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The preparation of so-called hybrid nanomaterials has been widely developed in terms of functional and morphological complexity. However, the specific control of the arrangement of organic and inorganic species, which determines the properties of the final material, still remains a challenge. This article offers a review of the strategies that have been used for the preparation of polymer–inorganic hybrid nanoparticles and nanocapsules via processes involving miniemulsions. Different polymer–inorganic nanostructures are classified into four main groups according to the sequential order followed between the synthesis of the polymer and the inorganic species, and the presence or not of their counterpart precursors. The minimization of the energy of the system governs the self-assembly of the different material components and can be addressed by the miniemulsion formulation to reduce the interfacial tensions between the phases involved. The state of the art in the preparation of hybrid nanoparticles is reviewed, offering insight into the structural possibilities allowed by miniemulsion as a versatile synthetic technique.

Background/Objectives: The Trypanosoma cruzi infection promotes an intense inflammatory process that affects several tissues. The cholinergic system may exert a regulatory immune response and control the inflammatory process. This study aimed to evaluate the comparative effect of free and nanoencapsulated benznidazole in acute T. cruzi infection to assess hematological, biochemical, and oxidative status triggered by the cholinergic system. Methods: For this, fifty female Swiss mice were distributed in eight groups, i.e., uninfected and infected animals under four treatment protocols: untreated (control—CT); vehicle treatment (Eudragit L 100—EL-100); benznidazole treatment (BNZ); and nanoencapsulated benznidazole treatment (NBNZ). After eight treatment days, the animals were euthanized for sample collection. Results: The peak of parasitemia was at day 7 p.i., and the BNZ and NBNZ controlled and reduced the parasite rate but showed no efficacy in terms of total elimination of parasites analyzed by RT-PCR in both infected groups. The infection promotes significant anemia, leukopenia, and thrombocytopenia, which the BNZ improves. There was an increase in AChE activity during infection, leading to a pro-inflammatory response and an increase in M1 and M2 mACh receptors in the BNZ group, showing that the treatment interacted with the cholinergic pathway. In addition, a pro-oxidative response was characterized in the infection and mainly in the infected BNZ and NBNZ groups. The histopathological analysis showed significative splenomegaly and inflammatory infiltrate in the heart, liver, and spleen. Conclusions: The administration of the BNZ or NBNZ reverses hematological, hepatic, and renal alterations through cholinergic signaling and stimulates a pro-inflammatory response during acute T. cruzi infection.

Nanocapsule preparation technology, as an emerging technology with great development prospects, has uniqueness and superiority in various industries. In this paper, the preparation technology of nanocapsules was systematically divided into three categories: physical methods, chemical methods, and physicochemical methods. The technological innovation of different methods in recent years was reviewed, and the mechanisms of nanocapsules prepared via emulsion polymerization, interface polymerization, layer-by-layer self-assembly technology, nanoprecipitation, supercritical fluid, and nano spray drying was summarized in detail. Different from previous reviews, the renewal iteration of core–shell structural materials was highlighted, and relevant illustrations of their representative and latest research results were reviewed. With the continuous progress of nanocapsule technology, especially the continuous development of new wall materials and catalysts, new preparation technology, and new production equipment, nanocapsule technology will be used more widely in medicine, food, cosmetics, pesticides, petroleum products, and many other fields.

Retinyl palmitate (RP) is a retinol ester with strong antioxidant and anti-inflammatory properties as an antiwrinkle agent. However, it has poor aqueous solubility and easily degrades into inactive forms for topical applications. Therefore, we developed chitosan-coated nanocapsules (ChiNCs) to encapsulate RP using a simple nanoprecipitation method for protection against physiological conditions and to enable deep skin penetration. The as-prepared RP-loaded nanocapsules (RP@ChiNCs) loaded with approximately 5 wt.% RP exhibited a hydrodynamic diameter of 86 nm and surface charge of 24 mV. They had adequate stability to maintain their physicochemical properties after lyophilization in a biological buffer. Notably, ChiNCs provided RP with remarkable protection against degradation for 4 weeks at 37 °C. Thus, RP@ChiNCs exhibited good antioxidant activity in situ for sufficiently long periods without considerable changes in their efficacy. Furthermore, ChiNCs enhanced the skin penetration of lipophilic RP based on the inherent nature of chitosan. RP@ChiNCs exhibited good in vitro antioxidant and anti-inflammatory effects without causing any cytotoxicity in dermal fibroblasts. Accordingly, they promoted cell proliferation in a wound-scratch test and enhanced collagen synthesis. These results suggest that RP@ChiNCs are promising candidates for cosmetic and biomedical applications.

