Polydopamine Functionalization Research Articles

Insights into antifouling mechanisms of carbon nanomaterials and enhancing performance with polydopamine functionalization for point-of-care propofol monitoring

Carbon nanomaterials, renowned for their exceptional sensitivity and selectivity towards various medical drugs, hold promise as electrode materials for electrochemical biosensors in propofol (PPF) monitoring. However, the issue of fouling has hindered their effective utilization in continuous point-of-care monitoring. In this research, we present a mechanism-driven approach to design a highly sensitive and durable electrochemical sensor tailored for PPF monitoring. We investigated the antifouling mechanism through density functional theory calculations and experiments and found that carboxyl functional groups contribute to the sensitivity and antifouling properties of the electrode. We have uncovered the antifouling ability of different carbon nanomaterials on PPF oxidation products. Factors such as hydrophilicity, geometric morphology, and active surface area played pivotal roles in antifouling. Furthermore, surface modification with hydrophilic polydopamine further enhanced the antifouling effects. In this study, we extensively investigated the electrochemical oxidation of PPF and its oxidation product on carbon nanomaterials, as well as the antifouling mechanism of carbon nanomaterials. The modified electrodes exhibit excellent antifouling performance and stability. This achievement presents a promising approach towards the development of point-of-care PPF analysis in clinical settings.

Polydopamine Functionalized Ti3AlC2 MAX based Electrochemical Biosensor for Early and Sensitive Detection of Mycobacterium Tuberculosis

MAX phase materials have attracted considerable attention for a variety of applications, including high temperature structures and coatings, electric contacts, heat exchangers, concentrated solar power, catalysis, owing to their versatile properties that include high corrosion-resistance and mechanical strength, tunable surface kinetics, excellent thermal and radiation stability, etc. However, chemically engineered MAX phase materials are yet to be explored in development of biosensing devices. Here, for the first time, we report the development of MAX-based electrochemical platform, functionalized with polydopamine (PDA), for the reliable detection of Mycobacterium tuberculosis (MTB), a high-risk infectious pathogen that is spreading at an alarming rate regardless of age. The probe DNA immobilizes onto the surface of MAX/PDA via avidin-biotin coupling to construct ssDNA/avidin/MAX/PDA modified biosensing electrode. Cyclic voltammetry and differential pulse voltammetry results confirm the high charge transfer kinetics, good redox behavior, and excellent stability in modified electrode. Moreover, modified biosensing electrode attains extremely low detection limit of 0.1 attomolar, excellent sensitivity of 1.67 × 10-4 mA μM-1, and high selectivity with low response time towards MTB. The applicability of developed PDA functionalized MAX bio-electrodes may be extended for the detection of other infectious diseases, thus signifying how crucial is the present discovery from the perspective of controlling conventional and emerging infectious diseases and probing critical biomarkers.

A biomimetic approach to enhance selectivity of direct dyes using VGCNF in polysulphone based nanofiltration membranes

Mussel inspired chemistry has gain tremendous interest in the field of membrane science and technology. Inspired by the adhesive proteins present in mussels, approaches involving the dopamine to modify the surfaces have become the predominantly striking strategy. In this work, an effective strategy is proposed to improve the selectivity of vapour grown carbon nanofibers (VGCNF) via the bio inspired polydopamine (PDA) functionalization approach. The varying concentration of modified VGCNF (D-A-VGCNFs) were employed in polysulphone (PS) membrane. The morphological characteristics of membranes were evaluated by SEM and AFM. Data depicted the uniform distribution of nanofibers (NFs) in the media and amended microstructure of the membranes. Modified membrane having the maximum amount of D-A-VGCNFs (DM5) proved to be more hydrophilic in nature with contact angle value of 57° whereas the CA value of pure PS membrane (DM0) was 76°. The performance test confirmed that the DM5 has enhanced dye rejection ratios which are 95%, 97% and 96% with improved permeate fluxes (like 56 L/m2.h, 40 L/m2.h and 53 L/m2.h for Direct Red 31, Direct Blue 86 and Direct Yellow 4 dyes respectively. Furthermore, DM5 showed much better anti-fouling properties after several cycles as compared to DM0. So, this work proved to be a milestone in the applications of nanofiltration (NF) membranes to remove the dyes from the textile wastewater.

