Hydrophilic Poly Ethylene Glycol Research Articles

New insights into high-rate and super-stable aqueous zinc-ion batteries via the design concept of voltage and solvation environment coordinated control

As the great potential host materials, the application of low-valent vanadium-based compounds for aqueous zinc-ion batteries are usually suffered from the insufficient storage capability and cycle performance. In this work, a unique voltage and solvation environment coordinated control strategy was developed to unlock the MXene derived VNxOy/C heterostructure as robust host applied for aqueous zinc-ion batteries. As the results indicated, such VNxOy/C can be completely converted to the new phase of Zn3(OH)2V2O7·2H2O when the cut-off voltage was controlled at 0.2–2.0 V. Moreover, unlike the mechanism of H+/Zn2+ co-insertion/extraction accompanied with the by-product formation in the electrolyte of pure H2O system, it was demonstrated that the introduction of hydrophilic polyethylene glycol (PEG) into electrolyte enables tailoring the solvation environment, forming the proton shielding to eliminate the blocking effect of by-products on interfacial transport kinetics and storage reversibility of the electrode, thus realizing controllable Zn2+-dominant insertion/extraction mechanism. Unexpectedly, such low-valent VNxOy/C electrode under the coordinated control of voltage and solvation environment enables achieving a significantly enhanced rate capability and ultralong cycle lifespan, which can retain the specific capacities of 369.4 and 112.7 mAh g−1 after 2000 cycles at 0.5 A g−1 and 14,200 cycles at 10 A g−1, respectively. Such novel and efficient avenue for the development of low-valent cathode material is expected to deepen the understanding of the construction of efficient energy storage systems including but not limited to aqueous zinc-ion batteries.

Supramolecular Theranostic Nanomedicine for In Situ Self-Boosting Cancer Photochemotherapy.

Although traditional nanomedicines have enhanced the therapeutic efficacy and improved the survival quality of cancer patients, random drug release and drug resistance are deep-rooted problems hindering their clinical application. A precise nanoplatform combing chemotherapy and photodynamic therapy (PDT) is developing as a new therapeutic strategy to overcome the above challenges. Herein, a novel supramolecular nanomedicine is ingeniously constructed for in situ self-boosting cancer photochemotherapy. Hydrophilic polyethylene glycol (PEG) chains or β-cyclodextrin (β-CD) hosts are first conjugated onto tetraphenyl porphyrin (TCPP) to improve the solubility of TCPP and decrease their π-π stacking interactions, guaranteeing a high-efficiency PDT. Then, two camptothecin (CPT) molecules are linked together via a reactive oxygen species (ROS)-responsive thioketal bond, which averts the premature burst release of CPT and realizes in situ drug release at the tumor site where PDT is performed, resulting in an enhanced chemotherapy. Benefiting from the collaboration of host-guest complexation between β-CD and CPT, multiple intermolecular hydrogen bonds of β-CD, π-π stacking interactions among CPT and TCPP as well as PEG shell protection, a prolonged blood circulation time, and a selective tumor accumulation are acquired, which facilitate the synergistic photochemotherapy and bring a pre-eminent antitumor response with a low systemic toxicity.

Chemically Crosslinked Amphiphilic Degradable Shape Memory Polymer Nanocomposites with Readily Tuned Physical, Mechanical, and Biological Properties.

Facile surgical delivery and stable fixation of synthetic scaffolds play roles just as critically as degradability and bioactivity in ensuring successful scaffold-guided tissue regeneration. Properly engineered shape memory polymers (SMPs) may meet these challenges. Polyhedral oligomeric silsesquioxanes (POSSs) can be covalently integrated with urethane-crosslinked polylactide (PLA) to give high-strength, degradable SMPs around physiological temperatures. To explore their potential for guided bone regeneration, here we tune their hydrophilicity, degradability, cytocompatibility, and osteoconductivity/osteoinductivity by crosslinking star-branched POSS-PLA with hydrophilic polyethylene glycol diisocyanates of different lengths and up to 60 wt % hydroxyapatite (HA). The composites exhibit high compliance, toughness, up to gigapascal storage moduli, and excellent shape recovery (>95%) at safe triggering temperatures. Water swelling ratios and hydrolytic degradation rates positively correlated with the hydrophilic crosslinker lengths, while the negative impact of degradation on the proliferation and osteogenesis of bone marrow stromal cells was mitigated with HA incorporation. Macroporous composites tailored for a rat femoral segmental defect were fabricated, and their ability to stably retain and sustainedly release recombinant osteogenic bone morphogenetic protein-2 and support cell attachment and osteogenesis was demonstrated. These properties combined make these amphiphilic osteoconductive degradable SMPs promising candidates as next-generation synthetic bone grafts.

