Biocidal polymer derived near white light-emitting polymeric carbon particles for antibacterial and bioimaging applications

A growing antimicrobial crisis has increased demand for antimicrobial materials. It has become increasingly popular to convert polymeric macromolecules into polymeric carbon particles (PCP) in order to achieve highly biocompatible materials with unique properties as a result of the ability to synthesize nanomaterials of the right size and add value to existing stable polymers. This work presents the tuning of PCP for antibacterial application by combining a biocidal polymer with one-pot solvothermal synthesis. PCP displayed broad-spectrum antibacterial activity via various mechanisms, including inhibition of bacterial cell walls, ROS generation, and antibiotic resistance. Furthermore, these biocidal PCP were observed to show excitation-independent near-white light emission which on the other hand is generally possible due to mixed sizes, doping, and surface effects. As opposed to the parent biocidal polymer, PCP added ROS-mediated bactericidal activity, increased cytocompatibility, and nanofibers with anti-adhesive effects and potential of imaging bacterial cells.

High-density zwitterionic polymer brushes exhibit robust lubrication properties and high antithrombotic efficacy in blood-contacting medical devices

High-performance catheters are essential for interventional surgeries, requiring reliable anti-adhesive and lubricated surfaces. This article develops a strategy for constructing high-density sulfobetaine zwitterionic polymer brushes on the surface of catheters, utilizing dopamine and sodium alginate as the primary intermediate layers, where dopamine provides mussel-protein-like adhesion to anchor the polymer brushes to the catheter surface. Hydroxyl-rich sodium alginate increases the number of grafting sites and improves the grafting mass by more than 4 times. The developed high-density zwitterionic polymer brushes achieve long-lasting and effective lubricity (μ<0.0078) and are implanted in rabbits for four hours without bio-adhesion and thrombosis in the absence of anticoagulants such as heparin. Experiments and molecular dynamics simulations demonstrate that graft mass plays a decisive role in the lubricity and anti-adhesion of polymer brushes, and it is proposed to predict the anti-adhesion of polymer brushes by their lubricity to avoid costly and time-consuming bioassays during the development of amphoteric polymer brushes. A quantitative influence of hydration in the anti-adhesion properties of amphiphilic polymer brushes is also revealed. Thus, this study provides a new approach to safe, long-lasting lubrication and anticoagulant surface modification for medical devices in contact with blood. STATEMENT OF SIGNIFICANCE: High friction and bioadhesion on medical device surfaces can pose a significant risk to patients. In response, we have developed a safer, simpler, and more application-specific surface modification strategy that addresses both the lubrication and anti-bioadhesion needs of medical device surfaces. We used dopamine and sodium alginate as intermediate layers to drastically increase the grafting density of the zwitterionic brushes and enabled the modified surfaces to have an extremely low coefficient of friction (μ = 0.0078) and to remain non-bioadhesive for 4 hours in vivo. Furthermore, we used molecular dynamics simulations to gain insight into the mechanisms behind the superior anti-adhesion properties of the high-density polymer brushes. Our work contributes to the development and application of surface-modified coatings.

Experimental study on fabrication, biocompatibility and mechanical characterization of polyhydroxybutyrate-ball clay bionanocomposites for bone tissue engineering

The poly (3-hydroxybutyrate) (PHB)/ball clay nanocomposites (B1-B10) were synthesized using solvent casting method with different weight percentage of ball clay in PHB matrix. Scanning electron microscope (SEM) showed maximum root mean square roughness (188.73 μm) for 10% ball clay loading. Fourier transforms infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) showed establishment of intercalated structure and formation of hydrogen bond between ball clay and PHB matrix. Contact angle values (67.3 - 51.3°) exhibited that the nanocomposites (B1-B10) are more hydrophilic than neat PHB (70.30°). Thermogravimetric (TGA) and differential scanning calorimetry (DSC) revealed maximum T_max (278 °C) and T_m (175 °C) for the nanocomposite B10 (PHB/PEG/ball clay: 80%/10%/10%). Maximum tensile strength (38.21 ± 0.15 MPa) and Young's modulus (1.74 ± 0.016 GPa) was observed for B10 nanocomposite. The values of protein adsorption, platelet adhesion, PT, APTT and complement activation for B10 nanocomposites were 165 ± 2 μg/cm², 72 ± 3 × 10⁹ platelets/cm², 23 ± 1 s, 44 ± 2 s, 102 ± 2 mg/dL and 631 ± 3 mg/dL, respectively. Hydroxyapatite formation was also observed for nanocomposite (B10) in in vitro simulated body fluid (SBF) study. Finally, the nanocomposite (B10) showed no harmful effect on MG-63 cells, indicating that they are physiologically safe.