A high-performance ZIF-8 membrane for gas separation applications: Synthesis and characterization

The demand for green energy sources is increasing rapidly, such as hydrogen, which is mainly produced through regeneration, filtration, and separation from exhaust gas sources. Inspired by the biological adhesion ability of the marine mussel, the H2 separation performance of ZIF-8 membranes was investigated, which were synthesized on polydopamine-functionalized stainless-steel-nets (SSNs). With the polydopamine (PDA) functionalization, the membrane achieves high separation efficiency while maintaining high membrane permeability, as the PDA layer promotes nucleation and continuous development of the ZIF-8 layer based on covalent bond treatment. First, the performances of the membranes prepared on PDA-functionalized SSNs and those prepared without functionalization were compared. For the single gas permeation test, the PDA functionalized ZIF-8 membrane separation abilities of CO2/N2, H2/N2, and H2/CO2 were found to be 1.25, 4.30, and 3.44, respectively. The separation factors of the ZIF-8 membrane without PDA for CO2/N2, H2/N2, and H2/CO2 were found to be 1.25, 4.06, and 3.16. Then, the effect on the separation ability of ZIF-8 solution concentration was conducted. The best efficiency for H2/CO2 was 11.3, respectively, for 0.2 M of the material solution under optimum conditions. Besides, the commercial ZIF-8 particles were used to prepare the membrane with the same method for comparison with the self-synthesized ZIF-8 particles. The performance of both membranes showed similar efficiency, and self-synthesized ZIF-8 particles showed economic and simplicity. The morphological structure and morphological face of the membrane were analyzed using various characterizations. The ZIF-8 membrane for gas separation is expected to apply to air purification and renewable energy sources in the near future.

Enhancing the interfacial bond strength of aluminum/polymer laminated film of the soft package lithium‐ion battery through polydopamine surface modification

AbstractThe aluminum (Al) foil used in Al/polymer laminated film of the soft package lithium‐ion battery (LIB) is widely treated with a hexavalent chromate conversion coating to increase the adhesive strength and durability of the adhesive joint. Given that hexavalent chromate is toxic and carcinogenic, a novel and chromate‐free method was developed in this study for surface modification of the Al foil using polydopamine (PDA) functionalization after titanium (Ti) chemical conversion. Ti conversion favors the deposition of PDA and introduces more functional groups of PDA on the Al surface. A novel polypropylene‐based hot melt adhesive, MAH‐g‐(PP/PBE), was prepared by melt grafting of maleic anhydride on the blend of polypropylene and propylene‐based elastomer for use as the inner adhesive of Al/polymer laminated film. Then, treated Al foil/MAH‐g‐(PP/PBE) composites were prepared and their interfacial adhesive strengths were investigated. The results show that the amine and catechol groups of PDA improve the interfacial adhesion between adhesive and Al foil by improving the wettability and interfacial interaction. The peel strength between MAH‐g‐(PP/PBE) and PDA functionalized Al foil after Ti conversion treatment can reach 3.55 N/mm, which is increased by 322% compared with that between MAH‐g‐PP and untreated Al foil. PDA functionalization after Ti chemical conversion and MAH‐g‐(PP/PBE) have great potential to improve interfacial adhesion of Al/polymer laminated film used in LIB package.

