Self-polymerization Of Dopamine Research Articles

Mussel – Inspired biosorbent combined with graphene oxide for removal of organic pollutants from aqueous solutions

In this work, we develop a mussel-inspired biosorbent combined with graphene oxide for removal of organic dyes in water sources. The composite was prepared via self-polymerization of dopamine in weak alkaline solution containing graphene oxide at ambient condition. Morphological and structural studies revealed that polydopamine has gradually grown to cover the surface of graphene oxide flakes, partially reduced these flakes, and somehow form many grains (size around 20 nm) on the flakes instead of making very large aggregates as usual. The mass ratio between two components of the composite was also investigated to find the optimal one which provides enough surface area (20 m2.g−1) and maintain adhesive sites in order to ensure high-efficiency removal of organic molecules. The adsorption kinetics and isotherms of as-prepared adsorbent towards methylene blue were found to fit well with pseudo-first order kinetics model and Langmuir isotherm. The maximum adsorption capacity (qm) and Langmuir constant (kL) were estimated to be 270 mg.g−1 and 0.49 L. mg−1. The as-prepared bio-sorbent is very promising for remediation of water sources contaminated with cationic organic molecules and heavy metal ions.

Simple bio-inspired coating of ureteral stent for protein and bacterial fouling and calcium encrustation control.

Encrustation, caused by deposition of calcium and magnesium salts present in urine, is a common problem of indwelling urinary devices, such as ureteral stent. Encrustation was also found to be related to urinary tract infections; thus, it is necessary to prepare ureteral stents with antibacterial and antifouling surfaces to mitigate the occurrence of encrustation. In this study, commercial ureteral stent was coated with polydopamine (PDA), formed from self-polymerization of dopamine. The PDA coating was optimized in terms of dopamine concentration, pH, and coating time using response surface methodology. The chosen response parameters for optimization were calcium oxalate (CaC2 O4 ) encrustation and protein adsorption. Optimized PDA coating conditions were determined to be the following: pH9.0, 2mg/mL DA, and 3 days coating. The optimized PDA-coated ureteral stent exhibited outstanding resistance against CaC2 O4 encrustation, protein fouling, and bacterial adhesion due to its hydrophilic and functional coating layer. In comparison with the pristine ureteral stent, PDA coating was able to suppress approximately 97% and 87% of CaC2 O4 and protein adsorption, respectively. The PDA-coated ureteral stent was compared against those of commercially available ureteral stents and found to have superior encrustation and protein fouling mitigation performance. Finally, PDA coating was found to be highly stable for a storage period of 90 days, whether stored in wet or dry conditions.

Ultrafine Co nanoparticles confined in nitrogen-doped carbon toward two-electron oxygen reduction reaction for H2O2 electrosynthesis in acidic media

Electrocatalytic production of hydrogen peroxide (H2O2) by two-electron oxygen reduction reaction (2e– ORR) under acidic condition has been considered to have great application value. Co nanoparticles (CoNPs) coupled with N-doped carbon are a class of potential electrocatalysts. The effective strategies to further enhance their performances are to improve the active sites and stability. Herein, the material containing ultrafine CoNPs confined in a nitrogen-doped carbon matrix (NC@CoNPs) was synthesized by pyrolyzing corresponding precursors, which was obtained through regulating the topological structure of ZIF-67/ZIF-8 with dopamine (DA). The DA self-polymerization process induced the formation of CoNPs with smaller sizes and formed polydopamine film decreased the detachment of CoNPs from the catalyst. High density of Co-Nx active sites and defective sites could be identified on NC@CoNPs, leading to high activity and H2O2 selectivity, with an onset potential of 0.57 V (vs. RHE) and ∼90% selectivity in a wide potential range. An on-site electrochemical removal of organic pollutant was achieved rapidly through an electro-Fenton process, demonstrating its great promise for on-site water treatment application.

