Controlling Charge Transfer from Quantum Dots to Polyelectrolyte Layers Extends Prospective Applications of Magneto-Optical Microcapsules

Impact of Macrophages on the Interaction of Cetuximab-Functionalized Polyelectrolyte Capsules with EGFR-Expressing Cancer Cells

Polyelectrolyte capsules (PCs) are a promising tool for anticancer drug delivery and tumor targeting. Surface functionalization of PCs with antibodies is widely used for providing their specific interactions with cancer cells. The efficiency of PC-based targeted delivery systems can be affected by the cellular heterogeneity of the tumor, particularly by the presence of tumor-associated macrophages. We used human epidermoid carcinoma cells and macrophages derived from human leukemia monocytic cells in either monoculture or coculture to analyze the targeting capacity and internalization efficiency of PCs with a mean size of 1.03 ± 0.11 μm. The PCs were functionalized with the monoclonal antibody cetuximab targeting the human epidermal growth factor receptor (EGFR). We have shown that surface functionalization of the PCs with cetuximab ensures a specific interaction with EGFR-expressing cancer cells and promotes capsule internalization. In monoculture, the macrophages derived from human leukemia monocytic cells have been found to internalize both nonfunctionalized PCs and cetuximab-functionalized PCs (Cet-PCs) more intensely compared to epidermoid carcinoma cells. The internalization of Cet-PCs by cancer cells is mediated by lipid rafts of the cell membrane, whereas the PC internalization by macrophages is only slightly influenced by lipid rafts. Experiments with a coculture of human epidermoid carcinoma cells and macrophages derived from human leukemia monocytic cells have shown that Cet-PCs preferentially interact with cancer cells, which are subsequently attacked by macrophages. These data can be used to further improve the strategy of PC functionalization for targeted delivery, with the cellular heterogeneity of the tumor microenvironment taken into consideration.

Behaviour of FITC-Labeled Polyallylamine in Polyelectrolyte Microcapsules

There are many studies devoted to the application of polyelectrolyte microcapsules (PMC) in various fields; however, there are significantly fewer studies devoted to the study of the polyelectrolyte microcapsules themselves. The study examined the mutual arrangement of the polyelectrolytes in 13-layered PMC capsules composed of (PAH/PSS)6PAH. The research showed that different layers of the polyelectrolyte microcapsules dissociate equally, as in the case of 13-layered PMC capsules composed of (PAH/PSS)6PAH with a well-defined shell, and in the case of 7-layered PMC capsules composed of (PAH/PSS)3PAH, where the shell is absent. The study showed that polyallylamine layers labeled with FITC migrate to the periphery of the microcapsule regardless of the number of layers. This is due to an increase in osmotic pressure caused by the rapid flow of ions from the interior of the microcapsule into the surrounding solution. In addition, FITC-polyallylamine has a lower charge density and less interaction with polystyrene sulfonate in the structure of the microcapsule. Meanwhile, the hydrophilicity of FITC-polyallylamine does not change or decreases slightly. The results suggest that this effect promotes the migration of labeled polyallylamine to a more hydrophilic region of the microcapsule, towards its periphery.

Versatile Fabrication of Polymer Microcapsules with Controlled Shell Composition and Tunable Performance via Photopolymerization

In this work, a series of polymer microcapsules based on UV-curable prepolymers are prepared by combining an emulsion template and photopolymerization. The modulation of the shell structure is achieved by employing UV-curable prepolymers with different chemical structures (polyurethane acrylates, polyester acrylates, and epoxy acrylates) and functionalities (di-, tetra-, and hex-). The relationships between the shell structure and the microcapsule properties are investigated in detail. The results show that the properties of the microcapsules can be effectively regulated by adjusting the composition and cross-linking density of the shell. Epoxy acrylate-based microcapsules exhibit higher impermeability, solvent resistance, and barrier and mechanical properties than polyurethane acrylate and polyester acrylate-based microcapsules. Using UV-curable prepolymer with high functionality as a shell-forming material could effectively improve the impermeability, solvent resistance, and barrier and mechanical properties of microcapsules. In addition, the dispersion of microcapsules in the coating matrix tends to follow the "similar component, better compatibility" principle, i.e., a uniform dispersion of the microcapsule in the coating matrix is more easily achieved when the compositions of the microcapsule shell and coating are similar in structure. The convenient adjustment of the shell structure and the investigation of the "structure-property" relationship provide guidance for the further controlled design of microcapsules.

Exploiting the layer-by-layer nanoarchitectonics for the fabrication of polymer capsules: A toolbox to provide multifunctional properties to target complex pathologies

Polymer capsules fabricated via the layer-by-layer (LbL) approach have attracted a great deal of attention for biomedical applications thanks to their tunable architecture. Compared to alternative methods, in which the precise control over the final properties of the systems is usually limited, the intrinsic versatility of the LbL approach allows the functionalization of all the constituents of the polymeric capsules following relatively simple protocols. In fact, the final properties of the capsules can be adjusted from the inner cavity to the outer layer through the polymeric shell, resulting in therapeutic, diagnostic, or theranostic (i.e., combination of therapeutic and diagnostic) agents that can be adapted to the particular characteristics of the patient and face the challenges encountered in complex pathologies. The biomedical industry demands novel biomaterials capable of targeting several mechanisms and/or cellular pathways simultaneously while being tracked by minimally invasive techniques, thus highlighting the need to shift from monofunctional to multifunctional polymer capsules. In the present review, those strategies that permit the advanced functionalization of polymer capsules are accordingly introduced. Each of the constituents of the capsule (i.e., cavity, multilayer membrane and outer layer) is thoroughly analyzed and a final overview of the combination of all the strategies toward the fabrication of multifunctional capsules is presented. Special emphasis is given to the potential biomedical applications of these multifunctional capsules, including particular examples of the performed in vitro and in vivo validation studies. Finally, the challenges in the fabrication process and the future perspective for their safe translation into the clinic are summarized.

