An Immunomodulatory Biomimetic Single-Atomic Nanozyme for Biofilm Wound Healing Management.

Nanozyme-driven catalytic antibacterial therapy has become a promising modality for bacterial biofilm infections. However, current catalytic therapy of biofilm wounds is severely limited by insufficient catalytic efficiency, excessive inflammation, and deep tissue infection. Drawing from the homing mechanism of natural macrophages, herein, a hollow mesoporous biomimetic single-atomic nanozyme (SAN) is fabricated to actively target inflamed parts, suppress inflammatory factors, and eliminate deeply organized bacteria for enhance biofilm eradication. In the formulation, this biomimetic nanozyme (Co@SAHSs@IL-4@RCM) consists of IL-4-loaded cobalt SANs-embedded hollow sphere encapsulate by RAW 264.7 cell membrane (RCM). Upon accumulation at the infected sites through the specific receptors of RCM, Co@SAHS catalyze the conversion of hydrogen peroxide into hydroxyl radicals and are further amplify by NIR-II photothermal effect and glutathione depletion to permeate and destroy biofilm structure. This behavior subsequently causes the dissociation of RCM shell and the ensuing release of IL-4 that can reprogram macrophages, enabling suppression of oxidative injury and tissue inflammation. The work paves the way to engineer alternative "all-in-one" SANs with an immunomodulatory ability and offers novel insights into the design of bioinspired materials.

Three-Pronged Flower-like Nanoplatforms for the Photothermal/Photodynamic/Quaternary Ammonium Salt Synergistic Antibacterial Method and Bioimaging.

Bacterial infections caused by pathogenic bacteria are extremely threatening to human health. Currently, the treatment of bacterial infections relies heavily on antibiotics, leading to a high incidence of antibiotic abuse. Bacterial resistance appeared along with the misuse of antibiotics that produced growing harm to human beings. Therefore, a cutting-edge strategy for treating bacterial infections is indeed needed. Here we prepared QCuRCDs@BMoS2 nanocomposites (QBs) for an efficient bacterial trapping and triple quaternary ammonium salt/photothermal/photodynamic bactericidal method. Copper-doped carbon quantum dots were first prepared by using a solvothermal method, modified with quaternary ammonium salts, and then combined with grafted MoS2 nanoflowers. The long alkyl chains of QBs and the sharp surface of MoS2 facilitate the destruction of bacterial structures, while the electrostatic adsorption binds closely to bacteria, shortening the bactericidal distance of the reactive oxygen species (ROS). Moreover, the excellent photothermal performance under 808 nm irradiation in the near-infrared (NIR) region and deep penetrating heat can accelerate oxidative stress and achieve a multisynergistic bactericidal purpose. Consequently, QBs with ideal antibacterial properties and inherent brightness hold great promise in the biomedical field.

Modulating the local coordination environment of cobalt single-atomic nanozymes for enhanced catalytic therapy against bacteria.

