Bifunctional Poly Research Articles

U-disk portable photoelectrochemical sensor based on bifunctional poly(o-phenylenediamine) for on-site detection of erythromycin

Developing portable sensing platform with robust signal intensity is essential for on-site detection. Here, a bifunctional poly(o-phenylenediamine) (PoPD)-involved portable photoelectrochemical (PEC) sensor is proposed for detecting erythromycin (Ery). Firstly, the PoPD polymer-semiconductor acts as a molecularly imprinted polymer for specific recognition of Ery and simultaneously serves as a key PEC-active component for constructing WSe2−x nanosheets/PoPD p–n heterojunction to enhance the PEC response. Secondly, a greatly simplified PEC sensing platform is developed utilizing a household flashlight and a lightweight U-disk workstation that connects to a smartphone via Bluetooth. The portable PEC sensor achieves high sensitivity with an excellent linear relationship in the range of 0.01–200 μM. It has a low detection limit of 3.9×10−3 μM (S/N = 3) and exhibits great stability, selectivity, and reproducibility. This work not only highlights the use of photoactive polymer semiconductors in the design of novel signal-enhancement PEC sensors, but also showcases an efficient portable sensing platform for potential on-site and real-time detection.

Pyridinium and trifluoromethanesulfonate bifunctional poly(ionic liquid)s for highly efficient and selective adsorption of anionic dyes

The efficient and selective removal of dyes from polluted water by low cost, durable, sustainable, and reusable adsorptions remain challenges. In this study, a pyridinium and trifluoromethanesulfonate bifunctional poly(ionic liquid)s, named Py-CF3SO3-PIL was prepared by co-polymerization of 4-vinyl pyridine (4VP), divinylbenzene (DVB) and styrene (ST), followed by quaternization with 1-bromobutane and anion exchange with lithium trifluoromethanesulfonate. The resulting bifunctional Py-CF3SO3-PIL exhibited remarkable adsorption capacity (2192 mg g−1) and efficiency (within 10 min) for selective removal (>99.9%) of methyl orange (MO) from (mixed) dye solutions. The superior adsorption capacity and selectivity of Py-CF3SO3-PIL towards the removal of MO was attributed to the strong electrostatic interactions and π-π stacking interaction between the adsorbent and MO dye. Detailed kinetic studies, adsorption isotherms, and thermodynamic experiments revealed an endothermic monolayer chemical adsorption mechanism of MO on Py-CF3SO3-PIL, which is perfectly matched with the Langmuir isotherm model (R2 > 0.999). Importantly, the Py-CF3SO3-PIL could be easily collected and regenerated for multiple repeated uses, highlighting its reusability. The exceptional adsorption capacity and selectivity towards anionic dyes make Py-CF3SO3-PIL a promising candidate for dye separation applications. Our findings will contribute to the rational design of functional poly(ionic liquid)s-based adsorbents for water purification.

Synthesis and Characterization of ABA-Type Triblock Copolymers Using Novel Bifunctional PS, PMMA, and PCL Macroinitiators Bearing p-xylene-bis(2-mercaptoethyloxy) Core.