Versatile hybrid nanoplatforms for treating periodontitis with chemical/photothermal therapy and reactive oxygen species scavenging

Given the limitations of clinical curettage for periodontitis, the thorough removal of dental plaque at deep periodontal pockets and periodontal tissue repair require improvement with the assistance of appropriate medical therapy. Despite the significant developments of various local drug delivery systems (LDDSs) for adjuvant periodontitis therapy, several issues exist, such as the relatively low anti-biofilm effect and the tissue damage caused by excessive reactive oxygen species (ROS). To address the issues, we fabricated the versatile nanoplatforms (PPM NPs) via coating polydopamine (PDA) on the surface of monodispersed Prussian blue nanoparticles (PB NPs) through the facile yet efficient self-polymerization of dopamine (PP NPs), and then loading minocycline (Mino). Notedly, these integrative nanocomposites-based PB NPs as photothermal agents enhanced the therapeutic effect of plaque biofilms in vitro utilizing the antibacterial photothermal therapy (PTT) under irradiation of NIR laser. Further, the designed nanocomposites efficiently scavenged ROS over oxidative-stress Raw267.4 cells and human periodontal ligament cells, attributing to the enzyme-like activity of PB nanozymes and the reducibility of catechol in PDA. In vitro and in vivo consequences demonstrate the significantly augmented antibacterial and anti-inflammatory effects from the live/dead staining of biofilms and western blot results of inflammatory factors compared with free Mino solution in periodontitis. Our fabricated nanoplatforms-based PB NPs conveniently modified with PDA not only significantly improved the antibacterial effect via the combinational therapies but also efficiently scavenged cellular ROS utilizing the enzyme-like activity of nanozymes contributing to the treatment of periodontitis.

High efficiency activation of peroxydisulfate by an Fe3O4@PDAn-CuxO core–shell composite for triclosan degradation: The role of oxygen vacancy

Rational design of catalysts with controllable active sites is crucial to promote their catalytic performances. Herein, a series of magnetic Fe3O4@PDAn-CuxO composites with adjustable oxygen vacancies (OVs) were successfully constructed by in situ self-polymerization of dopamine between Cu-Fe bimetallic composites. The obtained catalysts with abundant OVs exhibited outstanding performance in the activation of peroxydisulfate to degrade the antimicrobial contaminant triclosan (TCS). The removal efficiency of TCS is proportional to the OVs content, among which Fe3O4@PDA1.0-CuxO possessed the highest catalytic activity. Due to the rich localized electrons of OVs, it could accelerate the electron transfer of Fe3O4@PDA1.0-CuxO/PDS complex, thus promoting the generation of reactive oxygen species on catalyst surface and increasing the efficiency of oxidant with 97.9% RSE. Moreover, the catalyst possessed excellent long-term stability and could be easily recovered by magnetic separation, which would avoid secondary pollution in treated water. This discovery provides a sustainable strategy for developing novel environmental-friendly remediation technologies.

Electrochemical and Optical Properties of Fluorine Doped Tin Oxide Modified by ZnO Nanorods and Polydopamine

Various forms of zinc oxide (ZnO) are frequently used in the design of optical and electrochemical sensors. However, the optical and electrochemical properties of ZnO should be properly adjusted depending on the application area. Therefore, in this work, we have investigated changing/tuning the properties of ZnO by depositing a layer of polydopamine (PDA) on its surface. In order to perform this investigation, the surface of fluorine-doped tin oxide (FTO) was modified with the layer of ZnO nanorods and PDA. ZnO nanorods were synthesized by hydrothermal synthesis technique, and after the synthesis, they were coated with polydopamine exploiting the self-polymerization of dopamine. The nanostructures were investigated by using electrochemical and optical methods. Electrochemical impedance spectroscopy measurements showed that electrochemical properties of FTO-ZnO and FTO-ZnO-PDA nanostructures could be changed by the variation of both—applied electrical potential and/or exposition towards lighting. Interaction between ZnO-PDA and bovine serum albumin (BSA) molecules has been investigated by (photo)electrochemical and photoluminescence methods. A mechanism of possible interaction between BSA and the ZnO-PDA surface has been proposed.

