Self-cleaning materials are highly relevant for exterior surfaces, such as building facades, and for heritage conservation by preserving the original aesthetic appearance of surfaces with minimal effort and cost. The transparency of these coatings is essential to maintain the visual integrity of existing surfaces. In this context, nanotechnology has emerged as a promising alternative, introducing innovations in coatings and treatments that provide water resistance, self-cleaning properties, and protection against biological attack. Despite their potential, implementing these coatings on cementitious surfaces poses challenges related to long-term stability and performance. Unfixed particles are susceptible to displacement by environmental factors such as rain, wind, and wear, compromising durability and reducing their ability to degrade pollutants and maintain clean facades. This study developed self-cleaning cementitious panels by incorporating TiO₂ nanoparticles and ZnO microparticles at varying concentrations, applied using two deposition methods: spray and dip-coating. Rhodamine B (RhB), an organic dye, was used as a model pollutant to assess self-cleaning performance by monitoring dye degradation during irradiation cycles under simulated sunlight. A spectrophotometric analysis was conducted using the CIELAB color coordinate system to measure chromatic variation and evaluate self-cleaning efficiency. The effect of epoxy resin as a particle immobilizer was also examined, focusing on aesthetic preservation and photocatalytic performance. The results showed that neither the photocatalytic coating nor the resin significantly altered substrate aesthetics, confirming their suitability for facades and heritage preservation. Additionally, photocatalytic coatings improved the surfaces' self-cleaning properties; however, a slight reduction in photocatalytic efficiency was observed with resin application, likely due to a decrease in the photocatalyst’s active surface area. This highlights the need for further research into alternative resins or surface treatments that optimize particle fixation while maintaining high photocatalytic activity.

Can ensuring the longevity of decorative exterior coatings be as difficult a task as Goethe wrote Faust? The answer is probably not. Fortunately, more and more advanced auxiliaries and binders come to our aid. Moreover, the durability of coatings is significantly influenced by the pigments themselves and their compositions used during formulation. The key assumption of this project is to assess the probability of selecting raw materials and modifying topcoats subjected to aging tests under cyclically changing conditions (temperature, humidity and radiation) in order to maximally extend their usability, by maintaining, among others, colour and gloss. Thus, colour compositions based on two polyurethane binders dedicated to topcoats and pigments in shades of yellow, red and blue were tested. The change in colour, gloss, water contact angles, chemical structure (FTIR) and morphology (SEM) of coatings placed in climatic chambers and exposed to xenon lamps and/or UV were determined. It was shown that the factor with the greatest influence on the change in the performance parameters of coatings is UV radiation. The preservation of the decorative values ​​of coatings also depended on the qualitative composition of the pigments used in each colour group. Changes in humidity and temperature had a slightly smaller effect. In all tests, the surface free energy value and the structure and topography of the coatings did not differ significantly. Based on the obtained results, cycles with a full spectrum of impact on the coatings were selected and ranked, from those causing the least degree of degradation to those showing the most negative impact on the usability of the coatings.

Acknowledgments: The research work was carried out under the project ColourTune CORNET/31/20/2022 entitled "Tuning the colour of topcoats – method for selection of pigments and safeguarding colour stability" funded by the National Centre for Research and Development.

Wood has been used as a construction material for small objects, furniture, and large-scale buildings since antiquity. The protection of wooden objects and wooden buildings of significant cultural heritage from water-induced decay processes is of great importance. In the present work, hybrid coatings consisting of Sivo 121 and nanolignin were produced and deposited onto chestnut (Castanea sativa) and oak (Quercus frainetto) specimens. Sivo 121 is an aqueous siloxane-based product which is used for wood protection, whereas nanolignin was extracted from beechwood.

The effects of the nanolignin concentration on the wetting properties and surface structures of the hybrid coatings were investigated and an optimal Sivo/nanolignin mass ratio was found for each wood species. This optimal ratio provided enhanced hydrophobicity, as demonstrated by the elevated contact angles (CAs) of water drops. The maximum CA of 145° was measured for coated oak, which is approaching the threshold of superhydrophobicity. However, the rose-petal effect was evident, with water drops remaining pinned even when the coated samples were tilted to a perpendicular position. Notably, the drops rolled off the coatings' surfaces when the coated wood samples were agitated.

