Constructing graphene oxide/Au nanoparticle cellulose membranes for SERS detection of mixed pesticide residues in edible chrysanthemum.

Edible chrysanthemum is widely cultivated and used as an important ingredient of medicine, tea and multifunctional food. During the planting of chrysanthemum, pesticides are extensively used for preventing plant diseases and insect pests. To ensure the food safety of edible chrysanthemum, rapid detection methods are urgently needed for on-site inspection. In this study, a graphene oxide/Au nanoparticle (GO/Au NP) cellulose substrate was prepared through layer-by-layer assembly of GO and Au NPs on a mixed cellulose ester membrane. Surface-enhanced Raman spectroscopy (SERS) detection of four types of organophosphorus and organosulfur pesticides was achieved by filtering the extracting solution through the substrate and analysing SERS spectra. Qualitative and semi-quantitative detection of fenthion, phoxim, isocarbophos and thiram was accomplished with the detection limits of 38.01, 8.13, 48.97 and 8.74 ng mL-1, respectively. A spiking experiment further demonstrated the feasibility of this method for rapid and on-site detection of mixed pesticides in chrysanthemum. This study provides a new approach for rapid detection of multiple hazardous substances in flowering and herbal plants.

Physiological, Biochemical, and Molecular Analyses Reveal Dark Heartwood Formation Mechanism in Acacia melanoxylon.

Acacia melanoxylon is highly valued for its commercial applications, with the heartwood exhibiting a range of colors from dark to light among its various clones. The underlying mechanisms contributing to this color variation, however, have not been fully elucidated. In an effort to understand the factors that influence the development of dark heartwood, a comparative analysis was conducted on the microstructure, substance composition, differential gene expression, and metabolite profiles in the sapwood (SW), transition zone (TZ), and heartwood (HW) of two distinct clones, SR14 and SR25. A microscopic examination revealed that heartwood color variations are associated with an increased substance content within the ray parenchyma cells. A substance analysis indicated that the levels of starches, sugars, and lignin were more abundant in SP compared to HW, while the concentrations of phenols, flavonoids, and terpenoids were found to be higher in HW than in SP. Notably, the dark heartwood of the SR25 clone exhibited greater quantities of phenols and flavonoids compared to the SR14 clone, suggesting that these compounds are pivotal to the color distinction of the heartwood. An integrated analysis of transcriptome and metabolomics data uncovered a significant accumulation of sinapyl alcohol, sinapoyl aldehyde, hesperetin, 2', 3, 4, 4', 6'-peptahydroxychalcone 4'-O-glucoside, homoeriodictyol, and (2S)-liquiritigenin in the heartwood of SR25, which correlates with the up-regulated expression of CCRs (evm.TU.Chr3.1751, evm.TU.Chr4.654_667, evm.TU.Chr4.675, evm.TU.Chr4.699, and evm.TU.Chr4.704), COMTs (evm.TU.Chr13.3082, evm.TU.Chr13.3086, and evm.TU.Chr7.1411), CADs (evm.TU.Chr10.2175, evm.TU.Chr1.3453, and evm.TU.Chr8.1600), and HCTs (evm.TU.Chr4.1122, evm.TU.Chr4.1123, evm.TU.Chr8.1758, and evm.TU.Chr9.2960) in the TZ of A. melanoxylon. Furthermore, a marked differential expression of transcription factors (TFs), including MYBs, AP2/ERFs, bHLHs, bZIPs, C2H2s, and WRKYs, were observed to be closely linked to the phenols and flavonoids metabolites, highlighting the potential role of multiple TFs in regulating the biosynthesis of these metabolites and, consequently, influencing the color variation in the heartwood. This study facilitates molecular breeding for the accumulation of metabolites influencing the heartwood color in A. melanoxylon, and offers new insights into the molecular mechanisms underlying heartwood formation in woody plants.

Extensional Flow-Induced Dynamic Phase Transitions in Isotactic Polypropylene.

