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Bacterial infections are a common mode of failure for medical implants. This study aims to develop antibacterial polyelectrolyte multilayer (PEM) coatings that contain a plant-derived condensed tannin polymer (Tanfloc, TAN) with inherent antimicrobial activity. Tanfloc is amphoteric, and herein we show that it can be used as either a polyanion or a polycation in PEMs, thereby expanding the possibility of its use in PEM coatings. PEMs are ordinarily formed using a polycation and a polyanion, in which the functional (ionic) groups of the two polymers are complexed to each other. However, using the amphoteric polymer Tanfloc with weakly basic amine and weakly acidic catechol and pyrogallol groups enables PEM formation using only one or the other of its functional groups, leaving the other functional group available to impart antibacterial activity. This work demonstrates Tanfloc-containing PEMs using multiple counter-polyelectrolytes including three polyanionic glycosaminoglycans of varying charge density, and the polycations N,N,N-trimethyl chitosan and polyethyleneimine. The layer-by-layer (LbL) assembly of PEMs was monitored using in situ Fourier-transform surface plasmon resonance (FT-SPR), confirming a stable LbL assembly. X-ray photoelectron spectroscopy (XPS) was used to evaluate surface chemistry, and atomic force microscopy (AFM) was used to determine the surface roughness. The LDH release levels from cells cultured on the Tanfloc-containing PEMs were not statistically different from those on the negative control (p > 0.05), confirming their non-cytotoxicity, while exhibiting remarkable antiadhesive and bactericidal properties against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus), respectively. The antibacterial effects were attributed to electrostatic interactions and Tanfloc's polyphenolic nature. This work underscores the potential of Tanfloc as a versatile biomaterial for combating infections on surfaces. [ABSTRACT FROM AUTHOR]

Ultralow protein fouling behavior is a common target for new high-performance materials. Ultralow fouling is often defined based on the amount of irreversibly adsorbed protein (< 5 ng cm−2) measured by a surface ensemble averaging method. However, protein adsorption at solid interfaces is a dynamic process involving multiple steps, which may include adsorption, desorption, and irreversible protein denaturation. In order to better optimize the performance of antifouling surfaces, it is imperative to fully understand how proteins interact with surfaces, including kinetics of adsorption and desorption, conformation, stability, and amount of adsorbed proteins. Defining ultralow fouling surfaces based on a measurement at or near the limit of detection of a surface-averaged measurement may not capture all of this behavior. Single-molecule microscopy techniques can resolve individual protein-surface interactions with high temporal and spatial resolution. This information can be used to tune the properties of surfaces to better resist protein adsorption. In this work, we demonstrate how combining surface plasmon resonance, X-ray photoelectron spectroscopy, atomic force microscopy, and single-molecule localization microscopy provides a more complete picture of protein adsorption on low fouling and ultralow fouling polyelectrolyte multilayer and polymer brush surfaces, over different regimes of protein concentration. In this case, comparing the surfaces using surface plasmon resonance alone is insufficient to rank their resistance to protein adsorption. Our results suggest a revision of the accepted definition of ultralow fouling surfaces is timely: with the advent of time-resolved studies of protein adsorption kinetics at the single-molecule level, it is neither necessary nor sufficient to rely on a surface averaging techniques to qualify ultralow fouling surfaces. Since protein adsorption is a dynamic process, understanding how surface properties affect the kinetics of protein adsorption will enable the design of future generations of advanced antifouling materials. The design of ultralow fouling surfaces is often optimized based on a single surface-averaging technique measuring the amount of irreversibly adsorbed protein. This work provides a critical comparison of alternative techniques for evaluating protein adsorption on low fouling and ultralow fouling surfaces, and demonstrates how additional information about the dynamics of protein-surface interactions at the interface can be obtained by application of single-molecule microscopy. This approach could be used to better elucidate mechanisms of protein resistance and design principles for advanced ultralow fouling materials. Image, graphical abstract [ABSTRACT FROM AUTHOR]

