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1.
Inorg Chem ; 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39058891

RESUMEN

One-dimensional (1D) perovskites (perovskitoids) occupy an important place among modern semiconducting materials, offering design flexibility together with a wide range of properties. However, most such materials have a large bandgap, which limits their application in photovoltaics. Here, we present a new 1D hybrid perovskite containing the functional cation aminophenyl viologen (APhV). Similar to other materials from the viologen perovskite family, aminophenyl viologen iodidoplumbate(II) (APhV[Pb2I6]·2NMP) exhibits a broad absorption with a narrow and direct bandgap of 1.66 eV, which was calculated from the experimental data and is supported also by our first-principles simulations. Close contact between electron-rich inorganic chains and electron-accepting viologen molecules suggests charge transfer within the hybrid, which is also visible in the density of states. Considering its reasonable thermal stability, aminophenyl viologen iodidoplumbate can find a wide application in photovoltaics.

2.
Int J Mol Sci ; 25(3)2024 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-38338873

RESUMEN

State-of-the-art Li batteries suffer from serious safety hazards caused by the reactivity of lithium and the flammable nature of liquid electrolytes. This work develops highly efficient solid-state electrolytes consisting of imidazolium-containing polyionic liquids (PILs) and lithium bis(trifluoromethane sulfonyl)imide (LiTFSI). By employing PIL/LiTFSI electrolyte membranes blended with poly(propylene carbonate) (PPC), we addressed the problem of combining ionic conductivity and mechanical properties in one material. It was found that PPC acts as a mechanically reinforcing component that does not reduce but even enhances the ionic conductivity. While pure PILs are liquids, the tricomponent PPC/PIL/LiTFSI blends are rubber-like materials with a Young's modulus in the range of 100 MPa. The high mechanical strength of the material enables fabrication of mechanically robust free-standing membranes. The tricomponent PPC/PIL/LiTFSI membranes have an ionic conductivity of 10-6 S·cm-1 at room temperature, exhibiting conductivity that is two orders of magnitude greater than bicomponent PPC/LiTFSI membranes. At 60 °C, the conductivity of PPC/PIL/LiTFSI membranes increases to 10-5 S·cm-1 and further increases to 10-3 S·cm-1 in the presence of plasticizers. Cyclic voltammetry measurements reveal good electrochemical stability of the tricomponent PIL/PPC/LiTFSI membrane that potentially ranges from 0 to 4.5 V vs. Li/Li+. The mechanically reinforced membranes developed in this work are promising electrolytes for potential applications in solid-state batteries.


Asunto(s)
Líquidos Iónicos , Propano/análogos & derivados , Litio , Electrólitos , Iones , Poli A , Polímeros
3.
Angew Chem Int Ed Engl ; : e202407472, 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38847278

RESUMEN

The membranization of membrane-less coacervates paves the way for the exploitation of complex protocells with regard to structural and cell-like functional behaviors. However, the controlled transformation from membranized coacervates to vesicles remains a challenge. This can provide stable (multi)phase and (multi)compartmental architectures through the reconfiguration of coacervate droplets in the presence of (bioactive) polymers, bio(macro)molecules and/or nanoobjects. Herein, we present a continuous protocell transformation from membrane-less coacervates to membranized coacervates and, ultimately, to giant hybrid vesicles. This transformation process is orchestrated by altering the balance of non-covalent interactions through varying concentrations of an anionic terpolymer, leading to dynamic processes such as spontaneous membranization of terpolymer nanoparticles at the coacervate surface, disassembly of the coacervate phase mediated by the excess anionic charge, and the redistribution of coacervate components in membrane. The diverse protocells during the transformation course provide distinct structural features and molecular permeability. Notably, the introduction of multiphase coacervates in this continuous transformation process signifies advancements toward the creation of synthetic cells with different diffusible compartments. Our findings emphasize the highly controlled continuous structural reorganization of coacervate protocells and represents a novel step toward the development of advanced and sophisticated synthetic protocells with more precise compositions and complex (membrane) structures.

