ACS Applied Bio Materials最新文献

Biofilm-associated wound infections require antibacterial materials that can control attached bacteria while limiting excessive silver exposure. In this study, we prepared a sponge-like hierarchical porous silver–carbon material through in situ glucose foaming and carbonization. The material had a Brunauer–Emmett–Teller surface area of 1067.8 m² g^–1 and a total silver content of 9.22% by weight after complete digestion. During dialysis against phosphate-buffered saline containing 1% bovine serum albumin, the material released approximately 0.27% of its total silver over 72 h. Comparative results showed differences in pore structure and silver transport but did not link release to a specific pore class. The porous silver–carbon material inhibited Escherichia coli and Staphylococcus aureus. The minimum inhibitory and bactericidal concentrations were 4 and 8 μg mL^–1, respectively, for Escherichia coli and 8 and 16 μg mL^–1, respectively, for Staphylococcus aureus. Propidium iodide staining and scanning electron microscopy were consistent with increased membrane permeability and cell-surface damage. Assays using 2′,7′-dichlorodihydrofluorescein diacetate and electron spin resonance measurements supported reactive oxygen species-related stress. Plate-counting assays showed concentration-dependent inhibition of biofilm formation and reduced viable bacterial recovery from established biofilms. Murine fibroblast viability remained above 95%, and hemolysis remained below 5% under the tested conditions. In a full-thickness mouse wound model infected with Escherichia coli, the material and silver nitrate were applied at equal elemental silver doses of approximately 35 μg per wound. The material treatment yielded lower wound-derived colony counts per plate than the silver nitrate treatment on day 4 and reached approximately 95% wound closure by day 14. Endpoint histology showed no obvious structural abnormalities in the examined major organs. These findings suggest that pore structure, dialyzable-silver transport, and bacteria-material interactions should be considered together when designing porous silver–carbon antibacterial materials.

Photodynamic therapy has attracted significant attention in treating serious bacterial skin infections. Herein, the carbon dots@Cu Tetrakis (4-carboxyphenyl) porphyrin microneedle arrays (CDs@CuTCPP MNs) were prepared by using a 3D printing technology for efficient photodynamic therapy of deep bacterial infected wounds. The CDs decorated on CuTCPP nanosheets facilitated the spatial charge separation for reactive oxygen species generation under irradiation. The CDs as a nanozyme could help to alleviate the local oxidative stress once they power off the light. Importantly, the release of ROS from the microneedle (length about 800 μm) to the deeply infected sites for damaging the bacteria can be achieved in a short time by the dissolution of the hyaluronic acid. As expected, the typical CDs@CuTCPP MNs achieved an average antibacterial rate of more than 95% against Staphylococcus aureus and Escherichia coli under visible-light irradiation (λ ≥ 420 nm). Moreover, during the wound healing evaluation test, the microneedle arrays achieved a remarkably high wound closure rate of 96.8%. The antibacterial mechanism of the CDs@CuTCPP MNs was investigated through reactive oxygen capture experiments, electrochemical characterization, and density functional theory calculations. This work offers a viable, visible light-driven approach for the treatment of deep-seated bacterial infections, highlighting the synergy between charge-decoupling photosensitizers and microneedle-assisted delivery.

Bacterial and cellular imaging at the outset allows us to visualize microbial and cellular behavior and how they interact and respond to their surroundings. However, developing biocompatible and photostable fluorescent probes for visualizing and tracking biological processes in living systems remains a significant challenge. Conventional staining agents, particularly organic dyes, are limited by photobleaching, cytotoxicity, and reduced performance in complex biological environments. In this work, we present citric-acid-based carbon quantum dots (CQDs) as a versatile fluorescent probe capable of enabling multicolor bioimaging across diverse biological systems. The CQDs exhibit strong and tunable photoluminescence, excitation-dependent emission, and high photostability, allowing sustained imaging without signal deterioration. Their performance was validated in both Gram-positive and Gram-negative bacteria, mammalian cells such as stem cells, muscle cells, and cancerous cells, demonstrating efficient uptake and bright fluorescence. Importantly, these CQDs enable multicolor imaging under different excitation wavelengths, eliminating the need for multiple fluorophores. Beyond conventional imaging, they facilitate simultaneous visualization of bacteria-infected mammalian cells in both live and fixed conditions and show effective penetration and staining in three-dimensional spheroid models. The ability to reliably stain and image diverse biological systems, from bacteria to complex 3D cellular structures, underscores the distinct advantage of CQDs over conventional probes. This work thus highlights their potential as a cost-effective, stable, and biocompatible tool for advanced bioimaging, intracellular tracking, and diagnostic applications.

