Heterogeneous toroidal spiral particles for islet encapsulation.

Transplantable cell encapsulation systems present a promising approach to deliver a therapeutic solution from hormone-producing cells for the treatment of endocrine diseases like type 1 diabetes. However, the development of a broadly effective and safe transplantation system has been challenging. While some current micro-sized capsules have been optimized for adequate nutrient and metabolic transport, they lack the robustness and retrievability for the clinical safety translation that macro-devices may offer.

Microscopic Models of Drug/Chemical Diffusion Through the Skin Barrier: Effects of Diffusional Anisotropy of the Intercellular Lipid.

Owing to the systematic alignment and ordering of fatty acid and ceramide chains, lipid layers in biological membranes have strongly anisotropic diffusion properties. The diffusivity D for solute transport in the direction parallel to the lipid layer is typically 10-10 times the diffusivity D for the perpendicular direction. This article explores the consequences of this strong degree of anisotropy on solute diffusion through the stratum corneum (barrier) layer of the skin based on a realistic representation of a unit cell of the microstructure.

Toroidal-spiral particles for codelivery of anti-VEGFR-2 antibody and irinotecan: a potential implant to hinder recurrence of glioblastoma multiforme.

Heterogeneous toroidal-spiral particles (TSPs) were generated by polymer droplet sedimentation, interaction, and cross-linking. TSPs provide a platform for encapsulation and release of multiple compounds of different sizes and physicochemical properties. As a model system, we demonstrate the encapsulation and independently controlled release of an anti-VEGFR-2 antibody and irinotecan for the treatment of glioblastoma multiforme.

Formation of polymeric toroidal-spiral particles.

Compared to spherical matrices, particles with well-defined internal structure provide large surface to volume ratio and predictable release kinetics for the encapsulated payloads. We describe self-assembly of polymeric particles, whereby competitive kinetics of viscous sedimentation, diffusion, and cross-linking yield a controllable toroidal-spiral (T-S) structure. Precursor polymeric droplets are splashed through the surface of a less dense, miscible solution, after which viscous forces entrain the surrounding bulk solution into the sedimenting polymer drop to form T-S channels.

Vesicle formation and endocytosis: function, machinery, mechanisms, and modeling.

Vesicle formation provides a means of cellular entry for extracellular substances and for recycling of membrane constituents. Mechanisms governing the two primary endocytic pathways (i.e.