A novel micropattern platform constructed by TiO2 oxidation of PDA

Dopamine is a small molecule inspired by the dopamine motif of mussel foot proteins, and PDA is formed by the self-polymerization of dopamine. Under the UV-irradiation，PDA would be oxidized by reactive oxygen species (ROS) which were produced by photocatalytic reactions on TiO2 surfaces，thus regulating the adhesion behavior of endothelial cells (ECs) TiO2 inhibited platelet (Plt) adhesion after UV exposure. Polydopamine (PDA)-TiO2 micropatterns (P-PDA-TiO2) were prepared by magnetron sputtering and photolithography. This micropatterns successfully achieves selective adhesion of Plt and ECs. The selective adhesion of ECs disappears after vacuum reduction. In contrast to conventional cell patterning strategies, P-PDA-TiO2 can easily achieve pattern separation of ECs and Plts and provide a new concept for building complex blood-contacting devices.

Cubic MOF coated stainless steel mesh with underwater superoleophobicity for highly efficient oil/water separation

A novel superhydrophilic and underwater superoleophobic material (MOF-5/PDA/SSM) with high flux, outstanding oil/water separation performance and durability was prepared. The stainless steel mesh (SSM) was modified by MOF-5 crystals and PDA. The introduction of MOF-5 can improve the hydrophilicity of SSM and achieve high water flux at the same time. PDA is a substance with strong adhesion which can be used as an effective bonding intermediate. The preparation strategy includes the self-polymerization of dopamine and the deposition of cubic clusters on SSM via hydrothermal reaction. The MOF-5 particles on the mesh are cubic hexahedral crystal with a uniform size diameter, which can trap water in the rough microstructure, forming a strong hydration barrier layer or composite water-solid interface on its surface, hindering the penetration of oil. The super-hydrophilicity and underwater superoleophobicity of the modified meshes were introduced by pre-wetting surface. The FTIR, XRD, XPS and SEM characterizations demonstrated that the successfully growth of MOF-5 and a rough structure was obtained on the mesh. The special wetting and the robustness of the fabricated mesh led to the outstanding separation efficiency (up to 99.5%), excellent recyclability (about 20 cycles) and high water flux (53.9 k L m−2 h−1). The mesh also showed remarked water flux and various oil/water mixtures separation performance. Particularly, the successfully prepared materials were found to be significant stable under various physical and chemical extremes environments, including maintain UWOCA>150 under acid/alkali media, marvelous performance after 120 min of continuous separation and high anti-oil intrusion pressure. The combination of metal organic framework and stainless steel mesh may provide a candidate application to effective oil-water separation.

Aqueous green synthesis of organic/inorganic nanohybrids with an unprecedented synergistic mechanism for enhanced near-infrared photothermal performance.

Silver sulfide (Ag2S) nanoparticles (NPs) represent one of the most popular inorganic reagents for near-infrared (NIR) photothermal therapy (PTT). However, the extensive biomedical applications of Ag2S NPs are greatly compromised by the hydrophobicity of the NPs prepared in organic solvents, their low photothermal conversion efficiency, certain surface modification-induced damage to their intrinsic properties and short circulation time. To develop a facile yet efficient green approach to overcome these shortcomings for improved properties and performance of Ag2S NPs, we report herein the construction of Ag2S@polydopamine (PDA) nanohybrids via a "one-pot" organic-inorganic hybridization strategy, which produces uniform Ag2S@PDA nanohybrids with well-modulated sizes in the range of 100-300 nm via the self-polymerization of dopamine (DA) and subsequent synergistic assembly of PDA with Ag2S NPs in a three-phase mixed medium containing water, ethanol and trimethylbenzene (TMB). Integration of dual photothermal moieties, i.e., Ag2S and PDA at a molecular level, endows Ag2S@PDA nanohybrids with synergistically enhanced NIR photothermal properties that are much better than those of either PDA or Ag2S NPs due to calculated combination indexes (CIs) of 0.3-0.7 between Ag2S NPs and PDA based on a modified Chou-Talalay method. Therefore, this study not only developed a facile "one-pot" green approach toward producing uniform Ag2S@PDA nanohybrids with well-modulated dimensions, but also revealed an unprecedented synergistic mechanism for organic/inorganic nanohybrids that is based on dual photothermal moieties providing enhanced near-infrared photothermal performance.

