Search Results (162)

A series of boron-functionalised exo-norbornene monomers bearing boronic ester groups were synthesised via a condensation reaction and subsequently polymerised through ring-opening metathesis polymerisation (ROMP) to afford well-defined poly(norbornene-B-arylene-dioxaborepine)s. The incorporation of Lewis acidic boron centres into the norbornene-derived polymer backbone enables access to coordination-active macromolecular systems with tuneable interactions towards nucleophilic species. The resulting polymers demonstrate enhanced structural definition and stability, thereby confirming the robustness of the synthetic approach and the successful incorporation of boron functionalities into ROMP-derived architectures. This work establishes a general and efficient strategy for the preparation of boron-containing ROMP polymers, providing a versatile platform for the development of coordination-responsive polymeric materials. Full article

Background/Objectives: Thrombotic cardiovascular diseases remain a major cause of morbidity and mortality worldwide. Current antithrombotic therapies are limited by insufficient thrombus targeting. This study aimed to develop a fibrin-binding peptide-functionalized, hydrogen peroxide (H₂O₂)-responsive polymeric micelle and to evaluate its physicochemical properties and biological effects under H₂O₂-induced endothelial oxidative stress and preliminary FeCl₃-induced thrombosis conditions. Methods: A fibrin-binding peptide, P2 (VTFIKC), was screened using computer-aided drug design and evaluated through microscale thermophoresis and in vitro thrombus adhesion assays. An all-trans retinoic acid (atRA)-based boronate ester prodrug, BORA, was synthesized to enable H₂O₂-triggered degradation and drug release. BORA was co-assembled with P2-modified Mal-PEG-b-PAsp to prepare P2-Mal-PEG-b-PAsp/BORA micelles. Their physicochemical properties, H₂O₂ responsiveness, H₂O₂-scavenging activity, cytocompatibility, cytoprotective effects, anti-inflammatory activity, and preliminary in vivo efficacy were evaluated. Results: The resulting micelles exhibited a suitable nanoscale size, acceptable cytocompatibility, H₂O₂-responsive changes in particle size distribution, and concentration-dependent H₂O₂-scavenging activity. In H₂O₂-stimulated human umbilical vein endothelial cells, micelle treatment was associated with improved cell viability, lower intracellular ROS-associated fluorescence, and reduced TNF-α and IL-1β concentrations. In a FeCl₃-induced rat carotid artery thrombosis model, P2-Mal-PEG-b-PAsp/BORA micelles altered platelet- and leukocyte-related hematological indices and exhibited preferential accumulation in the thrombotic carotid artery. Conclusions: P2-Mal-PEG-b-PAsp/BORA micelles combine P2-mediated fibrin-binding potential, H₂O₂-responsive release behavior, and H₂O₂-scavenging activity. The findings provide preliminary support for further investigation of this peptide-functionalized nanoplatform. Full article

Background: The fibrous tumor extracellular matrix (ECM), driven by cancer-associated fibroblasts (CAFs), forms a physical barrier against drugs and immune cells, yet direct CAF elimination risks promoting metastasis. Methods: In this study, we developed a locally injectable hydrogel based on synergistic dynamic covalent crosslinking (imine and boronate ester bonds), enabling instant gelation, shear thinning, and dual-pH/ROS-responsive degradation. Two types of drug-loaded nanoparticles (NPs), coated with homotypic cell membranes, were incorporated into this hydrogel. In the acidic, reactive oxygen species (ROS)-rich tumor microenvironment (TME), the system responsively releases the antifibrotic drug SIS3 to reprogram CAFs while simultaneously delivering doxorubicin (DOX) specifically to tumor cells. Biological effects were evaluated in vitro using cell cultures and in vivo in mouse models. Results: This dynamic hydrogel-based co-delivery system effectively reprograms CAFs, reduces tumor mechanical stress, breaks the fibrotic barrier, and promotes the deep infiltration of chemotherapeutics and immune cells, thereby enhancing the efficacy of chemotherapy. Conclusions: This injectable pH/ROS-responsive dynamic covalent hydrogel, loaded with CAF- and cancer cell-targeting NPs, remodels the TME, enhances drug and immune cell penetration, and offers a promising biomaterial-based strategy for cervical cancer treatment. Full article