The performance of the hybrid coating with the optimal Sivo/nanolignin mass ratio was evaluated through a series of tests. The coating caused only minor alterations to the natural colour of the two untreated woods (ΔE<5) and offered very good protection against water absorption through capillarity. The results of the graveyard durability test highlighted the treatment's protective efficacy. Furthermore, the coating exhibited excellent chemical and mechanical stability, as confirmed by applying drops of various pHs and conducting the tape peeling test. Finally, the CAs of the coated chestnut and oak were monitored over time after placing the samples outdoors and within an artificially accelerated aging chamber. The results showed that the CAs remained stable over time, confirming the coating's durability.

The success of an implant depends on its osseointegration, while its long-term survival is determined by its resistance to bacterial infections. Titanium, commonly used for its mechanical properties and corrosion resistance, has limitations regarding its osteointegration and antibacterial efficiency ^[1,2]. The present work's aim is to functionalize the Ti surface with hydroxyapatite doped with copper, known for its antibacterial properties and ability to stimulate bone regeneration.

The coatings were obtained by electrochemical deposition of HAp on Ti and subsequent doping by an ion exchange method with a copper solution. The HAp deposition was carried out in pulsed galvanostatic mode at 75°C from two types of electrolytes: Ca nitrate and Ca chlorate salts. The coatings were characterized in terms of morphology, chemical and phase composition, surface roughness, and thickness. SEM images showed that the HAp coating morphology consists of ribbon-like crystals, irrespective of the electrolyte or the presence of Cu. The EDS analysis highlighted the presence of Cu ions and a (Ca+Cu)/P ratio between 1.54 and 1.59. In terms of coating thickness, it was noted that when chloride salts were used, the thickness was smaller than when nitrates were used. Cu addition to HAp resulted in a slight decrease in thickness, regardless of the electrolyte. XRD analysis confirmed the presence of the HAp phase and HAp coatings successfully doped with Cu.

In conclusion, it can be stated that hydroxyapatite-based coatings obtained through electrochemical techniques can be successfully doped with copper by using the ion exchange method.

[1] F. A. Al-Mulhim, M. A. Baragbah, M. Sadat-Ali, A. S. Alomran, M. Q. Azam, Int Surg 2014, 99, 264.

[2] D. M. Vranceanu, E. Ungureanu, I. C. Ionescu, A. C. Parau, V. Pruna, I. Titorencu, M. Badea, C.-Ștefania Gălbău, M. Idomir, M. Dinu, A. V. (Dragomir), C. M. Cotrut, Biomimetics 2024, 9, 244.

Mg alloys are promising materials for implants due to their biodegradability which can allow the gradual substitution of the implant with new bone. On the other hand, their degradation rate is actually too rapid to match bone regeneration, reducing their clinical application. Moreover, inflammation, pH rise and hydrogen development are often associated with Mg alloy degradation, representing a further obstacle. The aim of this research is the development of natural coatings able to tailor the degradation rate of AZ91 Mg alloy. Polyphenol-based coatings can also add anti-inflammatory and pro-osteogenic properties to the implant. AZ91 Mg alloy was considered as substrate in the form of plane samples or 3D porous structures (by a combination of 3D printing and investment casting). Aqueous solutions of tannic acid (TA) or green tea polyphenols (TPH) were used for the obtainment of natural organic coatings. The combination of the PEO (Plasma Electrolytic Oxidation) of the AZ91 substrate and subsequent polyphenol coating was also considered. The process was optimized to maximize coating homogeneity and absence of cracks. Soaking is a simple and suitable strategy for the treatment of various samples, including complex porous structures, thus assuring homogeneity. Continuous thin coatings were obtained with TA, but the presence of small (micrometric) cracks was evidenced on these surfaces. TPH coatings resulted in thicker layer, with a globular morphology and free of cracks. In static degradation studies (PBS soaking) pH and degradation control were reached more effectively for tannic acid coatings, compared to the TPH ones. On the other hand, TPH coatings resulted in more effective corrosion protection in electrochemical tests. Preliminary investigations showed the possibility of obtaining uniform thin TPH coating on PEO-coated AZ91 samples able to control pH rise and degradation in PBS. Tannic acid and Tea Polyphenols were successfully employed for the obtainment of natural organic coatings for degradation control in AZ91 Mg alloy for orthopedic applications.