Sensitive detection of synthetic cannabinoids in human blood using magnetic polydopamine molecularly imprinted polymer nanocomposites.

Synthetic cannabinoids (SCs) are a series of artificial chemical substances with pharmacological properties similar to those of natural cannabinoids and their abuse poses a great risk to social security and human health. However, the highly sensitive detection of low concentrations of SCs in human serum remains a great challenge. In this work, we developed a highly sensitive, rapid and highly selective method for the detection of SCs in human serum. Magnetic molecularly imprinted polymer (MIP) nanocomposites were prepared through self-polymerization of dopamine and template molecules on the surfaces of magnetic beads. 9H-Carbazole-9-hexanol (9CH) was used as a template molecule because of its long chain structure shared with six synthetic cannabinoids and its ability to provide specific recognition sites. With these magnetic MIP nanoparticles, six SCs could be rapidly and effectively extracted from human blood. The concentrations of six SCs could be accurately determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis. The limits of detection were in the range of 0.1-0.3 ng mL-1. The proposed method is characterized by high sensitivity and selectivity, and has great potential for application in the analysis of practical samples.

Enhanced bioactivity and antimicrobial properties of α-tricalcium phosphate cement via PDA@Ag coating

The ideal orthopedic material demands excellent antimicrobial properties and bioactivity after initial implantation in vivo. In this paper, a polydopamine (PDA) film was prepared by dopamine self-polymerization on α-tricalcium phosphate (α-TCP) cement, and then silver (Ag) particles were immobilized in-situ on the surface of PDA via a dipping method. The presence of PDA and Ag in the composition of modified cement was confirmed by XPS. The results showed that after the modification of PDA coating and Ag particles, the roughness and contact angle of the cement increased from 36.4 nm to 120 nm and 18.8° to 58.8°, respectively. Moreover, the mineralization capacity of modified cement was considerably enhanced, generating dense hydroxyapatite (HA) layer with a thickness of 3.04 μm. Furthermore, the modified cement was revealed to provide antibacterial rate over 99 %. It is suggested that good bioactivity and antimicrobial properties of the cement can be achieved using the promising method.

Bioinspired Synthesis of Ag Nanoparticles onto Polytetrafluoroethylene with Enhanced Antibacterial Activity for Dental Implant Application.

Endosseous implants are widely used as a treatment for tooth loss, but gaps in the implant-abutment interface, and the cavity inside the implant, can cause inflammation of the tissue surrounding the implant. Currently available filling materials, however, cannot solve these problems. Therefore, the development of new antibacterial materials is key. In this study, we synthesized Ag nanoparticle-coated polytetrafluoroethylene (PTFE), analyzed the effect of Ag ion concentration, and estimated the antibacterial effects against oral pathogens in vitro. Method: The Ag nanoparticles (AgNPs)-modified PTFE was achieved using self-polymerized dopamine in an alkaline solution (2 mg/mL) and reduction reaction of Ag ions (0.01 mol/L and 0.05 mol/L). The surface features, chemical components, and wettability were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The antibacterial effect against Streptococcus mutans and Porphyromonas gingivalis was evaluated by counting colony-forming units on agar media and the visualization of bacteria present on the specimens by SEM and confocal laser scanning microscope (CLSM). The surface characterization results indicated that a polydopamine film was successfully formed on the PTFE membrane, and spherical AgNPs were successfully reduced. With increasing concentration of the Ag precursor, the contents of the AgNPs increased (p < 0.05). The antibacterial ratio of AgNP-coated PTFE against Streptococcus mutans and Porphyromonas gingivalis reached 94.2% and 80.6%, respectively. The results of antibacterial testing analyzed via SEM and CLSM also demonstrated the robust antibacterial ability of AgNPs-modified PTFE (p < 0.05). AgNPs-modified PTFE has great potential to function as an implant filling material with enhanced antibacterial properties, and has the potential to be a novel antimicrobial material for the prevention of peri-implantitis in the clinic.

