Chromium nitride (CrN) can be used as a coating material deposited via physical vapour deposition (PVD), thereby improving the corrosion and wear resistance of the substrate. However, this level of corrosion protection may not be sufficient in an aggressive corrosion environment. The coatings often contain intrinsic microstructural defects, such as microcraters, which can serve as pathways for the corrosive medium to reach the substrate, thereby initiating and promoting corrosion. In this study, the influence of parameters on the formation of a TiO₂ layer using the ALD technique was investigated. In particular, the work focused on assessing the effectiveness of the TiO₂ layer as a sealing barrier for CrN coatings (PVD) applied to austenitic 316L steel. The TiO₂ ALD coatings were produced at a constant temperature of 200 °C with a varying number of cycles, ranging from 200 to 1000 cycles. Structural investigations were carried out using scanning electron microscopy SEM and atomic force microscopy. Electrochemical properties were investigated using a potentiodynamic test and electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution. SEM observations indicate that the morphology of the hybrid coatings is strongly influenced by the number of ALD cycles. The TiO₂ layer conformally reproduces the underlying PVD topography while progressively sealing the coating by filling intrinsic defects and discontinuities. Hybrid coatings (PVD/ALD) with titanium oxide deposited at 500 ALD cycles were found to have the best corrosion resistance. The polarisation resistance for these coatings was nearly four times higher than that of both the single PVD (CrN) coating and the uncoated stainless steel 316L substrate. At the same time, the corrosion current density was several times lower than that of the reference systems. The corrosion mechanisms were investigated by observing the surfaces of the samples after corrosion testing using SEM. Abrasion resistance tests using the pin-on-disc method and adhesion tests (scratch tests) were also performed, which showed that appropriate optimisation of the layer architecture in the PVD/ALD hybrid system significantly improves its tribological durability, interlayer stability, and adhesion to the substrate.

Zinc oxide (ZnO) is currently one of the most significant wide-bandgap semiconductor materials, attracting extensive research across diverse fields including materials science, chemistry, physics, medicine, electronics, and power engineering. Its exceptional properties, such as high optical transparency, high electron mobility, chemical stability, and compatibility with low-cost fabrication techniques, have established ZnO as a versatile material with immense application potential. A critical application for ZnO is its role as a transparent conducting oxide (TCO) in modern optoelectronic and photovoltaic devices, as well as in sensors, transparent electronics, and spintronics. To meet the requirements of these advanced applications, precise control over the structural, optical, and electrical properties of ZnO thin films is essential. This is effectively achieved through the selection of specific synthesis methods and intentional modification techniques, such as doping. This review provides a comprehensive overview of the synthesis and modification of ZnO thin films, with a particular focus on how various dopants influence their fundamental characteristics. The work discusses a range of deposition techniques, including physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), sol–gel methods, spray pyrolysis, and other solution-based approaches. The novelty of this review lies in its comparative analysis of different doping strategies combined with various thin-film deposition techniques, highlighting how specific synthesis routes influence dopant incorporation and ultimately determine functional properties. Furthermore, recent advances in tailoring ZnO thin films are summarized, alongside the identification of key challenges and future research directions. Ultimately, this work aims to provide researchers with a systematic perspective on the synthesis–structure–property relationships in doped ZnO thin films to support the development of optimized materials for next-generation electronic and optoelectronic devices. This review, thus, serves as a comprehensive reference for researchers and engineers seeking to optimize the functionality of ZnO-based thin films for emerging technological applications.

Bacterial biofilm formation remains a critical challenge in modern implantology, significantly contributing to peri-implant infections and implant failure. This phenomenon is strongly influenced by the physicochemical properties of implant surfaces, which govern corrosion behavior as well as bacterial adhesion and proliferation. Due to the high resistance of biofilms to antibiotics and antiseptics, conventional therapeutic approaches are often ineffective, emphasizing the need for preventive strategies based on surface modification.Titanium alloys, particularly Ti-13Nb-13Zr, are widely applied in orthopedic and dental implants owing to their excellent mechanical properties and corrosion resistance. However, their susceptibility to microbial colonization and degradation in physiological environments limits long-term performance. Consequently, there is a need to develop surface coatings that enhance both electrochemical stability and antibacterial performance.Tin oxide (SnO₂) represents a promising candidate due to its antibacterial properties and low cytotoxicity. The application of atomic layer deposition (ALD) enables the fabrication of uniform, conformal coatings with precise thickness control, even on complex implant geometries.This study evaluates the electrochemical and biological properties of Ti-13Nb-13Zr modified with ALD-deposited SnO₂ coatings. Results indicate improved corrosion resistance and reduced bacterial adhesion, demonstrating the potential of such modifications to enhance implant durability and safety.