4.
Adv Funct Mater ; 33(50)2023 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-38344241

RESUMEN

The intricate nature of eukaryotic cells with differently viscous intracellular compartments provides (membrane-active) enzymes to trigger time- and concentration-dependent processes in the intra-/extracellular matrix. Herein, we capitalize on membrane-active artificial organelles (AOs) to develop fluidic and stable proteinaceous membrane-based protocells. AOs in protocells induce the self-assembly of oligopeptides into an artificial cytoskeleton that underline their influence on the structure and functionality of protocells. A series of microscopical tools is used to validate the intracellular assembly and distribution of cytoskeleton, the changing protocells morphology, and AOs inclusion within cytoskeletal growth. Thus, the dynamics, diffusion and viscosity of intracellular components in the presence of cytoskeleton are evaluated by fluorescence tools and enzymatic assay. Membrane-active alkaline phosphatase in polymersomes as AOs fulfills the requirements of biomimetic eukaryotic cells to trigger intracellular environment, mobility, viscosity, diffusion and enzymatic activity itself as well as high mechanical stability and high membrane fluidity of protocells. Thus membrane-active AOs in protocells thoroughly provide a variable reaction space in a changing intracellular environment and underline their regulatory role in the fabrication of complex protocell architectures and functions. This study demonstrates an important contribution to effective biomimicry of cell-like structures, shapes and functions.

5.
Biomacromolecules ; 24(6): 2489-2500, 2023 06 12.
Artículo en Inglés | MEDLINE | ID: mdl-37253064

RESUMEN

Structures and functions of eukaryotic cells with an outer permeable membrane, a cytoskeleton, functional organelles, and motility can be mimicked by giant multicompartment protocells containing various synthetic organelles. Herein, two kinds of artificial organelles with stimuli-triggered regulation ability, glucose oxidase-(GOx)-loaded pH-responsive polymersomes A (GOx-Psomes A) and urease-loaded pH-responsive polymersomes B (Urease-Psomes B), and a pH-sensor (Dextran-FITC) are encapsulated into proteinosomes via the Pickering emulsion method. Thus, a polymersomes-in-proteinosome system is constructed which is able to probe biomimetic pH homeostasis. Alternating fuels (glucose or urea) introduced from outside the protocell penetrate the membrane of proteinosomes and enter into GOx-Psomes A and Urease-Psomes B to produce chemical signals (gluconic acid or ammonia) resulting in pH-feedback loops (pH jump and pH drop). This will counteract the catalytic "switch on" or "switch off" of enzyme-loaded Psomes A and B owing to their different pH-responsive membranes. Dextran-FITC in the proteinosome allows self-monitoring of slight pH fluctuations in the lumen of protocells. Overall, this approach shows heterogeneous polymersome-in-proteinosome architectures with sophisticated features such as input-regulated pH changes mediated by negative and positive feedback in loops and cytosolic pH self-monitoring, features that are imperative for advanced protocell design.


Asunto(s)
Dextranos , Ureasa , Citosol , Fluoresceína-5-Isotiocianato , Dextranos/química , Retroalimentación , Biomimética , Concentración de Iones de Hidrógeno
6.
Biomacromolecules ; 24(12): 5797-5806, 2023 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-37939018

RESUMEN

Amyloid ß peptide can aggregate into thin ß-sheet fibrils or plaques deposited on the extracellular matrix, which is the hallmark of Alzheimer's disease. Multifunctional macromolecular structures play an important role in inhibiting the aggregate formation of amyloidogenic materials and thus are promising candidates with antiamyloidogenic characteristics for the development of next-generation therapeutics. In this study, we evaluate how small differences in the dendritic topology of these structures influence their antiamyloidogenic activity by the comparison of "perfectly dendritic" and "pseudodendritic" macromolecules, both decorated with mannose units. Their compactness, the position of surface units, and the size of glyco-architectures influence their antiamyloidogenic activity against Aß 40, a major component of amyloid plaques. For the advanced analysis of the aggregation of the Aß peptide, we introduce asymmetric flow field flow fractionation as a suitable method for the quantification of large and delicate structures. This alternative method focuses on the quantification of complex aggregates of Aß 40 and glycodendrimer/glyco-pseudodendrimer over different time intervals of incubation, showing a good correlation to ThT assay and CD spectroscopy results. Kinetic studies of the second-generation glyco-pseudodendrimer revealed maximum inhibition of Aß 40 aggregates, verified with atomic force microscopy. The second-generation glyco-pseudodendrimer shows the best antiamyloidogenic properties confirming that macromolecular conformation in combination with optimal functional group distribution is the key to its performance. These molecular properties were validated and confirmed by molecular dynamics simulation.