Influence of polydopamine functionalization on the rapid protein immobilization by alternating current electrophoretic deposition

Biomolecule immobilization onto implant surfaces is an interesting approach which allows fine-tuning the biological response upon implantation. However, the relatively low adsorption rates seen in current methodologies typically lead to long processing times, which can affect the activity of the biomolecules. Here, we investigate the effect of combining a bioinspired polydopamine (PDA) functionalization strategy with alternating current electrophoretic deposition (AC-EPD) for the immobilization of bovine serum albumin (BSA) on Ti6Al4V. PDA films introduce a high density of functional groups on the metal surface for the permanent attachment, while AC-EPD has the potential to actively concentrate biomolecules at the implant surface within a short time. First, PDA films were optimized in terms of the dopamine (DA) starting concentration. Next, amine-rich PDA-functionalized Ti6Al4V substrates served as electrodes during AC-EPD of BSA. While an improved deposition yield could already be observed for the PDA and AC-EPD strategies individually, significant merit lays in their combination, as was revealed by thicker proteinaceous deposits on the PDA-functionalized Ti6Al4V serving as anode during the high-amplitude half cycle of the AC signal. This provides a proof-of-concept for the synergistic effect of a PDA coupling chemistry in combination with AC electrophoresis as a time-efficient coating methodology for the proteins.

Magnetic Halloysite Nanotube/α-Amylase Based Nanobiocatalytic Transformation of Food Processing Waste into an Active Fermentation Ingredient

The concept of “nanobiocatalysis” creates exciting opportunities for improving enzyme performance via immobilization onto nanomaterials. A nanobiocatalyst consisting of magnetic halloysite nanotube (MHNT)/α-amylase was evaluated to transform food processing waste into an active fermentation medium formulation for low-cost bioprocessing. A high loading of α-amylase (185.5 mg (g of support)−1) was achieved on the surface of MHNTs through polydopamine functionalization. We validated the establishment of an enzyme-support system retaining >89% catalytic activity (27332 IU (g of support)−1) with improved enzyme handling (>99.1% recovery) and reusability (>56% activity, 10 cycles). MHNTs remarkably improved the enzyme kinetics and thermodynamic characteristics along with operational and storage stabilities and mitigated the likely inhibitory effects of cellulose/metal ions as contaminants. In addition to facilitating a continuous production of reducing sugars from the extracted starch over 72 h, the nanobiocatalyst was equally effective in preparing a nutritive food waste hydrolysate as a fermentable medium substitute for batch culturing of E. coli and a single-cell protein (A. niger). The commercial relevance of waste hydrolysate was also investigated to promote calcite precipitation via Bacillus sp. induced biocementation. We evidenced that nanobiocatalyst-assisted “starch depolymerization” released more nutritional components into the hydrolysate suspension, easily accessible to growing microbial cultures.

An accessible strategy for high-performance copper layer fabrication on polyphenylene oxide substrates via polydopamine functionalization and electroless deposition

An accessible strategy for high-performance copper layer fabrication on polyphenylene oxide substrates via polydopamine functionalization and electroless deposition

Biomimetic surface modification of UHMWPE fibers to enhance interfacial adhesion with rubber matrix via constructing polydopamine functionalization platform and then depositing zinc oxide nanoparticles

Aimed at enhancing the interfacial adhesion property of ultrahigh molecular weight polyethylene (UHMWPE) fibers reinforced rubber composites, a biomimetic surface modification strategy was put forward by constructing polydopamine (PDA) functionalization platform and then depositing zinc oxide nanoparticles (nano-ZnO). Inspired by the mechanism of mussel adhesion, a layer of PDA film was coated onto the fiber surface by dopamine oxidative self-polymerization reaction. Subsequently, through the coordination interaction between nano-ZnO and PDA, the deposition of nano-ZnO was realized. The results of characterization analysis, including fiber surface morphologies, chemical compositions and structures, not only confirmed the process of the proposed modification but also elucidated the interactions among UHMWPE, PDA and nano-ZnO. The H-pull test showed that the maximum H-pull force of modified UHMWPE fibers to rubber matrix was up to 34.3 N, increased by 85.4% compared with that of pristine UHMWPE fibers, which could be mainly attributed to the combined action of interfacial physicochemical interactions and mechanical interlocking. Moreover, it was found that the reaction time should be controlled to avoid the degradation of adhesion due to excessive modification.