A multi-in-one strategy with glucose-triggered long-term antithrombogenicity and sequentially enhanced endothelialization for biological valve leaflets

Bioprosthetic heart valves are commonly applied in heart valve replacement, while the effectiveness is limited by inflammation, calcification and especially thrombosis. Surface modification is expected to endow the biological valves with versatility. Herein, a multi-in-one strategy was established to modify biological valves with long-term antithrombogenicity and sequentially enhanced endothelialization triggered by glucose, in which the direct thrombin inhibitor rivaroxaban (RIVA)-loaded nanogels were embedded and the detachable polyethylene glycol (PEG) was grafted. These two anticoagulant strategies were connected by glucose oxidase (GOx), which catalyzed the oxidation of glucose to produce hydrogen peroxide (H₂O₂) and local acidic environment. The generated H₂O₂ stimulated H₂O₂-responsive nanogels release RIVA to obtain continuous antithrombogenicity. Meanwhile, PEG was attached to the surface via pH-sensitive bonds, which prevented thrombus formation by resisting the serum proteins and platelets adhesion at the initial stage of material/blood contact. Sequentially, PEG gradually peeled off under the local weak acidic environment, which ultimately resulted in the endothelialization enhancement. Within such multi-in-one strategy, the biological valve leaflets induced long-term anticoagulant performance, gradually enhanced endothelialization and improved tissue affinity, including anti-calcification and anti-inflammation, indicating the potential of the response sequence matching between materials and tissues after implantation, which might improve performance of biological heart valves.

Formation of an Artificial Mg2+-Permeable Interphase on Mg Anodes Compatible with Ether and Carbonate Electrolytes

Rechargeable Mg-ion batteries typically suffer from either rapid passivation of the Mg anode or severe corrosion of the current collectors by halogens within the electrolyte, limiting their practical implementation. Here, we demonstrate the broadly applicable strategy of forming an artificial solid electrolyte interphase (a-SEI) layer on Mg to address these challenges. The a-SEI layer is formed by simply soaking Mg foil in a tetraethylene glycol dimethyl ether solution containing LiTFSI and AlCl₃, with Fourier transform infrared and ultraviolet-visible spectroscopy measurements revealing spontaneous reaction with the Mg foil. The a-SEI is found to mitigate Mg passivation in Mg(TFSI)₂/DME electrolytes with symmetric cells exhibiting overpotentials that are 2 V lower compared to when the a-SEI is not present. This approach is extended to Mg(ClO₄)₂/DME and Mg(TFSI)₂/PC electrolytes to achieve reversible Mg plating and stripping, which is not achieved with bare electrodes. The interfacial resistance of the cells with a-SEI protected Mg is found to be two orders of magnitude lower than that with bare Mg in all three of the electrolytes, indicating the formation of an effective Mg-ion transporting interfacial structure. X-ray absorption and photoemission spectroscopy measurements show that the a-SEI contains minimal MgCO₃, MgO, Mg(OH)₂, and TFSI^-, while being rich in MgCl₂, MgF₂, and MgS, when compared to the passivation layer formed on bare Mg in Mg(TFSI)₂/DME.