With a combination of fast extension rheometer and in situ synchrotron radiation ultra-fast small- and wide-angle X-ray scattering, flow-induced crystallization (FIC) of isotactic polypropylene (iPP) is studied at temperatures below and above the melting point of α crystals (Tmα). A flow phase diagram of iPP is constructed in strain rate-temperature space, composing of melt, non-crystalline shish, α and α&ß coexistence regions, based on which the kinetic and dynamic competitions among these four phases are discussed. Above Tmα , imposing strong flow reverses thermodynamic stabilities of the disordered melt and the ordered phases, leading to the occurrence of FIC of ß and α crystals as a dynamic phase transition. Either increasing temperature or stain rate favors the competiveness of the metastable ß over the stable α crystals, which is attributed to kinetic rate rather than thermodynamic stability. The violent competitions among four phases near the boundary of crystal-melt may frustrate crystallization and result in the non-crystalline shish winning out.

Colloidal Phenol-Amine Coating on Implants for Improved Anti-Inflammation and Osteogenesis.

Phenol-amine coatings have attracted significant attention in recent years owing to their adjustable composition and multifaceted biological functionalities. The current preparation of phenol-amine coatings, however, involves a chemical reaction within the solution or interface, resulting in lengthy preparation times and necessitating specific reaction conditions, such as alkaline environments and oxygen presence. The facile, rapid, and eco-friendly preparation of phenol-amine coatings under mild conditions continues to pose a challenge. In this study, we use a macromolecular phenol-amine, Tanfloc, to form a stable colloid under neutral conditions, which was then rapidly adsorbed on the titanium surface by electrostatic action and then spread and fused to form a continuous coating within several minutes. This nonchemical preparation process was rapid, mild, and free of chemical additives. The in vitro and in vivo results showed that the Tanfloc colloid fusion coating inhibited destructive inflammation, promoted osteogenesis, and enhanced osteointegration. These remarkable advantages of the colloidal phenol-amine fusion coating highlight the suitability of its future application in clinical practice.

Using an aromatic amide as nucleating agent to enhance the crystallization and dimensional stability of poly(3-hydroxybutyrate-co-3-hydroxyhexanate).

Biosynthesized poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) has emerged as a promising biodegradable polymer with a great potential to compete with traditional petroleum-based plastics, however, the poor crystallization ability makes it challenge to transform into high-performance products via common melt-processing methods. Herein, we demonstrate that N,N'-dicyclohexyl-2,6-naphthalenedicarboxamide (TMB) can serve as an efficient nucleating agent to significantly enhance the crystallization and resulting storage stability of PHBHHx. The results indicate that PHBHHx with small amounts of TMB (0.3-0.5 wt%) can crystallize completely even under a rapid cooling rate of 100 °C/min and the isothermal crystallization time is greatly reduced. As a result, the crystallinity of the injection-molded PHBHHx products is increased from 24.5 % to 39.5 %, without secondary crystallization after being stored at room temperature for 6 h. The products exhibit superior dimensional stability and the post-shrinkage can be decreased to as low as 0.1 %. Our work offers a feasible method to develop high-performance PHBHHx materials with remarkably enhanced crystallization ability.

Built-up sodium alginate/chlorhexidine multilayer coating on dental implants with initiating anti-infection and cyto-compatibility sequentially for soft-tissue sealing.

