Advances in Silicone Implants Characterization: A Comprehensive Overview of Chemical, Physical and Biological Methods for Biocompatibility Assessment.

Silicone implants are widely used in medical applications, particularly for breast augmentation and reconstruction. However, ongoing concerns regarding their long-term safety and biocompatibility necessitate comprehensive characterization. This review critically evaluates the chemical, physical, and biological testing approaches currently used to assess silicone implants, and specifically silicone breast implants, biocompatibility, and highlights the limitations of existing ISO 10993-based protocols, which often apply a one-size-fits-all model. We propose an application-specific framework to improve the relevance and precision of biocompatibility assessments. Chemical analyses, including Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy, provide essential information on polymer structure, integrity, and composition, thereby supporting quality control and market surveillance. Physical characterization methods, such as scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle measurements, assess the surface morphology, hydrophobicity, and potential defects that may influence the host response. Mechanical testing, which evaluates properties such as tensile strength and fatigue resistance, simulates in vivo stress conditions to predict the long-term durability. Biological evaluations guided by ISO 10993 use in vitro and in vivo models to assess cytotoxicity, adhesion, inflammation, and tissue integration. However, these are often not tailored to the implant type, surface features, or duration of exposure. Emerging tools, such as organ-on-a-chip platforms and machine learning models, offer new possibilities for predictive and context-specific evaluation. We advocate a standardized, modular strategy that integrates chemical, physical, and biological testing with clinical data to bridge preclinical assessments and real-world outcomes, with a specific focus on silicone breast implants. The aim of this approach is to improve patient safety, regulatory clarity, and device innovation across the global landscape of silicone implant development.