High Uranium Extraction by Polydopamine Functionalized MXene from Aqueous Solutions

MXenes were outstanding materials for aqueous environment remediation, MXenes with a high capacity for radionuclides uranium (U(VI)) remains a challenge. In this study, a noval polydopamine functionalized MXene (defined as MXene@PDA) was successfully synthesised and evaluated for the aggregation towards U(VI) from wastewater. Versatile PDA owing functional groups provided more sites to capture contaminant ions. The mechanism research with MXene@PDA was explored by batch experiments toghther with the XPS analyses. The results revealed MXene@PDA with abundant functional groups exhibited superior elimination ability (90.4 mg/g) at pH = 5.0. The mechanism of U(VI) on MXene@PDA was primarily ascribed to the surface complexation force between the UO22+ and -OH, NH2 groups. The PDA modification of MXene materials are proved to be excellent materials for the extraction of radionuclides in the aqueous solution.

Stretchable silver@CNT-poly(vinyl alcohol) films with efficient electromagnetic shielding prepared by polydopamine functionalization

The design of CNT/polymer composite shields is reduced to resolve the issue of CNTs agglomeration which has been tackled by complex and harsh chemical treatments damaging their electrical conductivity and limiting shielding capability. Herein, CNTs were coated with polydopamine (PDA) by exploiting the in-situ spontaneous polymerization of PDA on organic/inorganic surfaces. The PDA functional layer not only resulted in improved CNT dispersion after 2 h-coating time but also served as a platform for subsequent immobilization of silver nanoparticles by the catechol and nitrogen-containing groups of PDA. The well-dispersed CNT and the incorporation of extra silver particles conductive phase resulted in flexible and highly conductive Ag@PDA@CNT-poly(vinyl alcohol) (PVA) films with significantly improved shielding effectiveness of 42.75 dB with respect to pristine CNTs (21 dB). The size of silver particles controlled by PDA polymerization time, the formation of an efficient conductive network and conduction/interfacial polarization-induced loss mechanisms were reasoned to be responsible for dictating the films shielding performance. Such low-key and green approach could be instrumental to developing other metal/CNT polymer films as next-generation lightweight shields for flexible electronics.

An improving aqueous dispersion of polydopamine functionalized vapor grown carbon fiber for the effective sensing electrode fabrication to chloramphenicol drug detection in food samples

Antibiotic drugs are comprehensively used in treating infectious animals, mainly food-producing animals, which may severely affect other living organisms. Hence, it is necessary to develop a device to monitor trace level of these drug in food samples by a sensitive method. Carbon nanomaterials are usually fabricated as a disposable electrode in an electrochemical sensing application; however, its hydrophobicity nature causes poor electrode stability. An effective strategy is followed in this study to improve the aqueous dispersion of vapor-grown carbon fiber (VGCF) materials through the bio-inspired polydopamine (PDA) functionalization approach. The PDA functionalized VGCF (PDA-VGCF) is significantly characterized by spectroscopic and microscopic methods. The improved hydrophilicity of PDA-VGCF composite materials can offer an easy way to prepare catalyst slurry for the coating of a glassy carbon electrode (GCE) and used to determine the chloramphenicol (CAP) antibiotic drug. Interestingly, cyclic and differential pulse voltammetry studies are performed to observe the electrocatalysis of CAP using PDA-VGCF/GCE, displays a good linear response range (0.01–142 µM), lower detection limit (3 nM), and higher sensitivity (0.68 µAµM−1 cm−2) with long-time stability up to 30 days. Furthermore, PDA-VGCF/GCE shows an admirable selectivity while existing with other interference compounds and practical feasibility are also evaluated in apple juice, milk, and honey samples.

