and antimicrobial capability against the Gram-negative E. coli and Gram-positive S. aureus were assessed. The likely effects of the alkyl chain length and modification schemes on the surface properties and antibacterial activity are discussed and compared. The highest antimicrobial activity against E. coli was noted on the modified surfaces prepared by the two-layer approach with the cationic compound having the shortest alkyl chain, C1, at 2 mg/mL (DA_C1-2) and 8 mg/mL (DA_C1-8). The DA_C1-8 surface also exhibited the highest antimicrobial activity against S. aureus. These findings indicated that the antibacterial activity of titanium can be greatly improved by selecting the appropriate compound and a proper, facile immersion procedure. Full article

Background: Intrauterine adhesions, a leading cause of female infertility, frequently recur in 30–62.5% of patients despite hysteroscopic adhesiolysis and adjuvant therapies. Current intrauterine barriers, including injectable hydrogels, often lack sufficient bioactivity and tissue retention, failing to address the underlying pathological inflammation and oxidative stress driving abnormal fibrosis. Methods: Herein, we tailored a reactive oxygen species (ROS)-responsive, mussel-inspired adhesive injectable hydrogel (OHA-CP@TA) to intelligently modulate the inflammatory niche and promote normal endometrial regeneration. OHA-CP@TA was fabricated through Schiff base bonds between oxidized hyaluronic acid (OHA) and phenylboronic acid-modified carboxymethyl chitosan (CMCS-PBA), and boronate ester bonds between CMCS-PBA and tannic acid (TA). Results: OHA-CP@TA exhibited good mechanical strength, injectability, self-healing, and shear-thinning properties, and importantly, robust and stable adhesion to uterine tissue, overcoming endometrial mucus clearance. It also showed favorable in vivo uterine cavity retention for at least 7 days that covered the critical endometrial repair period. Within the postoperative inflammatory milieu, OHA-CP@TA intelligently released TA in a ROS-dependent manner, which effectively scavenged various ROS and significantly alleviated inflammation, and promoted M1 macrophage polarization into M2 phenotype. This targeted ROS scavenging and immunoregulation inhibited endometrium fibrosis progression, evidenced by downregulation of α-SMA and Col-1, and actively promoted endometrial repair and regeneration, demonstrated by enhanced angiogenesis, increased endometrial thickness, and restoration of glandular numbers. Furthermore, OHA-CP@TA exhibited good biocompatibility, in vivo biodegradability and safety. Conclusions: Therefore, OHA-CP@TA represents a promising, clinically translatable strategy for overcoming the limitations of current IUA management. Full article

Urinary cancers present a severe clinical challenge due to high recurrence rates. Standard intravesical therapies suffer from limited efficacy because of the urinary tract’s robust physiological defenses, namely, the dynamic washout effect during voiding and highly restrictive urothelial barriers, such as the anti-adhesive glycosaminoglycan layer and intercellular tight junctions. This review aims to explore how biomimetic engineering can overcome these obstacles by transitioning drug delivery from passive carriers to active, nature-inspired systems. We conducted a comprehensive review of the recent literature focusing on biomimetic strategies for intravesical drug delivery and urinary cancer theranostics. The analyzed approaches are categorized into chemical biomimicry (such as adhesion and camouflage) and structural/functional biomimicry (including adaptive devices and microrobots). Biomimetic strategies significantly enhance targeted drug retention and tissue penetration. Chemical biomimicry, utilizing mussel-inspired catechol chemistry and cell membrane camouflage, effectively bypasses the urothelial anti-adhesive defenses and reduces the immune clearance. Structural and functional biomimicry, such as naturally derived carriers and actively propelled magnetic or biohybrid microrobots, enables the precise spatial localization and controlled payload release in dynamic fluid environments. Furthermore, lab-on-a-chip technologies and patient-derived organoids (PDOs) offer scalable platforms for screening cargo-specific efficacies and tailoring treatments, providing a crucial bridge to personalized precision medicine. Integrating nature-inspired designs with advanced nanotechnologies provides a highly promising pathway with which to overcome the mechanical and biological barriers of the urinary tract. These biomimetic innovations hold the potential to shift the therapeutic paradigm for urinary oncology, paving the way for more efficient, targeted, and personalized precision medicine. Full article

