Search Results (104)

Kaolinite-group minerals and kaolin rock occupy a distinct position in cultural heritage conservation. They occur both as original constituent materials and as components of conservation treatments. This review critically synthesizes the scattered literature on their use in the conservation of cultural heritage objects. It highlights the structure–property–performance relationships, including composition, particle morphology, pore structure, water retention, sorption properties, moisture transport, and residue formation on heritage substrates. Kaolin-based poultices are useful for desalination and cleaning where pore-size distribution, drying conditions, and application parameters can be controlled. Kaolinite and metakaolinite are mainly used in consolidation, the first acting as mineral filler/scaffold and the second as a reactive pozzolanic component, while halloysite is a potential nanocontainer for controlled release. This review highlights that kaolinite-group minerals should not be treated as generic clays, inert fillers, or automatically sustainable additives and particular attention should be given to issues of reversibility, formulation design, performance testing, long-term durability, and residue assessment, as well as to emerging data on toxicity and environmental impact. Future research should prioritize comparative testing, long-term field monitoring, and predictive modelling, alongside clearer assessment of health, environmental and sustainability impacts, to support evidence-based, sustainable use of kaolinite-group minerals in cultural heritage conservation practice. Full article

Corrosion-protective coatings have progressed from passive barrier systems and chromate-based technologies toward multifunctional materials that integrate barrier durability, interfacial adhesion, active inhibition, electrochemical response, and self-healing capabilities. However, the intellectual framework connecting these technological developments remains fragmented, as most reviews focus on specific material families rather than on the broader evolution of the field. This study examines technological paradigms in corrosion-protective coatings through a citation network analysis of highly cited publications retrieved from Web of Science and processed with CitNetExplorer. The most influential publications were thematically reviewed to identify dominant materials, coating architectures, protection mechanisms, seminal contributions, and bridge articles. Four principal paradigms were identified: smart and self-healing coatings based on nanocontainers, layered double hydroxides, mesoporous silica, halloysite, zeolites, hydroxyapatite reservoirs, and microcapsules; chromate-free sol–gel and silane pretreatments based on organic–inorganic hybrid matrices, organosilanes, rare-earth inhibitors, and oxide nanoparticles; graphene and graphene oxide-based nanocomposite coatings in which two-dimensional fillers enhance tortuosity, reduce water uptake, and reinforce polymer matrices and coating–substrate interfaces; and electroactive coatings based mainly on polyaniline and polypyrrole, where protection is associated with passivation, redox mediation, and dopant-controlled inhibition. The findings indicate that corrosion-protective coatings have evolved through partially overlapping and increasingly integrated paradigms rather than through a single technological trajectory. This citation network analysis clarifies the transition from chromate replacement toward active, nanostructured, electroactive, and self-healing corrosion-protective systems. Full article

Micro- and nano-container-based self-healing coatings have emerged as a promising strategy for the long-term conservation of cultural heritage artifacts, including metals, stone, organic matter, and construction materials. These coatings incorporate microcapsules or nanocapsules with tailored shell and core materials, enabling autonomous release of healing agents or corrosion inhibitors in response to damage. For metallic artifacts, benzotriazole@mesoporous silica nanoparticles (BTA@MSN) microcapsules achieve selective pH-responsive release, reaching 77% at pH 9.0 and 42% at pH 5.0, effectively mitigating localized corrosion. Temperature-adaptive poly(methyl methacrylate-co-methacrylic acid) (PMMA-MA)/MgO microcapsules exhibit controlled rupture rates, with a 75% reduction at elevated temperatures, enhancing crack repair efficiency by approximately 5%. Organic artifacts, such as wooden or paper manuscripts, benefit from clove oil nanocapsules, which increase tensile strength by 43.5% and fracture toughness by 101.9%, with only 2.91% weight loss over 7 days compared to 33.1% for unencapsulated oil. Advanced fabrication methods—including microfluidics, Pickering emulsions, and multi-core systems—enable high encapsulation efficiency (up to 73.5%), uniform particle size, and repeatable healing. Multi-stimuli responsiveness (pH, temperature, light, magnetic fields) and biobased, environmentally friendly materials further enhance adaptability and sustainability. In this review, “self-healing” is defined broadly to include both physical crack repair and autonomous restoration of protective functions. Overall, self-healing micro/nanocapsule coatings provide a highly controllable, efficient, and durable solution for active heritage protection, representing a shift from passive to intelligent conservation strategies. Furthermore, a systematic comparison of different capsule systems is provided to clarify their respective advantages and limitations. Overall, hybrid systems exhibit the most balanced performance, while inorganic nanocontainers offer superior stability and controlled release, and polymeric capsules enable rapid healing but limited reusability. Full article