Assembly of polyoxometalates/polydopamine nanozymes as a multifunctional platform for glutathione and Escherichia coli O157:H7 detection

A new P2W18Fe4/PDA (P2W18Fe4 = K10P2W18Fe4(H2O)2O68 and PDA = polydopamine) nanocomposite has been synthesized with peroxidase activity for glutathione (GSH) and Escherichia coli O157:H7 (E. coliO157:H7) detection. The size of P2W18Fe4/PDA is about 104 ± 16 nm, which is the smallest among the reported polyoxometalates (POMs)/PDA composites. The polydopamine functionalization not only provides an adhesive surface for the immobilization of biomolecules onto P2W18Fe4, but also, significantly increases the peroxidase-like activity of P2W18Fe4, probably due to its enhanced affinity to organic substrates. P2W18Fe4/PDA can catalyze the oxidation of o-phenylenediamine (OPD) to form yellow 2, 3-diaminophenazine (DAB) in the presence of H2O2 through hydroxyl radical. The GSH can efficiently react with the hydroxyl radicals from H2O2 catalyzed by P2W18Fe4/PDA to inhibit the production of DAB. Thus, we can determination the concentration of GSH with the decreasing spectrometric signal of the DAB. The limit of colorimetric detection was 0.18 mM with the linear range from 2 to 8 mM. The limit of fluorescent detection was 4.02 μM with the linear range from 15.63 to 250 μM. The assay was successfully applied to the detection of GSH in SH-SY5Y cells lysate samples with higher sensitivity and specificity. The detection of E. coli O157:H7 was achieved by the sandwich immunoassay with the P2W18Fe4/PDA nanozymes as labeling markers. A linear correlation was established between absorbance intensity and E. coli O157:H7 from 103 to 106 CFU / mL with a detection limit of 4.2 × 102 CFU/mL. These primary results enlarge the POMs’ analytic application field.

Polydopamine Functionalized Graphene Oxide as Membrane Nanofiller: Spectral and Structural Studies.

High-degree functionalization of graphene oxide (GO) nanoparticles (NPs) using polydopamine (PDA) was conducted to produce polydopamine functionalized graphene oxide nanoparticles (GO-PDA NPs). Aiming to explore their potential use as nanofiller in membrane separation processes, the spectral and structural properties of GO-PDA NPs were comprehensively analyzed. GO NPs were first prepared by the oxidation of graphite via a modified Hummers method. The obtained GO NPs were then functionalized with PDA using a GO:PDA ratio of 1:2 to obtain highly aminated GO NPs. The structural change was evaluated using XRD, FTIR-UATR, Raman spectroscopy, SEM and TEM. Several bands have emerged in the FTIR spectra of GO-PDA attributed to the amine groups of PDA confirming the high functionalization degree of GO NPs. Raman spectra and XRD patterns showed different crystalline structures and defects and higher interlayer spacing of GO-PDA. The change in elemental compositions was confirmed by XPS and CHNSO elemental analysis and showed an emerging N 1s core-level in the GO-PDA survey spectra corresponding to the amine groups of PDA. GO-PDA NPs showed better dispersibility in polar and nonpolar solvents expanding their potential utilization for different purposes. Furthermore, GO and GO-PDA-coated membranes were prepared via pressure-assisted self-assembly technique (PAS) using low concentrations of NPs (1 wt. %). Contact angle measurements showed excellent hydrophilic properties of GO-PDA with an average contact angle of (27.8°).

The mussel-inspired polydopamine surface treatment influences bond strength of glass fiber posts to radicular dentin

The aim of this study was to compare the efficacy of silane and a novel bioinspired polydopamine functionalization on the adhesion strength of glass fiber posts cemented to root dentin. Sixty-four surface treated posts [polydopamine (group 1 = 32) or silane (group 2 = 32)] were cemented in root canals of 64 extracted and decoronated mandibular premolars by using 3 commercial brands of self-adhesive resin cements (subgroups A, B and C) or a total-etch resin cement (subgroup D). The samples were subjected to push-out bond strength testing at 24 h and at 6 months after storage in water. Each sample was subdivided into six slices (three slices of the coronal and three slices of the apical) to determine the push-out bond strength in the coronal and apical third. The mean bonding strength value of the 3 slices both for the coronal and apical third was calculated as megapascals (MPa) and the data were statistically analyzed using post hoc Tukey HSD and Student t tests using four-way ANOVA (P = 0.05). Failure modes were investigated using scanning electron microscopy (SEM). The number of adhesive failures at the dentin-cement interface dropped when polydopamine was used (12–33%). Failure between the post and cement interface also dropped (4–13%) in all the resin cement groups, except the Subgroup C (17%). Polydopamine treatment significantly increased the adhesion strength for all cements compared to silanization at 24 h (P < 0.05), however at 6 months, only for the self-adhesive cements (P < 0.05). Polydopamine surface treatment improves the short-term bond strength of fiber-posts cemented to root canal dentin. The positive effect of polydopamine on long-term bond strength did not appear to be significant for the total-etch resin cement.

