Synthesis, Characterization, and Long-Term Stability of Hollow Polymer Nanocapsules with Nanometer-Thin Walls

Abstract

Hollow polymer nanocapsules are produced by the polymerization within hydrophobic interior of lipid bilayers that act as temporary self-assembled scaffolds. Pore-forming templates are codissolved with monomers in the bilayers to create pores with controlled size and chemical environment. Polymerization was monitored with UV spectroscopy and dynamic light scattering. High resolution magic angle spinning NMR characterization provided detailed structural information about nanocapsules. Spherical shape was confirmed by electron microscopy. Mediumsized molecules can be entrapped within porous nanocapsules. No release of encapsulated molecules was observed within 240 days.

Facile Directed Assembly of Hollow Polymer Nanocapsules within Spontaneously Formed Catanionic Surfactant Vesicles

“…22 Vesicle-templated nanocapsules showed good control of permeability, ultrafast transport rates, and excellent long-term stability. 9,10,23,24 Because of the high potential utility, a simple and scalable method for the synthesis of nanocapsules from inexpensive materials is likely to have a broad impact.…”

Hollow Nanocapsules in Biomedical Imaging Applications

“…In a previous study [17], we showed that polystyrene capsules did not release Procion Red, a dye used as 1.1 nm size probe, for 240 days. A follow-up study on the same samples showed no measurable release after 40 months.…”

“…The copolymerization of styrene with a small amount of polymerizable surfactant gave a "wrapped parachute" or "matrioshka" structure, wherein each parachute vesicle-polymer hybrid is encapsulated in a unilamellar vesicle. These types of architectures were formed probably because of phase separation of the polymer matrix from the bilayers and additionally because of insufficient amount of monomers in bilayer as discussed earlier [17].…”

“…The permeability of the NC shell can be controlled by creating nanopores [13][14][15][16][17][18]. To achieve this goal, pore-forming templates are loaded into the bilayer interior together with monomers and cross-linkers ( Fig.…”

“…The monomer-to-surfactant and monomer-to-cross-linker ratios play a large role in determining the structural rigidity and permeability of NCs [17]. Figure 4.5 shows TEm and DLS data for experiments varying these ratios.…”