Sulfonated Poly Ether Ether Ketone Research Articles

Size exclusion chromatography characterization of poly (ether ether ketone), PEEK, after chemical modification

AbstractCharacterization of the molar mass distribution (MMD) of poly (ether ether ketone) (PEEK) is very troublesome due to the insolubility of PEEK in common solvents. The solubility of PEEK may be substantially improved after its sulfonation. Sulfonated PEEK (SPEEK) was prepared by sulfonation of PEEK with 98% concentrated H2SO4 at room temperature. The presence of sulfonic acid group (‐SO3H) in PEEK matrix was confirmed by nuclear magnetic resonance and Fourier transform infrared spectroscopy. The degree of sulfonation (DS ~ 95%) was determined by proton nuclear magnetic resonance in deuterated dimethyl sulfoxide and by thermal analysis methods. The equivalent molar mass and MMD of sulfonated PEEK was determined at 30°C in three polar solvents (N,N‐dimethylacetamide, N,N‐dimethylformamide N‐methyl‐2‐pyrollidone) in PS/DVB column using calibration with PMMA standards. A salt (LiBr) was added to the solvents for suppression of undesired interactions of analytes with the column packing. Moreover, the sulphonated PEEK was separated with size exclusion chromatography (SEC) coupled to a multi‐angle light scattering (MALS) detector. It was found that the absolute average molar mass of SPEEK from the MALS detection is much closer to the value measured by SEC in N,N‐dimethylacetamide +LiBr than the values determined in N,N‐dimethylformamide and N‐methyl‐2‐pyrollidone.

In Situ-Doped Sulfonated Schiff-Base Networks in SPEEK Composite Membranes with Enhanced Proton Conductivity.

Sulfonated polyether ether ketone (SPEEK) has been widely investigated in proton exchange membrane fuel cells (PEMFCs) due to its excellent thermal stability, chemical stability, and low cost compared with Nafion. However, excessive degree of sulfonation will easily lead to the decrease in thermal stabilities and mechanical properties of SPEEK membranes, which limits the enhancement of proton conductivity. In this work, a series of Schiff-base networks (SNWs) with different contents are in situ synthesized in the SPEEK membrane by a Schiff-base co-condensation reaction, and then, the composite membranes are soaked in sulfonic acid for further improvement of proton conductivity. The highest doping amount of the SNW filler in SPEEK can reach 20 wt %. High loading and low leaching rate of H2SO4 are easily achieved owing to the similar size between sulfuric acid molecules and micropores in SNW. Moreover, abundant amino and imine groups in SNW networks contribute to the anchoring of H2SO4 into the pores by acid-base interactions. The proton conductivity of the SPEEK/S-SNW-15 composite membrane can reach 115.53 mS cm-1 at 80 °C and 100% RH. Meanwhile, the composite membrane also exhibits satisfied stability and mechanical property.

Surface modification, counter-ion exchange effect on thermally annealed sulfonated poly (ether ether ketone) membranes for vanadium redox flow battery

In this work, we report new approaches to sulfonated poly ether ether ketone (SPEEK) membranes to improve its inhibition to vanadium ions along with polymer reinforcement. First approach includes facile thermal annealing of SPEEK membrane (SPEEK-T) which could reinforce the polymer matrix. Second approach was to exchange the labile proton of SPEEK with benzimidazole to protect the hydrolytic decomposition of sulfonic acid followed by thermal annealing (SPEEK-Benz), and third approach focused on creating barrier layer for vanadium ions by coating polyethyleneimine on SPEEK membrane followed by thermal treatment (SPEEK-PEI). The chemical stability study of the membranes revealed acceptable dimension change and VO2+ electrolyte sorption for all the membranes with least dimension change and weight gain of 5 % and 12 %, respectively, for SPEEK-PEI. Amongst four prepared membranes, SPEEK-PEI membrane displayed least diffusion coefficient of 8.04 × 10−7, 8.94 × 10−7, 4.20 × 10−7 cm2 min−1 for V3+, VO2+, and VO2+ ions respectively. VRFB assembled with SPEEK-PEI resulted highest Coulombic efficiency (CE) of 97 % and energy efficiency (EE) of 66 % over 50 charge/discharge cycles at 100 mA cm−2. Peak power density of 255, 248, 240 and 235 mW cm−2 at current density of 300 mA cm−2 was observed for SPEEK-PEI, SPEEK-Benz, SPEEK-T, and SPEEK-48, respectively; these values were higher than 225 mW cm−2 for Nafion®117 in identical experimental conditions. The excellent VRFB performance suggest that the developed new approaches have pronounced effect on the membrane properties and can be further improved to obtain an ideal VRFB separator. Furthermore, the surface modification approaches adopted in this work is facile, reproducible and scalable and can be further designed to develop high performance ion exchange membranes for separation/purification and energy.