Heat-polymerized poly(methyl methacrylate) (PMMA) is widely used for denture bases but remains susceptible to surface deformation and sliding wear. This study evaluated the structure, chemistry, surface morphology, microhardness, and dry-sliding tribology of PMMA reinforced with 1, 3, and 5 wt.% cubic boron nitride (c-BN). Disk specimens (10 mm diameter × 2 mm thickness) were prepared; ten specimens per group were tested for Vickers microhardness and wear/coefficient of friction, while one representative specimen per group was examined by XRD, ATR-FTIR, and SEM/EDS before and after wear. The PMMA amorphous/semi-amorphous response and characteristic ester bands were retained, whereas c-BN-related diffraction features and B/N signals became more evident with reinforcement. Microhardness increased from 20.00 ± 0.70 to 45.00 ± 1.61 HV0.03. After 1000 m at 10 N and 1 m s⁻¹, mass loss decreased from 32.4 to 9.8 mg and the overall coefficient of friction from 0.58 to 0.28. Post-wear SEM/EDS showed reduced grooving, smearing, and material detachment at higher c-BN contents. Statistical analysis confirmed large composition effects, and composition-window models reproduced the measured hardness and wear trends. Within the tested range, 5 wt.% c-BN provided the strongest surface-hardening and wear-suppression response under controlled dry-sliding conditions. Full article

Carbohydrates are among the most highly oxygenated biomolecules in nature, possessing dense arrays of hydroxyl, ether, carbonyl, carboxylate, phosphate, and sulfate functionalities that govern hydration, hydrogen bonding, molecular recognition, and supramolecular organization. Their stereochemically organized oxygen-donor groups provide numerous appropriately oriented diol motifs capable of selective and reversible coordination with boric acid and borate ions. This review examines the structural and physicochemical principles underlying carbohydrate–borate interactions, with particular emphasis on oxygen-rich biological interfaces. Pentoses, hexoses, oligosaccharides, polysaccharides, glycolipids, and membrane-associated glycoconjugates are considered to illustrate how hydroxyl-group orientation, molecular conformation, pH, hydration, and local environment determine borate recognition, complex stability, and dynamic assembly. Evidence from NMR and other spectroscopic methods, crystallography, mass spectrometry, calorimetry, and molecular simulations demonstrates that borate coordination follows common stereochemical and thermodynamic principles despite the remarkable structural diversity of carbohydrates. Biological examples include borate-mediated crosslinking in plant cell walls and interactions involving microbial carbohydrates, marine polysaccharides and glycoconjugates, photosynthetic membrane lipids, and cyanobacterial heterocyst glycolipids. Particular attention is given to distinguishing experimentally established borate complexes from membrane-associated interactions that remain proposed and require further characterization. Reversible borate crosslinking of oxygen-rich carbohydrate networks also provides the chemical basis for emerging applications in responsive hydrogels, biosensors, supramolecular assemblies, drug-delivery systems, and functional biomaterials. Collectively, the available evidence indicates that the spatial organization of oxygen donor atoms within carbohydrates provides the molecular basis for selective borate recognition, whereas boron can convert this functionality into reversible higher-order organization. This oxygen-centered perspective integrates coordination chemistry, glycobiology, membrane biology, and materials science into a unified framework for understanding carbohydrate–borate interactions in natural and engineered systems. Full article