Single-atomic nanozymes (SANZs) characterized by atomically dispersed single metal atoms have recently contributed to breakthroughs in biomedicine due to their satisfactory catalytic activity and superior selectivity compared to their nanoscale counterparts. The catalytic performance of SANZs can be improved by modulating their coordination structure. Therefore, adjusting the coordination number of the metal atoms in the active center is a potential method for enhancing the catalytic therapy effect. In this study, we synthesized various atomically dispersed Co nanozymes with different nitrogen coordination numbers for peroxidase (POD)-mimicking single-atomic catalytic antibacterial therapy. Among the polyvinylpyrrolidone modified single-atomic Co nanozymes with nitrogen coordination numbers of 3 (PSACNZs-N3-C) and 4 (PSACNZs-N4-C), single-atomic Co nanozymes with a coordination number of 2 (PSACNZs-N2-C) had the highest POD-like catalytic activity. Kinetic assays and Density functional theory (DFT) calculations indicated that reducing the coordination number can lower the reaction energy barrier of single-atomic Co nanozymes (PSACNZs-Nx-C), thereby increasing their catalytic performance. In vitro and in vivo antibacterial assays demonstrated that PSACNZs-N2-C had the best antibacterial effect. This study provides proof of concept for enhancing single-atomic catalytic therapy by regulating the coordination number for various biomedical applications, such as tumor therapy and wound disinfection. STATEMENT OF SIGNIFICANCE: The use of nanozymes that contain single-atomic catalytic sites has been shown to effectively promote the healing of bacteria-infected wounds by exhibiting peroxidase-like activity. The homogeneous coordination environment of the catalytic site has been associated with high antimicrobial activity, which provides insight into designing new active structures and understanding their mechanisms of action. In this study, we designed a series of cobalt single-atomic nanozymes (PSACNZs-Nx-C) with different coordination environments by shearing the Co-N bond and modifying polyvinylpyrrolidone (PVP). The synthesized PSACNZs-Nx-C demonstrated enhanced antibacterial activity against both Gram-positive and Gram-negative bacterial strains, and showed good biocompatibility in both in vivo and in vitro experiments.

Designing Single-Atom Active Sites on sp2 -Carbon Linked Covalent Organic Frameworks to Induce Bacterial Ferroptosis-Like for Robust Anti-Infection Therapy.

With the threat posed by drug-resistant pathogenic bacteria, developing non-antibiotic strategies for eradicating clinically prevalent superbugs remains challenging. Ferroptosis is a newly discovered form of regulated cell death that can overcome drug resistance. Emerging evidence shows the potential of triggering ferroptosis-like for antibacterial therapy, but the direct delivery of iron species is inefficient and may cause detrimental effects. Herein, an effective strategy to induce bacterial nonferrous ferroptosis-like by coordinating single-atom metal sites (e.g., Ir and Ru) into the sp2 -carbon-linked covalent organic framework (sp2 c-COF-Ir-ppy2 and sp2 c-COF-Ru-bpy2 ) is reported. Upon activating by light irradiation or hydrogen peroxide, the as-constructed Ir and Ru single-atom catalysts (SACs) can significantly expedite intracellular reactive oxygen species burst, enhance glutathione depletion-related glutathione peroxidase 4 deactivation, and disturb the nitrogen and respiratory metabolisms, leading to lipid peroxidation-driven ferroptotic damage. Both SAC inducers show potent antibacterial activity against Gram-positive bacteria, Gram-negative bacteria, clinically isolated methicillin-resistant Staphylococcus aureus (MRSA), and biofilms, as well as excellent biocompatibility and strong therapeutic and preventive potential in MRSA-infected wounds and abscesses. This delicate nonferrous ferroptosis-like strategy may open up new insights into the therapy of drug-resistant pathogen infection.

Multifunctional Integrated Superhydrophobic Coatings with Unique Fluorescence and Micro/Micro/Nano-Hierarchical Structures Enabled by In Situ Self-Assembly.

Conferring versatility to superhydrophobic materials is extremely desirable to advance their utility. Herein, we have developed a superhydrophobic material with montmorillonite as microskeleton supports and in situ grown ZIF-8 nanoparticles and loaded them with newly developed fluorescent carbon dots. In situ growth of the ZIF-8 on OMMT constructs a dense nanoscale rough structure and meanwhile self-assembly generates abundant microporous, thus forming unique hierarchical microporous/microsheet/nanoparticle tri-tier micro and nano structures. Then the multifunctional superhydrophobic coating is fabricated by a facile spraying technique using polydimethylsiloxane (PDMS) as a multifunctional polymer binder. The PDMS/RB-CDs/ZIF-8@OMMT exhibits superhydrophobicity with a water contact angle of 164.7° and a water sliding angle of 1.4°, which also possesses good self-cleaning performance. Moreover, novel carbon dots are developed in this work which can confer unique fluorescent properties and photothermal properties to materials. Fluorescence characterization reveals the multiple emission peaks among 300-800 nm and excitation wavelength dependence and independence. Photothermal experiments unveil an efficient light-to-heat conversion caused by the light traps and absorption wavelengths associated with photothermal heating. Benefiting from the dense microporous/microsheet/nanoparticle structures, the superhydrophobicity is still maintained after 120 cycles of abrasion. Moreover, electrochemical impedance spectroscopy (EIS) reveals a significant increase in impedance, which is associated with excellent corrosion resistance. The superhydrophobic coating also exhibits superior UV resistance and good thermal stability. Multifunctional fluorescent superhydrophobic materials will enable the development of various and potential applications in different fields.