Soft-tissue sealing at transmucosal sites is very important for preventing the invasion of pathogens and maintaining the long-term stability and function of dental implants. However, the colonization of oral pathogens on the implant surface and surrounding soft tissues can disturb the early establishment of soft-tissue sealing and even induce peri-implant infection. The purpose of this study was to construct two antibacterial coatings with 5 or 10 sodium alginate/chlorhexidine bilayers on titanium surfaces using layer-by-layer self-assembly technology to promote soft-tissue sealing. The corresponding chemical composition, surface topography, wettability and release behaviour were investigated to prove that the resultant coating of sodium alginate and chlorhexidine was coated on the porous titanium surface. In-vitro and in-vivo antibacterial results showed that both prepared coatings inhibited or killed the bacteria on their surfaces and the surrounding areas to prevent plaque biofilm formation, especially the coating with 10 bilayers. Although both coatings inhibited the initial adhesion of fibroblasts, the cytocompatibility gradually improved with coating degradation. More importantly, both coatings achieved cell adhesion and proliferation in an in-vitro bacterial environment and effectively alleviated bacteria-induced subcutaneous inflammation in-vivo. Therefore, this study demonstrated that the multilayered coating could prevent implant-related infections in the initial stage of implant surgery and then improve soft-tissue integration with implant devices.

A homogeneous dopamine-silver nanocomposite coating: striking a balance between the antibacterial ability and cytocompatibility of dental implants.

Silver has been widely used for surface modification to prevent implant-associated infections. However, the inherent cytotoxicity of silver greatly limited the scope of its clinical applications. The construction of surfaces with both good antibacterial properties and favorable cytocompatibility still remains a challenge. In this study, a structurally homogeneous dopamine-silver (DA/Ag) nanocomposite was fabricated on the implant surface to balance the antibacterial activity and cytocompatibility of the implant. The results show that the DA/Ag nanocomposites prepared under the acidic conditions (pH = 4) on the titanium surface are homogeneous with higher Ag+ content, while an obvious core (AgNPs)-shell (PDA) structure is formed under neutral (pH = 7) and alkaline conditions (pH = 10), and the subsequent heat treatment enhanced the stability of PDA-AgNPs nanocomposite coatings on porous titanium. The antibacterial test, cytotoxicity test, hypodermic implantation and osteogenesis test revealed that the homogeneous PDA-AgNPs nanocomposite coating achieved the balance between the antibacterial ability and cytocompatibility, and had the best outcomes for soft tissue healing and bone formation around the implants. This study provides a facile strategy for preparing silver-loaded surfaces with both good antibacterial effect and favorable cytocompatibility, which is expected to further improve the therapeutic efficacy of silver composite-coated dental implants.

A programmed surface on dental implants sequentially initiates bacteriostasis and osseointegration.

Osteogenesis surrounding dental implants is initiated by a series of early physiological events, including the inflammatory response. However, the persistence of an anti-infection surface often results in compromised histocompatibility and osseointegration. Here, we presented a programmed surface containing both silver nanoparticles (AgNPs) and silver ions (Ag+) with a heterogeneous structure and time-dependent functionalities. The AgNPs were located at the surface of the heparin-chitosan polyelectrolyte coating (PEM), whereas Ag+ was distributed at both the surface and inside of the coating under optimized conditions (pH=4). The optimized coating (Ag-4) exhibited potent bactericidal activity at the early stage (12 and 24 h after inoculation) and a sustained antibacterial efficacy in the subsequent stage (one or two weeks), as it gradually depleted. Furthermore, compared to coatings with sustained high silver concentrations in bacteria-cell coculture experiments, the degradable Ag-4 coating demonstrated improved cytocompatibility, better cell viability, and morphology over time. At a later stage (within one month), the in vivo test revealed that Ag-4-coated titanium had superior histocompatibility and osteogenesis outcomes compared to bare titanium in a bacteria-exposed environment. The programmed surface of dental implants presented in this study offers innovative ideas for sequential antibacterial effects and osseointegration.

Fretting stimulation enhances bone growth at the interface between hydroxyapatite coating and bone.