Syntheses of novel bifunctional poly(methyl methacrylate) (PMMA)-, poly(styrene) (PS)-, and (poly ε-caprolactone) (PCL)-based atom transfer radical polymerization (ATRP) macroinitiators derived from p-xylene-bis(1-hydroxy-3-thia-propanoloxy) core were carried out to obtain ABA-type block copolymers. Firstly, a novel bifunctional ATRP initiator, 1,4-phenylenebis(methylene-thioethane-2,1-diyl)bis(2-bromo-2-methylpropanoat) (PXTBR), synthesized the reaction of p-xylene-bis(1-hydroxy-3-thia-propane) (PXTOH) with α-bromoisobutryl bromide. The PMMA and PS macroinitiators were prepared by ATRP of methyl methacrylate (MMA) and styrene (S) as monomers using (PXTBR) as the initiator and copper(I) bromide/N,N,N',N″,N″-pentamethyldiethylenetriamine (CuBr/PMDETA) as a catalyst system. Secondly, di(α-bromoester) end-functionalized PCL-based ATRP macronitiator (PXTPCLBr) was prepared by esterification of hydroxyl end groups of PCL-diol (PXTPCLOH) synthesized by Sn(Oct)2-catalyzed ring opening polymerization (ROP) of ε-CL in bulk using (PXTOH) as initiator. Finally, ABA-type block copolymers, PXT(PS-b-PMMA-b-PS), PXT(PMMA-b-PS-b-PMMA), PXT(PS-b-PCL-b-PS), and PXT(PMMA-b-PCL-b-PMMA), were synthesized by ATRP of MMA and S as monomers using PMMA-, PS-, and PCL-based macroinitiators in the presence of CuBr/PMDETA as the catalyst system in toluene or N,N-dimethylformamide (DMF) at different temperatures. In addition, the extraction abilities of PCL and PS were investigated under liquid-liquid phase conditions using heavy metal picrates (Ag+, Cd2+, Cu2+, Hg2+, Pb2+, and Zn2+) as substrates and measuring with UV-Vis the amounts of picrate in the 1,2-dichloroethane phase before and after treatment with the polymers. The extraction affinity of PXTPCL and PXTPS for Hg2+ was found to be highest in the liquid-liquid phase extraction experiments. Characterizations of the molecular structures for synthesized novel initiators, macroinitiators, and the block copolymers were made by spectroscopic (FT-IR, ESI-MS, 1H NMR, 13C NMR), DSC, TGA, chromatographic (GPC), and morphologic SEM.

Influence of Surface Ligand Density and Particle Size on the Penetration of the Blood-Brain Barrier by Porous Silicon Nanoparticles.

Overcoming the blood-brain barrier (BBB) remains a significant challenge with regard to drug delivery to the brain. By incorporating targeting ligands, and by carefully adjusting particle sizes, nanocarriers can be customized to improve drug delivery. Among these targeting ligands, transferrin stands out due to the high expression level of its receptor (i.e., transferrin receptor) on the BBB. Porous silicon nanoparticles (pSiNPs) are a promising drug nanocarrier to the brain due to their biodegradability, biocompatibility, and exceptional drug-loading capacity. However, an in-depth understanding of the optimal nanoparticle size and transferrin surface density, in order to maximize BBB penetration, is still lacking. To address this gap, a diverse library of pSiNPs was synthesized using bifunctional poly(ethylene glycol) linkers with methoxy or/and carboxyl terminal groups. These variations allowed us to explore different transferrin surface densities in addition to particle sizes. The effects of these parameters on the cellular association, uptake, and transcytosis in immortalized human brain microvascular endothelial cells (hCMEC/D3) were investigated using multiple in vitro systems of increasing degrees of complexity. These systems included the following: a 2D cell culture, a static Transwell model, and a dynamic BBB-on-a-chip model. Our results revealed the significant impact of both the ligand surface density and size of pSiNPs on their ability to penetrate the BBB, wherein intermediate-level transferrin densities and smaller pSiNPs exhibited the highest BBB transportation efficiency in vitro. Moreover, notable discrepancies emerged between the tested in vitro assays, further emphasizing the necessity of using more physiologically relevant assays, such as a microfluidic BBB-on-a-chip model, for nanocarrier testing and evaluation.

Synthetic Strategy for the Development of Conjugated Polyelectrolytes as Cathode Interfacial Layers: Toward Sustainable Organic Devices

AbstractThe use of conjugated polyelectrolytes (CPEs) as interfacial layers (ILs) to increase the efficiency of organic light‐emitting diodes (OLEDs), organic solar cells (OSCs), and organic transistors is a well‐established strategy. Here, the rational process is reported that led to develop the bifunctional poly[(2,7‐(9,9’‐bis(6’‐diethoxylphosphorylhexyl)‐fluorene)‐alt‐(2,7‐(9,9′‐bis(6″‐trimethylammonium bromide)hexyl)‐fluorene)] (PF‐NBr‐EP). PF‐NBr‐EP is successfully incorporated as a cathode IL (CIL) in diverse electronic and optoelectronic devices. The properties of two fluorene‐based CPEs containing, respectively, phosphonate (EP) and ammonium (NBr) moieties used as building blocks for the synthesis of the PF‐NBr‐EP copolymer and their mixtures are investigated to evaluate the combined effect of the two moieties and therefore to gain insight into the behavior of PF‐NBr‐EP chemical structure in the devices. Additionally, the performance of OLEDs and OSCs is analyzed based on established active layers, incorporating all these neat and mixed CILs.