Introduction: Plant-derived oils and fats are estimated to constitute at least 79% of annual global oil production. Flaxseed oil, which is rich in omega-3 fatty acids, has been linked to the prevention and reduction of several serious health conditions, including cancer, diabetes, atherosclerosis, hypertension, eczema, gastrointestinal disorders, and cardiovascular diseases. Despite its numerous health benefits, flaxseed oil is susceptible to oxidation. The process of extracting flaxseed oil from flaxseeds yields an equivalent to 32–45% of the seed mass, with the oil containing 55–57% alpha-linolenic acid (ALA) and 15–18% linolenic acid (n-6). Mixing flaxseed oil with other oils, such as olive and sesame, can create a balanced fatty acid profile while preserving oxidative stability. However, during storage, the peroxide and anisidine values of these oil blends tend to increase.

Methods and Materials: Microencapsulation techniques have been developed to enhance the stability and use of flaxseed oil in food products.

Results: Flaxseed, packed with alpha-linolenic acid, lignans, and fiber, provides multiple health benefits. A regular intake of flaxseed may enhance lipid metabolism, reduce hypertension, regulate blood sugar, and mitigate insulin resistance. Scientific studies focus on protective processing methods like coating milled flaxseed with Arabic gum, ascorbic acid, and hydrogenated fats to minimize its oxidation. Microencapsulation shields oxidation-sensitive compounds in foods, improving their stability. The key methods used in microencapsulation include physical (spray/freeze drying), chemical (interfacial polymerization/cross-linking), and physico-chemical (ionic gelation/coacervation) techniques. Incorporating flaxseed oil into zein films boosts their tensile strength and moisture resistance, while maltodextrin with sodium caseinate demonstrated the optimal encapsulation performance. These strategies enable the effective integration of flaxseed into foods while preserving their nutritional potency and absorption.

Conclusions: As a result, the food industry can develop functional products that harness the health-promoting properties of flaxseed oil while ensuring product stability and quality.

Flavonoid-based compounds have attracted significant attention in cancer research due to their potent anticancer properties, including their antioxidant, anti-inflammatory, and anti-proliferative effects. However, their application is often hindered by challenges such as their poor solubility, low bioavailability, and instability under physiological conditions. The MET-EFFECT project (EU-funded under HORIZON-MSCA-SE-2021) aims to address these limitations and focuses on the development of novel multifunctional flavonoid complexes based on rhenium and iridium, with the aim of these serving as metallodrugs and homogenous catalysts. Additionally, the project will propose personalized drug design delivery systems using new green methodologies for valorization in order to improve the delivery and bioavailability of active constituents with potential anticancer properties. These coatings will be tailored to provide controlled release mechanisms that enhance the bioavailability of the active compounds and ensure their targeted delivery to cancerous tissues. The ability to immobilize these biofunctional molecules within films and coatings holds significant potential in advancing the field of drug delivery, enhancing therapeutic efficacy, and contributing to the development of next-generation anticancer therapies. Therefore, the MET-EFFECT project will offer a cutting-edge approach to overcoming the current barriers in cancer treatment by harnessing the power of novel flavonoid-based complexes incorporated into functionalized coatings, presenting a promising solution for localized drug delivery and improved therapeutic outcomes.

Gelatin-based hydrogels incorporating chitosan-encapsulated essential oil microcapsules have emerged as promising antimicrobial materials for biomedical applications. These hydrogels offer a biocompatible and biodegradable platform with enhanced antibacterial efficacy against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. Chitosan provides inherent antimicrobial properties while acting as an effective carrier for essential oils, ensuring controlled release and prolonged antibacterial activity. The hydrogel matrix typically consists of 5–15% (w/v) gelatin and 1–5% (w/v) chitosan, and crosslinking agents at 0.1–1% (w/v) are used to enhance mechanical stability. Chitosan acts as both a structural component and an antimicrobial agent while also serving as an effective carrier for essential oils. Essential oils such as peppermint (1–2%), clove (0.5–2%), cinnamon (1–3%), and ginger (1–1.5%) were encapsulated (essential oil-to-chitosan ratio: 1:3 to 1:5), and an encapsulation efficiency of 70–90% was achieved. The antibacterial mechanism is attributed to chitosan’s electrostatic interactions with bacterial cell membranes and the sustained controlled release of bioactive compounds. The hydrogels also offer moisture retention, mechanical stability, and barrier protection, making them highly suitable for wound dressings, tissue engineering, and infection prevention. Recent studies have shown that gelatin–chitosan hydrogels incorporating essential oils not only enhance antibacterial efficacy but also support cellular proliferation and tissue regeneration. Therefore, due to their multifaceted advantages, the hydrogels represent a significant advancement in biomedical coatings. Further research is needed to optimize formulation parameters and evaluate long-term biocompatibility for clinical applications.