Surface-functionalization of hydrogen titanate nanowires for efficiently selective adsorption of methylene blue

Polydopamine coated hydrogen titanate nanowires (PDA-HTN) are prepared via dopamine self-polymerization. The obtained PDA-HTN is a cheap adsorbent for selective adsorption of methylene blue (MB). The adsorption characteristics of PDA-HTN are studied from three aspects: isotherm, kinetics and thermodynamics. Date show that PDA-HTN adsorbs MB spontaneously, and the adsorption process is agreement with the fitting results of Langmuir and pseudo-second-order model. PDA-HTN is used to selectively adsorb MB from dye mixtures, the removal rate of MB can reach as high as 99.8% and adsorption capacity can reach 241.3 mg g−1. PDA-HTN can be used to adsorb MB in 0.5 mol L−1 NaCl solution, and the increase of ionic concentration in NaCl solution will improve the adsorption performance of PDA-HTN for MB, because salt ions will induce the dimerization of MB. PDA-HTN exhibits excellent cyclic adsorption property, the removal rate of MB remains above 97.7% after 12 cycles of adsorption-desorption. The adsorption is explained by cooperative effects of π–π stacking, electrostatic interaction, 1,4–Michael addition reaction and hydrogen bonding. Compared to the pristine HTN, the adsorption capacity of PDA-HTN for MB is greatly increased. In addition, PDA-HTN can also be used to remove other cationic dyes, and its adsorption capacity for basic yellow 1 (BY1) and crystal violet (CV) is 586.7 mg g−1 and 865.1 mg g−1, respectively.

Improving the sensitivity and selectivity of sulfonamides electrochemical detection with double-system imprinted polymers

The extensive use of antibiotics leading to the rapid spread of antibiotic resistance poses high health risks to humans, but to date there is still lack of an on-site detection method of SA residues. In this study, we integrated radical polymerization using sodium p-styrenesulfonate as a functional monomer and the self-polymerization of dopamine to prepare double-system imprinted polymers (DIPs) using sulfonamide antibiotics as templates. We found that the DIPs were semi-interpenetrating polymer networks and introduction of poly(dopamine) improved the selectivity of the imprinted cavities as well as the conductivity. The selectivity and sensitivity of the sensor using DIPs were much higher than those using single-system MIPs. This sensor could determine sulfonamides in complex samples in the presence of structural analogues. The linear range was from 0.01 to 10.00 μmol L−1 with a detection limit of 4.00 nmol L−1. Furthermore, based on the highly selective DIPs and statistics analysis, this method could be used for simultaneous analysis of 4 sulfonamide types in real samples with an accuracy of 94.87 %. This work provides a strategy to improve the selectivity and sensitivity of MIPs based-sensor that can serve as tool for the simultaneous analysis of antibiotic residues in environment samples.

Polydopamine-Coated Alginate Microgels: Process Optimization and In Vitro Validation.

In the last decade, alginate-based microgels have gained relevant interest as three-dimensional analogues of extracellular matrix, being able to support cell growth and functions. In this study, core-shell microgels were fabricated by self-polymerization of dopamine (DA) molecules under mild oxidation and in situ precipitation of polydopamine (PDA) onto alginate microbeads, processed by electro fluid dynamic atomization. Morphological (optical, SEM) and chemical analyses (ATR-FTIR, XPS) confirmed the presence of PDA macromolecules, distributed onto the microgel surface. Nanoindentation tests also indicated that the PDA coating can influence the biomechanical properties of the microgel surfaces-i.e., σmaxALG = 0.45 mN vs. σmaxALG@PDA = 0.30 mN-thus improving the interface with hMSCs as confirmed by in vitro tests; in particular, protein adsorption and viability tests show a significant increase in adhesion and cell proliferation, strictly related to the presence of PDA. Hence, we concluded that PDA coating contributes to the formation of a friendly interface able to efficiently support cells' activities. In this perspective, core-shell microgels may be suggested as a novel symmetric 3D model to study in vitro cell interactions.