Modification of gelatin and photocured 3D‐printed resin to prepare biomimetic phantoms for ultrasound‐guided minimally invasive surgeries

AbstractThe main challenge of ultrasound‐guided minimally invasive surgeries is to carry out treatments through small boreholes in the patient's body surface with sub‐millimetric accuracy and facility offered by ultrasound instruments. Thus, the phantoms' biomimetic appearances, acoustic characteristics, and mechanical properties are essential for healthcare professionals. In this study, gelatin and 3D‐printed photo‐resin phantoms were developed for hard and soft tissues, respectively. Using glutaraldehyde (GA) and formaldehyde (FA) to crosslink gelatin phantoms, the mechanical strength, ultrasound velocity, acoustic impedance, needle insertion forces, and antiseptic periods were improved, and the addition of silica nanoparticles raised the acoustic impedance. For 3D‐printed phantoms, the acoustic impedance ascended with hydrophilic polyethylene glycol diacrylate (PEGDA) oligomers. The additives applied in this study successfully made the gelatin and photo‐resin phantoms more mimetic to muscle and bone tissues, allowing their application in preoperative preparations.

Novel O/W Emulsions by Utilizing a Vesicle/Disc Transformation of Polyether Modified Silicone.

Emulsification is an important technology in the field of cosmetics and household products. Emulsions are in non-equilibrium state; therefore, the products vary depending on the preparation process, and their state changes with time. Furthermore, it is known empirically that different types of oils have different emulsification properties (preparation and stability). For these reasons, the variables in emulsification research are numerous and complicated to analyze. As a result, many industrial applications have had to rely on empirical rules. In this study, emulsions with a lamellar liquid crystalline phase as an adsorption layer at the emulsion interface were investigated. The characteristics of O/W emulsions formed with the excess solvent phases (aqueous and oil phases) separated from the lamellar liquid crystalline phase were investigated based on the phase equilibrium of the ternary system.As a result, it was found that by agitating the aqueous phase containing dispersed vesicles of emulsifier (polyether modified silicone) together with the oil phase, an emulsion with a uniform interfacial membrane of lamellar liquid crystalline phase could be obtained. The emulsions prepared by this method were found to have good stability against coalescence. The process of transformation from vesicles to the uniform liquid crystal interfacial membrane during the emulsification process was clarified by a freeze-fracture transmission electron micrograph and the calculation of interfacial membrane thickness based on precise particle size analysis. Furthermore, the emulsification properties of polyether-modified silicones were clarified using polar oils and silicone oils, which are a combination of high/low and low/high compatibility with hydrophilic (polyethylene glycol) and lipophilic (polydimethylsiloxane) groups of polyether modified silicone, respectively. It is expected that this research will lead to the evolution of various functionalities in products in the fields of cosmetics, household products, food, pharmaceuticals, paint and others.

Doxorubicin-loaded polymeric micelles decorated with nitrogen-doped carbon dots for targeted breast cancer therapy

A pH-tunable “on-off” module polymeric micelles (PM) composed of two parts, a hydrophilic (polyethylene glycol) shell and a hydrophobic (resorcinol) core, was synthesized. Doxorubicin (DOX) was encapsulated into the micelle core via hydrophobic interaction. Due to the low toxicity, good fluorescence emission, water solubility, and biocompatibility, nitrogen-doped carbon quantum dots (NCDs) were used as labels to form PMs with robust fluorescence characteristics. NCDs were synthesized (particle size of 2.26 nm and fluorescence quantum yield of 8.2%). The prepared PM with 28 nm in size demonstrated desirable DOX-loading content of 33.64% and encapsulation efficiency of 48.90%. Analyses such as FT-IR, dynamic light scattering, and transmission electron microscopy were used to determine the characteristics of prepared fluorescence drug-loaded micelles (NCD@DOX/PM). The developed nanocarrier revealed a sustained release profile where 94.0% of the encapsulated DOX was released within 24 h in pH 5.0. Moreover, the in vitro cytotoxicity test of NCD@DOX/PM showed about 30% cell viability on MCF-7 cells at the maximum dose of 4.5 μg/mL. Overall, all these appealing attributes make micelles a promising modality for the delivery and controlled release of DOX in tumor cells.

