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.

Magnesium alloys are promising materials for orthopedic applications due to their biodegradability and mechanical properties compatible with bone. However, their rapid degradation in physiological environments limits clinical use. In this study, WE43B magnesium alloy was coated with a PEO layer followed by a P(L/G/TMC) polymer applied via ultrasonic spraying. The influence of polymer layer number (10, 20, 30) on coating properties was systematically investigated. Scanning electron microscopy (SEM) analysis revealed an approximately fourfold reduction in porosity after polymer deposition, with progressive pore filling at higher layer numbers, while Fourier transform infrared spectroscopy (FT-IR) mapping indicated uniform polymer coverage. Compared to PEO alone, polymer-modified samples exhibited an approximately 7-fold increase in water contact angle, a ~50% reduction in surface roughness, and improved adhesion. Degradation-related analyses, including ion release, post-immersion SEM, and scanning acoustic microscopy (SAM), indicated that increasing polymer thickness effectively limited degradation processes. Ion release decreased by ~40–50% for the 30-layer coating compared to PEO, with the most pronounced reduction observed between the uncoated PEO and polymer-modified samples. These results demonstrate that the number of polymer layers plays a key role in controlling the barrier properties and stability of hybrid PEO/polymer coatings under simulated physiological conditions.