In this work, innovative hybrid poly(ethylene terephthalate) (PET) materials with strong luminescence were successfully synthesized by doping PET with silicon‐linked poly(ethylene glycol)‐PET copolymer nanostructures either with (Si‐PEG‐PET) or with (ETP@Si‐PEG‐PET) luminescent Eu3+‐complexes. The chemical properties and nanostructures of the hybrid materials were characterized by Fourier‐transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, x‐ray photoelectron spectroscopy, and high‐resolution transmission electron microscopy. PET composites ranging from 0.25 to 4 wt% silicon additive were prepared by the melt blending method. The crystal properties, mechanical properties, and fluorescence properties of the composites were systematically studied by differential scanning calorimetry, x‐ray diffractometry, tensile testing, and fluorescence spectrometry. When the addition of Si‐PEG‐PET or ETP@Si‐PEG‐PET was 0.75 wt%, the relative crystallinity and maximum tensile strength increase substantially. Moreover, the fluorescence intensity of hybrid luminescent PET materials is the strongest at 0.75 wt% loading. ETP@Si‐PEG‐PET not only endows PET polyester with stronger fluorescence properties and mechanical properties but also acts as an effective nucleation additive for PET. Highlights: Silicon‐linked poly(ethylene glycol)‐poly(ethylene terephthalate) (PEG‐PET) nanostructures generate hybrid luminescent PET materials.ETP@Si‐PEG‐PET improves the crystallization rate and crystallinity of PET.The composite with 0.75% addition showed the best fluorescence performance.Three‐dimensional‐grid structure of ETP@Si‐PEG‐PET enhances the mechanical property of PET. [ABSTRACT FROM AUTHOR]

• Chitosan/alginate and N,N- dimethyl chitosan/alginate-based adsorbents are prepared. • An ionic liquid is used to carry out the polysaccharide-based adsorbents. • Adsorbents are produced by precipitating of blends performed in an ionic liquid. • The ionic liquid is recovered and reused to create new adsorbents. • The adsorbents have high capacity for removing Pb(II) ions from aqueous systems. Alginate/chitosan (ALG/CHT) and alginate/ N , N -dimethyl chitosan (ALG/DMC) polyelectrolyte complex (PEC)-based adsorbents with high capacities for removing Pb(II) from aqueous systems are produced in [1-hydrogen-3-methylimidazolium hydrogen sulfate ionic liquid ([Hmim][HSO 4 ―]). The [Hmim][HSO 4 ―] is recovered, characterized by 1H NMR and reused to yield novel polysaccharide-based adsorbents. As-obtained PEC materials are characterized through infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and Zeta potential measurements. Kinetic and equilibrium adsorption studies reveal that the pseudo-second-order Kinetic, as well as the Redlich-Peterson isotherm, provide the best fits for the experimental data, respectively. CHT/ALG and DMC/ALG adsorbents promoted maximum adsorption capacities (q m) of 529.4 mg g−1 and 560.2 mg g−1, respectively. After adsorption, the materials are characterized by infrared spectroscopy and X-ray photoelectron spectroscopy, confirming that the chemisorption prevails upon Pb(II) removal. Also, PECs produced in the recovered [Hmim][HSO 4 ―] have good capacities for removing Pb(II) ions from aqueous systems as well. This study showed that the [Hmim][HSO 4 ―] is an alternative solvent to prepare novel and eco-friendly PEC-based adsorbents. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride) (PVC), a synthetic polymer, is used in various biomedical applications, particularly in the development of catheters. PVC-based catheters are engineered for blood-contacting applications. However, these materials lack antimicrobial properties, resulting in bacterial proliferation and subsequent infections. To overcome this disadvantage, blood-compatible and antimicrobial polyphenolic tannin-based surface coatings, known as polyelectrolyte multilayers (PEMs), were adsorbed onto PVC for the first time. PEMs were created on reduced PVC (Red-PVC) or oxidized PVC (Oxi-PVC) substrates using the layer-by-layer (LbL) approach. An amino-functionalized polyphenolic tannin derivative (TN-NH 2), commercially known as Tanfloc, and an unmodified polyphenolic tannin (TN), commercially known as Weibull black, were assembled (15 layers) on Oxi-PVC or Red-PVC at pH 5.0. PVC substrates and PEMs were characterized through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA) measurements. The PEMs showed enhanced wettability compared to the unmodified PVC, with water contact angles ranging from 42° to 38°. The root mean square (R q) roughness of the PEMs ranged from 64.5 nm to 74.1 nm, while the unmodified PVC surface displayed a relatively smooth surface with a roughness of 5.4 nm. Stability tests demonstrated that the PEMs maintained their integrity in phosphate buffer (pH 7.4) over seven days at 37 ° C. The obtained PEMs were not toxic to human fibroblasts and human erythrocytes. The Live/Dead antimicrobial assay results indicated that the PEMs possessed biocidal activity against Pseudomonas aeruginosa (P. aeruginosa) and antiadhesive capacity toward Staphylococcus aureus (S. aureus) and P. aeruginosa after 24 h of incubation. Cytocompatible and antimicrobial tannin-based PEMs on modified PVC surfaces can represent a significant advancement in mitigating bacterial infections associated with PVC-based catheters. • Polyphenolic and amino-functionalized polyphenolic tannins were assembled on poly(vinyl chloride). • The surface coatings are cytocompatible toward fibroblast and red blood cells. • The surface coatings supported outstanding antiadhesive properties. • The surface coatings showed antimicrobial activity against Pseudomonas aeruginosa. • Surface coatings can mitigate bacterial infections associated with catheters. [ABSTRACT FROM AUTHOR]