Asunto(s)
Enfermedad de Alzheimer , Péptidos beta-Amiloides , Humanos , Péptidos beta-Amiloides/química , Cinética , Simulación de Dinámica Molecular , Estructura Molecular , Sustancias Macromoleculares , Fragmentos de Péptidos/química
7.
Biomacromolecules ; 24(12): 5807-5822, 2023 12 11.
Artículo en Inglés | MEDLINE | ID: mdl-37984848

RESUMEN

In recent years, there has been growing attention to designing synthetic protocells, capable of mimicking micrometric and multicompartmental structures and highly complex physicochemical and biological processes with spatiotemporal control. Controlling metabolism-like cascade reactions in coacervate protocells is still challenging since signal transduction has to be involved in sequential and parallelized actions mediated by a pH change. Herein, we report the hierarchical construction of membraneless and multicompartmentalized protocells composed of (i) a cytosol-like scaffold based on complex coacervate droplets stable under flow conditions, (ii) enzyme-active artificial organelles and a substrate nanoreservoir capable of triggering a cascade reaction between them in response to a pH increase, and (iii) a signal transduction component based on the urease enzyme capable of the conversion of an exogenous biological fuel (urea) into an endogenous signal (ammonia and pH increase). Overall, this strategy allows a synergistic communication between their components within the membraneless and multicompartment protocells and, thus, metabolism-like enzymatic cascade reactions. This signal communication is transmitted through a scaffold protocell from an "inactive state" (nonfluorescent protocell) to an "active state" (fluorescent protocell capable of consuming stored metabolites).


Asunto(s)
Células Artificiales , Células Artificiales/química , Células Artificiales/metabolismo , Transducción de Señal
8.
Macromol Rapid Commun ; 44(16): e2200885, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36755359

RESUMEN

Various cellular functions are successfully mimicked, opening the door to the next generation of therapeutic approaches and systems biology. Herein, the first steps are taken toward the construction of artificial organelles for mimicking cell communication by docking and undocking of cargo in the membrane of swollen artificial organelles. Stimuli-responsive and crosslinked polymeric vesicles are used to allow docking processes at acidic pH at which ferrocene units in the swollen membrane state can undergo desired specific host-guest interaction using ß-cyclodextrin as model cargo. The release of the cargo mediated by two different enzymes, glucose oxidase and α-amylase, is investigated, triggered by distinct enzymatic undocking mechanisms. Different release times for a useful transport are shown that can be adapted to different communication pathways. In addition, Förster resonance energy transfer (FRET) experiments further support the hypotheses of host-guest inclusion complexation formation and their time-dependent breakdown. This work paves a way to a platform based on polymeric vesicles for synthetic biology, cell functions mimicking, and the construction of multifunctional cargo delivery system.


Asunto(s)
Células Artificiales , Polímeros
9.
Macromol Rapid Commun ; 44(16): e2200869, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-36702804