Nanoparticle-Doped Hybrid Polyelectrolyte Microcapsules with Controlled Photoluminescence for Potential Bioimaging Applications

Fluorescent imaging is widely used in the diagnosis and tracking of the distribution, interaction, and transformation processes at molecular, cellular, and tissue levels. To be detectable, delivery systems should exhibit a strong and bright fluorescence. Quantum dots (QDs) are highly photostable fluorescent semiconductor nanocrystals with wide absorption spectra and narrow, size-tunable emission spectra, which make them suitable fluorescent nanolabels to be embedded into microparticles used as bioimaging and theranostic agents. The layer-by-layer deposition approach allows the entrapping of QDs, resulting in bright fluorescent microcapsules with tunable surface charge, size, rigidity, and functional properties. Here, we report on the engineering and validation of the structural and photoluminescent characteristics of nanoparticle-doped hybrid microcapsules assembled by the deposition of alternating oppositely charged polyelectrolytes, water-soluble PEGylated core/shell QDs with a cadmium selenide core and a zinc sulfide shell (CdSe/ZnS), and carboxylated magnetic nanoparticles (MNPs) onto calcium carbonate microtemplates. The results demonstrate the efficiency of the layer-by-layer approach to designing QD-, MNP-doped microcapsules with controlled photoluminescence properties, and pave the way for the further development of next-generation bioimaging agents based on hybrid materials for continuous fluorescence imaging.

Designing Functionalized Polyelectrolyte Microcapsules for Cancer Treatment

The engineering of delivery systems for drugs and contrasting labels ensuring the simultaneous imaging and treatment of malignant tumors is an important hurdle in developing new tools for cancer therapy and diagnosis. Polyelectrolyte microcapsules (MCs), formed by nanosized interpolymer complexes, represent a promising platform for the designing of multipurpose agents, functionalized with various components, including high- and low-molecular-weight substances, metal nanoparticles, and organic fluorescent dyes. Here, we have developed size-homogenous MCs with different structures (core/shell and shell types) and microbeads containing doxorubicin (DOX) as a model anticancer drug, and fluorescent semiconductor nanocrystals (quantum dots, QDs) as fluorescent nanolabels. In this study, we suggest approaches to the encapsulation of DOX at different stages of the MC synthesis and describe the optimal conditions for the optical encoding of MCs with water-soluble QDs. The results of primary characterization of the designed microcarriers, including particle analysis, the efficacy of DOX and QDs encapsulation, and the drug release kinetics are reported. The polyelectrolyte MCs developed here ensure a modified (prolonged) release of DOX, under conditions close to normal and tumor tissues; they possess a bright fluorescence that paves the way to their exploitation for the delivery of antitumor drugs and fluorescence imaging.

A Dually Charged Membrane for Seawater Utilization: Combining Marine Pollution Remediation and Desalination by Simultaneous Removal of Polluted Dispersed Oil, Surfactants, and Ions

Shortage of freshwater and deterioration of the marine environment have a serious effect on the human body and ecological environment. Here, we demonstrated a facile way to prepare a multiple-target superwetting porous material to obtain available water without cumbersome steps. Through the facile immersion and hydrothermal method, a charge-enhanced membrane material combining superwettability, electrostatic interaction, and the steric effect is prepared. Such a material breaks through the limitations of single size sieving and has a universal effect on different kinds of contaminants with accurate wettability manipulation and fluid separation control. The protonation and deprotonation of active carboxyl groups at the novel created solid/liquid interface facilitate the surface wettability and flux transition, which will bring out superior continuous separation and surface lubrication control.

Recent Progress of Layer-by-layer Assembly, Free-Standing Film and Hydrogel Based on Polyelectrolytes

Nowadays, polyelectrolytes play an essential role in the development of new materials. Their use allows creating new properties of materials and surfaces and vary them in a wide range. Basically, modern methods are divided into three areas-the process of layer-by-layer deposition, free-standing films, and hydrogels based on polyelectrolytes. Layer-by-layer assembly of polyelectrolytes on various surfaces is a powerful technique. It allows giving surfaces new properties, for example, protect them from corrosion. Free-standing films are essential tools for the design of membranes and sensors. Hydrogels based on polyelectrolytes have recently shown their applicability in electrical and materials science. The creation of new materials and components with controlled properties can be achieved using polyelectrolytes. This review focuses on new technologies that have been developed with polyelectrolytes over the last five years.

Carbon Nanoparticles and Materials on Their Basis

Carbon nanoparticles (CNPs) are novel nanostructures with luminescent properties. The development of CNPs involves the elaboration of various synthetic methods, structure characterization, and different applications. However, the problems associated with the CNP structure definition and properties homogeneity are not solved and barely described in depth. In this feature article, we demonstrate the approaches for the effective separation and purification of CNPs by size and size/charge ratio. We propose a promising way for the synthesis of the uniform-size structures by the application of calcium carbonate porous microparticles as reactors with defined size. Additionally, the application of the CNPs agglomerates for controllable release systems triggered by light and in-situ synthesis of fluorescent conductive carbonaceous films on the base of polyelectrolyte multilayers are under consideration.