Hydrophilic Nanocomposite Films with a Fence-Structure-Induced Labyrinth Effect for Greenhouse Cooling and Light Enhancement.

In this paper, we reported a new kind of cooling and light-enhanced hydrophilic nanocomposite film (PE/JW-0.8%) with low-density polyethylene (LDPE) as the substrate. The wetting, photophysical, and mechanical properties of PE/JW-0.8% were tested. The emission band of the fluorescence centers at 420 nm, which is perfectly consistent with the absorption spectrum of plant photosynthesis. In addition, light can be scattered by PE/JW-0.8% to achieve a larger light distribution area. PE/JW-0.8% showed a good durability of hydrophilicity in the water rinsing test. Meanwhile, the elongation at the break of the film was significantly increased. Benefiting from the fence structure induced labyrinth effect, a maximum reduction of 6.7 °C in temperature monitoring for PE/JW-0.8% was observed in the detailed field experiments. Light intensity monitoring showed that light intensity in PE/JW-0.8% increased by a maximum of 57.1% compared to PE/LH. In the biological quality analysis of melon, it was found that the soluble sugar, soluble solid, and vitamin C content of melon increased by 13.34, 22.96, and 50.95%, respectively. In conclusion, these results confirm that PE/JW-0.8% has great application potential in the field of facility agriculture, buildings, and photovoltaic modules.

Enzyme-Responsive COF-Based Thiol-Targeting Nanoinhibitor for Curing Bacterial Infections.

Pathogen infections impose severe challenges in clinical practice, especially for patients infected with antibiotic-resistant microbes. The thioredoxin (Trx) system in Gram-positive bacteria serves as an ideal antimicrobial target for novel medicine design due to the structural differences from corresponding system in mammals. However, a backup thiol-dependent antioxidant glutathione (GSH) system limits the effectiveness of drugs in many Gram-negative bacteria. Herein, we synthesize a thiol-targeting nanoinhibitor based on an enzyme-responsive covalent organic framework (COF) coloaded with silver nanoparticles (AgNPs) and ebselen (EBS) (Ag-TA-CON@EBS@PEG) to exert synergistic antibacterial effects. Since azoreductase can dissociate the enzyme-responsive COF, we adopt this strategy to achieve the accurate release of EBS and Ag+ at infection sites. Our research identifies that the functionalized nanoinhibitor shows excellent bactericidal performance for Gram-positive and Gram-negative bacteria in vitro and exhibits low toxicity to normal cells. Besides, the nanoinhibitor presents favorable biocompatibility, anti-inflammatory property, and effective wound healing ability in mice. This paper provides a promising clinical strategy for synergistic antibacterial therapy and enhanced wound healing properties via an optimized combination of the targeted nanomedicines with an intelligent drug conveying platform.

An Optimally Designed Engineering Exosome-Reductive COF Integrated Nanoagent for Synergistically Enhanced Diabetic Fester Wound Healing.

