nanocapsules

Nanocapsules are a class of nanometer-scale reservoir systems in which a core material is surrounded by a distinct polymeric or lipid shell, typically ranging from 10 to 1000 nanometers in diameter. The core can be liquid or solid, and the surrounding shell acts as a barrier that controls the release of the core contents. The architecture can be uniform, with a core-shell arrangement, or more complex with surface modifications for targeting.

Common methods include nanoprecipitation and emulsion-based techniques, interfacial polymerization, in-situ polymerization, layer-by-layer deposition, or solvent evaporation/diffusion. Production often yields monodisperse particles, but achieving scalable, reproducible manufacturing remains challenging.

Applications include drug delivery, where they enable controlled release and improved bioavailability; cosmetics and personal care; agrochemicals; imaging and diagnostics as contrast agents; and food and nutraceuticals.

Advantages and release mechanisms are governed by shell composition and thickness, enabling sustained release, payload protection from degradation, reduced systemic toxicity, and the possibility of stimuli-responsive release triggered by pH, temperature, or redox conditions.

Limitations and safety concerns include potential material toxicity, immune responses, and environmental impact; manufacturing complexity and batch variability; and regulatory oversight that requires thorough characterization of size, charge, stability, payload leakage, and long-term safety in preclinical and clinical contexts.