RESUMEN

The integration of microscopic hydrogels with high specific surface area and physically reactive groups into microfluidic systems for selective molecular interactions is attracting increasing attention. Herein, the reversible capture and release of molecules through host-guest interactions of hydrogel dots in a microfluidic device is reported, which translates the supramolecular chemistry to the microscale conditions under continuous flow. Polyacrylamide (PAAm) hydrogel arrays with grafted ß-cyclodextrin (ß-CD)  modified poly(2-methyl-2-oxazoline) (CD-PMOXA) chains are fabricated by photopolymerization and integrated into a polydimethylsiloxane (PDMS)-on-glass chip. The ß-CD/adamantane (ß-CD/Ada) host-guest complex is confirmed by two dimensional Nuclear Overhauser Effect Spectroscopy NMR (2D NOESY NMR) prior to transfer to microfluidics. Ada-modified molecules are successfully captured by host-guest interaction formed between the CD-PMOXA grafted chains in the hydrogel network and the guest molecule in the solution. Furthermore, the captured molecules are released by perfusing free ß-CD with higher binding affinity than those grafted in the hydrogel array. A small guest molecule adamantane-fluorescein-isothiocyanate (Ada-FITC) and a macromolecular guest molecule (Ada-PMOXA-Cyanine 5 (Cy5)) are separately captured and released for three times with a release ratio up to 46% and 92%, respectively. The reproducible capture and release of functional molecules with different sizes demonstrates the stability of this hydrogel system in microfluidics and will provide an opportunity for future applications.


Asunto(s)
Adamantano , Ciclodextrinas , Hidrogeles/química , Microfluídica , Ciclodextrinas/química , Sustancias Macromoleculares/química , Adamantano/química
10.
Biomacromolecules ; 23(9): 3648-3662, 2022 09 12.
Artículo en Inglés | MEDLINE | ID: mdl-35981858

RESUMEN

Most sophisticated biological functions and features of cells are based on self-organization, and the coordination and connection between their cell organelles determines their key functions. Therefore, spatially ordered and controllable self-assembly of polymersomes to construct clusters to simulate complex intracellular biological functions has attracted widespread attention. Here, we present a simple one-step copper-free click strategy to cross-link nanoscale pH-responsive and photo-cross-linked polymersomes (less than 100 nm) to micron-level clusters (more than 90% in 0.5-2 µm range). Various influencing factors in the clustering process and subsequent purification methods were studied to obtain optimal clustered polymeric vesicles. Even when polymeric vesicles separately loaded with different enzymes (glucose oxidase and myoglobin) are coclustered, the overall permeability of the clusters can still be regulated through tuning the pH values on demand. Compared with simple blending of those enzyme-loaded polymersomes, the rate of enzymatic cascade reaction increased significantly due to the interconnected complex microstructure established. The connection of catalytic nanocompartments into clusters confining different enzymes of a cascade reaction provides an excellent platform for the development of artificial systems mimicking natural organelles or cells.


Asunto(s)
Células Artificiales , Análisis por Conglomerados , Glucosa Oxidasa , Concentración de Iones de Hidrógeno , Polímeros/química
11.
Biomacromolecules ; 23(11): 4655-4667, 2022 11 14.
Artículo en Inglés | MEDLINE | ID: mdl-36215725

RESUMEN

The development of compartments for the design of cascade reactions in a local space requires a selective spatiotemporal control. The combination of enzyme-loaded polymersomes with enzymelike units shows a great potential in further refining the diffusion barrier and the type of reactions in nanoreactors. Herein, pH-responsive and ferrocene-containing block copolymers were synthesized to realize pH-stable and multiresponsive polymersomes. Permeable membrane, peroxidase-like behavior induced by the redox-responsive ferrocene moieties and release properties were validated using cyclovoltammetry, dye TMB assay, and rupture of host-guest interactions with ß-cyclodextrin, respectively. Due to the incorporation of different block copolymers, the membrane permeability of glucose oxidase-loaded polymersomes was changed by increasing extracellular glucose concentration and in TMB assay, allowing for the chemoenzymatic cascade reaction. This study presents a potent synthetic, multiresponsive nanoreactor platform with tunable (e.g., redox-responsive) membrane properties for potential application in therapeutics.