Tantalum pentoxide (Ta₂O₅) coatings deposited via atomic layer deposition (ALD) have emerged as promising protective barriers for NiTi shape memory alloys in biomedical applications. This study investigates the influence of 800 ALD cycles on the structural, tribological, and electrochemical stability of NiTi substrates during long-term exposure to physiological environments. A conformal, amorphous Ta₂O₅ layer with a thickness of ∼65 nm was achieved, effectively sealing the substrate topography. Our findings reveal that while the coating initially maintains a hydrophilic character, prolonged incubation (60 days) in PBS solution triggers a transition to a hydrophobic state of 104 ± 3°, driven by the accumulation of Ca- and P-mineralized deposits. Tribological assessments demonstrate that the Ta₂O₅ overlayer enhances wear resistance and load-bearing capacity, despite localized microdelamination observed postexposure. Most notably, the ALD coating acts as a robust diffusion barrier, reducing the corrosion current density to 7.60 × 10^–8 A/cm² and maintaining a high polarization resistance even after 60 days of incubation. These results highlight the efficacy of Ta₂O₅ overlayers in providing long-term biostability and corrosion protection for NiTi-based implants in demanding physiological conditions.

Breast implants are among the most frequently used long-term implantable medical devices in aesthetic and reconstructive surgery. In addition to correcting anatomical deficits, they have significant psychosocial effects, influencing body image, self-esteem, and quality of life, particularly in patients undergoing postmastectomy reconstruction. This review provides a comprehensive overview of the historical development, biological interactions, material characteristics, and clinical outcomes of breast implants. Early reconstructive attempts using foreign materials and injectable substances were associated with severe complications, underscoring the need for safer technologies. The introduction of silicone gel implants in the 1960s marked a pivotal advancement, followed by the development of saline-filled devices and highly cohesive silicone gels with enhanced mechanical stability. Key surgical considerations, including incision type and implant placement plane (subglandular, submuscular, dual-plane, and subfascial), are discussed in relation to aesthetic outcomes and complication risk. Emphasis is placed on the implant–tissue interface and the foreign body response (FBR), a process involving protein adsorption, immune cell activation, fibrous capsule formation, and potential chronic inflammation. Persistent inflammatory stimulation, often associated with bacterial biofilm formation, contributes to capsular contracture, the most common long-term complication. Additional adverse events include implant rupture, silicone gel bleed, granulomatous reactions, infection, hematoma, implant malposition, and rare but clinically significant conditions such as breast implant-associated anaplastic large cell lymphoma (BIA-ALCL). The review also summarizes implant classification according to construction, filling material, shape, and surface topography, highlighting the influence of surface characteristics on host response and clinical outcomes. Advances in biomaterials, cohesive gel formulations, and surface engineering aim to enhance biocompatibility and long-term safety, supported by standardized mechanical and biological testing protocols.

Co–Cr alloys are widely used in biomedical devices owing to their excellent mechanical properties and corrosion resistance; however, sustained metal-ion release in physiological environments remains an important materials concern. Low-temperature atomic layer deposition (ALD) enables the formation of conformal ceramic barriers that can restrict long-term metal-ion transport. In this study, nominally ~50 nm ALD-derived ZrO₂ coatings were deposited on Co–Cr substrates manufactured by investment casting (CAST), CAD/CAM milling (MILLED), and laser powder bed fusion (PRINTED). The coatings were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy, transmission electron microscopy with selected-area electron diffraction (TEM/SAED), and X-ray photoelectron spectroscopy (XPS), while the electrochemical response was evaluated by open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). Long-term barrier performance was quantified by inductively coupled plasma atomic emission spectroscopy (ICP-AES) as cumulative Co and Cr release for all manufacturing routes and Mo release for the Mo-containing CAST and PRINTED alloys after 28 days in artificial saliva at 37 °C. ZrO₂ deposition reduced cumulative Co and Cr release for all manufacturing routes. Mo release was also reduced in the Mo-containing alloys, with Mo remaining below the analytical detection limit (<0.005 µg cm⁻²) for the PRINTED + ZrO₂ system. Electrochemical measurements further demonstrated manufacturing-route-dependent differences in barrier response between the initial and 28-day exposure states. Overall, the findings establish a structure–barrier–release framework linking coating formation and electrochemical response with cumulative ion release, and identify 28-day cumulative ion release as a practical functional descriptor for comparing the long-term performance of ALD-derived ceramic barriers on Co–Cr alloys.