One-step uranium extraction and brine desalination via adsorptive pervaporation by graphene-oxide scaffold membranes

The ocean reserves nearly four billion tons of uranium, providing an inexhaustible supply of nuclear energy if the limits of ultralow U(VI) concentration (3.3 µg·L−1) are addressed. Membrane technology is promising to make this happen by simultaneous U(VI) concentration and extraction. Herein, we report a pioneering adsorption-pervaporation membrane for efficient enrichment and capture of U(VI) along with clean water production. A bifunctional poly(dopamine–ethylenediamine) and graphene oxide 2D scaffold membrane was developed and further crosslinked by glutaraldehyde, capable of recovering over 70% U(VI) and water from simulated seawater brine, which validates the feasibility of one-step water recovery, brine concentration, and uranium extraction from seawater brine. Moreover, compared with other membranes and adsorbents, this membrane exhibits fast pervaporation desalination (flux: 153.3 kg·m−2·h−1, rejection: >99.99%) and excellent uranium capture properties of 228.6 mg·m−2 benefiting from plentiful functional groups provided by embedded poly(dopamine–ethylenediamine). This study aims to provide a strategy for recovering critical elements from the ocean.

Intermolecular Acid–Base‐Pairs Containing Poly (p‐Terphenyl‐co‐Isatin Piperidinium) for High Temperature Proton Exchange Membrane Fuel Cells

How to optimize and regulate the distribution of phosphoric acid in matrix, and pursuing the improved electrochemical performance and service lifetime of high temperature proton exchange membrane (HT‐PEMs) fuel cell are significant challenges. Herein, bifunctional poly (p‐terphenyl‐co‐isatin piperidinium) copolymer with tethered phosphonic acid (t‐PA) and intrinsic tertiary amine base groups are firstly prepared and investigated as HT‐PEMs. The distinctive architecture of the copolymer provides a well‐designed platform for rapid proton transport. Protons not only transports through the hydrogen bond network formed by the adsorbed free phosphoric acid (f‐PA) anchored by the tertiary amine base groups, but also rely upon the proton channel constructed by the ionic cluster formed by the t‐PA aggregation. Thorough the design of the structure, the bifunctional copolymers with lower PA uptake level (<100%) display prominent proton conductivities and peak power densities (99 mS cm−1, 812 mW cm−2 at 160 °C), along with lower PA leaching and higher voltage stability, which is a top leading result in disclosed literature. The results demonstrate that the design of intermolecular acid–base‐pairs can improve the proton conductivity without sacrificing the intrinsic chemical stability or mechanical property of the thin membrane, realizing win‐win demands between the mechanical robustness and electrochemical properties of HT‐PEMs.

Bi-functional phosphonium poly(ionic liquid)s catalyzed CO2-promoted hydration of ethylene oxide

The highly selective production of monoethylene glycol (MEG) from ethylene oxide (EO) is desirable at low H2O/EO molar ratio, however, the development of an efficient heterogeneous catalyst for the reaction is a challenge. Herein, a series of bi-functional poly(ionic liquid)s (BF-PILs) were successfully synthesized by radical copolymerization of polymerizable phosphonium/ammonium ionic liquids, N-vinyl imidazole and cross-linker divinylbenzene (DVB). The structure and thermal stability of BF-PILs were characterized by NMR, FT-IR, elemental analysis and TGA. These BF-PILs could be swollen in the H2O and MEG mixture and the swelling ratio (Q) increased with the increase of the MEG mole fraction. Under swelling in the H2O and MEG mixture (1:1), BF-PILs presented an irregular channel structure with the diameter of 1–20 μm observed by the cryo-scanning electron microscope (cryo-SEM). BF-PILs were applied to catalyze the CO2-promoted hydration of EO at a low H2O/EO ratio of 1.5:1. The catalytic activities of phosphonium BF-PILs were superior to ammonium BF-PILs, and poly[(Ph)3VBPBr-VIm] with the greatest Q in the H2O and MEG mixture (1:1) gave highest yield (96.1%) and selectivity (97.3%) of MEG. The CO2-promoted hydration of EO involved the cycloaddition of EO with CO2 to produce ethylene carbonate (EC), and followed by the hydrolysis of EC to produce MEG. Kinetic experiments confirmed that phosphonium ionic liquid species mainly catalyzed CO2 cycloaddition and imidazole catalyzed hydrolysis of EC. Furthermore, poly[(Ph)3VBPBr-VIm] exhibited good generality and could be reused up to eight times without significant decrease of its initial activity.