3D PCL/fish collagen composite scaffolds incorporating osteogenic abalone protein hydrolysates for bone regeneration application: in vitro and in vivo studies

Three-dimensional (3 D) printing is an effective technology that has shown considerable potential for use in tissue regeneration. Of the many materials that have been proposed for this purpose, poly (ε-caprolactone) (PCL) 3 D scaffolds have been received significant attention in the bone tissue engineering field due to its advantageous mechanical properties and biocompatibility. In this study, a novel method was developed for tissue-engineered bone that combines PCL 3 D scaffolds with fish collagen (Col) and the osteogenic abalone intestine gastro-intestinal digests (AIGIDs) from Haliotis discus hannai. And then, mouse mesenchymal stem cells (MSCs) were seeded onto the fabricated scaffolds. After in vitro culturing, the proliferation of the MSCs on the scaffolds, alkaline phosphatase (ALP) activity, and the amount of deposited calcium were investigated. The results indicated that the ALP activity and mineralization in PCL/AIGIDs/Col was higher than that of the other scaffolds. In an in vivo experiment, the two fabricated scaffolds were implanted in a rabbit tibia. PCL/AIGIDs/Col group exhibited strong osteoinduction capability in the rabbit tibia defect model. These stimulated biological responses in vitro and in vivo suggest that the PCL/AIGIDs/Col scaffold are promising material for use in tissue implants and bone regeneration.

Versatile Cell-Specific Ligand Arrangement System onto Desired Compartments of Biodegradable Matrices for Site-Selective Cell Adhesion Using DNA Tags

A promising approach for the regeneration of tissues or organs with three-dimensional hierarchical structures is the preparation of scaffold-cell complexes that mimic these hierarchical structures. This requires an effective technique for immobilizing cell-specific ligands at arbitrarily chosen positions on matrices. Here, we report a versatile system for arranging cell-specific ligands onto desired compartments of biodegradable matrices for site-selective cell arrangement. We utilized the specific binding abilities of specific DNAs, immobilizing them as tags to arrange cell-recognition ligands at desired areas of the matrices by specific binding with cell-recognition ligand-DNA conjugates. We synthesized poly(l-lactide) (PLLA), a biodegradable polymer, with an oligo-DNA (trimer of deoxyguanosine: dG₃) attached via a poly(ethylene glycol) (PEG) spacer to generate dG₃-PEG-b-PLLA. The peptides Arg-Gly-Asp-Ser (RGDS) and Arg-Glu-Asp-Val (REDV) were chosen as cell-recognition ligands and were attached to an adapter DNA (aDNA), which can specifically bind to the dG₃ moiety through G-quadruplex formation. The obtained dG₃-PEG-b-PLLA was deposited on a small spot of the PLLA film, and the aDNA-RGDS or aDNA-REDV conjugate was added on the film to immobilize these ligands at the spot. We confirmed the specific adhesion of L929 cells (a mouse fibroblast cell line) and human umbilical vein endothelial cells (HUVECs) on the small areas coated with dG₃-PEG-b-PLLA in the presence of aDNA-RGDS and aDNA-REDV, respectively, even after applying shear stress by flowing medium across the spot. Cell-specific attachment of the target cells was effectively achieved in a spatially controlled manner. This technique has the potential for the construction of cell-scaffold complexes that mimic the hierarchical structures of natural organs and may represent a breakthrough in realizing regenerative medicine and tissue engineering of complex organs.

Photocatalytic Degradation of Methyl Orange by Magnetically Retrievable Supported Ionic Liquid Phase Photocatalyst

A magnetically retrievable ferrocene appended supported ionic liquid phase (SILP) photocatalyst containing a molybdate anion has been synthesized and characterized by Fourier transform infrared, X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction, energy dispersive spectroscopy, and vibrating sample magnetometer analysis. The optical properties of the photocatalyst were probed by photoluminescence and UV-vis diffuse reflectance spectroscopy. The discharge of undesirable dye effluents from textile industrial plants in the environment is the major concern of environmental pollution and toxicity. In this context, we employed the as-prepared SILP photocatalyst for degradation of methyl orange (MO) under UV light (365 nm) irradiation, and subsequently, recycling studies were performed. The histological alteration in gills of the fish is employed as a tool for monitoring toxins in the environment. In view of this, the histo-toxicological assessment on freshwater fish Tilapia mossambica gills asserted the damage of secondary gill lamellae due to MO. Conversely, structural modifications in the gill architecture were not observed by virtue of photodegraded products confirming that the degraded product is nontoxic in nature. Additionally, the normal behavior of fishes on exposure to photodegraded products reveals that research findings are beneficial for the aquatic ecosystem.

