Block Copolymer Capsules with Structure‐Dependent Release Behavior

Abstract

Although high-boiling non-solvent induced macrophase separation in emulsion droplets has been widely applied for the fabrication of polymeric capsules, precise control of their structures remains a great challenge. Herein, block copolymer capsules with tunable shell structures were fabricated by employing a non-solvent as a liquid template in emulsion droplets. The properties of the non-solvents dictate the phase separation sequence in the droplets and the capsule formation mechanism. Two different pathways for capsule formation were observed, and could be applied to predict the shell structure. The structured capsules could be transformed into mesoporous capsules, which demonstrated an intriguing structure-dependent release behavior. Capsules with spherical shell structures displayed the best permeability, while those with lamellar shell structures showed the slowest release, but with a stepwise profile. After loading with an anticancer drug, different capsules induced different apoptosis ratios in cancer cell studies.

Hydrogen Bonding Directed Colloidal Self‐Assembly of Nanoparticles into 2D Crystals, Capsids, and Supracolloidal Assemblies

“…Under appropriate conditions, the supramolecular interactions of viral capsid subunits can be tuned to achieve reversible assembly–disassembly and protein engineering can even be utilized to prepare artificial virus particles . Related self‐assembly concepts have been widely explored in supramolecular chemistry using molecular level building blocks, dendrimers, and block‐copolymers where the structure, functional groups, and intramolecular and intermolecular interactions can be controlled to certain precision . However, a similar approach using colloidal level building blocks such as inorganic nanoparticles has certain limitations due to challenges in controlling their size, shape, interactions, and stability …”

Recent Advances in Particulate Adjuvants for Cancer Vaccination

“…The chemical and mechanical properties of microcapsules can be accurately adjusted by choosing suitable polymers, adding nanoparticles into multi‐layer shells, changing deposition conditions, and controlling the number of layers 38b. These microcapsules possess several advantages, such as high loading capacity, protection of peptides/protein/viral structures from immune clearance, selective permeability allowing sustained/on‐demand release, and easy functionalization for targeting capabilities 38a,40. Moreover, the tunable shape, elastic surface, and hollow nature make microcapsules closely resemble the morphologic nature of bacteria, which can be easily recognized and processed by professional APCs.…”

Multicompartment Vesicles Formation by Emulsification‐Induced Assembly of Poly(ethylene oxide)‐block‐poly(ε‐caprolactone) and Their Dual‐Loading Capability

“…[7] Considering the prerequisite performance for drug or gene delivery nanovehicles, [9] the developed onion-like nanostructure can be recognized a useful nanoplatform for customized applications in many biomedical fields. [7,10] Indeed, the onion-like vesicles were fabricated by the control of the inherent crystalline nature of PCL. [11,12] Specifically, emulsification and solvent evaporation approaches were used (referred to as the emulsification-induced assembly, Figure S1, Supporting Information).…”

“…Contrary to the cylinders formed by their direct aqueous self‐assembly (Figure S2, Supporting Information), the resultant onion‐like vesicles show a high capacity for payloads and a stepwise and sustained release, which can be attributed to the presence of a multiwalled structure and its sequential hydrolytic degradation, respectively . Considering the prerequisite performance for drug or gene delivery nanovehicles, the developed onion‐like nanostructure can be recognized a useful nanoplatform for customized applications in many biomedical fields …”