Stabilization of Inverse Miniemulsions by Silyl-Protected Homopolymers

Inverse (water-in-oil) miniemulsions are an important method to encapsulate hydrophilic payloads such as oligonucleotides or peptides. However, the stabilization of inverse miniemulsions usually requires block copolymers that are difficult to synthesize and/or cannot be easily removed after transfer from a hydrophobic continuous phase to an aqueous continuous phase. We describe here a new strategy for the synthesis of a surfactant for inverse miniemulsions by radical addition–fragmentation chain transfer (RAFT) polymerization, which consists in a homopolymer with triisopropylsilyl protecting groups. The protecting groups ensure the efficient stabilization of the inverse (water-in-oil, w/o) miniemulsions. Nanocapsules can be formed and the protecting group can be subsequently cleaved for the re-dispersion of nanocapsules in an aqueous medium with a minimal amount of additional surfactant

Versatile preparation of silica nanocapsules for biomedical applications

Core–shell nanocapsules are receiving increasing interest for drug delivery applications. Silica nanocapsules have been the focus of intensive studies due to their biocompatibility, versatile silica chemistry, and tunable porosity. However, a versatile one-step preparation of silica nanocapsules with well-defined core–shell structure, tunable size, flexible interior loading, and tailored shell composition, permeability, and surface functionalization for site-specific drug release and therapeutic tracking remains a challenge. Herein, an interfacially confined sol–gel process in miniemulsion for the one-step versatile preparation of functional silica nanocapsules is developed. Uniform nanocapsules with diameters from 60 to 400 nm are obtained and a large variety of hydrophobic liquids are encapsulated in the core. When solvents with low boiling point are loaded, subsequent solvent evaporation converts the initially hydrophobic cavity into an aqueous environment. Stimuli-responsive permeability of nanocapsules is programmed by introducing disulfide or tetrasulfide bonds in the shell. Selective and sustained release of dexamethasone in response to glutathione tripeptide for over 10 d is achieved. Fluorescence labeling of the silica shell and magnetic loading in the internal cavity enable therapeutic tracking of nanocapsules by fluorescence and electron microscopies. Thus, silica nanocapsules represent a promising theranostic nanoplatform for targeted drug delivery applications.Fil: Jiang, Shuai. Max Planck Institute for Polymer Research; AlemaniaFil: Mottola, Milagro. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina. Max Planck Institute For Polymer Research; AlemaniaFil: Han, Shen. Max Planck Institute For Polymer Research; AlemaniaFil: Thiramanas, Raweewan. Max Planck Institute For Polymer Research; AlemaniaFil: Graf, Robert. Max Planck Institute For Polymer Research; AlemaniaFil: Lieberwirth, Ingo. Max Planck Institute For Polymer Research; AlemaniaFil: Mailänder, Volker. Max Planck Institute For Polymer Research; AlemaniaFil: Crespy, Daniel. Max Planck Institute For Polymer Research; AlemaniaFil: Landfester, Katharina. Max Planck Institute For Polymer Research; Alemani