Journal of materials chemistry. B最新文献

Tongue injuries are among the most common acute soft tissue injuries encountered in oral clinical practice. Suturing, as the conventional treatment, often leads to tissue distortion and tension-induced collagen over-deposition, resulting in scarring and restricted tongue mobility. Sutures are also prone to microbial accumulation and provoke inflammation as foreign bodies. In this study, a hydrogel patch specifically designed for the tongue's moist, frequently moving, and richly vascularized environment was developed for better healing of tongue injuries. Briefly, a chitosan-polyacrylic acid-tannic acid hydrogel matrix is loaded with Cu-MOF to form a CPTCu hydrogel, ensuring stable binding and controlled release of copper, while maintaining mechanical compliance with tongue tissue for continuous protection. The CPTCu hydrogel exhibited excellent biocompatibility, achieving a free radical scavenging rate of 73.6% and a bactericidal rate of over 99%. Compared with suturing, the CPTCu hydrogel significantly reduced the collagen volume by 35.9% and enhanced angiogenesis by 103.2%, and also effectively promoted regeneration of local muscle fibers in a rat tongue wound model. These results demonstrate that the CPTCu hydrogel is a promising candidate for optimized scarless tongue healing.

Dopamine (DA) is a key neurotransmitter required for attention, learning, movement, emotion, and cognition. Imbalance in DA levels is linked to disorders such as depression, addiction, schizophrenia, and neurodegenerative diseases. Therefore, a simple, sensitive, and selective method for DA detection is required. In this study, carbon and nitrogen co-doped zinc sulfide (ZnS@N/C) nanodots combined with multi-walled carbon nanotubes (MWCNT) were developed for DA detection in PC-12 live cells. The ZnS@N/C nanodots were synthesized from a leaf-like zeolite imidazolate framework (ZIF-L), carboxymethyl cellulose (CMC), and sodium diethyldithiocarbamate trihydrate (DEDTC) via thermal annealing. DEDTC acted as a sulfur source, while CMC acted as a carbon source and improved the dispersibility of the MWCNT in the composite. Electrochemical properties were confirmed using cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry (i-t). The ZnS@N/C/MWCNT composite exhibited excellent electrochemical performance due to the synergistic effects of ZnS@N/C (which provided high electrocatalytic activity and more active sites) and MWCNT (which enhanced conductivity). Amperometry (i-t) revealed that the ZnS@N/C/MWCNT/screen-printed electrode (SPCE) showed good linearity in the DA concentration range of 0.0125-1774 µM, with a low detection limit of 3.97 nM. Furthermore, the ZnS@N/C/MWCNT/SPCE successfully monitored the DA levels in PC-12 cells under K⁺ stimulation in a neurological environment. These results demonstrated that the ZnS@N/C/MWCNT/SPCE is an efficient, selective, and sensitive sensor for rapid DA detection, offering potential applications in biomedical research.

Transplantation of encapsulated islet cells can restore the normal physiological glycemic level in type-1 diabetic patients. However, the clinical rate of success of islet transplantation is limited by robust immune response, inadequate insulin release, and acute hypoxic stress. The physico-biochemical properties of an encapsulating hydrogel play an important role in successful islet transplantation, mitigating the challenges. Herein, we report a comprehensive screening of 20 different commonly available natural polymers based on their various physico-biochemical properties, ease of islet delivery (MIN6), and biological functioning. From the initial screening, the top four leads (alginate, pectin, agarose, and cellulose) were selected based on their long-term degradation, mechanical stability, and insulin release kinetics. Based on further in vitro assessment, pectin was identified as the lead polymer for the in vivo diabetes treatment study. Subcutaneous implantation of MIN6 (mouse beta pancreatic islet) encapsulated pectin hydrogel capsules restored and maintained normoglycemia for 60 days in both C57BL/6 (allogeneic) mice and Wistar rats (xenogeneic) in a streptozotocin-induced diabetic model, without the requirement of any external immunosuppressant. Furthermore, when pectin was used for encapsulation and delivery of isolated primary rat islets to diabetic C57BL/6 mice, it also restored normoglycemia within 3 days of transplantation in the xenogeneic setup and sustained it for 30 days. This study successfully identified a novel natural polymer, pectin, demonstrating potential for maintaining long-term islet viability in vivo and acting as an independent, promising platform for islet delivery in the management of type-1 diabetes.

Spinal cord injury (SCI) encompasses a series of pathophysiological processes, including inflammation, apoptosis, autophagy, and pyroptosis, leading to an imbalance in the microenvironment. The microenvironment following injury inhibits axonal regeneration, ultimately resulting in the loss of neurological function. Among these pathological processes, inflammation plays a critical role in the recovery from SCI. The inflammatory cascade triggered by SCI leads to cell apoptosis, cell death, and impaired angiogenesis, which collectively hinder axonal regeneration. In recent years, nano-enzymes exhibiting Prussian blue enzyme-like peroxidase activity have garnered significant attention as alternatives to natural enzymes in therapeutic applications, biosensing, and environmental remediation. Schisandra, a traditional Chinese medicine, contains schisantherin B as its principal component, which has been reported to possess neuroprotective effects in various neurological diseases. In this study, we designed a Prussian blue nanozyme drug delivery system, a schisantherin B-loaded Prussian blue nanozyme (SchB@PBzyme), for the treatment of SCI. Our findings indicate that the SchB@PBzyme significantly suppresses the inflammatory response and promotes neural remodeling, thereby offering a novel treatment strategy for SCI.

