Silica-based materials are recognized as effective functional materials across diverse industrial fields, including biomedicine (e.g., drug delivery systems (DDS), biosensors, and tissue engineering), owing to their excellent stability and physicochemical characteristics. Among them, diatom biosilica (DB), which constitutes a major part of aquatic biomass, recently gained significant attention as a valuable biomaterial following breakthroughs in its innovative surface structure, superior biocompatibility and multifunctionality. Therefore, DB is emerging as an alternative to synthetic materials used in the biomedical field. This review comprehensively examines the diverse biological properties of DB, followed by an analysis of harvesting and purification strategies. Then, the current application status of DB in two principal biomedical domains, DDS and biosensors, is evaluated. Furthermore, the convergence of these domains into theragnostic applications addresses a significant unmet clinical need for simultaneous therapeutic intervention and diagnostic monitoring, positioning DB as a transformative biomaterial solution. The unique combination of natural hierarchical architecture, tunable surface properties, and excellent biocompatibility make DB promising candidates for next-generation integrated biomedical platforms to address the growing demand of personalized medicine and precision healthcare solutions.

Mandarin peel (MP), a major citrus-processing by-product, contains flavanone glycosides with antioxidant potential, yet its effective valorization depends on the development of a safe, efficient, and scalable extraction process. In this study, an ethanol-based ultrasound-assisted extraction (UAE) process was developed for the simultaneous recovery of hesperidin, narirutin, and didymin from MP. Response surface methodology based on a central composite design was applied to evaluate the effects of ethanol concentration, temperature, solid loading, and ultrasound amplitude on flavonoid recovery. The developed regression models showed good predictive reliability, with R² values of 0.9321, 0.8996, and 0.9296 for hesperidin, narirutin, and didymin, respectively. The optimal conditions were determined to be 78.22 % ethanol, 68.12 °C, 64.31 g/L solid loading, and 28.16 % amplitude for 10 min. Under these conditions, the experimental recoveries of hesperidin, narirutin, and didymin were 36.15, 17.97, and 2.35 mg/g-biomass, respectively, which agreed with the predicted values by more than 90 %. The resulting MP extract contained 23.41 % total flavonoids and exhibited ABTS radical scavenging activity with an EC₅₀ value of 384 µg/mL. No cytotoxicity was observed in L929 cells at concentrations up to 1600 µg/mL, which was more than 4-fold higher than the EC₅₀ value. These findings indicate that ethanol-based UAE enables the rapid and simultaneous recovery of antioxidant flavonoids from MP using a generally recognized as safe solvent. This process provides a practical strategy for the sustainable valorization of mandarin peel as a natural antioxidant ingredient.

The biological fate of lipid-based nanocarriers (LBNs) is shaped at the interface. Whereas core architecture governs cargo loading, protection, and baseline release, surface architecture mediates the carrier’s initial interactions with proteins, cells, extracellular matrices, and tissue barriers, thereby influencing colloidal stability, immune recognition, targeting, biodistribution, barrier transport, and release initiation. Layer-by-layer (LbL) engineering provides a modular strategy for programming this interface through sequentially assembled coatings in which functional components are spatially separated yet mechanistically coordinated. By integrating polymers, biomolecules—including peptides and nucleic acids—and stimuli-responsive materials, LbL systems can decouple functions that are difficult to regulate independently within conventional single-layer or compositionally mixed surface architectures. This review examines recent advances in LbL-engineered LBNs (LbL-LBNs), focusing on how multilayer surface architecture reshapes physicochemical properties, cargo localization and release, biological identity, cellular interactions, and transport across physiological barriers. Particular attention is given to the multilayer interface as a dynamic biointerfacial bridge between a cargo-specific core architecture and the surrounding biological environment, including its capacity for stimuli-responsive switching in pathological microenvironments. The discussion further extends to biomimetic hybrid interfaces and establishes a framework for translating hierarchical surface architectures into reproducible, clinically tractable platforms for precision therapeutic delivery.