Antibacterial properties of antimicrobial peptide HHC36 modified polyetheretherketone.

Polyetheretherketone (PEEK) is considered to be a new type of orthopedic implant material due to its mechanical properties and biocompatibility. It is becoming a replacement for titanium (Ti) due to its near-human-cortical transmission and modulus of elasticity. However, its clinical application is limited because of its biological inertia and susceptibility to bacterial infection during implantation. To solve this problem, there is an urgent need to improve the antibacterial properties of PEEK implants. In this work, we fixed antimicrobial peptide HHC36 on the 3D porous structure of sulfonated PEEK (SPEEK) by a simple solvent evaporation method (HSPEEK), and carried out characterization tests. We evaluated the antibacterial properties and cytocompatibility of the samples in vitro. In addition, we evaluated the anti-infection property and biocompatibility of the samples in vivo by establishing a rat subcutaneous infection model. The characterization test results showed that HHC36 was successfully fixed on the surface of SPEEK and released slowly for 10 days. The results of antibacterial experiments in vitro showed that HSPEEK could reduce the survival rate of free bacteria, inhibit the growth of bacteria around the sample, and inhibit the formation of biofilm on the sample surface. The cytocompatibility test in vitro showed that the sample had no significant effect on the proliferation and viability of L929 cells and had no hemolytic activity on rabbit erythrocytes. In vivo experiments, HSPEEK can significantly reduce the bacterial survival rate on the sample surface and the inflammatory reaction in the soft tissue around the sample. We successfully loaded HHC36 onto the surface of SPEEK through a simple solvent evaporation method. The sample has excellent antibacterial properties and good cell compatibility, which can significantly reduce the bacterial survival rate and inflammatory reaction in vivo. The above results indicated that we successfully improved the antibacterial property of PEEK by a simple modification strategy, making it a promising material for anti-infection orthopedic implants.

Effect of Surface Modification of PEEK Artificial Phalanx by 3D Printing on its Biological Activity

Objective: Polyetheretherketone (PEEK) is widely used as an orthopedic implant material owing to its good biocompatibility and mechanical strength; however, PEEK implants are biologically inert, resulting in suboptimal cellular responses after implantation. The aim of this study was to enhance the biological activity of PEEK through sulfonation treatment. Methods: In this study, distal phalangeal implants of PEEK were customized by fused deposition modeling (FDM) printing technology and soaked in concentrated sulfuric acid at different times to obtain sulfonated PEEK (SPEEK). The groups were divided into five groups according to the sulfonation time as follows: 0 min (control group), 1 min (group SPEEK1), 2 min (group SPEEK2), 4 min (group SPEEK4), and 8 min (group SPEEK8). Then the physicochemical characteristics of implants were determined by SEM, XRD, EDS, etc. The implants were co-cultured with stem cells from human exfoliated deciduous teeth (SHED), and then the cell proliferation, adhesion, alkaline phosphatase (ALP) activity, and alizarin red staining were performed to detect the biological activity, biocompatibility, and osteogenic activity of the SPEEK implants. Results: The sulfonation time range of 1 to 8 min could promote the formation of micropores on the surface of PEEK implants, while slightly affecting the composition and compression performance of the implants. Compared with the control group, the hydrophilicity of PEEK materials was not improved after sulfonation treatment. Tests for adhesion and proliferation of SHED indicated that SPEEK2 showed superior biocompatibility. Furthermore, ALP activity and semi-quantitative analysis of Alizarin red staining showed that the osteogenic activity of SPEEK2 phalanges exhibited significantly stronger osteogenic activity than the other groups. Conclusions: The method presented here provides a promising approach to improve the surface bioactivity of PEEK implants prepared by FDM, providing a shred of primary evidence to support the application of SPEEK in orthopedics.