Marine biofouling is a major global concern affecting the marine industry, the environment, and public health. The accumulation of organisms on submerged surfaces causes significant economic losses, including increased fuel consumption, higher pollutant emissions, and accelerated corrosion. Antifouling (AF) coatings with biocides are widely used to prevent this problem. However, many conventional biocides have been banned due to toxicity, creating an urgent need for environmentally friendly alternatives. In previous studies, we synthesized a gallic acid derivative and three flavonoids that showed AF activity against the settlement of mussel larvae (Mytilus galloprovincialis) together with low ecotoxicity. In the present work, to further assess their potential in marine coatings and exploit the advantages of nanocarriers in protecting and prolonging bioactive effects, these compounds were loaded into halloysite nanotubes (HNTs) and incorporated into epoxy coatings. Coatings containing the same AF compounds in free form were also prepared for comparison. HNTs were characterized by scanning electron microscopy (SEM), and compound loading was quantified by thermogravimetric (TG) analysis. The resulting composites were analyzed by SEM and dynamic water contact angle measurements. Laboratory bioassays with M. galloprovincialis larvae showed that coatings containing HNT-loaded synthetic compounds generally reduced larval settlement more effectively than the corresponding coatings containing the same compounds directly dispersed in the epoxy matrix, with values below 20% after both 15 and 40 h of exposure for the best-performing formulation. These findings highlight the novelty of the proposed HNT-based delivery strategy for nature-inspired synthetic antifoulants and support its potential for the development of effective and environmentally safer AF coatings. Full article

Lubricants are essential for water-based drilling fluids. Catechol-based lubricants provide improved lubrication performance owing to their strong adhesion ability through the formation of coordination bonds inspired by mussel adhesion. However, the conventional synthetic ester and amide lubricants suffer from loss of adhesive capability due to hydrolysis and autoxidation. Inspired by mussels and melanin biosynthesis, a biomimetic strategy was developed to synthesize a high-adhesion lubricant with good stability via thiol-quinone Michael addition to restore and stabilize the catechol moiety. Bisphenol A was oxidized to the corresponding quinone using 2-iodoxybenzoic acid. Subsequent Michael addition reaction with 1-octadecanethiol produced a thiol-functionalized lubricant containing catechol moieties and long alkyl chains through an S-catecholyl linkage. Biomimetic principles were incorporated into both the molecular structure and the synthetic route, emulating the structural and functional features of mussel adhesion and melanin biosynthesis. Octadecanethiol provided sulfur-containing extreme-pressure functionality and contributed to strong adsorption on metal surfaces. The molecular structure was confirmed by FTIR, ¹H NMR, and ¹³C NMR. The thiol-functionalized lubricant formed strong coordination with Fe³⁺ and Fe²⁺ ions across a wide pH range, with an apparent complexation stoichiometry of 1:1 and conditional stability constants of 4.09 and 5.02, respectively. Bis-coordination formed a cross-linking network. It exhibited good resistance toward autoxidation and thermal stability up to 350 °C. In bentonite-based drilling fluids, the extreme pressure lubrication coefficient and adhesion coefficient at a 1% addition were 0.06 and 0.07, respectively. The coefficient of friction and wear scar diameter were 0.09 and 0.63 mm, respectively. The increased contact angle confirmed strong adsorption of the lubricant on metal surfaces. The lubricant combined strong adhesion, high stability, and excellent compatibility with drilling fluids, highlighting its potential as an advanced biomimetic lubricant. This biomimetic thiol-quinone addition strategy provides an effective approach to overcome the instability of conventional catechol-based lubricants. Full article