Innovative bifunctional heat storage nanocapsules containing polymerizable surfactant for antimicrobial thermoregulating clothes

Bifunctional poly(methyl methacrylate)/Rubitherms®27 (PMMA/RT27) nanocapsules were fabricated by miniemulsion polymerization using poly(2-methacryloyloxy dodecyl dimethyl ammonium chloride-4-allyloxy-2-hydroxy benzophenone)-block-polymethyl methacrylate-iodide (P(QAC12-BP)-b-PMMA-I) as a polymerizable surfactant. Approximately 50-nm spherical core-shell nanocapsules were formed with a highly positive surface charge (≥ +70 mV) derived from the quaternary ammonium (QA) groups in QAC12 units. The QA groups distributed on the nanocapsules’ surfaces effectively presented cationic characteristics and antimicrobial performance. High RT27 loading and encapsulation efficiency PMMA nanocapsules were produced using an MMA: RT27 ratio of 50: 50 with high latent heats of the encapsulated RT27, close to those of the pristine ones. Because of the existence of the BP unit in the polymerizable surfactant located on nanocapsules’ surfaces, the obtained nanocapsules were strongly coated on cotton fabrics by irradiation with UV light, giving them greater washing durability than using an external binder. The coated fabrics exhibited effective antimicrobial performance against S. epidermidis and C. glutamigum. Therefore, the fabricated PMMA/RT27 nanocapsules presenting thermoregulating and antimicrobial properties are well suited for application on textiles.

Bi-functional poly(vinylidene difluoride) coated Al anodes for highly rechargeable aqueous Al-ion batteries

Aqueous rechargeable aluminum (Al) ion batteries have attracted much attention due to the high abundance of Al metal and high volumetric energy density (8040 mAh cm−3). However, Al anode suffers from hydrogen evolution side reactions in aqueous electrolyte due to its low equilibrium redox potential. Here, we developed a poly(vinylidene difluoride) (PVDF) coating that can inhibit free H2O/O2 and alleviate the corrosion problem. Theoretical calculations verify that PVDF and Al3+ have a strong interaction through the F-Al bond towards the observed uniform Al deposition. As a result, the cell of PVDF-Al/K2CoFe(CN)6 achieved 98.2% Coulombic efficiency after 400 cycles at a current density of 100 mA g−1. This work presents an effective and facile strategy to the development of high-performance and low-cost aqueous Al-ion batteries.

Zwitterionic Bifunctional Layer for Reversible Zn Anode

A Zn metal anode suffers from severe dendrite issues and passive byproducts, which restrict the practical application of Zn-ion batteries. Herein, a bifunctional poly zwitterionic ionic liquid (PZIL) is designed as a new ion-migration layer to suppress Zn dendrites and side reactions. On one hand, the zwitterionic functional groups on the PZIL layer guide the Zn ion distribution to regulate the deposition behavior of Zn. On the other hand, the tight bond between zwitterionic groups and water molecules can build an H2O-poor interface on the surface of the Zn anode to avoid side reactions. Based on the above two functions, a symmetrical cell with the PZIL-layer-modified Zn exhibits a stable plating/stripping performance (2600 h at 1 mA cm–2) with low reversible deposition potential (∼50 mV). The concept of a zwitterionic bifunctional layer will open up a new avenue for reversible anodes for Zn-ion batteries as well as other battery systems.