Positive role of sulfonated PEEK coating for PEEK membrane in mass transfer of lithium extraction

Membrane extraction (ME) is a promising technology for efficiently separating lithium from salt-lake brine with high Mg/Li ratio. By utilizing a solvent resistant semicrystalline poly(ether ether ketone) (PEEK), an extraction-stripping loop is envisioned, but significant improvement in the lithium extraction flux is required. We report in this paper a new finding of strong interaction of the extractant, Tributyl phosphate (TBP), to PEEK, leading to reduction in Li extraction flux. Phosphorous element inside PEEK substrate supported the finding; significantly higher Li flux was observed when the top surface faces the organic extractant than that when the bottom surface faces the organic. Mass transfer model detailed the consequence of infiltration by TBP to the ion flux due to the low diffusion coefficient of the bulky ion-extractant complex. We further coated a sulfonated PEEK (SPEEK) layer to effectively improve the lithium extraction flux by 154 %. This new finding provides a coherent understanding for previous results that morphology optimization did not show significant changes in ME performance. With current findings, membrane extraction is one step further to practical applications.

Interfacial enhancement of CF/PEEK composites by coating sulfonated PEEK sizing agent

Because of the inert surface and low wettability of carbon fibers (CF), the interfacial binding between CF and polyetheretherketone (PEEK) matrix is poor. The surface of CF was modified by preparing sulfonated polyetheretherketone (SPEEK)/carboxylated carbon nanotubes (MWCNTS) sizing agent, which contributed to the developed physical and chemical compatibility of reinforcing fibers and the matrix. After sizing by the sulfonated polyether ether ketone with a sulfonation degree of 16.67% and 0.5wt% carboxylated carbon nanotubes, the flexural strength and interlaminar shear strength of the modified composites were significantly improved by 74.2% and 84.2% by comparison to CF/PEEK composites without sizing agent. The coating method by SPEEK-MWCNTS is confirmed to be an essential approach to constructing excellent interface between the enhancement phase and thermoplastic matrix.

Surface modification of polyether ether ketone implant with a novel nanocomposite coating containing poly (vinylidene fluoride) toward improving piezoelectric and bioactivity performance

Polyether ether ketone (PEEK) is an appropriate biomaterial for orthopedic implant applications due to its superior mechanical properties, chemical resistance, nontoxicity, and Magnetic resonance imaging (MRI) compatibility. Unfortunately, the inherent bio-inertness of PEEK restricted its application and required some modification to provide better bioactivity. Besides it, the generated electrical signals in the bone due to its piezoelectricity features have a vital role in regulating bone repair and regeneration. We aimed to modify the surface of PEEK with a dual-functionality nanocomposite that provides surface bioactivity and simulates the piezoelectricity of bone. So, we introduced a novel piezoelectric-bioactive nanocomposite of dispersed poly (vinylidene fluoride) (PVDF) in a sulfonated PEEK (SPEEK) matrix containing Nanohydroxyapatite (nHA) and Carbon nanofiber (CNF) fillers for coating on PEEK substrate to improve its biological activity and simulate the electrical microenvironment for bone tissue. Furthermore, sulfonation of the PEEK surface was conducted as an intermediate layer to prepare better adhesion between the coating nanocomposite and the PEEK sublayer. Surface and cross-section morphology, apatite formation, and cell attachment were investigated on the different treated PEEK surfaces using field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDX). Also, piezoelectric performance, electrical conductivity, contact angle, and mechanical properties were examined on the prepared samples. Moreover, cell viability and cell morphology were investigated for biological evaluation with human osteoblast-like MG-63 cells. Collectively, the hydrophilicity of modified PEEK (mPEEK) coated with nanocomposite was improved due to the synergistic effects of SPEEK functional groups and nHA. Also, comprehensive investigation on the mPEEK treated with nanocomposite indicated a noticeably better bone-like apatite formation, cell proliferation, and cell attachments in the presence of nHA. The transfer of induced piezoelectric charges from dispersed PVDF in the matrix to the surface of nanocomposite containing 2 wt% of CNF increased output voltage to 1893 mV. On the other hand, the presence of CNF in nanocomposites enhanced tensile strength and Young's modulus by 92% and 117%, respectively.