The alarming rise in antibiotic resistance necessitates the urgent development of novel therapeutic agents. Herein, we report a bifunctional approach to synthesize two series of dihydrofurocoumarins (DHFCs), one incorporating naphthalimide and the other featuring coumarin analogues, designed to explore their antibacterial potential and ability to combat antibiotic resistance through structural diversification. Preliminary assessments reveal that some synthesized analogues exhibit significant antibacterial potency. Notably, analogues with electron-withdrawing substituents, particularly 16b and 21e (MIC = 1.56 µg mL^-1), display outstanding activity against E. coli, demonstrating a higher potency than the marketed antibiotic amoxicillin. The low-frequency resistance observed for analogues 16b and 21e, as evidenced by stable MIC values even after extended passages, may be attributed to their rapid bactericidal action. Additionally, both analogues strongly inhibit biofilm formation, disrupting a critical pathway involved in the development of drug resistance. Mechanistic investigations revealed that both analogues effectively disrupt bacterial membranes, triggering cytoplasmic leakage and a significant loss of metabolic activity. They also induce reactive oxygen species (ROS) generation, catalyzing the oxidation of GSH to GSSG, thereby diminishing cellular GSH activity and weakening the bacterial antioxidant defense system, ultimately leading to oxidative damage and cell death. Active analogues were evaluated for their binding affinity to human serum albumin (HSA), demonstrating a balanced binding profile with optimal binding constants, indicative of their potential to facilitate targeted delivery without compromising drug release at the intended site. Site marker drug displacement studies further identified their binding sites, showing that 16b exhibited a preference for Sudlow site I, while 21e selectively associated with the heme site on HSA. Molecular docking studies further corroborated these findings, revealing perfect alignment with experimental results. Further investigations indicated that both active analogues intercalated into DNA, forming DNA-16b/21e complexes that disrupted essential biological functions, leading to bacterial death. Quantum chemical insights revealed a narrower HOMO-LUMO energy gap, facilitating electronic transitions and enhancing molecular reactivity, which may be pivotal for their antibacterial effectiveness. Amidst the limitations of conventional antibiotics, these findings underscore the potential of dihydrofurocoumarins as potent multitarget, broad-spectrum antibacterial agents. Their ability to impair bacterial defense mechanisms and combat persistent pathogens presents a promising avenue for advancing antibacterial therapeutics, paving the way for further clinical exploration and the development of novel antibacterial analogues.

Modulating membrane permeability and morphology remains a central challenge in the design of responsive colloidal and self-assembled systems. Here, we present a strategy that integrates fluorescently labelled, photoswitchable amphiphiles into lipid vesicles to enable real-time visualization of dynamic membrane behavior and light-triggered cargo release. A novel amphiphilic molecule based on an azobenzene core was synthesized and functionalized with the fluorophore Nile red. This compound was incorporated into giant and large unilamellar vesicles (GUVs and LUVs) composed primarily of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) lipids. The response of the vesicles to alternating UV and visible light was characterized using confocal microscopy, fluorescence spectroscopy, and molecular dynamics simulations. Upon irradiation, vesicles exhibited reversible morphological transformations including budding, swelling, and prolate deformation. Fluorescence imaging confirmed efficient incorporation of the amphiphiles into lipid membranes, and the solvatochromic behavior of Nile red enabled distinction between lipid domains. Simulations revealed that Z-isomerization induces asymmetric expansion of the outer membrane leaflet, increasing surface tension and bending modulus, key drivers of the observed shape changes. Furthermore, cargo release assays with LUVs demonstrated controlled, reversible light-induced permeability. The temporal mismatch between morphological response and ROS (reactive oxygen species) generation, along with the reversibility of the effects, supports a non-oxidative, photomechanical mechanism. Based on these findings, fluorescent photoswitchable amphiphiles can be considered as powerful tools for both functional membrane engineering and the study of the relationship between molecular-level interactions, polarity, and macroscale membrane behavior.

Hexagonal boron nitride nanosheets (BNNSs), produced via a simple NaOH-assisted liquid exfoliation of bulk BN (h-BN), have been employed for the first time for the electrochemical (EC) detection of sulfamethoxazole (SMZ), a widely detected antibiotic in surface and groundwater. The resulting BNNS-modified glassy carbon electrode (BNNS/GCE) exhibited enhanced sensitivity compared to the bare GCE, BNNS_(H2O)/GCE, and h-BN/GCE, and a detection limit of 1 nM. The enhanced performance of the BNNS/GCE is attributed to its nanosheet morphology, the NaOH-introduced functional groups, which promoted hydrogen bonding, and Lewis acid-base interactions between the intermediate acid boron (B) with the intermediate basic N-functional groups in SMZ, thus imparting strong affinity and efficient charge transfer with SMZ. The sensor demonstrated selectivity towards SMZ in the presence of potential interferents such as antibiotics, metal ions, and biological molecules. The BNNS/GCE showed repeatability and stability, and exhibited performance in real water samples with reliable recovery rates. This work highlights a cost-effective, environmentally friendly, and scalable EC sensor material for trace-level antibiotic monitoring in complex environmental matrices.