Wound bacterial infections pose a serious threat to human health. Nitric oxide (NO) is a broad-spectrum antimicrobial agent and widely participates in immune response, tissue repair, and inflammation regulation. The in situ controllable generation of NO is of crucial importance for the development of NO-based antibacterial agents. Herein, we have constructed a biomimetic, primitive cell-inspired antibacterial coacervate microdroplet for multimode synergistic antibacterial therapy and accelerating wound healing. In this system, the dual-functional photosensitizer indocyanine green (ICG) and the NO prodrug l-arginine (l-Arg) were co-encapsulated into a phospholipid-coated coacervate by liquid–liquid phase separation, yielding a near-infrared (NIR)-activatable NO-releasing platform (IACoac@M). Upon NIR laser irradiation, the loaded ICG not only directly generated the photonic hyperpyrexia for bacterial killing but also performed a photodynamic process for producing singlet oxygen (¹O₂) that further oxidated l-Arg into NO. The NO production suppresses the expression of the bacterial molecular chaperone DnaK, a heat shock protein, promoting the photothermal therapy. By the combination of multiple bactericidal modalities, IACoac@M showed high antibacterial activities against Gram-positive S. aureus and Gram-negative E. coli. Further in vivo animal assays revealed that IACoac@M could effectively eliminate bacteria cells in wound tissue; inhibit inflammatory factors; and promote angiogenesis, collagen deposition, and epidermal regeneration, thereby accelerating the wound healing process. This study provided a rationally designed multifunctional coacervate capable of generating NO and photonic hyperpyrexia for photothermal/photodynamic/gas trimode synergistic antibacterial therapy, offering a potential solution for the treatment of wound bacterial infections.

Wound healing involving persistent inflammation and fibrosis is driven by reactive oxygen species (ROS) and Yes-associated protein (YAP), often leading to scars. A polyvinyl alcohol/alginate ultrasound-responsive hydrogel was developed, containing free epigallocatechin gallate (EGCG) in the matrix and EGCG-verteporfin (VP) nanoparticles embedded in the hydrogel network. Free EGCG is released rapidly, whereas EGCG-VP nanoparticles release is triggered by ultrasound. In vitro, this system reduced ROS by ∼69%. Western blot revealed ∼71% reduction in α-smooth muscle actin and ∼47% in YAP. In vivo, it promoted wound closure in rats. This system enables programmable modulation of the wound microenvironment.

Infected wound repair requires hydrogel dressings that maintain antibacterial contact at wet, exudative, and mechanically dynamic tissue interfaces. Quaternary ammonium hydrogels provide intrinsic contact-active antibacterial activity, yet their performance is often limited by insufficient wet adhesion, weak network stability, and poor self-healing. Here, we report a dual-supramolecularly reinforced antibacterial hydrogel, PDQE/PAGD-gel, constructed by integrating a quaternary ammonium bactericidal network with β-cyclodextrin-grafted poly(vinyl alcohol) reinforcement. In this design, quaternary ammonium groups provide membrane-disruptive contact bactericidal activity, while β-cyclodextrin-grafted poly(vinyl alcohol) reinforces the hydrated network through dual supramolecular interactions, including β-cyclodextrin–alkyl host–guest association and hydrogen bonding. Freeze–thaw-induced PVA crystalline domains further serve as physical cross-linking points to improve network stability. This integrated network preserves antibacterial cationic accessibility while improving wet-tissue attachment, mechanical recovery, and interfacial stability. PDQE/PAGD-gel exhibited a high equilibrium swelling ratio of 1052.2%, recovered mechanical integrity after damage, and achieved more than 99.5% contact bactericidal efficiency against Staphylococcus aureus and Escherichia coli within 140 min. It also showed low cytotoxicity, increased the L929 scratch closure rate to 65.4%, and maintained hemocompatibility with hemolysis below 4.0%. In a Staphylococcus aureus-infected full-thickness mouse wound model, PDQE/PAGD-gel reduced bacterial burden and accelerated wound closure to 94.4% by day 12, accompanied by enhanced re-epithelialization and collagen deposition. This work establishes a dual-supramolecular physical-reinforcement strategy for contact-active antibacterial hydrogels in infected wound repair.

Lung cancer remains one of the most lethal malignancies worldwide, with survival rates dropping sharply at advanced stages. Conventional therapies are limited by systemic toxicity and poor selectivity, motivating the development of alternative strategies such as photothermal therapy (PTT). Herein, we investigate gold shell-isolated nanostars (AuNS@SiO₂) as photothermal agents for near-infrared (NIR)-triggered cancer treatment in A549 lung cancer cells. The silica shell enhances colloidal stability and protects the plasmonic core, while the nanostar morphology enables efficient NIR light-to-heat conversion. In addition to the photothermal response, AuNS@SiO₂ generated singlet oxygen (¹O₂) under NIR irradiation and was associated with irradiation-dependent changes in the intracellular ROS-related fluorescence, indicating a complementary photochemical oxidative contribution to the photoinduced cellular response. AuNS@SiO₂ exhibited minimal cytotoxicity in A549 cells in the absence of irradiation, but induced a concentration-dependent decrease in viability upon NIR photoactivation. Apoptosis/necrosis assays revealed a shift from viable cells toward populations exhibiting early and late apoptosis-associated features, with minimal necrosis-associated events. Taken together, these findings indicate that the biological response induced by NIR-photoactivated AuNS@SiO₂ involves efficient photothermal heating together with a complementary oxidative photochemical contribution and is predominantly associated with apoptosis-like cell death, supporting their potential as effective agents for NIR-based lung cancer therapy.