Efficiency Analysis of Fuel Cell Components with Ionic Poly-Arylether Composite Membrane.

We use polyethylene glycol as an additive to explore how the hydrogen bonding of this additive changes the properties of SA8 blended sulfonated polyetheretherketone (SPEEK) composite films. We mixed a 5%wt polyethylene glycol solution into a 12.5%wt SA8 solution, and then prepared a film with a total weight of 40 g at a ratio of 1:99. The SA8 (PEG) solution was prepared and then mixed with 5%wt SPEEK solution, and a film-forming solution with a total weight of 8g in different mixing ratios was created. Polyethylene glycol (PEG) was mixed into the sulfonated polyarylether polymer SA8 to form physical cross-linking. Therefore, the sulfonated polyether ether ketone SPEEK was mixed in, and it exhibited good thermal stability and dimensional stability. However, there was some decrease in proton conductivity as the proportion of SPEEK increased. Although SPEEK mixed with sulfonated polymer reduces the proton conductivity, the physical cross-linking of PEG can improve the proton conductivity of the composite membrane, and adding SPEEK can not only solve the problem of the high sulfonation film swelling phenomenon, it can also improve the dimensional stability of the film through the hydrogen bonding force of PEG and obtain a composite film with excellent properties.

Fabrication of a Cation Exchange Membrane with Largely Reduced Anion Permeability for Advanced Aqueous K-ion Battery in an Alkaline-Neutral Electrolyte Decoupling System.

Herein, an efficient method to prepare sulfonated polyether ether ketone (SPEEK) based cation exchange membranes (CEMs) is developed, where polyethersulfone (PES) is used as an additive. The optimized membrane of 30wt.%PES/SPEEK-M exhibits a rather low anion permeability and a high ionic conductivity of 9.52mScm-1 together with low volume swelling in water. Meanwhile, tensile strength of the membrane is as high as 31.4MPa with a tensile strain of 162%. As separators for aqueous K-ion batteries (AKIBs) with decoupled gel electrolytes (Zn anode in alkaline and Prussian blue (FeHCF) cathode in neutral). Discharge voltage of the AKIB can reach 2.3V. Meanwhile, Zn dendrites can be effectively suppressed in the gel anolyte. Specific capacities of the FeHCF cathode are 116.7mAhg-1 at 0.3Ag-1 (close to its theoretical value), and 95.0mAhg-1 at 1.0Ag-1 , indicating good rate performance. Capacity retention of the cathode is as high as 91.2% after 1000 cycles' cycling owing to the well remained neutral environment of the catholyte. There is almost no pH change for the catholyte after cycling, indicating good anion-blocking or cation-selecting ability of the 30wt.%PES/SPEEK-M, much better than other membranes.

Sulfonated polyether ether ketone composite proton exchange membranes incorporated with a novel hierarchical‐structure hybrid nanofiller consisting solid superacid zirconium phosphate and CNTs

AbstractHow to simultaneously improved the proton conductivity and mechanical strength is a key problem facing currently used proton exchange membranes (PEMs). Herein, a solid inorganic superacid‐zirconium phosphate (ZrP) with a two‐dimensional layer structure was combined with one‐dimensional carbon nanotubes (CNTs) to prepare hybrid nanofiller ZrP‐CNTs by an in situ chemical deposition method. The new hybrid nanofiller was then applied to modify sulfonated polyether ether ketone (SPEEK), a widely used PEM matrix, to obtain a series of composite membranes. The structure and properties of the membranes were fully characterized by SEM, XRD, FTIR, TG, tensile properties, and proton conductivity. The results showed that the proton conductivities of the membranes were significantly improved due to the addition of super solid acid‐ZrP that has abundant proton sources or proton sites. Moreover, the composite membranes exhibited better mechanical properties and thermal stability than those of pure SPEEK membrane, owing to the great interface interaction and good compatibility between ZrP‐CNTs and SPEEK. The composite membrane (2 wt% ZrP‐CNTs) demonstrated the optimal comprehensive performance. Its proton conductivity was 36.63 mS cm−1 and its tensile strength was 37.56 MPa, which was 70% and 10%, respectively, higher than those of the pure SPEEK membrane under the same condition.