Polyethylene reinforced by biomimetic (polydopamine, tannic acid) modified magnesium oxysulfate whisker: Mechanical properties, thermal properties and flame retardancy

Two-dimensional magnesium oxysulfate whisker (MOSw) was modified by polydopamine (PDA) and tannic acid (TA) instead of the traditional inorganic flame retardants activated by silane coupling agent ( γ -methacryloxypropyltrimethoxy silane, KH570) such as Mg(OH) 2 and Al(OH) 3 . Differential scanning calorimeter (DSC) results showed that MOSw could act as heterogeneous nucleation for crystallization of HDPE, and further increased the initial crystallization temperatures of composites treated with PDA and TA. Dynamic mechanical thermal analysis (DMTA) showed that both the storage modules and loss modules of the composites with modified MOSw were significantly increased, which suggested the improved compatibility and dispersion between the modified MOSw and matrix. The tensile strengths of HDPE/MOSw@PDA composite and HDPE/MOSw@TA composite could be 118.0% and 121.2% higher than that of HDPE/MOSw@KH570 composite, and the corresponding impact strengths could be 124.0% and 111.2% higher, respectively. Compared to HDPE, the synergistic effect of PDA- MOSw and TA- MOSw (combustion heat through the dehydration of MOSw, gas-phase flame-retarded effect of MOSw, scavenging of active free radicals) increased the limit oxygen index (LOI) of composites from 19.4% to 23.4% and 23.8%, respectively, which were higher than 20.6% of traditional HDPE/Al(OH) 3 @KH570 composite with the same 30 wt.% filler. Schematic of self-polymerization of dopamine, and chelation of tannic acid with metal ions • MOSw covered with PDA and TA substituted for the traditional inorganic flame retardants activated by silane coupling agent. • Different from traditional inorganic flame retardants such as Mg (OH) 2 and Al (OH) 3 , MOSw modified by PDA and TA could not only improved the flame retardancy of HDPE, but also improved the tensile strength to a certain extent. • The composites with MOSw modified by PDA and TA showed good thermal stability.

Preparation of magnetic microcapsules of α-amylase and α-glucosidase for dual-target affinity screening of active components from Toona sinensis

Natural products are an important source of drug development and have good prospects in the treatment of many diseases. However, the efficacy of many natural drugs is achieved through multi-targets, which poses a huge obstacle to their development. In this study, a bienzyme microcapsule system based on α-amylase and α-glucosidase was constructed for the ligand fishing of natural compounds. The microcapsules were formed on the surface of calcium carbonate particles by self-polymerization of dopamine, which physically encapsulated iron oxide and α-glucosidase. Then, α-amylase was immobilized on the surface of magnetic material with glutaraldehyde as crosslinking agent, and calcium carbonate template was removed by EDTA to form a bienzyme system for affinity screening of active components from Toona sinensis. The results showed that two compounds, 1,2,3,4,6-penta-O-galloyl-β-D-glucose and quercitrin were affinity screened from the extracts of Toona sinensis. In vitro activity experiment proved that they were α-amylase and α-glucosidase inhibitors, respectively. Moreover, both of them were mixed type inhibitors that can interact with active centers of corresponding enzymes through multiple hydrogen bonds, van der Waals forces, etc. This study not only proved the effectiveness of the bienzyme system, but also provided a successful example for multi-target screening of natural products.

Preparation of magnetic Fe3O4@PDA/CuS core-shell nanocomposite as a green photocatalyst

