Publications by authors named "Loai K E A Abdelmohsen"

Coacervate-based artificial cells have gained significant attraction in synthetic biology for their ability to mimic life-like functions such as compartmentalization, selective molecular uptake, and the hosting of biochemical reactions. However, the incorporation of motility, a key feature of natural cells, remains underexplored. This is mainly caused by the dynamic character of coacervates, which hampers their stability and limits control over functional motile components within the structure.

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Organic photothermal agents (OPTAs) are extensively utilized in applications such as therapy and imaging. However, enhancing their photothermal performance often depends on complex molecular designs, which are limited by the challenges of chemical synthesis. Herein, we present a straightforward strategy to optimize the optical absorbance of OPTAs by adjusting the morphology of assemblies of an amphiphilic block copolymer (PEG-PTA), leading to enhanced photothermal conversion efficiency.

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Polymersomes with surface-integrated nanoparticles, in which a smaller sphere is attached to a larger capsule, are typically formed through complex processes like membrane deformation, polymerization, or membrane functionalization. This complexity restricts facile application of this unusual topology, for example in drug delivery or nanomotor science. Our study introduces a robust method for crafting polymersomes with surface-integrated nanoparticles using a hierarchical phase separation approach.

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Polymeric nanoarchitectures are crafted from amphiphilic block copolymers through a meticulous self-assembly process. The composition of these block copolymers is finely adjustable, bestowing precise control over the characteristics and properties of the resultant polymeric assemblies. These nanoparticles have garnered significant attention, particularly in the realm of biological sciences, owing to their biocompatibility, favorable pharmacokinetics, and facile chemically modifiable nature.

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The morphology of nanodrugs is of utmost importance in photothermal therapy because it directly influences their physicochemical behavior and biological responses. However, clarifying the inherent relationship between morphology and the resultant properties remains challenging, mainly due to the limitations in the flexible morphological regulation of nanodrugs. Herein, we created a range of morphologically controlled nanoassemblies based on poly(ethylene glycol)--poly(d,l-lactide) (PEG-PLA) block copolymer building blocks, in which the model photosensitizer phthalocyanine was incorporated.

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Advances in liquid phase transmission electron microscopy (LP-TEM) have enabled the monitoring of polymer dynamics in solution at the nanoscale, but radiolytic damage during LP-TEM imaging limits its routine use in polymer science. This study focuses on understanding, mimicking, and mitigating radiolytic damage observed in functional polymers in LP-TEM. It is quantitatively demonstrated how polymer damage occurs across all conceivable (LP-)TEM environments, and the key characteristics and differences between polymer degradation in water vapor and liquid water are elucidated.

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Article Synopsis
  • Researchers explore collective behavior in systems chemistry using polymersome stomatocytes loaded with urease, demonstrating basic stigmergy-based communication.
  • These stomatocytes can produce, receive, and respond to signals by clustering due to pH-sensitive interactions between specific chemical groups on their surfaces.
  • The clustering behavior occurs at a pH of 6.3 to 7.3 and displays oscillations: as pH rises from urease activity, the clusters disassemble, but can reform once conditions stabilize, highlighting potential for cooperative tasks among active colloids.
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T cells play a critical role in adaptive immune responses. They work with other immune cells such as B cells to protect our bodies when the first line of defense, the innate immune system, is overcome by certain infectious diseases or cancers. Studying and regulating the responses of T cells, such as activation, proliferation, and differentiation, helps us understand not only their behavior but also their translation and application in the field of immunotherapy, such as adoptive T cell therapy and immune checkpoint therapy, the situations in which T cells cannot fight cancer alone and require external engineering regulation to help them.

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Article Synopsis
  • The study explores how artificial cell systems can communicate over time and space, similar to natural cells, by using chemical signals to trigger specific responses in distant cells.
  • Sender cells generate diffusive signals, like changes in pH, which influence the shape of compartmentalized DNA structures in receiving cells, affecting their functionality.
  • Results demonstrate that two different sender populations can temporally and spatially regulate the activation of the receivers, opening up new possibilities for designing programmable synthetic cell systems.
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Regulating innate immunity is an emerging approach to improve cancer immunotherapy. Such regulation requires engaging myeloid cells by delivering immunomodulatory compounds to hematopoietic organs, including the spleen. Here we present a polymersome-based nanocarrier with splenic avidity and propensity for red pulp myeloid cell uptake.

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Synthetic micro/nanomotors have been extensively exploited over the past decade to achieve active transportation. This interest is a result of their broad range of potential applications, from environmental remediation to nanomedicine. Nevertheless, it still remains a challenge to build a fast-moving biodegradable polymeric nanomotor.