One-step synthesis of Enteromorpha graphene aerogel modified by hydrophilic polyethylene glycol achieving high evaporation efficiency and pollutant tolerance

Photothermal evaporation using solar energy is a sustainable way to produce fresh water from seawater. Aiming to explore functional materials as a solar-energized evaporator with enhanced evaporation rate and pollutant tolerance, this study was to synthesize a self-floating composite graphene aerogel (GA) doped with Enteromorpha and modified polyethylene glycol (PEG), named as PEGA using solar energy for desalination. Physio-chemical properties and evaporative mechanism of PEGA were experimentally investigated and analyzed with respect to molecular weight, PEG dosage, and ratio of Enteromorpha and graphene oxide. Experimental data revealed that the modification of PEG improved hydrophilic functional ability of PEGA, resulting in increasing the evaporation rate and photothermal conversion efficiency up to 2.55 kg/(m2·h) and 105.71 %, respectively. The ion removal rate of seawater exceeds 99.99 % via the PEGA conducted solar evaporation. Furthermore, PEGA possessed an excellent property of salinity emulsion pollution tolerance. Particularly, the evaporation rate of the PEG-modified biomass-based aerogel was 2.84 kg/(m2·h) in a 15 wt% NaCl solution (1 sun, 6 h) and 2.50 kg/(m2·h) at 1 h. The formation of hydrogen bonds between –OH of PEG and water molecules assist to conduct water along the graphene matrix to improve water evaporation. The cost of the graphene aerogel modified by Enteromorpha was reduced by 38.88 % less than the original graphene aerogel. The results from this study will greatly promote the application of graphene aerogel for desalination via solar evaporation.

Influence of Dispersed TiO2 Nanoparticles via Steric Interaction on the Antifouling Performance of PVDF/TiO2 Composite Membranes.

Herein, the influence of various contents of polyethylene glycol (PEG) on the dispersion of TiO2 nanoparticles and the comprehensive properties of PVDF/TiO2 composite membranes via the steric hindrance interaction was systematically explored. Hydrophilic PEG was employed as a dispersing surfactant of TiO2 nanoparticles in the pre-dispersion process and as a pore-forming additive in the following membrane preparation process. The slight overlap shown in the TEM image and low TSI value (<1) of the composite casting solution indicated the effective dispersion and stabilization under the steric interaction with a PEG content of 6 wt.%. Properties such as the surface pore size, the development of finger-like structures, permeability, hydrophilicity and Zeta potential were obviously enhanced. The improved antifouling performance between the membrane surface and foulants was corroborated by less negative free energy of adhesion (about -42.87 mJ/m2), a higher interaction energy barrier (0.65 KT) and low flux declination during the filtration process. The high critical flux and low fouling rate both in winter and summer as well as the long-term running operation in A/O-MBR firmly supported the elevated antifouling performance, which implies a promising application in the municipal sewage treatment field.

Polyethylene Glycol-b-poly(trialkylsilyl methacrylate-co-methyl methacrylate) Hydrolyzable Block Copolymers for Eco-Friendly Self-Polishing Marine Coatings.