Biologically fixed arthroplasty is limited in its development by the long postoperative recovery time and the low quality of solidity of the fixed interface in the short postoperative period. Therefore, fretting stimulation is used to accelerate the combination between bone tissue and the biological fixation interface of artificial joint prostheses. The effects of different compression loads and tangential micro-motion amplitude on the growth rate of bone tissue and the firm quality of fixation interface were studied by using two kinds of micro-motion stimuli: compression and tangential micro-motion. The mechanism of micro-motion stimulation to promote bone growth at the fixation interface was revealed. The results of binding force detection of biological fixation interface and bone tissue section staining showed that the bone tissue and hydroxyapatite coating interface had the most tendency to produce new bone tissue under compression load of 4 N. In the tangential fretting environment, the tangential fretting amplitude of ± 40 µm and the normal load of 7.5 N were the most conducive to bone growth, making the combination of bone tissue and titanium alloy prosthesis coated with hydroxyapatite more firm. The study is important for accelerating the integration and shortening the rehabilitation time after artificial joint replacement.

Multifunctional Coatings of Titanium Implants Toward Promoting Osseointegration and Preventing Infection: Recent Developments.

Titanium and its alloys are dominant material for orthopedic/dental implants due to their stable chemical properties and good biocompatibility. However, aseptic loosening and peri-implant infection remain problems that may lead to implant removal eventually. The ideal orthopedic implant should possess both osteogenic and antibacterial properties and do proper assistance to in situ inflammatory cells for anti-microbe and tissue repair. Recent advances in surface modification have provided various strategies to procure the harmonious relationship between implant and its microenvironment. In this review, we provide an overview of the latest strategies to endow titanium implants with bio-function and anti-infection properties. We state the methods they use to preparing these efficient surfaces and offer further insight into the interaction between these devices and the local biological environment. Finally, we discuss the unmet needs and current challenges in the development of ideal materials for bone implantation.

Preparation and evaluation of hydrophobic biodegradable films made from corn/octenylsuccinated starch incorporated with different concentrations of soybean oil.

Corn/octenylsuccinated starch (C/OS) composite films incorporated with soybean oil (SO) at 0, 0.5%, 1.0%, 1.5% and 2.0% (w/w) were prepared to investigate their physicochemical properties. Fourier transform infrared analysis indicated that low concentrations of SO could facilitate molecular interaction and the formation of hydrogen bonds between starch molecules. All the films exhibited similar diffractograms and lower relative crystallinity values. Scanning electron microscopy and atomicforcemicroscopy showed that the irregular and coarse surface structures of the films were obtained more frequently with increasing SO concentration. A higher contact angle of 76.14° and lower water vapor permeability of 2.46 × 10-12 g cm/cm2 s Pa were obtained with increasing SO content, with the exception of the 2.0% SO sample. The highest tensile strength value of 6.54 MPa was obtained by the C/OS-1.0% SO composite film, while the optimumelongation at break of 71.84% was exhibited by the C/OS-1.5% SO composite film.

Mussel-inspired "built-up" surface chemistry for combining nitric oxide catalytic and vascular cell selective properties.

Specific selectivity of vascular cells and antithrombogenicity are crucial factors for the long-term success of vascular implants. In this work, a novel concept of mussel-inspired "built-up" surface chemistry realized by sequential stacking of a copper-dopamine network basement, followed by a polydopamine layer is introduced to facilitate the combination of nitric oxide (NO) catalysis and vascular cell selectivity. The resultant "built-up" film allowed easy manipulation of the content of copper ions and the density of catechol/quinone groups, facilitating the multifunctional surface engineering of vascular devices. For example, the chelated copper ions in the copper-dopamine network endow a functionalized vascular stent with a durable release of NO via catalytic decomposition of endogenous S-nitrosothiol. Meanwhile, the catechol/quinone groups on the film surface allow the facile, secondary grafting of the REDV peptide to develop a selectivity for vascular cells, as a supplement to the functions of NO. As a result, the functionalized vascular stent perfectly combines the functions of NO and REDV, showing excellent antithrombotic properties and competitive selectivity toward the endothelial cells over the smooth muscle cells, hence impressively promotes re-endothelialization and improves anti-restenosis in vivo. Therefore, the first mussel-inspired "built-up" surface chemistry can be a promising candidate for the engineering of multifunctional surfaces.