Ultrasonic-Assisted Rapid Preparation of Sulfonated Polyether Ether Ketone (PEEK) and Its Testing in Adsorption of Cationic Species from Aqueous Solutions.

Herein, we report a new approach for the sulfonation of polyether ether ketone (PEEK) following a shorter path of reaction undertaken at 60 °C under ultrasonication. The application of this method enabled the reduction of the reaction time from several hours to less than one hour, achieving a relevant sulfonation degree. The sulfonated-PEEK (SPEEK) was characterized by advanced chemical and physical instrumental methods. According to 1H-NMR analysis, the degree of sulfonation of the polymer was equal to 70.3%. Advanced microscopy (SEM) showed that the fabricated SPEEK beads (2-4 mm) were porous inside with a log-normal distribution of pore sizes within the range 1.13-151.44 μm. As an application, the SPEEK polymer was tested for the adsorption of a cationic organic pollutant (Methylene blue, MB) from aqueous solutions. The equilibrium studies (isotherms) disclosed maximum adsorption capacities of 217 mg/g, 119 mg/g, and 68 mg/g at temperatures of 323 K, 313 K, and 300 K, respectively. The thermodynamic calculations indicated an endothermic effect (ΔHad = +11.81 kJ/mol) of the investigated adsorption process. The maximum removal efficiency of 99.14% was established by process optimization using the design of experiments strategy and data-driven modeling. Additionally, molecular docking simulations were performed to disclose the mechanism of interaction at the molecular level between the adsorbent (SPEEK) and pollutant.

“SPEEK-COF” Composite Cation Exchange Membrane for Zn-I2 Redox Flow Battery

Zinc-based energy storage is increasingly getting attention owing to its outstanding characteristics over to the other systems. Their high abundance, user-friendliness, environmental benignity, and low reduction potential which can avoid unwanted hydrogen evolution are some of the attractive features. Appropriate membrane selection for the zinc-based redox flow battery is challenging. Herein we report the composite of SPEEK (sulfonated polyether ether ketones) with covalent organic frameworks (COF) as a potential membrane for zinc-based redox flow battery. Biphenyl-based knitting type COF was prepared, post sulfonated and blended with SPEEK. In a Zn/I2 redox flow battery system, the discharge capacity was found to be 19.8 AhL−1, 17.4 AhL−1, 15.1 AhL−1 for 20%, 15%, 10% SCOF loading respectively against 14.5 AhL−1 for pristine SPEEK at 20 mAcm−2 current density. The capacity was improved by about 36% higher than the neat SPEEK membrane. This improvement in the battery performance might be due to the higher ionic conductivity and hydrophilicity after SCOF loading. We found that the 15% loading was the maximum limit for the battery performance, beyond which the energy efficiency was found to be fading, which is due to the excessive dendrite growth on the membrane surface.

Consecutive and reliable proton transfer channels construction based on the compatible interface between nanofiber and SPEEK