Due to the non-polar and chemically inert nature of carbon fiber surfaces, the interfacial bonding strength between carbon fibers and norbornene-polyimide (PI-NA) resin matrix is relatively weak. To address this issue, this study constructed a composite coating on the carbon fiber surface and proposed a novel method to build robust interfaces based on multiple interfacial interactions, thereby effectively enhancing the interfacial properties between carbon fibers and PI-NA resin. Inspired by mussel adhesive proteins, this study established a multi-level synergistic interfacial reinforcement system by sequentially constructing a C-PEI@OPDA coating, in situ growing zinc oxide nanorods (ZW) arrays, and grafting 3-mercaptopropyltrimethoxysilane (MPS) onto carbon fiber surfaces. The C-PEI@OPDA coating, rich in amino (–NH₂) and hydroxyl groups (–OH), enhanced adhesion to carbon fibers and adsorbed Zn²⁺ via coordination interactions to provide nucleation sites for ZW growth. Meanwhile, the active hydrogen in the coating promoted the crosslinking of PI-NA resin, thereby increasing the resin crosslinking density in the interfacial region. The vertically aligned ZW significantly increased surface roughness, enhanced mechanical interlocking effects, and provided secondary reaction sites for MPS grafting. The thiol groups (–SH) in MPS formed covalent bonds with PI-NA resin through thiol-ene click reactions, further strengthening interfacial bonding. The results showed that the ILSS, IFSS, and flexural strength of C-PEI@OPDA/ZW/MPS modified carbon fiber composites reached 75.15 MPa, 102.93 MPa, and 1735.56 MPa, representing improvements of 39.09%, 48.79%, and 31.16%, respectively. This study effectively enhanced the carbon fiber-reinforced polymer composites interfacial bonding strength through the synergistic effects of hydrogen bonding, mechanical interlocking, chemical bonding, and increased resin crosslinking density. Full article

Polyester/cotton blended fabrics—valued for comfort and durability—face significant fire hazards due to a synergistic “scaffold effect” during combustion. Conventional treatments with high temperature or some acidic phosphorus flame retardants during preparation often compromise the mechanical strength. Inspired by mussel adhesion chemistry, a mechanically enhanced polyester/cotton fabric was developed by using a novel bio-inspired phosphorus/nitrogen (P/N) synergistic coating. A uniform polydopamine-polyethylenimine (PDA-PEI) layer is rapidly deposited via co-deposition, suppressing dopamine self-polymerization. Subsequent covalent bonding with 2,2-dimethyl-1,3-propanediyl bis (phosphoryl chloride) (DPPC) establishes a robust P/N network. The fabricated PDA-PEI/DPPC coating reduces peak heat release rate (pHRR) and total heat release (THR) by 57.7% and 32.6%, respectively, in cone calorimetry, achieving self-extinguishment and a high limiting oxygen index (LOI) of 24.6%. Remarkably, the coating simultaneously increases the weft-direction breaking strength by 55% and elongation at break by 27.2%; these changes overcome the typical mechanical degradation associated with acidic phosphorus flame retardants. A comprehensive analysis reveals a synergistic mechanism: phosphoric acids catalyze cellulose dehydration and char layer formation in the condensed phase (90% stable C–C bonds), while radical scavengers (PO·, HPO·, and PDA) and non-flammable gases suppressed gas-phase combustion. This work presents a facile and effective strategy for fabricating high-performance and mechanically robust flame retardant polyester/cotton textiles, demonstrating the significant potential for improving fire safety in practical applications. Full article

A combination of surface wettability and antibacterial performance is highly imperative for construction of antibacterial coatings. In this study, motivated by the antibacterial properties of zwitterionic polymer, mussel-inspired adhesion, and the “grafting to”, a novel DOMA-SBMA copolymer with adhesion and wettability is developed for constructing a bacteriostatic surface. Specifically, the antibacterial coating is prepared via free radical polymerization and grafting to methods on the surface of stainless steel, and characterized by SCA, FTIR, XPS, SEM, and AFM to confirm the modification process. Antibacterial activity evaluation using Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) shows that the coating presents satisfactory antibacterial performance. The results showed that DOMA-SBMA coating is enough for antibacterial application, with high antibacterial efficiency against E. coli (92.2%) and S. aureus (95.0%). In summary, the bioinspired coating developed here may improve the stability of zwitterionic coatings and provides a simple preparation strategy for constructing antibacterial coatings. Full article