Using removable silica templates, protein nanocapsules comprising the A subunit of Helicobacter pylori urease (UreA) were synthesised. The templates were of two sizes, with solid core mesoporous shell (SC/MS) silica templates giving rise to nanocapsules of average diameter 510 nm and mesoporous (MS) silica templates giving rise to nanocapsules of average diameter 47 nm. Both were shown to be highly monodispersed and relatively homogenous in structure. Various combinations of the nanocapsules in formulation were assessed as vaccines in a mouse model of H. pylori infection. Immune responses were evaluated and protective efficacy assessed. It was demonstrated that vaccination of mice with the larger nanocapsules combined with an adjuvant was able to significantly reduce colonisation.

This study demonstrates high drug-loading of novel pyridine derivatives (S1–S4) in lipid- and polymer-based core–shell nanocapsules (LPNCs) for boosting the anticancer efficiency and alleviating toxicity of these novel pyridine derivatives. The nanocapsules were fabricated using a nanoprecipitation technique and characterized for particle size, surface morphology, and entrapment efficiency. The prepared nanocapsules exhibited a particle size ranging from 185.0 ± 17.4 to 223.0 ± 15.3 nm and a drug entrapment of >90%. The microscopic evaluation demonstrated spherical-shaped nanocapsules with distinct core–shell structures. The in vitro release study depicted a biphasic and sustained release pattern of test compounds from the nanocapsules. In addition, it was obvious from the cytotoxicity studies that the nanocapsules showed superior cytotoxicity against both MCF-7 and A549 cancer cell lines, as manifested by a significant decrease in the IC50 value compared to free test compounds. The in vivo antitumor efficacy of the optimized nanocapsule formulation (S4-loaded LPNCs) was investigated in an Ehrlich ascites carcinoma (EAC) solid tumor-bearing mice model. Interestingly, the entrapment of the test compound (S4) within LPNCs remarkably triggered superior tumor growth inhibition when compared with either free S4 or the standard anticancer drug 5-fluorouracil. Such enhanced in vivo antitumor activity was accompanied by a remarkable increase in animal life span. Furthermore, the S4-loaded LPNC formulation was tolerated well by treated animals, as evidenced by the absence of any signs of acute toxicity or alterations in biochemical markers of liver and kidney functions. Collectively, our findings clearly underscore the therapeutic potential of S4-loaded LPNCs over free S4 in conquering EAC solid tumors, presumably via granting efficient delivery of adequate concentrations of the entrapped drug to the target site.

Self-healing polymers and nanocomposites form an important class of responsive materials. These materials have the capability to reversibly heal their damage. For aerospace applications, thermosets and thermoplastic polymers have been reinforced with nanocarbon nanoparticles for self-healing of structural damage. This review comprehends the use of self-healing nanocomposites in the aerospace sector. The self-healing behavior of the nanocomposites depends on factors such as microphase separation, matrix–nanofiller interactions and inter-diffusion of polymer–nanofiller. Moreover, self-healing can be achieved through healing agents such as nanocapsules and nanocarbon nanoparticles. The mechanism of self-healing has been found to operate via physical or chemical interactions. Self-healing nanocomposites have been used to design structural components, panels, laminates, membranes, coatings, etc., to recover the damage to space materials. Future research must emphasize the design of new high-performance self-healing polymeric nanocomposites for aerospace structures.

With the acceleration in oilfield developments, reservoir advantage channels have been gradually developed. This has led to ineffective circulation in the oilfield injection system and a significant decrease in production. The profile control and displacement technology of low-permeability and heterogeneous reservoirs are in urgent need of updating. In this paper, an intelligent profile control and displacement agent is proposed. The controlled release mechanism and profile control and displacement mechanism is clarified by physical simulation experiments. The profile control agent is a nanocapsule with environmental response and controlled release. The structure of the capsule is a core–shell structure, which is composed of an amphiphilic copolymer AP-g-PNIPAAM and Janus functional particles. The surface chemical stability of the micro/nanocapsule is analyzed by a potentiometric method. The study shows that a temperature at 45 °C causes a potential change in the micro/nanocapsule, indicating that the micro/nanocapsule has a slow release at this temperature. When the temperature is in the range of 40 to 45 °C, the absorbance greatly increases; therefore, it is considered that the capsule wall LCST is about 45 °C. Heating causes the surface contraction of the capsule wall to intensify, the micropores in the capsule wall to increase, the release amount to increase and the release rate per unit time to increase. The release time increases proportionally with the increase in capsule wall thickness. When the release time is the same, an alkaline or acidic environment can improve the release rate of the nanocapsule. The effect of profile control and flooding is evaluated through different differential core models. The research shows that the controlled release micro/nanocapsule has a good environmental response and the internal components can be effectively controlled by adjusting the temperature or pH value. This research has shown that the nanocapsules have good application prospects in low-permeability heterogeneous reservoirs.