Melanoma is a highly aggressive skin cancer that often develops resistance to chemotherapy, underscoring the need for new treatment strategies. Here we evaluate plasmonic gold nanocapsules (AuNCs) as photoresponsive agents for two-photon luminescence-assisted photothermal therapy in chemoresistant melanoma models. The performance of the AuNCs was assessed in two-dimensional cell cultures, three-dimensional paclitaxel-resistant B16-F10 melanoma spheroids, and a subcutaneous melanoma mouse model under near-infrared excitation. In vitro, AuNCs alone exhibited no cytotoxicity, but under 830 nm two-photon excitation, they produced strong two-photon luminescence and thermal effects that increased with nanocapsule concentration and laser power. This led to transient oxidative stress, apoptosis induction, and effective melanoma cell ablation under optimal conditions (80 μg mL^-1 AuNCs, 12 mW laser power). In vivo, the route of nanoparticle administration proved decisive. A single 4-min 806 nm irradiation after intratumoral injection uniformly heated the lesion (≈45-50 °C), yielded durable tumour eradication, and sequestered >99% of detected gold in the necrotic scab, with only trace renal clearance. In contrast, the same laser fluence after peritumoral injection generated a superficial hot rim, spared the tumour core, allowing eventual regrowth, and left ∼65% of the injected gold systemically redistributed, mainly in the spleen and liver. These findings highlight the potential of AuNCs as potent, image-guided photothermal agents for chemoresistant melanoma, offering targeted tumor destruction with limited systemic exposure. They reveal the injection route is a critical determinant of both therapeutic success and nanoparticle biodistribution.

The development of stimuli-responsive amphiphilic block copolymers and their nanoassemblies/nanogels integrated with degradable covalent chemistry undergoing chemical transitions has been extensively explored as a promising platform for tumor-targeting controlled/enhanced drug delivery. The conjugate aromatic imine bond is unique in responding to acidic pH through acid-catalyzed hydrolysis and visible light through photo-induced E/Z isomerization, thus allowing for a dual acid-light response via a single conjugate aromatic imine bond. Herein, we report a robust strategy for fabricating well-defined core-crosslinked nanogels bearing extended conjugate aromatic imine linkages that exhibit controlled degradation in response to acidic pH and visible light. This approach utilizes the pre-crosslinking of a poly(ethylene glycol)-based block copolymer bearing reactive imidazole pendants with a diol crosslinker bearing an extended conjugate aromatic imine, followed by the mechanical dispersion of the formed crosslinked polymers in an aqueous solution. The fabricated core-crosslinked nanogels with a hydrodynamic diameter of 119 nm are non-cytotoxic, colloidally stable, and capable of encapsulating cancer drug curcumin. They exhibit controlled/enhanced release of encapsulated curcumin at pH = 5 (acidic) or upon irradiation with visible light (λ = 420 nm) as well as exhibit promisingly accelerated and synergistic release under the combination of the above conditions. Furthermore, curcumin-loaded nanogels reduce cell viability in a controlled manner, unlike free drugs. This simplified yet efficient synthetic approach paves the way for the development of smart nanocarriers with potential applications in controlled drug release and cancer therapy.

Self-powered piezoelectric materials can generate continuous electrical stimulation in response to weak mechanical forces, holding great potential for accelerating wound healing. Herein, a multifunctional ZIF-8/PVDF piezoelectric fiber dressing was fabricated using the electrospinning method for generating electrical stimulation to enhance the endogenous electric field at the wound site. The incorporation of ZIF-8 nanoparticles and the stretching polarization effect of electrospinning on the fibers promote the formation of the piezoelectric β-phase in PVDF, leading to enhanced piezoelectricity. The improved piezoelectric and conductive properties collectively enhance the output electrical signals of the fiber. The short-circuit voltage and open-circuit current of the 5% ZIF-8/PVDF fiber were 2.97 V and 13.7 nA, respectively, showing significant improvement compared to the pure PVDF fiber. In vitro experiments demonstrate that the fiber can generate reactive oxygen species (ROS) and release Zn²⁺ under ultrasonic conditions, which together with electrical stimulation endows the dressing with effective antibacterial, anti-inflammatory, and angiogenic effects. In vivo studies of infected skin defect models demonstrated that the ZIF-8/PVDF fiber dressing can significantly inhibit bacterial infection, regulate inflammatory responses, enhance angiogenesis, and ultimately accelerate the infected wound healing process. This developed multifunctional piezoelectric fiber dressing provides an effective strategy for infected wound repair.