The influence of different treatments on fiber post and root canal to bond strength of fiber post

Different methods were used to treat the fiber posts and root canals, and evaluated their influence on the bond strength of fiber posts. After thirty extracted human, single-rooted premolars were endodontically treated and post space was prepared in each tooth with post drills, they were randomly assigned into nine groups with 33 fiber glass posts. Different treatment methods for fiber posts and root canals were applied. Following post cementation, slice specimens were prepared. The push-out test was performed using a universal testing machine, and the failure modes were examined with a stereomicroscope. Bond strengths (mean ± SD) were: CC group (7.07 ± 1.51 MPa); CE group (10.57 ± 2.90 MPa); CM group (10.06 ± 3.00 MPa); SiC group (7.23 ± 2.06 MPa); SiE group (10.51 ± 2.26 MPa); SiM group (10.50 ± 2.70 MPa); PC group (9.79 ± 2.79 MPa); PE group (11.70 ± 1.76 MPa); PM group (11.06 ± 3.17 MPa). The bond strength of polydopamine group was significantly higher than silane group and control group (p < 0.05). NaClO/EDTA group had higher bond strength than the MTAD group, and both were higher than the control group (p < 0.05). Combined treatment of fiber post and root canal was more advantageous to improve the bond strength between fiber post and root canal. Surface polydopamine functionalization was confirmed to be a reliable method for improving the bond strength of fiber posts. The effect of 5.25% NaClO + 17% EDTA solution on the bond strength is more significant than MTAD solution. When the fiber posts were treated with PDA and the root canals were treated with NaClO/EDTA, the best bond strength can be obtained. In this experiment, fiber posts and root canals were treated separately. The aim of this paper is to explore the influence of different treatment methods on the bond strength of fiber posts, in order to screen out the most effective processing methods and provide theoretical guidance for the clinical application.

Purification and Sorting of Halloysite Nanotubes into Homogeneous, Agglomeration-Free Fractions by Polydopamine Functionalization.

Halloysite nanotubes (HNTs) have attracted great attention in the field of nanotechnology as natural, high value-added nanomaterials. Despite their significant potential as carriers of active agents and fillers in nanocomposite structures, inhomogeneity of HNTs in terms of length and diameter along with their agglomeration tendency poses important obstacles for the utilization of them in a wider range of applications. Here, a facile, three-step separation protocol that allows the sorting of HNTs into agglomeration-free, uniform size fractions is reported. The protocol consists of coating of HNTs with polydopamine to impart hydrophilicity and aqueous dispersibility, followed by their ultrasonication and centrifugation at varying velocities for size-based separation. Particle size distribution analysis by scanning electron microscopy and dynamic light scattering has demonstrated that the separation protocol resulted in uniform HNT fractions of varying agglomeration states and particle sizes. The highest quality fraction obtained with 18% yield was free of agglomerations and consisted of HNTs of uniform lengths and diameters. The polydopamine coating on HNTs which facilitated the separation was demonstrated to be removed by a simple heat treatment that preserved the crystal structure of HNTs. The impact of the separation protocol on the loading and functionalization capacity of halloysites was investigated. Highest quality HNTs presented 4.1-fold increase in lumen loading and 1.9-fold increase in covalent surface coupling ratios compared to the loading and functionalization ratios obtained with raw HNTs. Similarly, sorted, high-quality HNTs were demonstrated to be better dispersed in a polymeric matrix, resulting in polymeric nanocomposites with significantly enhanced mechanical properties compared to nanocomposites prepared with raw HNTs. The three-step separation protocol presented here provides a toolbox that allows sorting of raw HNTs into uniform fractions of different size ranges, from which HNTs of desired qualities required by different applications can be selected.