Catalytic synthesis of carbon nanotubes (CNT) produces numerous various byproducts such as soot, graphite platelets, catalyst nanoparticles, etc. Identification of the byproduct formation mechanisms would help develop routes to more selective synthesis of better carbon-based materials. This work reports on the identification of the formation zone and conditions for rather unusual closed multishell carbon nanocapsules in a reactor for float-catalysis synthesis of longer CNT. Structural investigation of the formed nanocapsule material along with computational fluid dynamics (CFD) simulations of the reactor suggested a nanocapsule formation mechanism, in which CNT embryos are suppressed in growth by the in-reactor turbulence. By means of TEM and FFT investigation, it is found that differently oriented single crystals of γ–Fe2O3, which do not have clear connections with each other, determine a spherical surface. The carbon atoms that seep through these joints do not form crystalline graphite layers. The resulting additional product in the form of graphene-coated (γ–Fe/Fe3C)/γ–Fe2O3 nanoparticles can be a lightweight and effective microwave absorber.

A redox-responsive nanocarrier is a promising strategy for the intracellular drug release because it protects the payload, prevents its undesirable leakage during extracellular transport, and favors site-specific drug delivery. In this study, we developed a novel redox responsive core-shell structure nanohydrogel prepared by a water in oil nanoemulsion method using two biocompatible synthetic polymers: vinyl sulfonated poly(N-(2-hydroxypropyl) methacrylamide mono/dilactate)-polyethylene glycol-poly(N-(2-hydroxypropyl) methacrylamide mono/dilactate) triblock copolymer, and thiolated hyaluronic acid. The influence on the nanohydrogel particle size and distribution of formulation parameters was investigated by a three-level full factorial design to optimize the preparation conditions. The surface and core-shell morphology of the nanohydrogel were observed by scanning electron microscope, transmission electron microscopy, and further confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy from the standpoint of chemical composition. The redox-responsive biodegradability of the nanohydrogel in reducing environments was determined using glutathione as reducing agent. A nanohydrogel with particle size around 250 nm and polydispersity index around 0.1 is characterized by a thermosensitive shell which jellifies at body temperature and crosslinks at the interface of a redox-responsive hyaluronic acid core via the Michael addition reaction. The nanohydrogel showed good encapsulation efficiency for model macromolecules of different molecular weight (93% for cytochrome C, 47% for horseradish peroxidase, and 90% for bovine serum albumin), capacity to retain the peroxidase-like enzymatic activity (around 90%) of cytochrome C and horseradish peroxidase, and specific redox-responsive release behavior. Additionally, the nanohydrogel exhibited excellent cytocompatibility and internalization efficiency into macrophages. Therefore, the developed core-shell structure nanohydrogel can be considered a promising tool for the potential intracellular delivery of different pharmaceutical applications, including for cancer therapy.

Standards of care for human visceral leishmaniasis (VL) are based on drugs used parenterally, and oral treatment options are urgently needed. In the present study, a repurposing strategy was used associating tamoxifen (TMX) with polyethylene glycol-block-polylactide nanocapsules (NC) and its anti-leishmanial efficacy was reported in vivo. Stable surface modified-NC (5 mg/mL of TMX) exhibited 200 nm in size, +42 mV of zeta potential, and 98% encapsulation efficiency. Atomic force microscopy evidenced core-shell-NC. Treatment with TMX-NC reduced parasite-DNA quantified in liver and spleen compared to free-TMX; and provided a similar reduction of parasite burden compared with meglumine antimoniate in mice and hamster models. Image-guided biodistribution showed accumulation of NC in liver and spleen after 30 min post-administration. TMX-NC reduced the number of liver granulomas and restored the aspect of capsules and trabeculae in the spleen of infected animals. TMX-NC was tested for the first time against VL models, indicating a promising formulation for oral treatment.