Oxidative stress and local overactive inflammation have been considered major obstacles in diabetic wound treatment. Although antiphlogistic tactics have been reported widely, they are also challenged by pathogen contamination and compromised angiogenesis. Herein, a versatile integrated nanoagent based on 2D reductive covalent organic frameworks coated with antibacterial immuno-engineered exosome (PCOF@E-Exo) is reported to achieve efficient and comprehensive combination therapy for diabetic wounds. The E-Exo is collected from TNF-α-treated mesenchymal stem cells (MSCs) under hypoxia and encapsulated cationic antimicrobial carbon dots (CDs). This integrated nanoagent not only significantly scavenges reactive oxygen species and induces anti-inflammatory M2 macrophage polarization, but also stabilizes hypoxia-inducible factor-1α (HIF-1α). More importantly, the PCOF@E-Exo exhibits intriguing bactericide capabilities toward Gram-negative, Gram-positive, and drug-resistant bacteria, showing favorable intracellular bacterial destruction and biofilm permeation. In vivo results demonstrate that the synergetic impact of suppressing oxidative injury and tissue inflammation, promoting angiogenesis and eradicating bacterial infection, could significantly accelerate the infected diabetic fester wound healing with better therapeutic benefits than monotherapy or individual antibiotics. The proposed strategy can inspire further research to design more delicate platforms using the combination of immunotherapy with other therapeutic methods for more efficient ulcerated diabetic wounds treatments.

A multifunctional carbon dot-based nanoplatform for bioimaging and quaternary ammonium salt/photothermal synergistic antibacterial therapy.

The emergence of drug resistance and superbugs poses a devastating threat to public health and can even lead to death. Thus, it is significant to develop a novel antibacterial agent to combat bacterial infections. Herein, we developed quaternary ammonium salt (QAS) modified near-infrared carbon dots (RCDs-C35), which possesses synergistic antibacterial performance under 808 nm irradiation. This nanocomposite exhibits excellent photothermal performance and the photothermal conversion efficiency (PCE) could reach 35%. Generally speaking, the bacterial membrane sensitivity to hyperthermia would be enhanced after QAS caused the initial damage, and thus it can more easily cause bacterial inactivation after irradiation. In vitro and in vivo experiments indicated that the RCDs-C35 exhibit excellent biocompatibility, predominant synergistic antibacterial performance, and the capability of promoting wound healing. The antibacterial ratio against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) could reach 99.5% and 99.8%, respectively, after 808 nm irradiation. Additionally, the cellular imaging indicated that the RCDs-C35 could be used as a fluorescent probe in bioimaging. Therefore, RCDs-C35 with synergistic antibacterial performance and inherent luminescence possess great potential for application in the biomedical field.

Silica-supported near-infrared carbon dots and bicarbonate nanoplatform for triple synergistic sterilization and wound healing promotion therapy.

Widespread bacterial infection and the emergence of antibiotic resistance exhibit an increasing threat to public health. Additionally, chronic wounds caused by bacterial infection have become a major challenge and threat in medical. Therefore, it is of great significance to explore effective and safe nanomaterials which possess antibacterial and wound healing promotion performance. Herein, we developed silica-supported near-infrared carbon dots (QPCuRC@MSiO2) and bicarbonate (BC) nanoplatform (BC/QPCuRC@MSiO2@PDA), which possess triple synergistic antibacterial including quaternary ammonium compounds (QACs), photothermal therapy (PTT), and photodynamic therapy (PDT). Meanwhile, the nanoplatform realized the controlled release of CO2 in situ triggered by 808 nm laser irradiation for wound healing. In vitro and in vivo antibacterial assays displayed that the BC/QPCuRC@MSiO2@PDA possess excellent antibacterial property, the antibacterial rate up to 99.6% and 99.99% to Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. Wound healing evaluation proved that suitable release of CO2 could promote the process of infected wound healing, and the wound healing rate up to 100% after treatment for 14 days. Additionally, the cellular imaging experiment revealed that the BC/QPCuRC@MSiO2@PDA could be considered as fluorescence probe. Together, these results demonstrated that the BC/QPCuRC@MSiO2@PDA have great potential in biomedical field.

Light-Activated Biodegradable Covalent Organic Framework-Integrated Heterojunction for Photodynamic, Photothermal, and Gaseous Therapy of Chronic Wound Infection.