Plasma electrolytic oxidation (PEO) coatings and biodegradable polymers such as polylactic acid (PLA) present interest as drug-eluting systems for osseointegrated biomedical implants. Given the biodegradable nature of PLA, the coating system may induce crevices at one or more interfaces during degradation. Crevices are known to severely affect the corrosion performance of additively manufactured (AM) Ti alloys. Therefore, understanding the interactions between the PEO/PLA system and titanium alloys is crucial for enhancing the longevity of implants. This study investigates the corrosion of mill-annealed and AM Ti-6Al-4V alloys functionalized with porous hybrid hierarchical coatings comprising a ceramic layer produced by plasma electrolytic oxidation and one or more polylactic acid layers.

PEO coatings were formed using an AC power supply on wrought and DMSL-produced Ti6Al4V. PLA was applied on PEO-coated samples by dip-coating using the “breath figures” technique. Optical profilometry, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) were utilized to assess the topography, morphology, phase composition, and elemental distribution in the coated alloys. Corrosion performance was evaluated through DC and AC electrochemical tests, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), conducted in a simulated body-fluid at 37 ºC to mimic real-world conditions, including the presence of a controlled-size crevice.

The results revealed ~3.5-5.5 µm thick anatase- and rutile-based coatings enriched in several bioactive elements, at.%: 7.6% Ca, 5.76% P, 0.23% Zn, 1.5% Mg, 3.52 %Si. The ~2 µm thick PLA layer featured a 1-6 µm pore size and ~75000 pores mm^-2. The PEO coating helped in avoiding the localized corrosion of AM Ti6Al4V. The post-corrosion characterization also elucidates the role of biodegradable sealing layers in crevice formation.

In conclusion, the PEO/PLA system is a viable coating material for enhancing the durability of AM Ti6Al4V. This research provides a foundation for future studies aimed at exploring alternative biodegradable materials as drug-eluting media.

Introduction: The development of advanced coatings can play a pivotal role in combating antimicrobial resistance infections and the severe threats they pose to modern societies. To this end, the presentation will focus on a new family of layer-by-layer antimicrobial coatings that capitalise on the electrostatic attractions between negatively charged Nafion and positively charged graphene quantum dots (GQDs) and graphene oxide (GO).

Methods: Quartz crystal microbalance is used to monitor the build-up of nanocoatings in real time. Zeta potential measurements, Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and contact angle measurements were used to characterise the materials that were also assessed with respect to their antimicrobial performance against E. coli and S. aureus.

Results: Nafion demonstrates superior chemical, thermal, and mechanical stability stemming from its Teflon-like backbone coupled with its long-range bacteria exclusion zone (EZ) associated with the presence of charged pendant groups. The chemical modes of the bactericide activity of GQDs and GO are related to the induction of membrane stress and the release of reactive oxygen species (ROS), as well as binding with DNA to restrain cell proliferation and arrest gene expression. The Nafion/GO and Nafion/GQD nanocoatings can effectively inhibit the growth of representative Gram-positive and Gram-negative bacteria by more than 99%, and this performance is not compromised following extensive thermal annealing.

Conclusion: In addition to their excellent antimicrobial performance, the nanocoatings combine a number of attractive characteristics including structural and chemical stability, non-toxic characteristics, superior UV barrier properties along with their waterborne, transparent, and colourless nature. The nanocoatings are able to withstand dry heat sterilisation and are ideal for surgical blades, surfaces used for food processing and storage, and packaging for cosmetics, drugs, and biological materials.