Combinatorial functionalization with bisurea-peptides and antifouling bisurea additives of a supramolecular elastomeric biomaterial

The bioactive additive toolbox to functionalize supramolecular elastomeric materials expands rapidly. Here we have set an explorative step toward screening of complex combinatorial functionalization with antifouling and three peptide-containing additives in a bisurea-based supramolecular system. Thorough investigation of surface properties of thin films with contact angle measurements, X-ray photoelectron spectroscopy and atomic force microscopy, was correlated to cell-adhesion of endothelial and smooth muscle cells to apprehend their respective predictive values for functional biomaterial development. Peptides were presented at the surface alone, and in combinatorial functionalization with the oligo(ethylene glycol)-based non-cell adhesive additive. The bisurea-RGD additive was cell-adhesive in all conditions, whereas the endothelial cell-specific bisurea-REDV showed limited bioactive properties in all chemical nano-environments. Also, aspecific functionality was observed for a bisurea-SDF1α peptide. These results emphasize that special care should be taken in changing the chemical nano-environment with peptide functionalization. © 2019 The Authors. Journal of Polymer Science Part B: Polymer Physics published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1725-1735.

Zwitterionic PMCP-Modified Polycaprolactone Surface for Tissue Engineering: Antifouling, Cell Adhesion Promotion, and Osteogenic Differentiation Properties

Biodegradable polycaprolactone (PCL) has been widely applied as a scaffold material in tissue engineering. However, the PCL surface is hydrophobic and adsorbs nonspecific proteins. Some traditional antifouling modifications using hydrophilic moieties have been successful but inhibit cell adhesion, which is not ideal for tissue engineering. The PCL surface is modified with bioinspired zwitterionic poly[2-(methacryloyloxy)ethyl choline phosphate] (PMCP) via surface-initiated atom transfer radical polymerization to improve cell adhesion through the unique interaction between choline phosphate (CP, on PMCP) and phosphate choline (PC, on cell membranes). The hydrophilicity of the PCL surface is significantly enhanced after surface modification. The PCL-PMCP surface reduces nonspecific protein adsorption (e.g., up to 91.7% for bovine serum albumin) due to the zwitterionic property of PMCP. The adhesion and proliferation of bone marrow mesenchymal stem cells on the modified surface is remarkably improved, and osteogenic differentiation signs are detected, even without adding any osteogenesis-inducing supplements. Moreover, the PCL-PMCP films are more stable at the early stage of degradation. Therefore, the PMCP-functionalized PCL surface promotes cell adhesion and osteogenic differentiation, with an antifouling background, and exhibits great potential in tissue engineering.

Micropatterned immobilization of membrane-mimicking polymer and peptides for regulation of cell behaviors in vitro

The Ti-PDA-M/R(P) biomimetic micropattern was successfully fabricated with PMMPC-HD and GREDVY. The Ti-PDA-M/R(P) micropattern can regulate EC morphology, orientation and functions, and inhibit platelet adhesion and proliferation of SMCs.

Surface-Initiated Controlled Radical Polymerization: State-of-the-Art, Opportunities, and Challenges in Surface and Interface Engineering with Polymer Brushes

The generation of polymer brushes by surface-initiated controlled radical polymerization (SI-CRP) techniques has become a powerful approach to tailor the chemical and physical properties of interfaces and has given rise to great advances in surface and interface engineering. Polymer brushes are defined as thin polymer films in which the individual polymer chains are tethered by one chain end to a solid interface. Significant advances have been made over the past years in the field of polymer brushes. This includes novel developments in SI-CRP, as well as the emergence of novel applications such as catalysis, electronics, nanomaterial synthesis and biosensing. Additionally, polymer brushes prepared via SI-CRP have been utilized to modify the surface of novel substrates such as natural fibers, polymer nanofibers, mesoporous materials, graphene, viruses and protein nanoparticles. The last years have also seen exciting advances in the chemical and physical characterization of polymer brushes, as well as an ever increasing set of computational and simulation tools that allow understanding and predictions of these surface-grafted polymer architectures. The aim of this contribution is to provide a comprehensive review that critically assesses recent advances in the field and highlights the opportunities and challenges for future work.

Hyperbranched polyesters as biodegradable and antibacterial additives

Herein, we present novel hyperbranched poly(amino-ester)s functionalized with quaternary ammonium salts.