The field of wound healing has seen remarkable progress in recent years, and one of the most exciting innovations is the integration of 4D bioprinting with advanced coatings. 4D bioprinting, an emerging technology that adds the dimension of time to 3D printing, holds transformative potential in creating dynamic, adaptive, and self-regenerating tissue structures. This technology allows the fabrication of biocompatible materials that can respond to environmental stimuli, such as changes in temperature, pH, or mechanical forces, to enhance tissue regeneration.

By incorporating advanced coatings—composed of plant-based bioactive compounds (e.g., polyphenols) or nanomaterials (e.g., silver nanoparticles in hydrogels) and structured as thin, porous layers—into 4D-bioprinted scaffolds, we can create more effective, multifunctional systems for wound care. These coatings interact with the 4D structures by releasing therapeutic agents in response to the scaffolds’ shape or porosity changes over time, facilitating controlled delivery to the wound site. This approach’s novelty lies in the combination of time-responsive 4D-bioprinted structures with bioactive coatings that offer enhanced biocompatibility, antibacterial properties, and promote cellular activities necessary for wound closure, such as migration, proliferation, and extracellular matrix formation. Integrating such coatings with 4D-printed matrices creates dynamic wound-healing environments capable of responding to changes in the wound’s condition over time, optimizing healing and reducing the risk of chronic wounds.

This abstract discusses the potential of 4D bioprinting combined with advanced coatings to revolutionize wound healing by providing customized, adaptive solutions that address both immediate and long-term challenges in tissue regeneration. The proposed technology could significantly improve the efficacy and sustainability of wound care treatments, paving the way for more personalized, precision medicine approaches in the management of complex wounds.

The surface modification of titanium implants is essential for improving osteointegration and cellular contact, since untreated surfaces may result in fibrous tissue growth and an elevated risk of infections, hence diminishing implant efficacy. Plasma chemical treatment is an environmentally sustainable technique for applying polymer coatings to various surfaces, enabling meticulous regulation of surface characteristics. The integration of functional groups, including carboxyl and amino groups, enhances hydrophilicity and tissue contact, rendering these coatings particularly advantageous for biomedical applications. This study examines the impact of several plasma chemical treatments on the surface characteristics of titanium implants.

Plasma modification was conducted with the ZP-COVANCE-RFPE-3MP plasma system (13.56 MHz). Three therapy modalities were evaluated, commencing with plasma chemical activation in an Ar/O₂ environment (200 W, 10 minutes). In the initial mode, activated samples were submerged in a 25% collagen solution for one hour. The second approach entailed the deposition of amino groups by cyclopropylamine (C₃H₅NH₂) in a CPA/Ar plasma at 50 W. The third mode introduced carboxyl groups via a gas combination of Ar, CO₂, and C₂H₄ at 150 W. Plasma-deposited polymer films were examined utilizing SEM, EDX, XPS, FTIR, and WCA techniques. The adhesion and proliferation of mesenchymal stem cells were quantitatively assessed through fluorescence microscopy.

Plasma deposition yielded homogenous, well-adhered layers devoid of pinholes or fissures, as evidenced by SEM micrographs. Wettability assessments demonstrated a substantial enhancement, with an approximately 100° decrease in the contact angle in the optimal mode alongside notable stability. The coatings facilitated improved adherence and proliferation of mesenchymal stem cells.

Plasma treatment of titanium implants enhanced surface characteristics and biocompatibility. These findings underscore the promise of plasma-deposited polymer coatings for biomedical applications.

This research was funded by the Russian Science Foundation (№24-79-10121).

Introduction

High-performance steels have multiple applications; they are frequently used in tools for the manufacture of aluminium alloy parts, for instance, injection moulds, extrusion and stamping tools, or in forging dies. These materials provide high mechanical strength and high wear resistance during high-temperature operation. Their heat treatment determines the compromise between fracture toughness and hardness for each application. Thus, the degree of quenching and tempering is frequently selected based on these parameters. However, the mechanical durability of these materials is very sensitive to their surface condition and contact with potentially corrosive fluids. On the other hand, in the case of aluminium parts manufactured by this process, the use of surface treatments is very common in improving the finished component's performance. These treatments may or may not point to improvement in mechanical durability. Nevertheless, they can be a determining factor on the fatigue resistance of the manufactured component.