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Polymersomes, nanosized polymeric vesicles, have attracted significant interest in the areas of artificial cells and nanomedicine. Given their size, their visualization via confocal microscopy techniques is often achieved through the physical incorporation of fluorescent dyes, which however present challenges due to potential leaching. A promising alternative is the incorporation of molecules with aggregation-induced emission (AIE) behavior that are capable of fluorescing exclusively in their assembled state.

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Engineering chemical communication between micro/nanosystems (via the exchange of chemical messengers) is receiving increasing attention from the scientific community. Although a number of micro- and nanodevices (e.g.

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Viscoadaptation is an essential process in natural cells, where supramolecular interactions between cytosolic components drive adaptation of the cellular mechanical features to regulate metabolic function. This important relationship between mechanical properties and function has until now been underexplored in artificial cell research. Here, we have created an artificial cell platform that exploits internal supramolecular interactions to display viscoadaptive behavior.

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Using the diamagnetic anisotropy of polymers for the characterization of polymers and polymer aggregates is a relatively new approach in the field of soft-matter and polymer research. So far, a good and thorough quantitative description of these diamagnetic properties has been lacking. Using a simple equation that links the magnetic properties of an average polymer repeating unit to those of the polymer vesicle of any shape, we measured, using magnetic birefringence, the average diamagnetic anisotropy of a polystyrene (PS) repeating unit, Δ, inside a poly(ethylene glycol)-polystyrene (PEG-PS) polymersome membrane as a function of the PS-length and as a function of the preparation method.

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Functionalized polymer vesicles have been proven to be highly promising in biomedical applications due to their good biocompatibility, easy processability, and multifunctional responsive capacities. However, photothermal-responsive polymer vesicles triggered by near-infrared (NIR) light have not been widely reported until now. Herein, we propose a new strategy for designing NIR light-mediated photothermal polymer vesicles.

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The application of transition-metal catalysts in living cells presents a promising approach to facilitate reactions that otherwise would not occur in nature. However, the usage of metal complexes is often restricted by their limited biocompatibility, toxicity, and susceptibility to inactivation and loss of activity by the cell's defensive mechanisms. This is especially relevant for ruthenium-mediated reactions, such as ring-closing metathesis.

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Nanomotors have been extensively explored for various applications in nanomedicine, especially in cargo transportation. Motile properties enable them to deliver pharmaceutical ingredients more efficiently to the targeted site. However, it still remains a challenge to design motor systems that are therapeutically active and can also be effectively traced when taken up by cells.

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Article Synopsis
  • Researchers created pH-responsive bicontinuous nanospheres (BCNs) using block copolymers that change permeability based on pH.
  • The BCNs were loaded with enzymes urease and horseradish peroxidase (HRP), allowing for a controlled catalytic response to urea, which raises pH and changes their permeability.
  • Unlike standard spherical polymersomes, these BCNs exhibited a unique nonlinear dampening effect, enabling better modulation of catalytic activity through environmental pH changes.
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Polymersome nanoreactors that can be employed as artificial organelles have gained much interest over the past decades. Such systems often include biological catalysts (i.e.

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Unprecedented opportunities exist for the generation of advanced nanotechnologies based on synthetic micro/nanomotors (MNMs), such as active transport of medical agents or the removal of pollutants. In this regard, great efforts have been dedicated toward controlling MNM motion (e.g.

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Nanosized artificial antigen-presenting cells (aAPCs), synthetic immune cell mimics that aim to activate T cells or , offer an effective alternative to cellular immunotherapies. However, comprehensive studies that delineate the effect of nano-aAPC topology, including nanoparticle morphology and ligand density, are lacking. Here, we systematically studied the topological effects of polymersome-based aAPCs on T cell activation.

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Active materials can transduce external energy into kinetic energy at the nano and micron length scales. This unique feature has sparked much research, which ranges from achieving fundamental understanding of their motility to the assessment of potential applications. Traditionally, motility is studied as a function of internal features such as particle topology, while external parameters such as energy source are assessed mainly in bulk.

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Supramolecular nanomotors were created with two types of propelling forces that were able to counterbalance each other. The particles were based on bowl-shaped polymer vesicles, or stomatocytes, assembled from the amphiphilic block copolymer poly(ethylene glycol)--polystyrene. The first method of propulsion was installed by loading the nanocavity of the stomatocytes with the enzyme catalase, which enabled the decomposition of hydrogen peroxide into water and oxygen, leading to a chemically induced motion.

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