Asunto(s)
Peróxido de Hidrógeno , Polímeros , Metalocenos , Concentración de Iones de Hidrógeno , Polímeros/farmacología , Oxidación-Reducción , Peroxidasas
12.
Small ; 17(7): e2005749, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33373089

RESUMEN

The eukaryotic cell is a smart compartment containing an outer permeable membrane, a cytoskeleton, and functional organelles, presenting part structures for life. The integration of membrane-containing artificial organelles (=polymersomes) into a large microcompartment is a key step towards the establishment of exquisite cellular biomimetics with different membrane properties. Herein, an efficient way to construct a hierarchical multicompartment composed of a hydrogel-filled proteinosome hybrid structure with an outer homogeneous membrane, a smart cytoskeleton-like scaffold, and polymersomes is designed. Specially, this hybrid structure creates a micro-environment for pH-responsive polymersomes to execute a desired substance transport upon response to biological stimuli. Within the dynamic pH-stable skeleton of the protein hydrogels, polymersomes with loaded PEGylated insulin biomacromolecules demonstrate a pH-responsive reversible swelling-deswelling and a desirable, on-demand cargo release which is induced by the enzymatic oxidation of glucose to gluconic acid. This stimulus responsive behavior is realized by tunable on/off states through protonation of the polymersomes membrane under the enzymatic reaction of glucose oxidase, integrated in the skeleton of protein hydrogels. The integration of polymersomes-based hybrid structure into the proteinosome compartment and the stimuli-response on enzyme reactions fulfills the requirements of eukaryotic cell biomimetics in complex architectures and allows mimicking cellular transportation processes.


Asunto(s)
Biomimética , Polímeros , Células Eucariotas , Glucosa Oxidasa , Hidrogeles
13.
Macromol Rapid Commun ; 42(13): e2100083, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34048124

RESUMEN

For the local treatment of bone defects, highly adaptable macromolecular architectures are still required as drug delivery system (DDS) in solid bone substitute materials. Novel DDS fabricated by host-guest interactions between ß-cyclodextrin-modified dendritic glycopolymers and adamantane-modified temperature-sensitive polymers for the proteasome inhibitor bortezomib (BZM) is presented. These DDS induce a short- and long-term (up to two weeks) retarded release of BZM from calcium phosphate bone cement (CPC) in comparison to a burst release of the drug alone. Different release parameters of BZM/DDS/CPC are evaluated in phosphate buffer at 37 °C to further improve the long-term retarded release of BZM. This is achieved by increasing the amount of drug (50-100 µg) and/or DDS (100-400 µg) versus CPC (1 g), by adapting the complexes better to the porous bone cement environment, and by applying molar ratios of excess BZM toward DDS with 1:10, 1:25, and 1:100. The temperature-sensitive polymer shells of BZM/DDS complexes in CPC, which allow drug loading at room temperature but are collapsed at body temperature, support the retarding long-term release of BZM from DDS/CPC. Thus, the concept of temperature-sensitive DDS for BZM/DDS complexes in CPC works and matches key points for a local therapy of osteolytic bone lesions.


Asunto(s)
Cementos para Huesos , Inhibidores de Proteasoma , Bortezomib/farmacología , Fosfatos de Calcio , Sistemas de Liberación de Medicamentos , Temperatura
14.
J Phys Chem A ; 125(6): 1345-1354, 2021 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-33555196

RESUMEN

Materials exhibiting thermally activated delayed fluorescence (TADF) have been extensively explored in the last decade. These emitters have great potential of being used in organic light-emitting diodes because they allow for high quantum efficiencies by utilizing triplet states via reverse intersystem crossing. In small molecules, this is done by spatially separating the highest occupied molecular orbital from the lowest unoccupied molecular orbital, forming an intramolecular charge-transfer (iCT) state and leading to a small energy difference between lowest excited singlet and triplet states (ΔEST). However, in polymer emitters, this is harder to achieve, and typical strategies usually include adding known TADF units as sidechains onto a polymer backbone. In a previous work, we proposed an alternative way to achieve a TADF polymer by repeating a non-TADF unit, polymerizing it via electron-donating carbazole moieties. The extended conjugation on the backbone reduced the ΔEST and allowed for an efficient TADF polymer. In this work, we present a more in-depth study of the shift from a non-TADF monomer to TADF oligomers. The monomer shows non-TADF emission, and we find the delayed emission to be of triplet-triplet annihilation origin. An iCT state is formed already in the dimer, leading to a much more efficient TADF emission. This is confirmed by an almost two-fold increase of photoluminescence quantum yield, a decrease in the delayed luminescence lifetime, and the respective spectral lineshapes of the molecules.