Poly-l-lysine/Sodium Alginate Coating Loading Nanosilver for Improving the Antibacterial Effect and Inducing Mineralization of Dental Implants.

In recent years, antibacterial surface modification of titanium (Ti) implants has been widely studied in preventing implant-associated infection for dental and orthopedic applications. The purpose of this study was to prepare a composite coating on a porous titanium surface for infection prevention and inducing mineralization, which was initialized by deposition of a poly-l-lysine (PLL)/sodium alginate(SA)/PLL self-assembled coating, followed by dopamine deposition, and finally in situ reduction of silver nanoparticles (AgNPs) by dopamine. The surface zeta potential, SEM, XPS, UV-vis, and water contact angle analyses demonstrate that each coating was successfully prepared after the respective steps and that the average sizes of AgNPs were 20-30 nm. The composite coating maintained Ag+ release for more than 27 days in PBS and induced mineralization when incubated in SBF. The antibacterial results showed that the composite coating inhibited/killed bacteria on the material surface and killed bacteria around them. In addition, although this coating inhibited the initial adhesion of osteoblasts, the mineralized surface greatly enhanced the cytocompatibility. Thus, we concluded that the composite coating could prevent bacterial infections and facilitate mineralization in vivo in the early postoperative period, and then, the mineralized surface could enhance the cytocompatibility.

Metal-catechol-(amine) networks for surface synergistic catalytic modification: Therapeutic gas generation and biomolecule grafting.

Regarding the high requirement of cardiac and vascular implants in tissue engineering, a novel concept of surface chemistry strategy featuring multiple functions is proposed in this study, which provides glutathione peroxidase (GPx)-like catalytic activity and allows secondary reactions for grafting functional biomolecules. The suggested strategy is the fabrication of a metal-catechol-(amine) network (MCAN) containing copper ions with GPx-like activity, amine-bearing hexamethylenediamine (HD) and wet adhesive catechol dopamine (DA). With a simple one-step molecular/ion co-assembly, the developed copper-DA-HD (CuII-DA/HD) network can be used to catalyze the generation of therapeutic nitric oxide (NO) gas in a durable and dose-controllable manner. The primary amine groups in the CuII-DA/HD network facilitate the secondary immobilization of bivalirudin (BVLD) to further provide an antithrombotic activity as supplement to the functions of NO. The CuII-DA/HD + BVLD coating functionalized on cardiovascular stents successfully improved thromboresistance, anti-restenosis, and promotes re-endothelialization in vivo. With regard to the ease of operation and low cost, the synergetic modification using MCAN strategy is of great potential for developing multifunctional blood-contacting materials/devices.

Identifying the phase behavior of biodegradable poly(hexamethylene succinate-co-hexamethylene adipate) copolymers with FTIR.

Whether a phase separation or a cocrystallization occurs in poly(hexamethylene succinate-co-hexamethylene adipate) (P(HS-co-HA)) copolymers was studied with a combination of wide-angle X-ray diffraction (WAXD) and Fourier transform infrared (FTIR) spectroscopy. With HA as the majority, the presence of HS comonomers leads to weakening and broadening of (10l) peaks in the X-ray fiber diffraction patterns, while a crystal structure similar to PHS is formed in the copolymer with HS as the majority. The X-ray diffraction patterns imply possible cocrystallization between HS and HA comonomers, but cannot lead to an unambiguous conclusion, which was clarified with the compensative tool of FTIR. Following the characteristic absorption bands of crystals, cocrystallization of HS and HA comonomers was observed in copolymers with HA comonomer as the majority during which HA initiated the nucleation at high temperatures. With HA as minority, cocrystallization of HS and HA can still be achieved with a fast quenching to below 0 degrees C, while a phase separation occurs and only HS comonomer crystallizes at high temperatures. This demonstrates that P(HS-co-HA) has an asymmetric phase diagram. Because of the sensitivity to local conformations, FTIR spectroscopic method is demonstrated to be a powerful tool on study phase behaviors of polymers with similar crystal structure.