Nanocapsule preparation technology, as an emerging technology with great development prospects, has uniqueness and superiority in various industries. In this paper, the preparation technology of nanocapsules was systematically divided into three categories: physical methods, chemical methods, and physicochemical methods. The technological innovation of different methods in recent years was reviewed, and the mechanisms of nanocapsules prepared via emulsion polymerization, interface polymerization, layer-by-layer self-assembly technology, nanoprecipitation, supercritical fluid, and nano spray drying was summarized in detail. Different from previous reviews, the renewal iteration of core-shell structural materials was highlighted, and relevant illustrations of their representative and latest research results were reviewed. With the continuous progress of nanocapsule technology, especially the continuous development of new wall materials and catalysts, new preparation technology, and new production equipment, nanocapsule technology will be used more widely in medicine, food, cosmetics, pesticides, petroleum products, and many other fields.

Messenger RNA (mRNA) drugs have attracted considerable attention as promising tools with many therapeutic applications. The efficient delivery of mRNA drugs using non-viral materials is currently being explored. We demonstrate a novel concept where mCherry mRNA bearing a poly(A) tail is encapsulated into capsids co-assembled from viral β-annulus peptides bearing a 20-mer oligothymine (dT20) at the N-terminus and unmodified peptides via hybridization of dT20 and poly(A). Dynamic light scattering measurements and transmission electron microscopy images of the mRNA-encapsulated capsids show the formation of spherical assemblies of approximately 50 nm. The encapsulated mRNA shows remarkable ribonuclease resistance. Further, modification by a cell-penetrating peptide (His16) on the capsid enables the intracellular expression of mCherry of encapsulated mRNA.

Using removable silica templates, protein nanocapsules comprising the A subunit of Helicobacter pylori urease (UreA) were synthesised. The templates were of two sizes, with solid core mesoporous shell (SC/MS) silica templates giving rise to nanocapsules of average diameter 510 nm and mesoporous (MS) silica templates giving rise to nanocapsules of average diameter 47 nm. Both were shown to be highly monodispersed and relatively homogenous in structure. Various combinations of the nanocapsules in formulation were assessed as vaccines in a mouse model of H. pylori infection. Immune responses were evaluated and protective efficacy assessed. It was demonstrated that vaccination of mice with the larger nanocapsules combined with an adjuvant was able to significantly reduce colonisation., Competing Interests: The authors declare no conflict of interest.

Retinyl palmitate (RP) is a retinol ester with strong antioxidant and anti-inflammatory properties as an antiwrinkle agent. However, it has poor aqueous solubility and easily degrades into inactive forms for topical applications. Therefore, we developed chitosan-coated nanocapsules (ChiNCs) to encapsulate RP using a simple nanoprecipitation method for protection against physiological conditions and to enable deep skin penetration. The as-prepared RP-loaded nanocapsules (RP@ChiNCs) loaded with approximately 5 wt.% RP exhibited a hydrodynamic diameter of 86 nm and surface charge of 24 mV. They had adequate stability to maintain their physicochemical properties after lyophilization in a biological buffer. Notably, ChiNCs provided RP with remarkable protection against degradation for 4 weeks at 37 °C. Thus, RP@ChiNCs exhibited good antioxidant activity in situ for sufficiently long periods without considerable changes in their efficacy. Furthermore, ChiNCs enhanced the skin penetration of lipophilic RP based on the inherent nature of chitosan. RP@ChiNCs exhibited good in vitro antioxidant and anti-inflammatory effects without causing any cytotoxicity in dermal fibroblasts. Accordingly, they promoted cell proliferation in a wound-scratch test and enhanced collagen synthesis. These results suggest that RP@ChiNCs are promising candidates for cosmetic and biomedical applications.

A viral β-annulus peptide connected with a zinc oxide (ZnO)-binding sequence (HCVAHR) at its N-terminal was synthesized, and the inclusion behavior of quantum-sized ZnO nanoparticles into the peptide nanocapsules formed by self-assembly of the peptide in water was investigated. Dynamic light scattering (DLS) measurements showed that ZnO nanoparticles (approximately 10 nm) in the presence of the peptide (0.1 mM) formed assemblies with an average size of 48 ± 24 nm, whereas ZnO nanoparticles in the absence of the peptide formed large aggregates. Transmission electron microscopy (TEM) observations of the ZnO nanoparticles in the presence of the peptide revealed that ZnO nanoparticles were encapsulated into the peptide nanocapsules with a size of approximately 50 nm. Fluorescence spectra of a mixture of the peptide and ZnO nanoparticles suggested that the ZnO surface and the peptide interact. Template synthesis of ZnO nanoparticles with the peptide nanocapsules afforded larger nanoparticles (approximately 40 nm), which are not quantum-sized ZnO.