Benignly-fabricated supramolecular poly(amidoxime)-alginate-poly(acrylic acid) beads synergistically enhance uranyl capture from seawater

Design of amidoxime-based adsorbents in a cooperative and synergistic manner together with a concept of facile and green fabrication is becoming highly desirable to harvest uranium from seawater. Herein, taking benefit of supramolecular ionic-crosslinking and hydrogen bonding interactions, we have reported a simple and environmentally benign approach to construct novel bifunctional poly(amidoxime)-alginate-poly(acrylic acid) (PAO-A-PAA) composite beads. As a result of synergistic uranyl binding, the PAO-A-PAA composite beads reached a high adsorption capacity of 735.1 mg g−1 for uranium aqueous solution (36 ppm), which is 2.24 and 1.46 times that of monofunctional Alg-PAA (328.1 mg g−1) and Alg-PAO (502.2 mg g−1), respectively. More importantly, the PAO-A-PAA exhibits excellent selectivity towards U(VI) in the presence of natural organic matter and multiple coexisting metal ions in simulated seawater. The XPS analysis reveals the utilization and coordination of both amidoxime and carboxylate ligands of PAO-A-PAA for uranyl binding, which results in energetically more stable synergistic uranyl complexes (Ebinding = −9.45 to −10.34 eV) as proved by the density functional theory study. The adsorption efficiency of PAO-A-PAA is further supported by its ability to extract µg L−1-level uranium in real seawater (94.7–99.5%). The PAO-A-PAA also demonstrates good mechanical and chemical stability over a wide pH range, as well as good reusability. These findings provide insight into the significance of designing efficient sorbent material for enhanced uranyl capture via a supramolecular strategy.

Preparation and Characterization of a Liver Targeted, Poly(amidoamine) Based, Gene Delivery System.

Nonalcoholic steatohepatitis (NASH) is an aggressive liver disease that is considered a major cause of liver cirrhosis and hepatocellular carcinoma. NASH is characterized by multiple underlying genetic mutations, with no approved cure to date. Gene therapies that target those genetic mutations may play a major role in treating this disease, once delivered specifically to the hepatocytes. In this chapter we present, in detail, the synthesis and the characterization of an efficient gene delivery system capable of targeting hepatocytes by exploiting the overexpression of asialoglycoprotein receptors on their cell surface. The targeting ligand, galactose derivative, lactobionic acid (Gal), is first conjugated to bifunctional poly(ethylene glycol) (PEG), and then the formed PEG-Gal is further conjugated to the positively charged polymer, poly(amidoamine) (PAMAM) to form a PAMAM-PEG-Gal construct that can complex and deliver genetic material (e.g., pDNA, siRNA, mRNA) specifically to hepatocytes. We first synthesize PAMAM-PEG-Gal using carbodiimide click chemistry. The synthesized conjugate is characterized using 1H NMR spectroscopy and mass spectrometry. Next, nanoplexes are prepared by combining the positively charged conjugate and the negatively charged genetic material at different nitrogen to phosphate (N/P) ratios; then the size, charge, electrophoretic mobility, and surface morphology of those nanoplexes are estimated. The simplicity of complexing our conjugate with any type of genetic material, the ability of our delivery system to overcome the current limitations of delivering naked genetic material, and the efficiency of delivering its payload specifically to hepatocytes, makes our formulation a promising tool to treat any type of genetic abnormality that arises in hepatocytes, and specifically NASH.

A Membrane‐Supported Bifunctional Poly(amidoxime‐ethyleneimine) Network for Enhanced Uranium Extraction from Seawater and Wastewater

Uranium extraction from natural seawater and wastewater are quintessential requirements to supply uninterrupted carbon-free nuclear energy and to prevent potential radiochemical and toxicological effects, respectively. Owing to the complexity and low-concentration uranium of these water samples, the design and synthesis of sorbent materials for uranium extraction with meaningful efficiencies remains a grand challenge. Herein, we reported a novel three-dimensional bifunctional network of hyperbranched poly(amidoxime-ethyleneimine) (PAO-h-PEI) using PEI as the skeleton material via cyanoethylation, crosslinking and then amidoximation. As a result of the synergistic supramolecular strategy, the PAO-h-PEI membrane achieved a remarkable adsorption capacity of 985.7 mg/g for aqueous uranium solution, which was 2.5 folds that of the monofunctional h-PEI membrane (387.6 mg/g). The PAO-h-PEI membrane also exhibited good selectivity towards uranium in the presence of various metal ions, high-content salt, and natural organic matter as well as common anions. According to the XPS and FTIR results, the utilization of amines as the second ligand enhanced uranyl binding by providing additional coordination sites or by interacting with oxime to force N-OH dissociation. The good reusability (adsorption rate of 93% after six adsorption-desorption cycles) and satisfactory adsorption performance in extracting low-concentration uranium in real seawater demonstrate its practicability.