15.
Small ; 16(37): e2002135, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32783385

RESUMEN

Temporal activation of biological processes by visible light and subsequent return to an inactive state in the absence of light is an essential characteristic of photoreceptor cells. Inspired by these phenomena, light-responsive materials are very attractive due to the high spatiotemporal control of light irradiation, with light being able to precisely orchestrate processes repeatedly over many cycles. Herein, it is reported that light-driven proton transfer triggered by a merocyanine-based photoacid can be used to modulate the permeability of pH-responsive polymersomes through cyclic, temporally controlled protonation and deprotonation of the polymersome membrane. The membranes can undergo repeated light-driven swelling-contraction cycles without losing functional effectiveness. When applied to enzyme loaded-nanoreactors, this membrane responsiveness is used for the reversible control of enzymatic reactions. This combination of the merocyanine-based photoacid and pH-switchable nanoreactors results in rapidly responding and versatile supramolecular systems successfully used to switch enzymatic reactions ON and OFF on demand.


Asunto(s)
Polímeros , Protones , Nanotecnología , Permeabilidad
16.
Biomacromolecules ; 21(12): 5162-5172, 2020 12 14.
Artículo en Inglés | MEDLINE | ID: mdl-33180486

RESUMEN

To mimic organelles and cells and to construct next-generation therapeutics, asymmetric functionalization and location of proteins for artificial vesicles is thoroughly needed to emphasize the complex interplay of biological units and systems through spatially separated and spatiotemporal controlled actions, release, and communications. For the challenge of vesicle (= polymersome) construction, the membrane permeability and the location of the cargo are important key characteristics that determine their potential applications. Herein, an in situ and post loading process of avidin in pH-responsive and photo-cross-linked polymersomes is developed and characterized. First, loading efficiency, main location (inside, lumen, outside), and release of avidin under different conditions have been validated, including the pH-stable presence of avidin in polymersomes' membrane outside and inside. This advantageous approach allows us to selectively functionalize the outer and inner membranes as well as the lumen with several bio(macro)molecules, generally suited for the construction of asymmetrically functionalized artificial organelles. In addition, a fluorescence resonance energy transfer (FRET) effect was used to study the permeability or uptake of the polymersome membrane against a broad range of biotinylated (macro)molecules (different typology, sizes, and shapes) under different conditions.


Asunto(s)
Avidina , Polímeros , Concentración de Iones de Hidrógeno , Permeabilidad
17.
Biomacromolecules ; 21(1): 199-213, 2020 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-31619036

RESUMEN

While personalized therapy bears an enormous potential in cancer therapy, the development of flexible, tailorable delivery systems remains challenging. Here, we present a "tool-kit" of various avidin-based bioconjugates (BCs) for the preparation of personalized delivery systems. Corresponding BCs were synthesized using the self-assembly of avidin with various biotinylated ligands, such as one cationic glycodendrimer for dendriplex adsorption and two functional ligands for imaging (glycodendrimers with DOTA or NOTA units) or targeting (biotinylated PEG decorated with ligands). Substituting antibodies for targeting small molecules were coupled to biotin-PEG compounds for addressing the folate receptor (FR), epidermal growth factor receptor (EGFR), and prostate-specific membrane antigen (PSMA). After successful characterization and proof of good storage and redispersion properties of BCs, cytotoxicity assays and first in vivo imaging studies with 99mTc-complexing bioconjugates provide evidence that these BCs and their avidin analogues can be used as tool-kit components in theranostic systems for personalized medicine.