Patients in hospital environments are susceptible to bacterial colonization, which can lead to infections. In this study, electrospun fibers were manufactured using poly(vinyl alcohol) (PVA) crosslinked with citric acid (CA) and incorporating the ionic liquid (IL) 1-hexadecyl-3-methylimidazolium chloride (C 16 MImCl) to prevent microbial growth and biofilm formation. The presence of CA and IL reduced the surface tension of the PVA solution (12% w/v) from 52.07 mN/m to 35.84 mN/m. CA was introduced into PVA solutions, and the resulting fibers were thermally crosslinked through esterification between PVA hydroxyl groups and CA. X-ray photoelectron spectroscopy (XPS) confirmed the presence of IL on the fiber surfaces. The IL acted as a surfactant, imparting plasticity to the electrospun fibers and enhancing homogeneity and mechanical properties. Before crosslinking, the PVA/CA/IL fibers exhibited an elongation at break (%) of approximately 140%, a tensile strength of 5.3 MPa, and an elastic modulus of 18.2 MPa. After cross-linking, the elongation at break reduced to 86%, the tensile strength increased to 7.6 MPa, and the elastic modulus increased to 88 MPa. Mechanical measurements confirmed the thermal crosslinking of the fibers, primarily because of the increased elastic modulus. Adhesion and proliferation tests with Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) indicated reduced bacterial adhesion and growth on the PVA/CA/IL fibers. Antimicrobial assays further confirmed a 50.73% and 69.42% increase in bactericidal activity against S. aureus and P. aeruginosa , respectively. The PVA/CA/IL fibers exhibit promising potential for producing antimicrobial materials to prevent the attachment and proliferation of microbial strains on solid surfaces. • The ionic liquid 1-hexadecyl-3-methylimidazolium was electrospuned with poly(vinyl alcohol)/citric acid. • The ionic liquid improved the electrospinnability of the polymer solutions. • The fibers were thermally cross-linked through esterification reaction. • The fibers containing the ionic liquid promoted anti-adhesive and antimicrobial properties. [ABSTRACT FROM AUTHOR]

In this study, a surface modification strategy using natural biopolymers on titanium is proposed to improve bone healing and promote rapid and successful osseointegration of orthopedic implants. Titania nanotubes were fabricated via an anodization process and the surfaces were further modified with polyelectrolyte multilayers (PEMs) based on Tanfloc (a cationic tannin derivative) and glycosaminoglycans (heparin and hyaluronic acid). Scanning electron microscopy (SEM), water contact angle measurements, and X-ray photoelectron spectroscopy were used to characterize the surfaces. Adipose-derived stem cells (ADSCs) were seeded on the surfaces, and the cell viability, adhesion, and proliferation were investigated. Osteogenesis was induced and osteogenic differentiation of human ADSCs on the surfaces was evaluated via mineralization and protein expression assays, immunofluorescent staining, and SEM. The Tanfloc/heparin PEMs on titania nanotubes improved the rate of osteogenic differentiation of ADSCs as well as the bone mineral deposition, and is therefore a promising approach for use in orthopedic implants. [ABSTRACT FROM AUTHOR]

To obtain pectin-based films is challenging due to the aqueous instability of polyelectrolyte mixtures. We overcome this issue by blending chitosan to pectin of high O -methoxylation degree (56%), followed by solvent evaporation. A durable film containing 74 wt% pectin content was produced and used as an adsorbent material toward Cu(II) ions. Kinetic and adsorption equilibrium studies showed that the pseudo-second-order and Sips isotherm models adjusted well to the experimental data, respectively. Langmuir isotherm indicated a maximum adsorption capacity (q m) for Cu(II) removal of 29.20 mg g−1. Differential scanning calorimetry, contact angle measurements, and X-ray photoelectron spectroscopy confirm the adsorption. The chemisorption plays an essential role in the process; thereby, the film reusability is low. After adsorption, the cytocompatible film/Cu(II) pair prevents the proliferation of Escherichia coli. • A physically crosslinked film contains high pectin content (74 wt%). • The film presents sorption capacity for Cu(II) ions of 29.20 mg g−1. • The chemisorption plays an essential role in the Cu(II) adsorption. • After adsorption, the film/Cu(II) has cytocompatibility for mammalian cells. • The film/Cu(II) prevents the spreading of E. coli on its surface. [ABSTRACT FROM AUTHOR]