The global incidence of oral cancer has risen rapidly at progressively younger ages due to the impact of unhealthy lifestyle habits. Therefore, there is an urgent need to develop novel oral cancer treatments. Combination therapy with chemotherapy and photothermal therapy offers a superior therapeutic effect compared to conventional clinical methods. Herein, we report the development of a pH-responsive and charge-reversal nanomedicine system to enhance oral cancer therapy. Polydopamine (PDA), known for its excellent photothermal properties, was initially coated onto a copolymer PLGA loaded with the chemotherapeutic drug DOX. Subsequently, poly(2-ethyl-2-oxazoline) (PEOz) was employed for its surface modification. This charge-reversal system, equipped with a tertiary amide group on the main chain, ensures that the nanoparticles remain negatively charged during blood circulation and become positively charged at the tumor site under weakly acidic conditions. The results suggest that the nanoplatform system exhibits outstanding photothermal performance and controlled DOX release. Both in vitro and in vivo experiments have demonstrated that this drug delivery system exhibits excellent antitumor efficacy and biosafety. This study has significant implications for the clinical treatment of oral cancer.

Polymeric nanoparticles are known for their ability to encapsulate and release various compounds. We hypothesized that encapsulating anti-cancer drugs alongside therapeutic radionuclides could enable combination therapy using brachytherapy and localized chemotherapy. This study was aimed at developing biodegradable polymer-based nanocarriers that can serve as a radiation source for brachytherapy and determining whether this combination of brachytherapy and chemotherapy could offer a higher therapeutic response than conventional brachytherapy. A block polymer consisting of poly(l-lactic acid) and poly(N-n-propylglycine) units was chemically synthesized. Additionally, a poly(l-lactic acid) homopolymer was labeled with the β-ray-emitting radionuclide ⁶⁴Cu via a chelating moiety. Using a mixture of the block polymer, ⁶⁴Cu labeled poly(l-lactic acid), and the anti-cancer drug docetaxel, we prepared a core–shell-type polymer micelle in an ice-cooled aqueous solution. This micelle solution was locally injected into the tumor region of mice, and radioactivity distribution was evaluated using an animal positron emission tomography system. Therapeutic efficacy was assessed by monitoring changes in tumor volume over time. The block polymer exhibited thermodynamic behavior, forming micelles in ice-cold conditions. When the temperature of the micelle solution was raised, µm-sized aggregates formed rapidly at 25–30 °C due to the hydrophobization of poly(N-n-propylglycine) units on the micelle surface. Importantly, ⁶⁴Cu remained stable within the aggregates, while docetaxel was gradually released. After the local injection of the micelle solution into subcutaneously implanted tumors, radioactivity was stably detected at the injection site. The combination of ⁶⁴Cu brachytherapy and localized docetaxel chemotherapy significantly suppressed cancer progression compared to either ⁶⁴Cu brachytherapy or docetaxel chemotherapy alone. The thermosensitive micelles developed in this study can be used as a radiation source for brachytherapy, eliminating the need for permanent metal seed insertion. Moreover, combining local anti-cancer therapy with brachytherapy offers higher therapeutic efficacy than conventional brachytherapy alone.

Nanoscale graphene oxide (nGO) has emerged as a promising biomaterial for neurological applications because its ultrasmall dimensions, oxygen-containing surface chemistry, and colloidal behavior may support biologically relevant interfacial interactions. Here, we physicochemically defined nGO synthesized by a modified Taylor–Couette method using transmission electron microscopy, atomic force microscopy, particle size analysis, zeta potential measurement, X-ray diffraction, and Fourier-transform infrared spectroscopy. The resulting nGO exhibited ultrasmall lateral dimensions together with characteristic oxygen-containing functional groups and a negative zeta potential in distilled water. In a time-course dot blot assay using α-synuclein (α-syn) preformed fibrils, incubation with nGO was associated with reduced fibril-related α-syn immunoreactivity without a statistically significant change in total α-syn signal; a fractionation assay further revealed fraction-dependent differences in antibody-detectable α-syn signals. We then evaluated behavioral and nigral histological outcomes following intraperitoneal nGO administration in a rat model of Parkinson’s disease induced by unilateral adeno-associated virus-mediated overexpression of A53T α-syn in the substantia nigra. nGO administration was associated with improved stepping performance, greater preservation of nigral tyrosine hydroxylase-positive cells, reduced nigral α-syn immunoreactivity, and decreased Iba-1-positive area. Collectively, these findings support further consideration of physicochemically defined, unmodified nGO as an active biomaterial associated with fibril-related α-syn readouts in vitro and functional and histological outcomes consistent with neuroprotection in vivo.