Hydrolyzable block copolymers consisting of a polyethylene glycol (PEG) first block and a random poly(trialkylsilyl methacrylate (TRSiMA, R = butyl, isopropyl)-co-methyl methacrylate (MMA)) second block were synthesized by RAFT polymerization. Two PEGs with different molar masses (Mn = 750 g/mol (PEG1) and 2200 g/mol (PEG2)) were used as macro-chain transfer agents and the polymerization conditions were set in order to obtain copolymers with a comparable mole content of trialkylsilyl methacrylate (~30 mole%) and two different PEG mole percentages of 10 and 30 mole%. The hydrolysis rates of PEG-b-(TRSiMA-co-MMA) in a THF/basic (pH = 10) water solution were shown to drastically depend on the nature of the trialkylsilyl groups and the mole content of the PEG block. Films of selected copolymers were also found to undergo hydrolysis in artificial seawater (ASW), with tunable erosion kinetics that were modulated by varying the copolymer design. Measurements of the advancing and receding contact angles of water as a function of the immersion time in the ASW confirmed the ability of the copolymer film surfaces to respond to the water environment as a result of two different mechanisms: (i) the hydrolysis of the silylester groups that prevailed in TBSiMA-based copolymers; and (ii) a major surface exposure of hydrophilic PEG chains that was predominant for TPSiMA-based copolymers. AFM analysis revealed that the surface nano-roughness increased upon immersion in ASW. The erosion of copolymer film surfaces resulted in a self-polishing, antifouling behavior against the diatom Navicula salinicola. The amount of settled diatoms depended on the hydrolysis rate of the copolymers.

Evaluation of Transport Potential of Alkylated and Fluoroalkylated Amphiphilic Hybrid Nanoarchitectures

The unique segregation and self-assembly properties of fluorinated amphiphiles into supramolecular architectures have attracted substantial attention in recent years. In this study, we report the design and synthesis of six newer hybrid nonionic amphiphiles with hydrophobic alkyl/fluoroalkyl chains and hydrophilic polyethylene glycol (PEG) units of different lengths and evaluate and compare their drug delivery applications. On the hydrophobic side, the amphiphiles differ in having either two alkyl chains, two fluoroalkyl chains, or one alkyl and one fluoroalkyl chain. This allowed for a systematic comparison of the physicochemical and transport abilities. The aggregation phenomenon of the amphiphiles was monitored with Cryo-TEM. Cytotoxicity and cellular uptake studies were performed to evaluate the pharmacological potential. Candida antarctica lipase (Novozym-435) immobilized on solid support was used to facilitate the release of the encapsulated cargo. Our study highlights the potential and properties of the fluoroalkyl-based nanocarriers.

Adsorption Dynamics of Surface-Modified Silica Nanoparticles at Solid-Liquid Interfaces.

Understanding the adsorption dynamics of nanoparticles at solid-liquid interfaces is of paramount importance to engineer nanoparticles for a variety of applications. The nanoparticle surface chemistry is significant for controlling the adsorption dynamics. This study aimed to experimentally examine the adsorption of surface-modified round-shaped silica nanoparticles (with an average diameter of 12 nm), grafted with hydrophobic (propyl chains) and/or hydrophilic (polyethylene glycol chains) agents, at an aqueous solution-silica interface with spherical soda-lime glass beads (diameter of 3 mm) being used as adsorbents. While no measurable adsorption was observed for solely hydrophobic or hydrophilic nanoparticles, a considerable level of adsorption was detected for nanoparticles comprising both hydrophobic and hydrophilic agents. Various kinetic models were employed to model the adsorption dynamics of the responsive nanoparticles. The results demonstrated that the mixed diffusion-kinetics models could predict the dynamics better than the adsorption diffusion models, indicating that the dynamics is controlled by a combination of liquid film diffusion, intra-particle diffusion, and mass action. Additionally, the adsorption of the surface-modified silica nanoparticles onto a mineral silica surface was examined using molecular dynamics simulations. The interaction energy for nanoparticles comprising both hydrophobic and hydrophilic agents was evaluated to be more favorable than that of solely hydrophobic or hydrophilic nanoparticles.

An amphiphilic ratiometric fluorescent probe with aggregation-induced emission feature for specific detection of hypochlorite in aqueous solution and living cells