Abstract: The influence of particle size on the activity and recycling capabilities of enzyme conjugated magnetic nanoparticles was studied. Co-precipitation and oxidation of Fe(OH)2 methods were used to fabricate three different sizes of magnetic nanoparticles (5nm, 26nm and 51nm). Glucose oxidase was covalently bound to the magnetic nanoparticles by modifying the surfaces with 3-(aminopropyl)triethoxysilane (APTES) and a common protein crosslinking agent, glutaraldehyde. Analysis by Transmission Electron Microscopy (TEM) showed that the morphology of the magnetic nanoparticles to be spherical and sizes agreed with results of the Brunauer, Emmett, and Teller (BET) method. Magnetic strength of the nanoparticles was analyzed by magnetometry and found to be 49emug−1 (5nm), 73emug−1 (26nm), and 85emug−1 (51nm). X-ray photoelectron spectroscopy (XPS) confirmed each step of the magnetic nanoparticle surface modification and successful glucose oxidase binding. The immobilized enzymes retained 15–23% of the native GOx activity. Recycling stability studies showed approximately 20% of activity loss for the large (51nm) and medium (26nm) size glucose oxidase-magnetic nanoparticle (GOx-MNP) bioconjugate and about 96% activity loss for the smallest GOx-MNP bioconjugate (5nm) after ten cycles. The bioconjugates demonstrated equivalent total product conversions as a single reaction of an equivalent amount of the native enzyme after the 5th cycle for the 26nm nanoparticles and the 7th cycle for the 51nm nanoparticles. [ABSTRACT FROM AUTHOR]

This study reports the synthesis, characterization and biological properties of films based on poly(vinyl alcohol) (PVA) and a cationic tannin polymer derivative (TN). Films are obtained from polymeric blends by tuning the PVA/TN weight ratios. The materials are characterized through infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle measurements, mechanical analyses, and scanning electron microscopy. More hydrophilic surfaces are created by modulating the PVA and TN concentrations in the blends. Disintegration tests showed that the films present durability in phosphate buffer (pH 7.4) and low stability in simulated gastric fluid (pH 1.2). The film created at 90/10 PVA/TN weight ratio and crosslinked at 109 PVA/glutaraldehyde molar ratio (sample PVA10/TN10) supports the attachment and proliferation of bone marrow mesenchymal stem cells after 7 days of culture. The scaffolding capacity of the PVA10/TN10 surface is compared with titanium, one of the most important biomedical materials used in bone replacements. Also, the PVA/TN films exhibited cytocompatibility, antioxidant and antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. These properties make PVA/TN films are candidates for biomedical applications in the tissue engineering field. Image 1 • New poly(vinyl alcohol)/cationic tannin films are produced. • The more hydrophilic film surface has antimicrobial and antioxidant activities. • The hydrophilic film supports the attachment and proliferation of cells. [ABSTRACT FROM AUTHOR]

Curcumin (CUR) is a hydrophobic drug which has been loaded into polymeric carrier matrices by using experimental strategies with many steps, as well as by using conventional and volatile organic solvents. For the first time, this study reports the use of an ionic liquid ([Hmim][HSO 4 −]) to solubilize polycation-polyanion polymer pairs and hydrophobic CUR in the same system. By using the [Hmim][HSO 4 −] as an appropriated solvent, CUR (ca. 10% wt) is loaded into a polyelectrolyte complex (PEC) based on chitosan and commercial iota -carrageenan, following a straightforward method (in-situ approach). A solution containing chitosan, iota -carrageenan, and CUR is produced in [Hmim][HSO 4 −] and subsequently precipitated in an ice-water bath to form the CUR-loaded PEC. The ionic liquid is synthesized following a straightforward experimental route, and after PEC production, it is recovered and reused. X-ray photoelectron spectroscopy analysis shows that chitosan and iota -carrageenan are principally interacting by coulombic forces. Also, X-ray photoelectron spectroscopy and infrared spectroscopy analyses confirm that CUR is loaded into the PEC structure. Wide-angle X-ray scattering, scanning electron microscopy, and differential scanning calorimetry also confirm that CUR loaded PEC (ca. 105 mg g−1) comprise a more disorganized structure when compared to the pristine drug. The CUR is released in simulated gastric fluid (SGF, pH 1.2) because the PEC material increases 3.3-fold its solubility in SGF when compared to the raw curcumin. The ionic liquid can remain in the PEC structure, potentially imparting cytotoxicity. A simple aqueous washing step is sufficient to remove the residual [Hmim][HSO 4 −] and promote cytocompatibility. Cell viability assay performed on bone marrow-derived stem cells demonstrates that CUR significantly increases the cell viability promoted by the PEC. • Chitosan/carrageenan polyelectrolyte complexes are prepared. • A polyelectrolyte complex/curcumin-based material is created by precipitation of a miscible mixture. • A strategy in-situ is developed to load curcumin into the polyelectrolyte complex. • An aqueous washing step removes the residual ionic liquid into the material structure. • The loaded curcumin improves the cytocompatibility and cell viability on mesenchymal stem cells. [ABSTRACT FROM AUTHOR]