Peroxovanadic based core-shell bifunctional poly(ionic liquid)s catalyst CuO/SiO2@V-PIL: Its in-situ free radical initiation mechanism for air oxidative desulfurization

Air oxidative desulfurization (ODS) is a green technology, and its catalytic activation or upgrading is necessary. Herein, air ODS performance is greatly enhanced through in-situ radical initiation on the interface of peroxovanadic based catalyst CuO/SiO2@V-PIL. The core-shell structure shortens the radical initiation period from 90 min to 40 min, and over 99.9% of desulfurization ratio, 91.5 % of cumene conversion, and 82.8% of cumene hydroperoxide (CHP) selectivity can be retained after 5 recycled uses. On the core-shell interface, V(O)2 is decomposed into oxygen radicals, which in-situ initiate formation of CHP using O2 outside the CuO, and is regenerated by the resultant CHP. Further, different alkylbenzenes in real diesel can be directly used as substituents of cumene. The present ODS process is perspective for industrial application, and the in-situ radical initiation mechanism may be applicable for oxidative removal of other heteroatom organic pollutants.

Bifunctional poly(ionic liquid) catalyst with dual-active-center for CO2 conversion: Synergistic effect of triazine and imidazolium motifs

Developing heterogeneous catalyst containing both CO2-philic groups and catalytic active sites is highly desirable for efficient CO2 chemical fixation. In this work, a triazine-functionalized poly(ionic liquid) (T-PIL) was designed and synthesized. This metal free catalyst showed extremely enhanced CO2 adsorption and improved catalytic ability for the cycloaddition reaction of CO2 without co-catalysts. Especially for the epoxides of large size and strong steric hindrance, the yields of the cyclic carbonates were improved up to three times in the presence of triazine motifs. An intramolecular synergistic mechanism of triazine and imidazolium motifs was proposed on the basis of density functional theory (DFT) calculations and diffused reflectance infrared Fourier transform spectroscopy (DRIFTS). The imidazolium groups with paired bromine anions acted as catalytic active sites and would enhance CO2 activation and the ring-opening of epoxides. While the triazine groups acting as CO2-philic groups could enhance the CO2 adsorption and activation. This work highlights that the incorporation of two motifs with synergistic effect in one catalyst can significantly improve its catalytic performance.

Photo- and Acid-Degradable Polyacylhydrazone-Doxorubicin Conjugates.

Light-mediated polymer degradation has attracted considerable attention in various applications, including photo-patterning, tissue engineering and photo-triggered drug delivery. In this study, we report the synthesis and characterization of a new, linear, main-chain photo- and acid-degradable copolymer based on acylhydrazone linkages. The polymer was synthesized via a step-growth copolymerization of adipic acid dihydrazide with a bifunctional poly(ethylene glycol) bearing benzaldehyde end-groups, under mild acidic conditions, to afford a hydrophilic PEG-alt-adipic acid (PEG-alt-AA) alternating copolymer. The synthesized polymer was characterized by size exclusion chromatography, proton nuclear magnetic resonance and attenuated total reflection-Fourier transform infrared spectroscopies. The main-chain photo- and acid-induced degradation of the copolymer in dimethylsulfoxide and water, respectively, was verified by UV-vis spectroscopy at light intensities as low as 0.1 mW cm−2 at λ = 254 nm. Next, a model anticancer drug, doxorubicin (DOX), was chemically linked to the polymer chain end(s) via acylhydrazone bond(s), resulting in amphiphilic PEG-alt-adipic acid-DOX (PEG-alt-AA-DOX) polymer–drug conjugates. The conjugates were self-assembled in water to form spherical nanoparticles, as evidenced by scanning and transmission electron microscopies. The irradiation of the self-assembled PEG-alt-AA-DOX conjugates with UV light and the decrease of the solution pH resulted in the disruption of the assemblies due to the photolysis and acidolysis of the acylhydrazone bonds, and the release of the therapeutic cargo.