Adhesives represent an unparalleled material because of their wide utilization in various fields. However, reversible adhesives with recyclability or reprocessability are unexploited yet necessary in practical applications. Mussel-inspired chemistry is a powerful tool for the development of reversible adhesives owing to its multiple dynamic molecular-scale interactions. Here, we design and synthesize a mussel-inspired reversible adhesive with tough mechanical properties and great energy dissipation ability using a dynamic covalent crosslinking network. The mussel structure-based adhesive exhibits excellent adhesion strength and toughness due to the formed B–O bonds, coordination, and hydrogen interactions between substrates. Meanwhile, the dynamic boronic ester bonds endow the polymer with recyclability and debonding–rebonding capacity to satisfy the stable cyclic use of the materials, providing a sustainable adhesive for multi-bonding fields. Full article

Healthcare-associated infection, mainly through medical device-associated infection, remains a critical issue in hospital care. Bacterial adhesion, proliferation, and biofilm formation on the device surface have been considered the foremost cause of medical device-associated infection. Different means have been explored to reduce microbial attachment and proliferation, including forming a bactericidal or microbial adhesion-resistant surface layer. Fear of limited bactericidal capability if the dead microbes remained adhered to the surface has withheld the widespread use of a bactericidal surface in medical devices if it was intended for long-term use. By contrast, constructing a microbial adhesion-resistant or antifouling surface, such as a surface with zwitterionic functionality, would be more feasible for devices intended to be used for the long term. Nevertheless, a sophisticated multi-step chemical reaction process would be needed. Instead, a simple immersion method that utilized a novel mussel-inspired catechol compound with zwitterionic sulfobetaine functionality, ZDS, was explored in this investigation for the surface modification of substrates with distinctively different surface characteristics, including titanium and polyvinyl chloride. Dopamine, NaIO₄ oxidants, and chemicals that could affect ionic interactions (NaCl and polyethyleneimine) were added to the ZDS-containing immersion solution to compare their effects on modifying titanium and PVC substrates. Furthermore, a layer-by-layer immersion method, in which the substrate was first immersed in the no-ZDS-added dopamine-containing solution, followed by the ZDS-containing solution, was also attempted on the PVC substrate. By properly selecting the immersion solution formulation and additional NaIO₄ oxidation modification, the antibacterial capability of ZDS-modified substrates can be optimized without causing cytotoxicity. The maximum antibacterial percentages against S. aureus were 84.2% and 81.7% for the modified titanium and PVC substrate, respectively, and both modified surfaces did not show any cytotoxicity. Full article

Marine biofouling, the process of marine microorganisms, algae, and invertebrates attaching to and forming biofilms on ship hulls, underwater infrastructure, and marine equipment in ocean environments, severely impacts shipping and underwater operations by increasing fuel consumption, maintenance costs, and corrosion risks, and by threatening marine ecosystem stability via invasive species transport. This study reports the development of a hydrogel-metal-organic framework (MOF)-quorum sensing inhibitor (QSI) antifouling coating on 304 stainless steel (SS) substrates. Inspired by mussel adhesion, a hydrophilic bionic hydrogel was first constructed via metal ion coordination. The traditional metal ion source was replaced with a zeolitic imidazolate framework-8 (ZIF-8) loaded with 2-(5H)-furanone (HF, a QSI) without altering coating formation. Physicochemical characterization using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), the Brunauer–Emmett–Teller (BET) method, and the diffraction of x-rays (XRD) confirmed successful HF loading into ZIF-8 with intact crystal structures. Antifouling tests showed HF@ZIF-8 enhanced antibacterial inhibition against Staphylococcus aureus (97.28%) and Escherichia coli (>97%) and suppressed Chromobacterium violaceum CV026 pigment synthesis at 0.25 mg/mL (sub-growth concentration). The reconstructed PG/PVP/PEI/HF@ZIF-8 coating achieved 72.47% corrosion inhibition via synergistic anodic protection and physical shielding. This work provides a novel green approach for surface antifouling and drag reduction, highlighting MOF-loaded QSIs as promising additives to enhance the antifouling performance of hydrogel coatings, anti-corrosion performance, and QSI performance for sustainable marine engineering applications. Full article