Chronic wound healing, impeded by bacterial infections and drug resistance, poses a threat to global human health. Antibacterial phototherapy is an effective way to fight microbial infection without causing drug resistance. Covalent organic frameworks (COFs) are a class of highly crystalline functional porous carbon-based materials composed of light atoms (e.g., carbon, nitrogen, oxygen, and borane), showing potential applications in the biomedical field. Herein, we constructed porphyrin-based COF nanosheets (TP-Por CON) for synergizing photodynamic and photothermal therapy under red light irradiation (e.g., 635 nm). Moreover, a nitric oxide (NO) donor molecule, BNN6, was encapsulated into the pore volume of the crystalline porous framework structure to moderately release NO triggered by red light irradiation for realizing gaseous therapy. Therefore, we successfully synthesized a novel TP-Por CON@BNN6-integrated heterojunction for thoroughly killing Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus in vitro. Our research identified that TP-Por CON@BNN6 has favorable biocompatibility and biodegradability, low phototoxicity, anti-inflammatory properties, and excellent mice wound healing ability in vivo. This study indicates that the TP-Por CON@BNN6-integrated heterojunction with multifunctional properties provides a potential strategy for COF-based gaseous therapy and microorganism-infected chronic wound healing.

MoO3-x nanosheets-based platform for single NIR laser induced efficient PDT/PTT of cancer.

Traditional combination therapy of photodynamic therapy (PDT) and photothermal therapy (PTT) is limited in the field of clinical cancer therapy due to activation by light with separate wavelengths, insufficient O2 supply, antioxidant ability of glutathione (GSH) in tumor cell, and low penetration depth of light. Here, a multifunctional nanoplatform composed of MoO3-x nanosheets, Ag nanocubes, and MnO2 nanoparticles was developed to overcome these drawbacks. For this nanoplatform, hyperthermia and reactive oxygen species (ROS) were simultaneously generated under single 808 nm near-infrared (NIR) light irradiation. Once this nanoplatform accumulated in the tumor region, GSH was depleted by MnO2 and intracellular H2O2 was catalyzed by MnO2 to produce O2 to relieve hypoxia. Ultrasound (US) imaging confirmed in-situ O2 generation. Magnetic resonance (MR) imaging, photoacoustic (PA) imaging, and fluorescence imaging were used to monitor in vivo biodistribution of nanomaterials. This provides a paradigm to rationally design a single NIR laser induced multimodal imaging-guided efficient PDT/PTT cancer strategy.

Insight into the effect of particle size distribution differences on the antibacterial activity of carbon dots.

Carbon dots (CDs) have a profound effect on elimination of bacteria, fungi, and viruses, but the lack of an exact mechanism to interact with bacterial cells limits their development. Herein, we separated the CDs derived from chlorhexidine gluconate into three groups with uniformly small-scale, middle-scale, and large-scale particle sizes by using different molecular weight cut-off membranes. These positively charged particles exhibit significant antibacterial activity against the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Staphylococcus aureus; they can cause an increase in bacterial cell permeability, synergistic destabilization, and broken integrity of the plasma membrane. Impressively, we found that antibacterial activity increases as the size of the CDs decreases. This phenomenon may stem from the differences in cellular uptake and distribution of CDs in the plasma membrane or restriction between the polar functional group and DNA molecule. Our study of the size effect as a target may improve the understanding of killing microorganisms by antibacterial CD drugs.

Genipin cross-linked carbon dots for antimicrobial, bioimaging and bacterial discrimination.

Multifunctional carbon dots (CDs) present enormous potential in numerous applications and have attracted widespread attention for various applications in the biomedical field. Bacterial infection is a common health issue; the development of antibacterial materials with low toxicity and good biocompatibility is becoming more important. In this work, we synthesized a new type of nitrogen co-doped carbon dots-genipin covalent conjugate (N-CDs-GP) via hydrothermal methods. The microstructure and chemical composition of the N-CDs-GP were characterized. The biocompatibility, stability, antibacterial activity, and fluorescence performance of the N-CDs-GP were assessed. The results revealed that N-CDs-GP possessed high biocompatibility, high light stability, and broad antibacterial activity. Additionally, selective Gram-positive bacterial imaging by N-CDs-GP provided a more rapid method of bacterial detection. The N-CDs-GP have the potential to be applied as bioimaging and antibacterial agents and for bacterial discrimination.