Mussel-inspired dopamine-CuII coatings for sustained in situ generation of nitric oxide for prevention of stent thrombosis and restenosis.

Nitric oxide (NO) is a highly potent, yet short-lived bioactive molecule with a broad spectrum of physiological functions. Continuous and controllable in situ generation of NO from vascular stent surface can effectively prevent restenosis and thrombosis after its implantation. In this study, inspired by the adhesion and protein cross-linking in the mussel byssus, through immersing the stents into an aqueous solution with dopamine (DA) and copper ions (CuII), we developed a one-step metal-catecholamine assembled strategy to prepare a durable in situ NO-generating biomimetic coating (DA-CuII). Due to the high NO catalytic efficacy and robust chelation of CuII into the DA-CuII network, the coated stents exhibited excellent hemocompatibility. The coating also catalytically decomposed endogenous S-nitrosothiols (RSNOs) from fresh blood, and locally generated NO for over 30 days with a flux comparable to its physiological range (0.5-4 × 10-10 mol × cm-2 × min-1). Moreover, the optimized biomimetic coatings displayed specific cell selectivity to significantly enhance endothelial cell (EC) growth while substantially inhibit smooth muscle cell (SMC) growth and migration. This feature impressively promoted regeneration of a new endothelial cell layer after stent implantation, hence improved the anti-thrombogenic and anti-restenosis qualities of vascular stents in vivo. We envision that our long-term in situ NO-generating coatings could serve as biosurfaces for long-term prevention of stent thrombosis and restenosis.

Plant-inspired gallolamine catalytic surface chemistry for engineering an efficient nitric oxide generating coating.

A novel concept of generating therapeutic gas, nitric oxide (NO) via catalytic phenolic-amine "gallolamine" surface chemistry is developed. The concept is realized using plant polyphenol, gallic acid, and a glutathione peroxidase-like organoselenium compound cystamine or selenocystamine through one-step phenol-amine molecular assembling process. The resulting NO-generating coating with phenolic-cystamine or -selenocystamine framework showed the ability for long-term, steady and controllable range of NO release rates being unparalleled with any existing NO-releasing or NO-generating surface engineering toolkits. STATEMENT OF SIGNIFICANCE: Developing a facile and versatile strategy for a NO-generating coating with long-term, stable and adjustable NO release is of great interest for the application of blood-contacting materials and devices. Covalent immobilization of glutathione peroxidase (GPx)-like compound to generate NO from a material surface by exposure of endogenously existed S-nitrothiol (RSNO) is a popular strategy. However, it is generally involved in multi-step and complicated processes. Moreover, the amount of immobilized GPx-like compounds is limited by the density of introduced reactive functional groups on a surface. Herein, we propose a novel concept of catalytic plant-inspired gallolamine surface chemistry for material-independent NO-generating coatings. The concept is realized using plant polyphenol, gallic acid, and a GPx-like organoselenium compound cystamine or selenocystamine through one-step phenol-amine molecular assembling process. Without tedious multi-step synthesis, complicated surface treatments, and leakage of toxic chemicals, our unprecedentedly simple, histocompatible and biocompatible phenolic-cystamine or -selenocystamine framework demonstrated long-term, on-demand and facile dose controls of NO generated from the engineering surfaces. These unique features of such a NO-generating coating imparted a material with ability to impressively improve anti-thrombogenicity in vivo. This work constitutes the first report of an interfacial catalytic coating based on material-independent surface chemistry by plant polyphenols. This concept not only expands the application of material-independent surface chemistry in an interfacial catalytic area, but also can be a new platform for antithrombotic materials.

Mussel-inspired catalytic selenocystamine-dopamine coatings for long-term generation of therapeutic gas on cardiovascular stents.