Injectable and self-healing hydrogels hold tremendous promise for biomedical applications; however, synchronously integrating robust mechanical adaptability, excellent cytocompatibility, and intrinsic antibacterial capabilities within a single matrix remains a significant challenge. In this study, we engineered an injectable, self-healing hydrogel based on dynamic cross-linking using guanosine-derived G-quadruplex supramolecular self-assembly and 3-aminophenylboronic acid (3-APBA)-mediated dynamic boronate ester. Systematic evaluation of various phenylboronic acid derivatives, GMP concentrations, K⁺ sources, and 3-APBA levels on gelation behavior yielded an optimized formulation. Scanning electron microscopy revealed that the optimized hydrogel exhibits a continuous, interconnected porous network structure after lyophilization. Thioflavin T fluorescence enhancement assays and circular dichroism spectroscopy further verify the formation of G-quadruplex-related ordered assemblies within the system. Rheological assessments demonstrate elasticity-dominated gel behavior, pronounced shear-thinning characteristics, and reversible structural breakdown and recovery under high and low strain cycles, indicating excellent injectability and self-healing properties. In vitro cytocompatibility evaluations show that the hydrogel possesses favorable cellular compatibility. Further antimicrobial studies reveal excellent in vitro antibacterial activity against Staphylococcus aureus and Escherichia coli. In summary, the injectable, self-healing G-quadruplex hydrogel constructed in this study integrates a porous architecture, dynamic reversibility, and robust biological functionality, highlighting its promising potential in antibacterial applications. Full article

Superhydrophobic materials offer promising prospects for utilization in energy, environmental, and related fields. However, their long-term stability in natural environments is constrained by factors such as mechanical wear and aging, which compromise their practical effectiveness and service life. While notable experimental results have been obtained worldwide, scalable application remains limited by the complexity of the requisite fabrication processes. In this study, a durable superhydrophobic coating was developed through a facile one-step process, utilizing a polyaspartic ester (PAE) matrix reinforced with a composite of self-synthesized fluorinated silica (F-SiO₂) and hexagonal boron nitride (h-BN) micro-/nano-structures. This strategy effectively enhanced filler dispersion within the resin matrix and promoted hydrophobicity, yielding a stable superhydrophobic surface. The resulting coating exhibits significant potential for scalable application. The optimized coating demonstrated a water contact angle of 161.2° and a roll-off angle of 7.6°, showing excellent repellency to water, corrosive liquids, and fluids across a wide pH range, along with remarkable self-cleaning performance. Benefiting from the synergistic enhancement of h-BN and F-SiO₂, the coating also exhibits superior mechanical durability, maintaining a contact angle of 144.4° after 1000 abrasion cycles. Furthermore, in low-temperature anti-icing tests, the coating significantly delayed ice formation on its surface. Notably, after 1000 h of UV aging tests, the F-SiO₂@BN/PAE coating retained its intact superhydrophobic structure, with the water contact angle only slightly decreasing from 159.6° to 152.8°, still within an excellent superhydrophobic state, demonstrating outstanding weather resistance. By integrating surface functionalization with mechanical reliability through a facile one-step fabrication process, this study provides significant insights for the large-scale application of hydrophobic materials in the energy and transportation sectors. 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

Xanthophylls are oxygenated carotenoids widely distributed in photosynthetic microorganisms, plants, algae, and certain invertebrates, where they function as key photoprotective and antioxidant pigments. Among them, xanthophylls containing vicinal 1,2-diol moieties exhibit unique chemical reactivity that enables reversible coordination with boron species naturally present in marine and terrestrial environments. The formation of cyclic borate esters between boron and diol-containing xanthophylls induces structural and electronic modifications that may enhance pigment stability and functional performance. Emerging evidence suggests that boron–xanthophyll complexes display improved resistance to photooxidative degradation, enhanced singlet oxygen quenching capacity, and increased radical-scavenging activity compared with their uncomplexed counterparts. In addition, boron coordination can influence molecular conformation, polarity, and supramolecular organization within lipid bilayers, thereby promoting membrane stabilization under conditions of high light exposure and oxidative stress. Together, these effects indicate a cooperative role of boron complexation in amplifying the intrinsic photoprotective and antioxidant properties of xanthophylls. A deeper understanding of the structural basis and biological implications of boron–xanthophyll interactions may provide new insights into adaptive stress tolerance in marine and photosynthetic organisms, as well as guide the development of advanced photoprotective systems for biomedical and technological applications. Full article