To solve the emerging aromatic organic pollutants in aqueous environment, in this study, the efficient recyclable core-shell structured photocatalyst Fe3O4@PDA/CuS was prepared by in situ reduction method. Firstly, Fe3O4 as cores were prepared to provide magnetic recovery. Through the self-polymerization of dopamine (DA), polydopamine (PDA) was coated on Fe3O4 as shells to protect Fe3O4 cores. Then, Cu2+ coordinated with PDA on the surface of Fe3O4@PDA and in situ reduced by Na2S to obtain core-shell structural Fe3O4@PDA/CuS with CuS uniformly growing on the PDA. CuS with a narrow band gap will endow Fe3O4 @PDA/CuS excellent photocatalytic performance for organic dyes degradation. The decomposition rate of methylene blue (MB) reached to 92.1 % within 180 min under visible light irradiation of Fe3O4@PDA/CuS as photocatalyst without any cocatalyst. When pH= 10, the decomposition rate of MB can reach to 92.7 % in 60 min, indicated Fe3O4@PDA/CuS was more suitable for use under alkaline conditions. The capture experiment determined that·OH was the main active substance. This also explained that under alkaline conditions, numerous OH- was conducive to the formation of ·OH, thus accelerated the degradation rate. And the decomposition rate of MB by Fe3O4@PDA/CuS can still reach 83.95 % after reused three times.

Dopamine-based polyisoquinoline derivative: Facile preparation and dual applications in efficient iodine capture and Ag nanoparticles immobilization

Apart from the traditional polydopamine (PDA), which produced by the self-polymerization of dopamine (DA), there are scarce reports regarding the construction of functional polymer by directly using DA as the starting material. The relevant work could provide a beneficial supplement for further expanding the downstream utilization of DA’s chemical activity. In this study, a type of novel DA-based polytetrahydroisoquinoline derivative (PDT) was facilely prepared by metal-free Pictet-Spengler (P-S)/Mannich cascade reaction by using dopamine and formaldehyde as starting substrates. The influence of formaldehyde dosage and the introduction of triethylamine on the preparation of PDT was discussed, and the chemical structure and elementary properties of PDT were systematically characterized here. The iodine adsorption performance of PDT was investigated. Experimental results showed that PDT could effectively adsorb iodine in both steam (75 oC, under atmospheric pressure) and solution (in cyclohexane) states, and the corresponding equilibrium adsorption capacities reached ∼ 4.07 and 1.21 g g-1, respectively. The adsorption mechanism was investigated by X-ray photoelectron spectroscopy (XPS), Raman and FT-IR analyses. Experimental results suggested that N/O-containing units (tertiary amine and phenolic hydroxyl) and aromatic frameworks in the structure of PDT participated in the adsorption process. In addition, polymer/silver nanoparticles (AgNPs) composite (PDT-AgNPs) was prepared by using PDT as AgNPs’ support, and the catalytic performance of PDT-AgNPs for the reduction of p-nitrophenol, an aqueous pollutant, was investigated. Corresponding results told that PDT-AgNPs illustrated good catalytic activity (with reaction constant Kc of ∼ 17.82 L s-1 g-1) and cycling stability.

Antibody functionalized intravascular devices combined with genetically engineered endothelial colony-forming cells for targeted drug delivery: A proof-of-concept study

This study was designed to test the ability of ex vivo antibody-coated intravascular devices to capture genetically engineered pig endothelial colony-forming cells (ECFCs) as proof of concept for their potential for in vivo targeted drug delivery. Human α-calcitonin gene-related peptide (α-CGRP) was chosen as the therapeutic molecule as it is unsuitable for systemic administration due to its potent peripheral arterial vasodilatory effect and short half-life in blood, requiring local delivery to yield therapeutic benefit in a particular vascular bed. H-2Kk, a murine leukocyte surface antigen, served as the selection marker for genetically modified ECFCs. H-2Kk antibody was immobilized on electropolished cobalt-chromium (CC) discs, CC stents and ePTFE grafts through dopamine self-polymerization. The functionalized surface was integral and smooth, lacked or had significantly reduced chemical signals specific for substrates. Pig bone marrow-derived ECFCs transfected with a plasmid constructed for H-2Kk and α-CGRP expression produced H-2Kk on cell surface and biologically active α-CGRP in culture medium. H-2Kk antibody-coated substrates bound H-2Kk ECFCs but not control ECFCs in vitro. Bare or only dopamine-coated substrates did not bind H-2Kk ECFCs. These data suggest that implantation of antibody functionalized devices combined with injection of genetically modified ECFCs could be potentially applied for targeted drug delivery.