The objective of this study was to compare the protective effects of native and nanostructured quercetin on the initiation of oxidative stress in human keratinocytes exposed to tert-butyl hydroperoxide (tBHP). Quercetin was encapsulated within gelatin-based nanocontainers, forming nanoparticles with diameters ranging from 140 to 180 nm. Two formulations were prepared: uncoated gelatin nanoparticles (NP1) and gelatin nanoparticles coated with a shell composed of dextran sulfate and a chitosan–dextran copolymer (NP2). Cell viability was assessed using PrestoBlue™ reagent. Apoptotic and necrotic cell populations were identified via flow cytometry using an Annexin V-FITC/PI staining kit. DNA damage was evaluated using the comet assay. The results demonstrate that gelatin nanoparticles effectively encapsulate quercetin, and the nanostructured form enables its application in aqueous suspensions without compromising its antioxidant, gene-protective, and cytoprotective effects under conditions of cellular oxidative stress. These findings suggest that gelatin nanoparticles are suitable carriers for quercetin, owing to their high aqueous solubility, which may improve its potential for oral or topical delivery. Full article

Marine biofouling is a major global concern affecting the marine industry, the environment, and public health. The accumulation of organisms on submerged surfaces causes significant economic losses, including increased fuel consumption, higher pollutant emissions, and accelerated corrosion. Antifouling (AF) coatings with biocides are widely used to prevent this problem. However, many conventional biocides have been banned due to toxicity, creating an urgent need for environmentally friendly alternatives. In previous studies, we synthesized a gallic acid derivative and three flavonoids that showed AF activity against the settlement of mussel larvae (Mytilus galloprovincialis) together with low ecotoxicity. In the present work, to further assess their potential in marine coatings and exploit the advantages of nanocarriers in protecting and prolonging bioactive effects, these compounds were loaded into halloysite nanotubes (HNTs) and incorporated into epoxy coatings. Coatings containing the same AF compounds in free form were also prepared for comparison. HNTs were characterized by scanning electron microscopy (SEM), and compound loading was quantified by thermogravimetric (TG) analysis. The resulting composites were analyzed by SEM and dynamic water contact angle measurements. Laboratory bioassays with M. galloprovincialis larvae showed that coatings containing HNT-loaded synthetic compounds generally reduced larval settlement more effectively than the corresponding coatings containing the same compounds directly dispersed in the epoxy matrix, with values below 20% after both 15 and 40 h of exposure for the best-performing formulation. These findings highlight the novelty of the proposed HNT-based delivery strategy for nature-inspired synthetic antifoulants and support its potential for the development of effective and environmentally safer AF coatings. Full article

Framework nucleic acids (FNAs) are a class of nucleic acid-based nanostructures characterized by their unique precise structures, excellent biocompatibility and stability, robust loading capacity, and distinctive distribution and metabolic behaviors. They are widely applied in frontier fields such as nanodevices, biosensing, and drug delivery. In recent years, research on FNAs has gradually developed from the design and synthesis of nucleic acid nanostructures to practical applications, particularly in providing precise nanocontainers for heterogeneous molecular drugs such as small molecules, peptides, and proteins. Acting as a drug delivery system, FNA nanocontainers could be utilized to address multiple issues inherent in the application of heterogeneous molecular drugs, including hydrophobicity, affinity, and stability. However, they also face challenges such as low drug carrier capacity, potential immunogenicity, and insufficient long-term stability in vivo, necessitating the development of new strategies. This article focuses on composite drugs of small molecules, peptides, and proteins carried by FNAs, elucidates the design principles of FNA carriers, the interaction modes between FNAs and drug molecules, and the physicochemical properties and biological effects/efficacy of FNA–drug complexes, and summarizes the structure–activity relationship patterns. Furthermore, obstacles limiting clinical transformation are proposed to provide beneficial suggestions for the future development of FNA-based drugs. Full article

Marine biofouling presents a persistent challenge for maritime industries, necessitating the development of eco-friendly and intelligent antifouling strategies. In this work, an ATP-responsive nanocontainer was developed by encapsulating a natural organic compound (CS106-10), isolated from Talaromyces trachyspermus in cold seep sediments, together with D-phenylalanine (D-Phe) into ZIF-90 nanoparticles (D-Phe/CS106-10@ZIF-90). These nanoparticles were incorporated into zinc acrylate resin to fabricate a novel self-polishing antifouling coating. CS106-10, as a natural antifoulant, provided efficient and environmentally sustainable bactericidal activity, while D-Phe acted as a synergistic adjuvant to inhibit and disrupt biofilm formation. More importantly, the ATP-responsive ZIF-90 framework enabled controlled, on-demand release of antifouling agents in response to local metabolic signals associated with biofilm growth. Laboratory and real-sea evaluations confirmed that the composite coating effectively suppressed biofilm formation and significantly reduced the required dosage of conventional toxic antifoulants. This study integrates a natural antifoulant with an ATP-responsive metal–organic framework, providing new insight for developing antifouling coatings. Full article