Methods

For this work, the effect of the surface state, the contact with operational fluids, and different surface treatments on fatigue resistance has been studied experimentally. The fundamental materials of the hot forging process, both the high-performance steels used for the dies, and the aluminium alloys of the manufactured components, have been studied. Surface modification treatments such as shot peening and anodisation have been tested, and their influence on the mechanical durability was assessed.

Results and conclusions

The results of this work confirm the sensitivity of fatigue resistance, both in low-cycle and high-cycle regimes, for high-performance steels when exposed to aggressive environments that can generate surface corrosion. Likewise, the behaviours of high-strength aluminium alloys, when subjected to surface finishing treatments for increasing mechanical durability and corrosion resistance, such as shot peening and anodisation, respectively, are presented.

Biobased and home-compostable films were produced by blending poly(lactic acid) (PLA) and poly(butylene succinate-co-adipate) (PBSA). These films, which can be applied on different substrates by exploiting their thermoplastic feature, were found to be easily recyclable in an industrial environment. The composition of PLA/PBSA blends, produced using a mini-extruder, was varied to identify the films with the best barrier properties for perishable liquid foods, such as whey. The weight of the whey contained in the sealed film was measured over time. The blends were also evaluated for their mechanical and melt fluidity properties, as well as their surface composition, using infrared spectroscopy. The results demonstrated that the composition of the blends significantly influenced the barrier properties of the films.

These findings are not only applicable to dairy products but also hold potential for packaging perishable fruits, which are abundant in the Mediterranean region. Fruits such as strawberries, dates, and tangerines could benefit from this innovative packaging solution. The high availability of these fruits in the Mediterranean area makes the hereby proposedapplication particularly relevant. The development of such films could contribute to reducing food waste and improving the shelf life of perishable goods, thereby offering a sustainable and practical packaging alternative. This research highlights the importance of material composition in designing effective and environmentally friendly packaging solutions.

Cold spraying is a prominent solid-state deposition technique for depositing nickel-based alloy coatings without causing microstructural changes due to its lower operating temperatures than other thermal spray processes. However, depositing nickel-based coatings via cold spraying is more challenging than other metals due to their thermo-mechanical behavior. Thermal sensitivity (m), a constant parameter in the Johnson–Cook (JC) plasticity model, is used to estimate the flow stress of plastically deformed materials at higher strain rates. Since nickel-based alloys such as NiCr, IN625, and IN718 alloys exhibit high thermal sensitivity (m>1), their deposition becomes easier at elevated particle temperatures, particularly when air is used as a process gas instead of more expensive gases like nitrogen or helium. In this work, higher particle temperatures were achieved by increasing the stagnation temperature and the nozzle convergent length. In cold-sprayed coatings, corrosion liquids percolate through unbonded inter-splat boundaries, significantly affecting the corrosion rate. These unbonded boundaries also contribute to a reduction in the elastic modulus. Hence, this study examines the effect of particle temperature on the inter-splat bonding percentage of as-sprayed and heat-treated coatings and its impact on oxidation, corrosion resistance, and elastic modulus. The inter-splat bonding is estimated through numerical simulation using ABAQUS explicit code. The results demonstrate that increasing the particle temperature enhances the oxidation resistance for NiCr coatings. The parabolic oxidation rate is constant for coatings deposited using air as the process gas, comparable to that obtained from other thermal spray techniques (such as Arc spray and HVOF). Corrosion resistance is higher and equivalent to the bulk Inconel after the heat treatment of the coating, which is deposited at a higher stagnation temperature. The elastic modulus was estimated through numerical simulation, and nanoindentation was validated. The obtained results demonstrated that the estimated modulus is improved with inter-splat bonding percentage.