It is indispensable to balance the proton conductivity and dimensional stability, as well as maintain the high long-term durability of proton exchange membranes (PEMs). Herein, we proposed the sandwich structure composite membrane containing a middle layer of sulfonated polyetheretherketone (SPEEK) sandwiched by two layers of hybrid polyimide (PI) nanofiber. The hybrid nanofibers were fabricated via in situ loading different contents of NH2-UiO-66 (NU6) onto PI nanofiber as proton acceptors for amino-functionalization, resulting in NU6@PI nanofibers (NP) with different forms of assembly. By incorporating three-dimensional nanofibers into SPEEK, the dimensional stability of the composite membrane was dramatically boosted. The –SO3H groups on SPEEK interact with –NH2 groups on NP to form long-range acid-base pairs and acid-rich layer along the NP-SPEEK interface, which can provide abundant proton-conducting sites for proton transfer. Significantly, the continuous and uniform assembly of NU6 on PI nanofiber can form a compatible interface with SPEEK, ensuring the reliability of the proton pathways and robust mechanical properties. Insufficient or excessive loads of NU6 will lead to an imperfect NP-SPEEK interface, resulting in discontinuous proton channels or forming numerous defects that hinder continuous proton transport. The composite membrane of 4NP-SPEEK-4NP (40%NU6@PI-SPEEK-40%NU6@PI) with consecutive and reliable proton transfer channels displays enhanced stress, optimal proton conductivity, and excellent H2/O2 fuel cell performance. The durability test at 60 °C and 100% RH for 32 days reveals that the proton conductivity retention and tensile strength of the composite membrane are 89.8% and 47.8 MPa, which are 33.8% and 52.7% higher than those of SPEEK, respectively. The prepared membranes not only can be potential candidates for fuel cells but also provides a useful strategy for the longtime effective construction and regulation of proton transport channels in PEMs.

A sulfonated modification of PEEK for ultralow friction

Polyether ether ketone (PEEK) is a widely used material for friction pairs due to its excellent mechanical strength, good wear resistance, and chemical inertness. However, some modifications are necessary when PEEK is used as a water-lubricated friction pair. In this study, a novel sulfonation method was developed to design a water-lubricated friction pair with ultralow friction, good wear resistance, and high loading capacity. PEEK powders were sulfonated using ClSO3H and sintered to form bulk plastic. The sulfonated PEEK (SPEEK) plastic exhibited good tribological properties. At a low sliding speed, the friction coefficient was smaller than 0.02 when a 3 wt% NaCl solution was used as the lubricant. The order of magnitude of the wear rate was as low as 10−8 mm3/(N·m). The mechanism of friction reduction was mainly hydration lubrication. The negatively charged −SO3− groups on the friction pair can adsorb hydrated Na+ cations by electrostatic interactions. These hydrated Na+ cations have a high load capacity and low shearing resistance. The ultralow wear mechanism observed in this study is possibly due to ultralow friction properties of the friction pairs prepared through the proposed sulfonation and thermoforming procedures.

Development of highly permeable self-standing nanocomposite sulfonated poly ether ketone membrane using covalent organic frameworks

This study developed a new symmetric and ultrathin membrane by incorporating Schiff base network-1 (SNW-1), which are covalent organic framework (COF) nanoparticles, as fillers in the sulfonated poly ether ketone (SPEK) matrix to improve forward osmosis (FO) performance. The amine-rich and porous SNW-1 nanoparticles enhanced the surface wettability of the SPEK membranes and offered additional passages for the water molecules' transport, which assisted in the elevation of membrane water flux. The modified membrane loaded with 20 wt% SNW-1 (COF-20) exhibited the best performance with a significantly higher water flux (28.5 L m−2 h−1) and lower specific reverse solute flux (SRSF, 0.05 g L−1) than that of the unmodified SPEK (COF-0) membrane (water flux of 12 L m−2 h−1 and SRSF of 0.16 g L−1) when experimented with deionized water and 1 M Na2SO4 as feed and draw solutions, respectively. The impressive FO performances of nanocomposite SPEK membranes suggest that SNW-1 nanoparticles could be used as fillers for improving the SPEK membrane's performance in the FO application.

A novel insight into green food preservation: Design of equilibrium modified atmosphere packaging (EMAP) based on gas barrier (GB) - gas conductor (GC) blending materials

In this work, the design of equilibrium modified atmosphere packaging (EMAP) was achieved by adjusting gas permeability using gas barrier (GB) - gas conductor (GC) blending material. Sulfonated poly ether ether ketone (SPEEK) was used as promoter for gas permeation, i.e. GC, and introduced into poly ether sulfone (PES) as GB. As the results, the introduction of SPEEK cannot only enhance the gas permeability of the blending material, but also modify the physic and chemical properties. When the blending material used as EMAP for peppers, significant effects were exhibited on inhibiting the variations in sensory, color, texture, and chemical properties of the preserved peppers, especially when the samples preserved in packaging consisted of 60 % SPEEK and 40 % PES, in which suitable atmosphere with 5.18 % v/v CO2 and 3.16 % v/v O2 was maintained. The overall findings revealed the feasibility of GB - GC theory for EMAP design.