Hypochlorite (ClO−) as one of reactive oxygen species (ROS), that has been widely used in our daily life and played a crucial role in immune function systems of living organisms. However, due to the hydrophobic nature of most fluorescent probes, direct utilization of these probes for detection of ClO− in biological systems has demonstrated to be problem. In this work, hydrophilic amino-terminated polyethylene glycol (PEG-NH2) and the organic dye (named as TPAMA) with aggregation-induced emission (AIE) feature were conjugated together using hexachlorocyclotriphosphazene (HCCP) as linking agent. The resultant probe (named as TPAMA-HCCP-PEG) was examined as ratiometric fluorescent probe for detection of ClO− in pure aqueous solution by taking advantage of its amphiphilic property. After adding ClO−, the fluorescence of TPAMA was quickly quenched, therefore it can be used for sensing ClO− with high sensitivity and selectivity. The mechanism was attributed to the reaction of TPAMA with ClO−, resulting in a blue-shift in absorbance and fluorescence emission. The potential of TPAMA-HCCP-PEG for sensing ClO− in biological systems was also evaluated further. Results showed that TPAMA-HCCP-PEG could form highly dispersible nanoparticles in aqueous solution and displayed low cytotoxicity towards model cancer cell lines, making it promising for monitoring ClO− in living systems. We believe this work will provide a general tool for fabrication of fluorescent probes suitable for visual detection various molecules with important biological roles.

Hybrid Star-Shaped Block Copolymers for Fabricating Fouling-Resistant Membranes

Star-shaped block copolymers (SPs), comprising a hydrophobic cross-linked polystyrene (PS) core with extended hydrophilic polyethylene glycol (PEG) arms, showed high promise as a class of branched amphiphilic coating material, since the coatability and antifouling properties of the SPs could be tailored simply by tuning the core and/or arm compositions. However, the complex reaction sequences required for synthesizing SPs have been an obstacle for scale-up and, therefore, their practical applications. Herein, we have developed an SP architecture from an inorganic silica nanoparticle (SiO2NP) core, significantly simplifying the synthesis and enabling scale-up at much lower costs. The pressure-assisted coatability of three SiSPs with three different PEG lengths (i.e., SiSP1, SiSP2, and SiSP3 with 28, 54, and 129 PEGMA repeating units) on polysulfone ultrafiltration membranes was evaluated by scanning electron microscopy (SEM) and contact angle measurement. The SiSPs with medium PEG arm length (i.e., SiSP2 with 54 PEGMA repeating units) demonstrated superior thin-layer coatability and UV-induced stabilization. The protein solution filtration exhibited very low fouling, ca. 3% flux decline ratio (FDR) and ca. 97% flux recovery ratio (FRR), for UV-SiSP2 coated PSF UF membrane compared to significant fouling for pristine membrane (ca. 41% FDR and ca. 71% FRR). The three times enhancement in oleophobicity of the SiSP2 coated membrane has endowed almost seven times improvement in the permeation flux during oil emulsion filtration and 100% FRR contrary to zero flux recovery for pristine membrane. This study offers insights regarding the cost-efficient and facile synthesis of block copolymer nanoarchitecture SiSPs, which has the potential for water purification, lubrication, emulsification, and biomedical applications.

Preparation of Epoxy Resin Emulsifiers with Different Structures and a Comparative Study of their Properties

AbstractThe structure of epoxy resin emulsifier has important influence on the stability of epoxy resin emulsion/dispersion. However, there is no systematic comparative study so far about the effect of the structure of the epoxy resin emulsifier on their physiochemical properties and performance. In this work, two types of linear (AB and ABA types) and one type of branched epoxy resin emulsifiers were prepared by using bisphenol A epoxy resin E‐44 as the hydrophobic chain segment A and polyethylene glycol (PEG) as the hydrophilic chain segment B, and their physicochemical properties were compared. It has been found that the branched epoxy resin emulsifier is more hydrophilic than the two kinds of linear epoxy resin emulsifiers as a result of higher content of hydrophilic PEG chains. More importantly, the solubilization ability of the branched epoxy resin emulsifier to toluene is much higher than that of the two linear epoxy resin emulsifiers and exhibits an unique behavior, i. e., it increases monotonically with increasing hydrophilic PEG chain length. This work shed a light on the structural importance of epoxy resin emulsifier on its physicochemical properties and may provide a better choice of emulsifiers for the preparation of stable epoxy resin emulsions/dispersions.