Thermosets are widely used in engineering applications due to their high mechanical strength, thermal stability, and chemical resistance; however, their permanently crosslinked networks also limit repair, reshaping, and recycling. Dynamic covalent chemistry offers a route to addressing these limitations through the incorporation of reversible bond exchange into thermoset networks. A range of dynamic thermosets has been developed based on transesterification, Diels–Alder reactions, imine exchange, disulfide metathesis, boronic ester exchange, and siloxane equilibration, enabling self-healing, reprocessing, welding, and closed-loop recycling. This review examines representative dynamic thermosets in terms of exchange mechanisms, network topology evolution, and macroscopic response. By correlating molecular exchange processes with network-level mechanics and macroscopic performance, this review identifies design principles for dynamic thermosets with improved sustainability and processing compatibility. Full article

Self-healing materials have attracted increasing attention as a strategy to enhance durability, extend service life, and reduce maintenance in advanced material systems. Among these, cellulose-based self-healing materials represent a sophisticated intersection between sustainable macromolecular chemistry and adaptive materials science. This review provides a synthesis of recent advancements in the field, systematically categorizing materials derived from cellulose raw materials. We evaluate the fundamental chemical strategies employed to achieve autonomous repair, distinguishing between extrinsic mechanisms—utilizing cellulose-based micro/nano-capsules to sequester healing agents—and intrinsic mechanisms governed by dynamic covalent chemistry (Schiff-base, boronic ester, Diels–Alder) and supramolecular interactions (hydrogen bonding, metal–ligand coordination, and host–guest assemblies). The analysis highlights how cellulose’s hierarchical structure and abundant surface functionality are leveraged to overcome the traditional trade-off between mechanical toughness and healing efficiency. Particular emphasis is placed on the transition from simple structural hydrogels to sophisticated multifunctional systems. These include ultra-stretchable strain and pressure sensors for e-skin applications, biocompatible and injectable matrices for chronic wound management and stem cell delivery, and advanced anti-freezing eutectogels for performance in extreme environments. Furthermore, we explore the integration of cellulose into traditional sectors, such as self-healing concrete utilizing microbe-induced calcification and smart, eco-friendly coatings for corrosion protection. Finally, we discuss critical challenges, including environmental stability, scalability, and the development of standardized evaluation protocols, providing a roadmap for the next generation of bio-derived, sustainable and intelligent materials. Full article

Catechol (benzene-1,2-diol) is a highly versatile chemical motif that plays a central role in both terrestrial and marine systems, where its reactivity is governed by a combination of enzymatic oxidation and non-enzymatic interactions. This review examines the diverse enzymatic pathways responsible for catechol oxidation, including polyphenol oxidases, laccases, peroxidases, and microbial dioxygenases, and highlights how these conserved systems are adapted to distinct ecological functions such as plant defense, carbon cycling, bioadhesion, and material formation. A key focus is placed on the non-enzymatic formation of boron–catechol complexes, which can significantly modulate catechol reactivity. These complexes, formed through reversible interactions between boron species and the 1,2-diol group, can act as inhibitors of catechol oxidation by limiting substrate availability and altering redox behavior. Importantly, the extent of this inhibition is strongly dependent on pH, which governs both the speciation of boron (e.g., boric acid vs. borate) and the stability of borate esters, as well as the activity of oxidative enzymes. In terrestrial systems, variable pH conditions and soil chemistry influence the balance between oxidation, complexation, and degradation, whereas in marine environments, relatively stable and slightly alkaline conditions favor distinct modes of regulation. By integrating enzymatic and non-enzymatic perspectives, this review underscores the importance of boron–catechol interactions as a previously underappreciated control on catechol oxidation across ecosystems, with implications for biogeochemical cycling and the design of bioinspired materials. Full article