The development of a nitric oxide (NO)-generating surface with long-term, stable and controllable NO release improves the therapeutic efficacy of cardiovascular stents. In this work, we developed a "one-pot" method inspired by mussel adhesive proteins for copolymerization of selenocystamine (SeCA) and dopamine (Dopa) to form a NO-generating coating on a 316 L stainless steel (SS) stent. This "one-pot" method is environmentally friendly and easy to popularize, with many advantages including simple manufacturing procedure, high stability and no involvement of organic solvents. Such SeCA/Dopa coatings also enabled us to develop a catalytic surface for local NO-generation by reaction of endogenously existing S-nitrothiol species from fresh blood. We found that the developed SeCA/Dopa coatings could release NO in a controllable and stable manner for more than 60 days. Additionally, the released NO significantly inhibited smooth muscle cell (SMC) proliferation and migration, as well as platelet activation and aggregation through the up-regulation of cyclic guanosine monophosphate synthesis. Moreover, such NO generation enhanced the adhesion, proliferation and migration of endothelial cells (ECs), and achieved rapid in vivo re-endothelialization, effectively reducing in-stent restenosis and neointimal hyperplasia. We envision that the SeCA/Dopa-coated 316 L SS stent could be a promising platform for treatment of cardiovascular diseases.

Polydopamine Modified TiO2 Nanotube Arrays for Long-Term Controlled Elution of Bivalirudin and Improved Hemocompatibility.

Sustained and controllable release characteristics are pivotal factors for novel drug delivery technologies. TiO2 nanotube arrays prepared by self-ordering electrochemical anodization are attractive for the development of biomedical devices for local drug delivery applications. In this work, several layers of polydopamine (PDA) were deposited to functionalize TiO2 nanotube arrays. The anticoagulant drug bivalirudin (BVLD) was used as a model drug. PDA extended the release period of BVLD and maintained a sustained release kinetic. Depending on the number of PDA layers, the release characteristics of BVLD improved, as there was a reduced burst release (from 45% to 11%) and extended overall release period from 40 days to more than 300 days in the case of 5 layers. Besides, the BVLD loaded 5-layer PDA coating maintained the high bioactivity of BVLD and effectively reduced the thrombosis formation by inhibition of the adhesion and denaturation of fibrinogen, platelets, and other blood components. Both in vitro and ex vivo blood evaluation results demonstrated that this coating significantly improved the hemocompatibility. These results confirmed the capability of PDA fitted TiO2 nanotube systems to be applied for local drug delivery over an extended period with well retained bioactivity and predictable release kinetics.

Assembly of Metal-Phenolic/Catecholamine Networks for Synergistically Anti-Inflammatory, Antimicrobial, and Anticoagulant Coatings.

The development of a facile and versatile strategy to endow surfaces with synergistically anti-inflammatory, antimicrobial, and anticoagulant functions is of particular significance for blood-contacting biomaterials and medical devices. In this work, we report a simple and environmentally friendly "one-pot" method inspired by byssal cuticle chemistry, namely, [Fe(dopa)3] coordination chemistry for assembly of copper ions (Cu2+) and plant polyphenol (tannic acid)/catecholamine (dopamine or norepinephrine) to form metal-phenolic/catecholamine network-based coatings. This one-pot method enabled us to easily develop a multifunctional surface based on the combination of the characteristic functions of metal ions and plant polyphenol or catecholamine. The residual phenolic hydroxyl groups on the coatings imparted the modified surface with excellent antioxidant and anti-inflammatory functions. The robust chelation of copper ions to the metal-phenolic/catecholamine networks provided not only durable antibacterial property but also glutathione peroxidase like catalytic capability to continuously and controllably produce antithrombotic nitric oxide by catalyzing endogenous S-nitrothiol. The biological functions of such coatings could be well regulated by adjusting the ratios of the feed concentration of Cu2+ ions to plant polyphenol or catecholamine. We envision that our simple, multifunctional, and bioinspired coating strategy can hold great application promise for bioengineering blood-contacting devices.