Osmotic pressure-dependent release profiles of payloads from nanocontainers by co-encapsulation of simple salts

Abstract

The encapsulation of payloads in micro- to nano-scale capsules allows protection of the payload from the surrounding environment and control of its release profile. Herein, we program the release of hydrophilic payloads from nanocontainers by co-encapsulating simple inorganic salts for adjusting the osmotic pressure. The latter either leads to a burst release at high concentrations of co-encapsulated salts or a sustained release at lower concentrations. Osmotic pressure causes swelling of the nanocapsule's shell and therefore sustained release profiles can be adjusted by crosslinking it. The approach presented allows for programing the release of payloads by co-encapsulating inexpensive salts inside nanocontainers without the help of stimuli-responsive materials.

Stabilization of Inverse Miniemulsions by Silyl-Protected Homopolymers

“…After the polyaddition reaction, the typical morphology of hollow nanocapsules was detected by electron microscopy (see Figure 3 and Figure S6). The nanocapsules determined in Figure 3 are collapsed and broken due to high vacuum chamber (3.8 × 10 −6 mbar) during electron microscopy measurement and led to evaporation of the liquid core independent of the polymer shell material [60,61,62].…”

Self-sustaining enzyme nanocapsules perform on-site chemical reactions

“…Because the shell of the nanoreactors is semi-permeable, 37,38 small hydrophilic molecules like glucose or peroxide can diffuse through the walls of the nanoreactors, and the catalytic reaction can be performed both on and in the nanoreactors, as observed in the previous cases. However, the method used here to synthesize the enzyme nanoreactors allows for the encapsulation of different reagents inside the hollow aqueous core, 36,48 and macromolecules can be efficiently trapped inside the nanoreactor without leaking out (Fig.…”

“…Such interfacial crosslinking reaction occurring on inverse-miniemulsion droplets is an ideal technique to control the size of the resulting nanocapsules and to control the shell thickness. 36 Furthermore, the shell of the resulting nanocapsules is semi-permeable, and while salts and small molecules can freely diffuse in and out of the inner core of the capsules, 37,38 large macromolecules are trapped inside the core if added to the solution of capsule precursor before emulsification. The encapsulation of different payloads in such enzyme nanocapsules can potentially lead to the release of the degradation products of large macromolecular payloads such as polyprodrugs, 14 or to the release of large payloads through the enzymatic degradation of the nanoreactor itself, which could occur under specific conditions.…”

Polyelectrolyte Multilayer Capsule (PEMC)-Based Scaffolds for Tissue Engineering

“…This concept is fairly common in cells and the same theory applies. The van ’t Hoff equation (Equation (1)) is used to determine the osmotic pressure [ 211 ] on a system. where π is osmotic pressure, R is the universal gas constant, T is absolute temperature, C s is the molar concentration of solute inside the capsule, and φ s is the osmotic coefficient, a factor applied to the equation when in non-ideal conditions—for instance, if there is salt in solution or if there is deviation in temperature.…”