We present a straightforward emulsion-induced interfacial anisotropic assembly method for in- situ synthesis of bowl-shaped, self-encapsulated mesoporous polydopamine (BMPDA) nanocontainers (M-M@P) loaded with 2-mercaptobenzimidazole (2-MBI). Results showed that the loading capacity of the bowl-shaped mesoporous polydopamine reaches 24 wt.%. The M-M@P exhibits a cumulative MBI release of 91.61% after immersion in a 3.5 wt.% NaCl solution at pH = 2 for 24 h, accompanied by a corrosion inhibition efficiency of 95.54%. Additionally, the acid-responsive M-M@P not only enables controlled release of MBI but also synergistically promotes the formation of a protective film on the carbon steel substrate via the chelation of PDA-Fe³⁺, thereby enhancing the self-healing performance of waterborne epoxy coatings. Full article

A new method of the design of stimuli-sensitive multiliposomal containers for encapsulation and controlled drug release is described. Despite quite a wide choice of pH-sensitive containers, there is still a considerable challenge to synthesize those that respond quickly to small variations in pH and release most of the encapsulated drug in a short time. The suggested AMS-containing multiliposomal complexes demonstrated an excellent rate of encapsulated substance release under altering the pH of the outer solution. To improve the efficiency of the delivery of bioactive compounds to target cells and to increase the therapeutic effect, pH-sensitive liposomes were concentrated on the surface of the carrier- PEG-coated cationic liposomes. A pH-sensitive ampholytic derivative of cholan-24-oic acid embedded into the membrane of anionic liposomes allowed the rapid release of the cargo in the areas of low pH, such as tumors, inflammation sites, etc. The diameter of the complexes was optimized for passive targeting and typically ranged from 250 to 400 nm. The biodegradability of liposomes ensured enzymatic destruction of the multiliposomal containers and their elimination from the body after performing their transport function. The multiliposomal complexes and products of their biodegradation demonstrated low cytotoxicity. The composition of multiliposomal complexes, in particular, the amount of PEGylated lipid in the bilayer, was estimated to provide a high speed of the cargo release upon changing the pH. The novel developed pH-sensitive containers show potential for biomedical applications. Full article

To address the issue of metal corrosion in marine environments, we developed a nanofiller with corrosion resistance and UV absorption capabilities. This nanofiller is prepared using a coprecipitation hydrothermal method and consists of TTA intercalated into an LDH structure with an outer layer containing CeO₂, forming a layered double hydroxide (LDH) sandwich structure nanocontainer. TTA can be successfully released in corrosive environments, and the filler exhibits excellent corrosion inhibition and interlayer ion exchange properties. Polarization curve analysis shows that the corrosion inhibition efficiency of MgAl-TTA LDH@CeO₂ reaches 89.87%. After immersion in a corrosion solution for 60 days, the EP/MgAl-TTA LDH@CeO₂ coating maintains a high impedance of 3.88 × 10⁸ Ω·cm² in the low-frequency region, which is 166 times that of the pure EP coating. Even after 240 h of UV aging, the impedance of the EP/MgAl-TTA LDH@CeO₂ coating remains high at 3.10 × 10⁸ Ω·cm² (20,000 times higher than the pure EP coating). This significantly enhances the coating’s anti-aging and corrosion resistance, providing a feasible method for creating new long-lasting corrosion-resistant coatings in challenging environments. Full article

The development of environmentally friendly materials is a subject of increasing interest in corrosion protection research. The objective of the present investigation is to propose the preparation procedure of chitosan–alginate (CHI/ALG) nanocontainers loaded with zinc oxide (ZnO) nanoparticles or combining ZnO nanoparticles with corrosion inhibitor caffeine (CAF), both suitable for incorporation into the matrix of ordinary zinc coatings on mild steel substrates. The nanocontainers were synthesized through spontaneous polysaccharide complexation in the presence of ZnO nanoparticles and CAF using a cross-linking agent, namely tripolyphosphate (TPP). Dynamic light scattering and laser Doppler velocimetry measurements are used for evaluation of the size distribution and zeta potentials of the nanocontainers, both loaded or unloaded with CAF. Using UV-spectroscopy, entrapment efficiency and release amounts of CAF are quantitatively evaluated. The nanocontainers thus obtained were incorporated into the matrices of ordinary zinc coatings via co-electrodeposition with zinc from zinc sulfate solution, aiming to improve the corrosion protection of steel in corrosive environments containing chloride ions. The surface morphology and elemental composition of the electrodeposited hybrid coatings before and after treating in the model corrosive medium of 3.5% NaCl is studied by scanning electron microscopy (SEM). The cyclic voltammetry method (CVA) is applied to characterize the cathodic (electrodeposition) and anodic (dissolution) processes. The protective characteristics of the hybrid coatings are investigated by application of potentiodynamic polarization (PDP) curves and polarization resistance (Rp) measurements after a time interval of 40 days. The obtained results indicate that both hybrid coating types could prolong the life time of mild steel in aggressive Cl⁻ ion-containing solution, combining the protection effect of sacrificial zinc with barrier (ZnO) and active (CAF) protective effects. Full article