Asunto(s)
Quelantes/química , Medios de Contraste/química , Péptidos/química , Animales , Antígenos de Superficie/metabolismo , Avidina/química , Biotina/química , Dendrímeros/química , Diagnóstico por Imagen , Receptores ErbB/metabolismo , Ácido Fólico/química , Glutamato Carboxipeptidasa II/metabolismo , Células HEK293 , Compuestos Heterocíclicos con 1 Anillo/química , Humanos , Masculino , Ratones Endogámicos BALB C , Terapia Molecular Dirigida/métodos , Nanomedicina/métodos , Polietilenglicoles/química , Neoplasias de la Próstata/tratamiento farmacológico , Ensayos Antitumor por Modelo de Xenoinjerto
18.
Soft Matter ; 16(29): 6733-6742, 2020 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-32588870

RESUMEN

We report a novel double cross-linked hydrogel system based on polyacrylamide and poly(2-methyl-2-oxazoline) (PMOXA) network chains, as well as on supramolecular host-guest interactions with on-demand tailored mechanical properties. Well-defined vinyl-bearing PMOXA macromonomers, functionalized with either ß-cyclodextrin units (ß-CD-PMOXA) or adamantane units (Ada-PMOXA), were synthesized and confirmed using 1H NMR, MALDI-TOF-MS and GPC measurements. The complexation between adamantane and ß-CD modified macromonomers in solution towards bismacromonomers was confirmed by 2D NOESY NMR and DLS. After introducing these bismacromonomers into the polyacrylamide hydrogel, the supramolecular non-covalent Ada/ß-CD bond was responsible for the presence of PMOXA network chains to form a dense network. Once the interactions broke, the PMOXA chains no longer contributed to the network, but became dangling graft side chains in a predominated polyacrylamide network. Their dissociative nature influenced the physical properties, including the swelling behavior and mechanics of the final hydrogel. Rheological experiments proved that the E-modulus of the network was significantly increased by the supramolecular host-guest interactions. Tuning the lengths of PMOXA network chains even allowed the modification of the changes in mechanical strength, also through the addition of free ß-CD. The tunable properties of the double cross-linked supramolecular hydrogel proved their unique strength for future applications.

19.
Macromol Rapid Commun ; 41(1): e1900521, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31788895

RESUMEN

A Pd/Pt-Bu3 catalyst having bulky, electron-rich ligands significantly outperforms conventional "step-growth catalysts" Pd(PPh3 )4 and Pd(Po-Tol3 )3 in the Suzuki polycondensation of the AB-type arylene-based monomers, such as some of the substituted fluorenes, carbazoles, and phenylenes. In the AA+BB polycondensation, Pd/Pt-Bu3 also performs better under homogeneous reaction conditions, in combination with the organic base Et4 NOH. The superior performance of Pd/Pt-Bu3 is discussed in terms of its higher reactivity in the oxidative addition step and inherent advantages of the intramolecular catalyst transfer, which is a key step joining catalytic cycles of the AB-polycondensation. These findings are applied to the synthesis of a carbazole-based copolymer designed for the use as a hole conductor in solution-processed organic light-emitting diodes.


Asunto(s)
Paladio/química , Fosfinas/química , Carbazoles/química , Catálisis , Cinética , Polimerizacion , Polímeros/síntesis química , Polímeros/química
20.
Chemistry ; 25(60): 13694-13700, 2019 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-31441547

RESUMEN

Stimulus-responsive polymeric nanocapsules usable as cell mimics can be engineered to precisely control cargo release. This work reports the release behavior of post-loaded nanoparticles through permeable membranes of stable pH and temperature dual-responsive polymeric nanocapsules (CP1, CP2, and CP3) with the same membrane thickness but different membrane composition, prepared by layer-by-layer assembly and surface-initiated single electron transfer living radical polymerization, respectively. These nanocapsules differ in their tunable membrane permeability for post-loaded nanoparticles as protein mimics, tailored by pH and temperature stimuli. Release mechanisms are dominated by membrane composition, such as polyelectrolyte multilayer membrane for CP1, pure cationic membrane for CP2, and valve-like functions for CP3. Thus, one can postulate the main locations of post-loaded protein mimics in the different nanocapsules. Understanding the post-loading and diffusion mechanism of nanoparticles through permeable membranes in cell mimics paves the way for the construction of new "smart" synthetic protocells with control over the exchange of bioactive nanoparticles between different compartments.

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