Simvastatin-loaded sulfonated PEEK enhances angiogenesis and osteogenesis via miR-29cb2-mediated HIF-3α downregulation

Bio-implants are widely used in clinic for repair defected bone, however, clinical trace always found that the poor osseointegration often results in bone repair failure. In this study, we investigated whether simvastatin loaded onto sulfonated PEEK (SP) surfaces enhances the bone formation effect of the SP samples. Our results showed that simvastatin loading could significantly enhance the formation of type H vessels, which are pivotal and specific vessels showing strong association with bone formation. Further, osteogenesis was found to be strongly correlated with simvastatin release. Based on experiments involving miR-29cb2 knockout and bone defect mice, simvastatin upregulated the expression of miR-29cb2, which suppressed HIF-3α expression, leading to the promotion of osseointegration and angiogenesis.

Fusion Peptide-Engineered Polyetheretherketone Implants with Photo-Assisted Anti-Pathogen and Enhanced Angiogenesis for in vivo Osseointegrative Fixation

Owing to its superior mechanical and physicochemical characteristics, polyetheretherketone (PEEK) is considered a potent orthopedic material. Yet, poor bactericidal, osseointegrative and angiogenic properties of bioinert PEEK collectively hamper its clinical adoption. Herein, we present a strategy for developing multifunctional hierarchical coatings bearing a synthetic fusion peptide and polydopamine/silver nanoparticles (pDA/AgNPs) bio-heterojunctions (bio-HJs), in an attempt to empower PEEK with triple-modal abilities, which prevents bacterial infection, enhances ossification and promotes re-vascularization for physiological osseointegrative fixation. By harnessing the adhesion of bioinspired pDA, AgNPs are facilely immobilized onto peripheral surface and incorporated into interior cavity of micro/nano-porous sulfonated PEEK (SP) to form hierarchical pDA/AgNPs heterostructures. The bio-HJs coatings exhibit robust and repeatable bacteria-eradicating ability, assisted by near-infrared illumination, due to the synergistic effects of the metal ion/photothermal therapy. The fusion peptide-engineered PEEK exhibits osteogenesis activity in terms of promoting osteoblast proliferation, spreading, boosting the synthesis and secretion of osteogenesis-related genes. Besides, the fusion peptide-engineered PEEK also has the ability to promote HUVECs growth, reproduction, and tube formation, facilitating the synthesis and secretion of angiogenesis-associated genes. Moreover, the results of the in vivo experiments further corroborate the in vivo osteointegration and angiogenic abilities of materials. Expectantly, the multifunctional coatings with the presented triple-therapeutic effects represent a prospective clinical solution to address the current clinical challenges associated with the use of PEEK implants.

Physicochemical Studies of Chitosan Blended Sulfonated Poly Ether-Ether Ketone and Graphene Oxide as Filler for Direct Methanol Fuel Cell

Chitosan (CS) was successfully extracted from the shrimp shell of Litopenaeus vanamei and used as a biopolymer for the fuel cells. The composite membranes containing chitosan blended poly ether-ether ketone (PEEK) and graphene oxide (GO) as filler were fabricated using solvent evaporation method and its physicochemical studies were also investigated. The sulfonation degree of sulfonated poly ether-ether ketone (SPEEK) was 60.61%. Among the fabricated membranes, the CS/SPEEK/SGO membrane was the best membrane to achieve high ion exchange capacity (IEC) which is 5.94 mmol.g-1. Moreover, its methanol uptake and permeability were 6.21% and 6.34×10-6 cm2.s-1, respectively. The highest water uptake was also obtained by CS/SPEEK/SGO membrane which is 61.54% followed by other membranes CS/SGO, CS/GO, CS/SPEEK, CS/SPEEK/GO, and CS. In a comparison, the lowest water uptake was obtained by pristine CS membrane which is 52.17%.