Nanomaterials have attracted significant attention as signal reporters for immunoassays. They can directly generate detectable signals or release a large number of signaling elements for readout. Among various nanolabels, nanomaterials composed of multiple signaling molecules have shown great potential in immunoassays. Generally, signaling molecules can be entrapped in nanocontainers or self-assemble into nanostructures for signal amplification. In this review, we summarize the advances of signaling molecules-entrapped or assembled nanomaterials for colorimetric and fluorescence immunoassays. The nanocontainers cover liposomes, polymers, mesoporous silica, metal–organic frameworks (MOFs), various nanosheets, nanoflowers or nanocages, etc. Signaling molecules mainly refer to visible and/or fluorescent organic dyes. The design and application of immunoassays are emphasized from the perspective of nanocontainers, analytes, and analytical performances. In addition, the future challenges and research trends for the preparation of signaling molecules-entrapped or assembled nanolabels are briefly discussed. Full article

The article is devoted to the creation of enzymatic nanoreactors based on polystyrene–block–poly(acrylic acid) (PS-b-PAA) copolymers containing bioscavengers capable of neutralizing toxic esters both in the body and in the environment. Block copolymers of different amphiphilicity, hydrophilicity and molecular weights were synthesized and characterized using gel permeation chromatography, NMR and UV spectroscopy. Polymeric nanocontainers in the absence and presence of human butyrylcholinesterase were made by film hydration and characterized by dynamic light scattering and microscopy methods. Enzyme activity was determined using the Ellman method. For the first time, factors that need to be taken into account for the creation of effective enzymatic nanoreactors based on PS-b-PAA are presented. The data obtained open up the possibility of PS-b-PAA nanoreactor use for future in vivo bioscavenger studies. Full article

Outdoor bronze statues are constantly exposed to weather conditions and reactive compounds in the atmosphere that can interact with their surfaces. To avoid these interactions, a commonly used method is the application of coatings with corrosion inhibitors. However, a significant limitation of these inhibitors is their gradual loss over time. In this study, we aimed to improve the durability of 5-ethyl-1,3,4-thiadiazol-2-amine (AEDTA), the inhibitor chosen to formulate new acrylic coatings for outdoor bronzes. Methyl-β-cyclodextrin (Me-β-CD) was selected to host the inhibitor due to the capability of cyclodextrins to form complexes incorporating small organic molecules. The complexes of Me-β-CD and AEDTA were prepared and the inclusion of AEDTA was proved by Fourier-transform infrared spectroscopy, X-ray diffraction and nuclear magnetic resonance spectroscopy. Then, acrylic coatings were prepared at different concentrations of the Me-β-CD/AEDTA system. They were thermally aged and monitored every 24 h. To evaluate the volatilization of the corrosion inhibitor, solid phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS) and thermal desorption-GC/MS (TD-GC/MS) analyses were performed during the first 72 h. The results were compared to those of pure AEDTA films and Incralac^®. The outcomes showed that Me-β-CD/AEDTA complexes are promising candidates for developing coatings with improved stability and longer retention of AEDTA. Full article

The concept of intelligence has many applications, such as in coatings and cyber security. Smart coatings have the ability to sense and/or respond to external stimuli and generally interact with their environment. Self-healing coatings represent a significant advance in improving material durability and performance using microcapsules and nanocontainers loaded with self-healing agents, catalysts, corrosion inhibitors, and water-repellents. These smart coatings can repair damage on their own and restore mechanical properties without external intervention and are inspired by biological systems. Properties that are affected by either momentary or continuous external stimuli in smart coatings include corrosion, fouling, fungal, self-healing, piezoelectric, and microbiological properties. These coating properties can be obtained via combinations of either organic or inorganic polymer phases, additives, and pigments. In this article, a review of the advancements in micro/nanocapsules for self-healing coatings is reported from the aspect of extrinsic self-healing ability. The concept of extrinsic self-healing coatings is based on the use of capsules or multichannel vascular systems loaded with healing agents/inhibitors. The result is that self-healing coatings exhibit improved properties compared to traditional coatings. Self-healing anticorrosive coating not only enhances passive barrier function but also realizes active defense. As a result, there is a significant improvement in the service life and overall performance of the coating. Future research should be devoted to refining self-healing mechanisms and developing cost-effective solutions for a wide range of industrial applications. Full article