Marine invertebrates produce a remarkable diversity of polyhydroxylated steroids and secosteroids whose structural features—particularly vicinal (1,2-)diols, 1,3-diols, and clustered hydroxyl arrays—make them well suited for coordination with boron species. In the marine environment, where boron is abundant, chemically stable, and predominantly present as borate under mildly alkaline conditions, such interactions are not only plausible but may be widespread. This review examines the chemistry of boron–steroid complexation in marine systems, emphasizing how rigid steroidal frameworks preorganize diol motifs to form reversible yet stable borate esters under environmentally relevant conditions. We discuss how polyhydroxy steroids may exist in dynamic equilibria between free and boron-bound forms, with speciation governed by pH, boron concentration, and local microenvironmental factors rather than enzymatic control. Boron complexation can modulate key physicochemical properties, including solubility, conformation, and membrane affinity, thereby influencing the biological activity of marine steroids without covalent modification of the carbon framework. By integrating examples from sponges, echinoderms, and corals together with well-characterized model polyols, this review highlights boron complexation as an underrecognized but potentially important factor influencing the structure, function, and bioactivity of marine steroid metabolites. Full article

The fracturing development of low-permeability and ultra-low-permeability oil and gas reservoirs urgently requires a fracturing fluid that combines high performance and low damage. To overcome this challenge, this study synthesized a novel polyamine boron crosslinker (PBC) suitable for 0.2% guar gum. The molecular structure was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectroscopy (¹H NMR). Meanwhile, this study introduced the response surface methodology and established a second-order regression model to determine the optimal synthesis conditions (polyetheramine 10.8 g, n-butanol 7.4 g, and ethylene glycol 20.7 g) with a model prediction error of only 0.7%. The results indicated that PBC exhibited excellent performance in 0.2% guar gum. The viscosity of crosslinked gel fracturing fluid remained stable at approximately 100 mPa·s under 60 °C and 100 s⁻¹ shear. The wall forming filtration coefficient was 2.30 × 10⁻⁴ m/s^1/2, and the initial filtration was 1.30 × 10⁻³ m³/m². The static settling rate was 2.4 cm·min⁻¹, demonstrating good suspended sand capacity. Furthermore, the synergistic interaction between borate ester bond and polyetheramine in the PBC conferred dynamic reversible crosslinking and uniform network formation. This enabled high-strength, low-damage crosslinking effects at low concentrations. This study provides an efficient crosslinker solution for 0.2% guar gum, holding both theoretical and engineering significance for advancing the low-cost development of fracturing fluid. Full article

Our recent work has focused on red light-mediated photoreduction of p-benzoquinones and both o-, and p-naphthoquinones using methylene blue and the chlorophyll metabolite, pheophorbide A as photosensitizers. Photoreduction of biologically relevant quinones mimics photoreduction of plastoquinone by chlorophyll in photosynthesis. We examined photo-oxidation and photoreduction reactions of catechols because their oxidation to o-quinones by reactive oxygen species is implicated in protein damage in neurodegeneration. Photo-oxidation of catecholamines including dopamine, epinephrine and norepinephrine required red light, methylene blue or pheophorbide A, and molecular oxygen. Their cyclized oxidation products, aminochrome, adrenochrome and noradrenochrome, were detected by UV/visible spectroscopy. Hydrogen peroxide was generated during photo-oxidation by singlet oxygen-dependent oxidation of catecholamines. Inclusion of tertiary amine electron donors decreased cyclized products but did not affect hydrogen peroxide yield consistent with concurrent photo-oxidation followed by photoreduction of the o-quinone intermediate. Unreacted dopamine and norepinephrine were quantified using 3-hydroxyphenyl boronic acid following photochemical reactions. Dopamine and norepinephrine boronate esters absorb at 417 and 550 nm. Photo-oxidation of dihydroxycaffeic acid and dihydroxyphenyl acetic acid was also evaluated by detecting their boronate esters at 475 nm. We hypothesize that photoreduction of transient o-quinones by the combination of red light and dietary chlorophyll metabolites may be a path to limit protein damage and to recycle catechol antioxidants. Full article