Global growth in antimicrobial resistance (AMR) has accelerated the need for novel therapy beyond the scope of conventional antibiotics. In the last decade, polydopamine (PDA), a mussel-inspired polymer with redox capability, remarkable adhesion, and biocompatibility, has emerged as a universal antimicrobial coating with widespread uses. At the same time, extracellular vesicles (EVs) and particularly exosomes have gained prominence for their intrinsic cargo delivery and immune-modulating properties. Here, we summarize the synergistic value of PDA and exosome integration into multifunctional antimicrobial nanoplatforms. We discuss the inherent antimicrobial activity of PDA and exosomes; the advantages of PDA coating, including increased exosome stability, ROS generation, and surface functionalization; and current methodologies towards designing PDA-exosome hybrids. This review also mentions other antimicrobial polymers and nanocomposites that may be employed for exosome modification, such as quaternized chitosan, zwitterionic polymers, and polymer–metal composites. Most significant challenges, such as the maintenance of exosome integrity, coating uniformity, biocompatibility, scalability, and immunogenicity, are addressed. Finally, future research directions are highlighted, with emphasis on intelligent, stimulus-responsive coatings, AMP incorporation, and clinical translation. Collectively, this review underscores the promise of PDA-coated exosomes as potential antimicrobial therapeutics against AMR with potential applications in wound healing, implant protection, and targeted infection control. Full article

Polydopamine (PDA) is an emerging biomimetic material that stimulates the distinctive physicochemical properties of the blue mussel byssus. In this study, we report a rapid and facile method for the decoration of gold nanoparticles (AuNPs) onto the mussel-inspired polydopamine nanospheres (PDA NSs) via cold atmospheric plasma treatment. After 10 min of plasma treatment, AuNPs with a size of 10.3 ± 2.0 nm were formed on the surface of PDA NSs. This reaction was performed without the need for any additional reducing agents, thereby eliminating the use of harsh chemicals during the process. The synthesized AuNP-decorated PDA nanohybrids (PDA-Au) exhibit effective catalytic activity for the decoloration of Rhodamine B, with a pseudo-first-order rate constant of 1.405 min⁻¹. The green synthesis approach in this work highlights the potential of plasma-assisted methods for decorating biomimetic materials with metallic nanoparticles for catalytic and environmental applications. Full article

Guided bone regeneration (GBR) membrane has proven to be a fundamental tool in the realm of bone defect repair. In this study, we develop a mussel-inspired composite biomaterial through polydopamine-assisted, combining gelatin–WPU matrix with the ion-release behavior of Cu–MSNs for augmented bone regeneration. The optimized composite membrane exhibits enhanced mechanical stability, demonstrating a tensile strength of 11.23 MPa (representing a 2.3-fold increase compared to Bio-Gide^®), coupled with significantly slower degradation kinetics that retained 73.3% structural integrity after 35-day immersion in physiological solution. Copper ions act as angiogenic agents to promote blood vessel growth and as antimicrobial agents to prevent potential infections. The combined effect of these components creates a biomimetic environment that is ideal for cell adhesion, growth, and differentiation. This research significantly contributes to the development of advanced biomaterials that combine regeneration and infection-prevention functions. It provides a versatile and effective solution for treating bone injuries and defects, offering new hope for patients in need. Full article

The application background of mussel-inspired materials is based on the unique underwater adhesive ability of marine mussels, which has inspired researchers to develop bionic materials with strong adhesion, self-healing ability, biocompatibility, and environmental friendliness. Specifically, 3, 4-dihydroxyphenylalanine (DOPA) in mussel byssus is able to form non-covalent forces on a variety of surfaces, which are critical for the mussel’s underwater adhesion and enable the mussel-inspired material to dissipate energy and repair itself under external forces. Mussel-inspired hydrogels are ideal medical adhesive materials due to their unique physical and chemical properties, such as excellent tissue adhesion, hemostasis and bacteriostasis, biosafety, and plasticity. This paper reviewed chitosan, cellulose, hyaluronic acid, gelatin, alginate, and other biomedical materials and discussed the advanced functions of mussel-inspired hydrogels as wound dressings, including antibacterial, anti-inflammatory, and antioxidant properties, adhesion and hemostasis, material transport, self-healing, stimulating response, and so on. At the same time, the technical challenges and limitations of the biomimetic mussel hydrogel in biomedical applications were further discussed, and its potential solutions and future research developments in the field of biomedicine were highlighted. Full article