Hollow Porous Carbon Coated FeS2-Based Nanocatalysts for Multimodal Imaging-Guided Photothermal, Starvation, and Triple-Enhanced Chemodynamic Therapy of Cancer.

Specific chemical reactions only happen in the tumor region and produce abundant special chemicals to in situ trigger a train of biological and pathological effects that may enable tumor-specific curative effects to treat cancer without causing serious side effects on normal cells or organs. Chemodynamic therapy (CDT) is a rising tactic for cancer therapy, which induces cancer cell death via a localized Fenton reaction. However, the tumor therapeutic effect is limited by the efficiency of the chemical reaction and relies heavily on the catalyst. Here, we constructed hollow porous carbon coated FeS2 (HPFeS2@C)-based nanocatalysts for triple-enhanced CDT. Tannic acid was encapsulated in HPFeS2@C for reducing Fe3+ to Fe2+, which had a better catalytic activity to accelerate the Fenton reaction. Afterward, glucose oxidase (GOx) in nanocatalysts could consume glucose in the tumor microenvironment and in situ synchronously produce H2O2, which could improve Fenton reaction efficiency. Meanwhile, the consumption of glucose could lead to the starvation effect for cancer starvation therapy. The photothermal effects of HPFeS2@C could generate heat, which further sped up the Fenton process and implemented synergetic photothermal therapy/starvation therapy/CDT. The biodistribution of nanoparticles was investigated by multimodal magnetic resonance, ultrasound, and photoacoustic imaging. These nanocatalysts could trigger the catalytic Fenton reaction at a high degree, which might provide a good paradigm for nanocatalytic tumor therapy.

Quaternized Chitosan-Coated Montmorillonite Interior Antimicrobial Metal-Antibiotic in Situ Coordination Complexation for Mixed Infections of Wounds.

Conventional drug delivery systems for natural clay materials still face critical challenges in their practical application, including multiple bacterial infections, combined infection of bacteria and fungi, and low sterilization efficiency. In this work, we address these challenges using the multifunctional montmorillonite nanosheet-based (MMT-based) drug nanoplatform, which involves the antibiotic 5-fluorocytosine (5-FC), antibacterial metal copper ions, and quaternized chitosan (QCS). Composite material QCS/MMT/5-FCCu can can strongly inhibit Staphylococcus aureus (a typical Gram-positive bacterium), Escherichia coli (a typical Gram-negative bacterium), and Candida albicans (a fungus) because 5-FC coordinates with copper ions in situ and due to the deposition of QCS. The subsequent drug release behavior of 5-FCCu was studied, and the results show an initial high concentration kills microorganisms and long-acting sustained release inhibition. Moreover, in vivo wound experiments and toxicity experiments show the promotion of wound healing and excellent biocompatibility. As a demonstration of the utility of the latter, we have shown that the MMT-based smart platform can be used for the treatment of mixed infections of wounds.

Hyaluronic Acid-Modified Porous Carbon-Coated Fe3O4 Nanoparticles for Magnetic Resonance Imaging-Guided Photothermal/Chemotherapy of Tumors.

Chemotherapy is an effective method for treating cancer, clinically. However, side effects of drug and multidrug resistance restrict its application. In recent years, the combined treatment of chemotherapy and photothermal therapy (PTT) is becoming a promising method for treating cancer. PTT utilizes nanomaterials absorbing near-infrared light and producing heat to acquire advanced hyperthermia strategy for cancer treatment. Carbon nanomaterials with good biocompatibility, high surface area, and excellent photothermal properties are an excellent nanoplatform for drug delivery and PTT. Herein, porous carbon-coated magnetite nanoparticles (PCCMNs) were successfully synthesized by a one-pot solvothermal method. Magnetite, a contrast agent, can be used for magnetic resonance imaging. Hyaluronic acid was used to modify the PCCMNs to achieve targeted therapy. The obtained nanohybrid with a good photothermal effect can realize combined PTT/chemotherapy and will be a promising nanoplatform for high efficacy theranostics.