The prosurvival protein kinase CK2, androgen receptor (AR), and nuclear factor kappa B (NFκB) interact in the function of prostate cells, and there is evidence of crosstalk between these signals in the pathobiology of prostate cancer (PCa). As CK2 is elevated in PCa, and AR and NFκB are involved in the development and progression of prostate cancer, we investigated their interaction in benign and malignant prostate cells in the presence of altered CK2 expression. Our results show that elevation of CK2 levels caused increased levels of AR and NFκB p65 in prostate cells of different phenotypes. Analysis of TCGA PCa data indicated that AR and CK2α RNA expression are strongly correlated. Small molecule inhibition or molecular down-regulation of CK2 caused reduction in AR mRNA expression and protein levels in PCa cells and in orthotopic xenograft tumors by various pathways. Among these, regulation of AR protein stability plays a unifying role in CK2 maintenance of AR protein levels. Our results show induction of various endoplasmic reticulum stress signals after CK2 inhibition, which may play a role in the PCa cell death response. Of note, CK2 inhibition caused loss of cell viability in both parental and enzalutamide-resistant castrate-resistant PCa cells. The present work elucidates the specific link of CK2 to the pathogenesis of PCa in association with AR and NFκB expression; further, the observation that inhibition of CK2 can exert a growth inhibitory effect on therapy-resistant PCa cells emphasizes the potential utility of CK2 inhibition in patients who are on enzalutamide treatment for advanced cancer.

For the development of effective drug carriers, nanocapsules that respond to micro-environmental changes including a decrease in pH and a reductive environment were prepared by the stabilization of polymer vesicles formed from head-tail type polycations, composed of a polyamidoamine dendron head and a poly(L-lysine) tail (PAMAM dendron-PLL), through the introduction of disulfide bonds between the PLL tails. Disulfide bonds were successfully introduced through the reaction of Lys residues in the PAMAM dendron-PLL polymer vesicles with 2-iminothiolane. The stabilization of PAMAM dendron-PLL polymer vesicles was confirmed by dynamic light scattering measurements. In acid-base titration experiments, nanocapsules cross-linked by disulfide bonds had a buffering effect during the cellular uptake process. The PAMAM dendron-PLL nanocapsules were used to incorporate the fluorescent dyes rhodamine 6G and fluorescein as a drug model. Cationic rhodamine 6G was generally not released from the nanocapsules because of the electrostatic barrier of the PLL membrane. However, the nanocapsules were destabilized at high glutathione concentrations corresponding to intracellular concentrations. Rhodamine 6G was immediately released from the nanocapsules because of destabilization upon the cleavage of disulfide bonds. This release of rhodamine 6G from the nanocapsules was also observed in HeLa cells by laser confocal microscopy.

Stimuli-responsive systems for controlled drug release have been extensively explored in recent years. In this work, we developed a reduction-responsive camptothecin (CPT) nanocapsule (CPT-NC) by combining nanoprecipitation and in situ polymerization using a polymerized surface ligand and a disulfide bond-containing crosslinker. Dissolution rate studies proved that the CPT-NCs have robust drug-release profiles in the presence of glutathione (GSH) owing to the division of the disulfide bond crosslinker which triggers the collapse of the polymer layer. Furthermore, the in vitro investigations demonstrated that the CPT-NCs exhibited a high-cellular uptake efficiency and cytotoxicity for cancer cells of squamous cell carcinoma (SCC-15). Our approach thus presents an effective intracellular drug delivery strategy for anticancer therapy.

A viral β-annulus peptide connected with a zinc oxide (ZnO)-binding sequence (HCVAHR) at its N-terminal was synthesized, and the inclusion behavior of quantum-sized ZnO nanoparticles into the peptide nanocapsules formed by self-assembly of the peptide in water was investigated. Dynamic light scattering (DLS) measurements showed that ZnO nanoparticles (approximately 10 nm) in the presence of the peptide (0.1 mM) formed assemblies with an average size of 48 ± 24 nm, whereas ZnO nanoparticles in the absence of the peptide formed large aggregates. Transmission electron microscopy (TEM) observations of the ZnO nanoparticles in the presence of the peptide revealed that ZnO nanoparticles were encapsulated into the peptide nanocapsules with a size of approximately 50 nm. Fluorescence spectra of a mixture of the peptide and ZnO nanoparticles suggested that the ZnO surface and the peptide interact. Template synthesis of ZnO nanoparticles with the peptide nanocapsules afforded larger nanoparticles (approximately 40 nm), which are not quantum-sized ZnO.