Mussel-Inspired Organic–Inorganic Implant Coating Based on a Layer-by-Layer Method for Anti-infection and Osteogenesis

Lack of antibacterial properties and poor bioactivity of implants’ surfaces will increase the risk of implant-associated infections and poor osseointegration, subsequently leading to implant failure. In the present study, an organic–inorganic coating with anti-infection and osteogenesis properties was constructed on the titanium (Ti) implants to enhance the osseointegration. Inspired by the mussel, tannic acid (TA) with abundant catechol groups was chosen as a bonding medium to combine inorganic hydroxyapatite nanoparticles (nHA) with organic polyethylene glycol (PEG) via Layer-by-Layer (LbL) assembly methods. The prepared organic–inorganic coating on the implant (Ti-HP) could effectively prevent the adherence of protein and bacteria including S. aureus and E. coli through highly hydrophilic PEG, and the nHA ingredient endowed the coating with sufficient osteogenic ability to accelerate osteoblast differentiation of rat bone marrow stromal cells (BMSCs). Furthermore, the new bone formation around Ti-HP in vivo was significantly promoted compared with the pure Ti. The study provides a convenient and flexible way based on a polyphenol-assisted LbL method to form an organic–inorganic implant coating with multiple functions, demonstrating its potential for clinical applications in surface engineering of bone repair.

C2-linked alkynyl poly-ethylene glycol(PEG) adenosine conjugates as water-soluble adenosine receptor agonists.

A series of 12 novel polyethylene-glycol(PEG)-alkynyl C2-adenosine(ADN) conjugates were synthesized using a robust Sonogashira coupling protocol and characterized by NMR spectroscopy and mass spectrometry analysis. The ADN-PEG conjugates showed null to moderate toxicity in murine macrophages and 12c was active against Mycobacterium aurum growth (MIC=62.5mg/L). The conjugates were not active against Mycobacterium bovis BCG. Conjugates 10b and 11b exhibited high water solubility with solubility values of 1.22 and 1.18 mg/ml, respectively, in phosphate buffer solutions at pH6.8. Further, 10b and 11b induced a significant increase in cAMP accumulation in RAW264.7 cells comparable with that induced by adenosine. Analogues 10c, 11c and 12c were docked to the A1 , A2A , A2B and A3 adenosine receptors (ARs) using crystal-structures and homology models. ADN-PEG-conjugates bearing chains with up to five ethyleneoxy units could be well accommodated within the binding sites of A1 , A2A and A3 ARs. Docking studies showed that compound 10b and 11b were the best A2A receptor binders of the series, whereas 12c was the best binder for A1 AR. In summary, introduction of hydrophilic PEG substituents at the C2 of adenine ring significantly improved water solubility and did not affect AR binding properties of the ADN-PEG conjugates.

Experimental and molecular dynamic studies of amphiphilic graphene oxide for promising nanofluid flooding

Owing to its extremely high aspect ratio, water dispersibility, and dramatic lightness, graphene oxide (GO) has been considered a promising alternative to chemical enhanced oil recovery (CEOR). However, the long-term stability of GO under reservoir conditions and the mechanisms underpinning the cost-effectiveness of this nanofluid flooding remain underexplored. Herein, a two-dimensional (2D) GO derivative in the form of amphiphilic graphene oxide (GOA) composed of a hydrophobic graphene center and a hydrophilic polyethylene glycol periphery for CEOR was investigated by combining experimental characterizations and molecular dynamics simulations. The thickness of the GOA is only 2.33 nm, but the lateral dimension extends up to a few micrometers, which endows GOA with good dispersibility and stability in brine. GOA functions as a 2D amphiphile, which adheres to the interface and decreases the interfacial energy after reaching a threshold concentration as low as 45 mg/L. These nanosheets spontaneously accumulate at the oil–brine interface to produce colloidal lamellae with higher local viscosity at the water–oil interface. GOA tuned the oil-wet and water-wet surfaces to almost neutrally wet surfaces, but the amount of physical adsorption of GOA was rather low. GOA-based nanofluid has desirable compatibility with rock pores. The oil recovery factor of GOA-based nanofluid after extensive brine flooding was characterized at the pore scale, being 18.2 % of the original oil in place at a GOA concentration of 100 mg/L. The dimensionless capillary number of GOA-based nanofluid flooding is ∼ 1000-fold that of brine flooding. The results confirm that this atomically thin, amphiphilic, highly water dispersible 2D sheet should enable highly cost-effective application in CEOR.

