Tuning microcapsules surface morphology using blends of homo- and copolymers of PLGA and PLGA-PEG

Abstract

We modulate precisely the surface morphology of polymer microcapsules containing perfluorooctyl bromide prepared by the solvent-evaporation technique by varying the percentage of PLGA-PEG copolymer in the formulation. As copolymer percentage increases, protrusions start to appear, become more numerous and finally fuse to yield sponge-like capsules. It has been postulated that the shell morphology arises from an interfacial tension instability. We show here that if an interfacial tension instability develops, it happens during the final step of polymer desolvation, when the interface is no longer fluid and interfacial tension changes cannot be monitored. The formation of protrusions occurs in order to accommodate all the PEG chains of the copolymer in a hydrophilic environment, since PEG and PLGA moieties are not miscible in the solid state.

Tuning Innate Immune Activation by Surface Texturing of Polymer Microparticles: The Role of Shape in Inflammasome Activation

“…Here, we take advantage of a recently developed route to prepare polymeric microparticles with complex but well-controlled surface topographies, based on emulsion processing of amphiphilic block copolymers (36, 37). This provides a simple platform to compare the response of phagocytes to particles of similar overall size and surface chemistry, but where the particle surfaces are either smooth or densely covered with micro-scale protrusions (which we refer to as textured or ‘budding’ particles).…”

Buckling Instability Causes Inertial Thrust for Spherical Swimmers at All Scales

“…Except in chiral systems [10,11], this necessary condition requires at least two degrees of freedom, which commonly implies two control parameters. Such heavy double steering could indeed be bypassed if flow rates can be rendered high enough so that inertia cannot be neglected anymore, or if any hysteresis in the deformation "naturally" prevents reciprocity.We suggest fulfilling these two conditions together with simple spherical colloidal shells full of air that are microscopic objects quite easy to manufacture [17,18]. Deflation from a spherical geometry occurs via buckling, which is a subcritical instability, likely to provide both swiftness and hysteresis during a deflation-re-inflation cycle driven by a single scalar control parameter : pressure.…”

“…We suggest fulfilling these two conditions together with simple spherical colloidal shells full of air that are microscopic objects quite easy to manufacture [17,18]. Deflation from a spherical geometry occurs via buckling, which is a subcritical instability, likely to provide both swiftness and hysteresis during a deflation-re-inflation cycle driven by a single scalar control parameter : pressure.…”

Enhancing Lysozyme Loading in Powderized Liposomes by Controlling Encapsulation Processes

“…This result might be caused by different physicochemical properties of organic solvents used, which could affect the interfacial tension between the aqueous and organic phase during the transformation process of the inverted micelles in the two‐phase system into liposomes. The interfacial tension values between the aqueous and organic phase for dichloromethane, ethyl acetate, and diethyl ether at 20°C have been reported as 28.2, 6.8, and 10.7 mN/m, respectively, and this indicates that the interfacial tension of dichloromethane is comparatively much greater than that of the other two organic solvents. Therefore, in the two‐phase system of dichloromethane with high interfacial tension, the greater energy is required to disperse the aqueous droplets homogeneously in the organic phase compared to that needed for the other tested solvents with low interfacial tension values.…”