Carboxymethyl Chitosan Modified Carbon Nanoparticle for Controlled Emamectin Benzoate Delivery: Improved Solubility, pH-Responsive Release, and Sustainable Pest Control.

Environmentally friendly pesticide delivery systems have drawn extensive attention in recent years, and they show great promise in sustainable development of agriculture. We herein report a multifunctional nanoplatform, carboxymethyl chitosan modified carbon nanoparticles (CMC@CNP), as the carrier for emamectin benzoate (EB, a widely used insecticide), and investigate its sustainable antipest activity. EB was loaded on CMC@CNP nanocarrier via simple physisorption process, with a high loading ratio of 55.56%. The EB@CMC@CNP nanoformulation showed improved solubility and dispersion stability in aqueous solution, which is of vital importance to its practical application. Different from free EB, EB@CMC@CNP exhibited pH-responsive controlled release performance, leading to sustained and steady EB release and prolonged persistence time. In addition, the significantly enhanced anti-UV property of EB@CMC@CNP further ensured its antipest activity. Therefore, EB@CMC@CNP exhibited superior pest control performance than free EB. In consideration of its low cost, easy preparation, free of organic solution, and enhanced bioactivity, we expect, CMC@CNP will have a brilliant future in pest control and green agriculture.

Anticoagulant polyurethane substrates modified with poly(2-methacryloyloxyethyl phosphorylcholine) via SI-RATRP.

A novel catalyst system of Reverse Atom Transfer Radical Polymerization (RATRP) to prepare Polyurethane (PU) films modified by poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC) was studied in this article. In this system, PU film was pretreated by LaCl3/CA ethanol solution to obtain a hydrated surface allowing more initiators to be immobilized on it. Moreover, complexes composed of silane coupling agent 3-chloropropyltrimethoxysilane (CPTM), chlorhexidine acetate (CA) and lanthanum(III) worked as ligands of copper ions as a whole during RATRP process. PU films before and after modification were characterized by X-ray photoelectron spectroscopy (XPS) and static contact angle (SCA) to confirm that pMPC chains were successfully grafted from the substrates. Results of Plasma recalcification time assay, platelet adhesion test indicated excellent blood compatibility. Furthermore, the antibacterial activity of the material have been improved which proved by adhesion test of E.coil.

Study on montmorillonite-chlorhexidine acetate-terbinafine hydrochloride intercalation composites as drug release systems.

This paper focuses on the intercalation of chlorhexidine acetate (CA) and terbinafine hydrochloride (TBH) into montmorillonite as sustained release drug carriers. The intercalation compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The basal spacing of montmorillonite increased from 1.23 to 2.97 nm. It was confirmed that CA and TBH molecules were well-stabilized in the interlayer space of clay via mono-, double or triplicate layer stacking. The adsorption amounts and molecular structures of CA and TBH appeared to depend on the cation exchange capacity of MMT, which in turn, tailored the drug release patterns. In vitro release tests of MMT-CA-TBH in 0.9 wt% NaCl solution at 37 °C show a biphasic and sustained profile of CA and TBH ion release. After release, dissolution-diffusion kinetic models were fitted. The mechanism of MMT-CA-TBH release is probably due to surface diffusion and bulk diffusion via ionic exchange of MMT ions on or in the MMT with ions in the NaCl solution. The in vitro release experiments revealed that CA and TBH were released from MMT steadily, depending on the cooperation between the drugs themselves and the electrostatic interactions between the drugs and MMT. It was found that the cross-linking ratio increased due to a decrease in the free volume available for diffusion.