Bifunctional poly (l-lactic acid)/hydrophobic silica nanocomposite layer coated on magnesium stents for enhancing corrosion resistance and endothelial cell responses

Biodegradable magnesium (Mg)-based vascular stents can overcome the limitations of conventional permanent metallic stents, such as late in-stent restenosis and thrombosis, but still have difficulty retarding degradation while providing adequate mechanical support to the blood vessel. We incorporated silica nanoparticles surface-functionalized with hexadecyltrimethoxysilane (mSiNP) into a poly (l-lactic acid) (PLLA) coating as a physical barrier to disturb the penetration of the corrosive medium as well as a bioactive source that releases silicon ions capable of stimulating endothelial cells. The corrosion resistance and biocompatibility of this bifunctional PLLA/mSiNP nanocomposite coating were investigated using different weight ratios of mSiNP. The nanocomposite coating containing more than 10 wt% of the mSiNP (PLLA/10mSiNP and PLLA/20mSiNP) significantly delayed the corrosion of the Mg substrate and exhibited favorable endothelial cell responses, compared to the pure PLLA coating. Specifically, the calculated corrosion rates of PLLA/10mSiNP and PLLA/20mSiNP decreased by half, indicating the durability of the coating after immersion in simulated body fluid for 12 days. Based on the in vitro cellular response, the incorporation of the mSiNPs into the PLLA coating significantly improved the endothelial cell responses to the Mg substrate, showing better initial cell surface coverage, migration, and proliferation rate than those of pure PLLA. These results indicate that the PLLA/mSiNP nanocomposite coatings have significant potential to improve the corrosion resistance and vascular compatibility of biodegradable Mg-based vascular stents.

PEG Linker Improves Antitumor Efficacy and Safety of Affibody-Based Drug Conjugates.

Antibody drug conjugates (ADCs) have become an important modality of clinical cancer treatment. However, traditional ADCs have some limitations, such as reduced permeability in solid tumors due to the high molecular weight of monoclonal antibodies, difficulty in preparation and heterogeneity of products due to the high drug/antibody ratio (4–8 small molecules per antibody). Miniaturized ADCs may be a potential solution, although their short circulation half-life may lead to new problems. In this study, we propose a novel design strategy for miniaturized ADCs in which drug molecules and small ligand proteins are site-specifically coupled via a bifunctional poly(ethylene glycol) (PEG) chain. The results showed that the inserted PEG chains significantly prolonged the circulation half-life but also obviously reduced the cytotoxicity of the conjugates. Compared with the conjugate ZHER2-SMCC-MMAE (HM), which has no PEG insertion, ZHER2-PEG4K-MMAE (HP4KM) and ZHER2-PEG10K-MMAE (HP10KM) with 4 or 10 kDa PEG insertions have 2.5- and 11.2-fold half-life extensions and 4.5- and 22-fold in vitro cytotoxicity reductions, respectively. The combined effect leads to HP10KM having the most ideal tumor therapeutic ability at the same dosages in the animal model, and its off-target toxicity was also reduced by more than 4 times compared with that of HM. These results may indicate that prolonging the half-life is very helpful in improving the therapeutic capacity of miniaturized ADCs. In the future, the design of better strategies that can prolong half-life without affecting cytotoxicity may be useful for further improving the therapeutic potential of these molecules.

Efficient fixation of CO2 into carbonates by tertiary N-functionalized poly(ionic liquids): Experimental-theoretical investigation

The efficiency and versatility of catalysts in the multi-step reaction of carbonates with carbon dioxide (CO2) as raw material are barely satisfactory. Herein, ternary copolymerized bifunctional poly(ionic liquid)s (TBPILs) rich in hydroxyls, halogen anions and tertiary N were fabricated via free radical copolymerization. Due to the ingenious modification of tertiary N in the polymeric framework to form multi-site activation with hydroxyls and halogen anions, the specific activity of TBPILs reached to 17.87 mmolSC m−2catal h−1 in CO2 cycloaddition reaction. Meanwhile, for the transesterification reaction of cyclic carbonates with methanol, by the introduction of tertiary N, the yield of dimethyl carbonate increased from trace to 80.31 % in the absence of any solvent or co-catalyst. Density functional theory calculations, combined with electrostatic potential and average local ionization energy analyses confirmed the dual roles of tertiary N in the formation of carbonates by CO2. This work provides an originality idea to design high-efficiency catalysts for CO2 insertion into carbonates, and study the effects of basic sites on CO2 conversion.