Water-Dispersed High-Quality Graphene: A Green Solution for Efficient Energy Storage Applications.

Graphene has been the subject of widespread research during the past decade because of its outstanding physical properties which make it an ideal nanoscale material to investigate fundamental properties. Such characteristics promote graphene as a functional material for the emergence of disruptive technologies. However, to impact daily life products and devices, high-quality graphene needs to be produced in large quantities using an environmentally friendly protocol. In this context, the production of graphene which preserves its outstanding electronic properties using a green chemistry approach remains a key challenge. Herein, we report the efficient production of electrode material for micro-supercapacitors obtained by functionalization of water-dispersed high-quality graphene nanosheets with polydopamine. High-frequency (terahertz) conductivity measurements of the graphene nanosheets reveal high charge carrier mobility up to 1000 cm-2 V-1 s-1. The fine water dispersibility enables versatile functionalization of graphene, as demonstrated by the pseudocapacitive polydopamine coating of graphene nanosheets. The polydopamine functionalization causes a modest, i.e., 20%, reduction of charge carrier mobility. Thin film electrodes based on such hybrid materials for micro-supercapacitors exhibit excellent electrochemical performance, namely a volumetric capacitance of 340 F cm-3 and a power density of 1000 W cm-3, thus outperforming most of the reported graphene-based micro-supercapacitors. These results highlight the potential for water-dispersed, high-quality graphene nanosheets as a platform material for energy-storage applications.

Polydopamine Functionalization: A Smart and Efficient Way to Improve Host Responses to e-PTFE Implants

Among the different materials used as protheses for the treatment of Congenital Diaphragmatic Hernia, expanded polytetrafluoroethylene (e-PTFE) plays a leading role owing to its mechanical properties as explained in the first part of this review. However, this material is poorly cell adhesive, which is expected for its contact on the abdominal face, but should display specific tissue adhesion on its thoracic exposed faced. A side specific functionalization method is hence required. The deposition of a nanosized polydopamine film on PTFE is known to be possible but immersion of the e-PTFE membrane in an aerated dopamine solution leads to a functionalization not only on both faces of the membrane but also in its porous volume. The fact that polydopamine also forms at the water/air interface has allowed to transfer a polydopamine film on only one face of the e-PTFE membrane. The deposition method and applications of such Janus like membranes are reviewed in the second part of the review.

Drug loading/release and bioactivity research of a mesoporous bioactive glass/polymer scaffold

Abstract Mesoporous materials have attracted widespread attention in the field of drug delivery. Nevertheless, the weak interfacial interaction between them and drug molecules affects drug loading capacity and release kinetics. In this work, mesoporous bioactive glass (MBG) was functionalized via polydopamine to enhance the interfacial interaction with dexamethasone (DEX). Concretely, on the one hand, the amine groups of polydopamine could form hydrogen bonds with the hydroxyl groups of MBG. On the other hand, the catechol groups could form π-π bonds with the benzene rings of DEX molecules. Subsequently, DEX-loaded polydopamine-functionalized MBG (pMBG@DEX) was incorporated into polyglycolic acid/poly-1-lactic acid (PGPL) to construct a scaffold (PGPL/pMBG@DEX) via laser additive manufacturing process. The results indicated that the loadage of DEX increased by about 40% after polydopamine functionalization, from 1.28 to 1.75 μg/mg. More importantly, the burst effect was avoided. The enhanced intermolecular interaction between pMBG and DEX may be primarily responsible for this phenomenon, as it acts as a driving force to drug loading and a restraining force to drug release. PGPL/pMBG@DEX scaffold also exhibited significantly enhanced cell differentiation, mechanical properties and biomineralization activity.