Sequential acid/reduction response of triblock copolymeric nanomicelles to release camptothecin and toll-like receptor 7/8 agonist for orchestrated chemoimmunotherapy

BackgroundImmunosuppressive tumor immune microenvironment (TIME) lowers immunotherapy effectiveness. Additionally, low penetration efficiency and unpredictable drug release in tumor areas restrict tumor therapy.MethodsA triblock copolymeric micelle (NanoPCPT+PIMDQ) was developed to carry the chemotherapeutic drug camptothecin (CPT) and the TLR7/8 agonist 1-(4-(aminomethyl)benzyl)-2-butyl-1H-imidazo[4,5-c] quinoline-4-amine (IMDQ) to achieve deep tumor penetration and on-demand drug release by responding to acid and reduction stimuli sequentially. The synergistic antitumour efficacy of NanoPCPT+PIMDQ was assessed both in vitro and in vivo.ResultsNanoPCPT+PIMDQ is composed of a hydrophilic PEG(polyethylene glycol) outer layer, an acid-sensitive EPEMA middle layer, and a drug inner core. Upon intratumoral injection, (i) NanoPCPT+PIMDQ first responds to the acidic tumor microenvironment and disintegrates to PIMDQ and PCPT, penetrating deep regions of the tumor; (ii) tumor cells are killed by the released CPT; (iii) DCs are activated by PIMDQ to increase the infiltration of cytotoxic T lymphocyte (CTL); and (iv) both downregulated Foxp3+ Tregs by CPT and repolarized M2 macrophages by PIMDQ can relieve the TIME.ConclusionThis pH/GSH-responsive triblock polymer-drug conjugate reduces immunosuppression and enhances the infiltration of CTLs by codelivering CPT and IMDQ in a controllable manner, providing a promising platform for synergistic tumor chemoimmunotherapy.

Mechanically flexible bulky imidazolium-based anion exchange membranes by grafting PEG pendants for alkaline fuel cells

Imidazoliums with bulky substitutes are promising alternative cations for anion exchange membranes due to their superior stability under alkaline conditions. However, bulky imidazolium-based AEMs suffer from low conductivity as well as poor film-forming ability, and thus unfavorable fuel cell performance. Herein, we presented a strategy to graft hydrophilic and flexible polyethylene glycol (PEG) chains on the imidazoliums to prepare imidazolium-type AEMs. The resulting AEMs showed excellent film-forming ability with reasonable tensile strengths of 18.7 MPã31.8 MPa and high elongation at break of 21.2%–133.3%. Owing to the well-developed microphase-separated morphology and increased water uptake, the AEMs with a low ion exchange capacity of 0.95 meq./g displayed the hydroxide conductivity of 32.3 mS/cm at 20 °C. After immersion in 1 M NaOH at 80 °C for 1248 h, the initial conductivity was maintained by 37.1%–47.9%, and the degradation mechanism was explored by model imidazolium cations investigation. In addition, the Im-PEG-PPO-70 membrane having the highest conductivity was fabricated into membrane electrode assembly, exhibiting a peak power density of 179 mW/cm2 at 60 °C in a single H2/O2 alkaline fuel cell. A short-term life test on this MEA under 200 mA/cm2 showed a performance decay rate of 2.3 mV/h over 100 h of operation.

Solid dispersions of quercetin-PEG matrices: Miscibility prediction, preparation and characterization

Quercetin is a bioflavonoid compound with low water solubility in both foods and the gastrointestinal tract, which limits the exploitation of its health-promoting properties. This study aims to formulate solid dispersions (SDs) of quercetin with hydrophilic polyethylene glycol PEG matrices, using the melt-mixing method, to improve the dissolution and antioxidant activity of quercetin. Initially, the total Gibbs free energy for different binary mixtures was modelled to predict the miscibility of the compounds. Then, the physicochemical properties of the formulated SDs were characterised and dissolution tests and antioxidant activity measurements were performed in vitro to evaluate the improved profiles and antioxidant activity of the SDs developed. The group contribution methods of Hoy and Van Krevelen and Hoftyzer, used for PEG solubility parameter calculations, presented a suitable prediction of interaction and miscibility behaviour. The results suggested the presence of amorphous quercetin precipitates in the crystalline matrix of PEG 4000 and PEG 6000, and the formation of an amorphous SD between quercetin and PEG 1000. These formulations achieved good radical scavenging activity and better dissolution, especially the quercetin-PEG 1000 SDs.