ABSTRACT
Homogeneous and heterogeneous nanoparticle assembly induced by ligand-specific immunorecognition is commonly used for biosensing applications. In recent years, mesoporous silica nanoparticles have attracted attention as a promising component of multimodal nanoparticle systems. Nanoparticle drug delivery vehicles with peptides conjugated on the outside present a bioactive surface that is efficient at interacting with immune cells. Using polyethylene glycol (PEG) has become a popular strategy to create long-circulating drug delivery nanoparticles and other vehicles by reducing protein adsorption, macrophage uptake, and particle aggregation, thus increasing systemic circulation lifetime. The stealth properties of PEG arise from its hydrophilicity, neutral charge, and steric repulsion, forming a hydrating shell on the nanoparticles’ surface that minimizes the interaction with plasma proteins and, consequently, the recognition and internalization by the mononuclear phagocytic system cells. The introduction of bio-reducible disulfide bonds has attracted much interest in the design of redox-responsive nanoparticles that can release their payloads efficiently in intracellular reductive environments.
