Layer-by-layer self-assembly of giant polyelectrolyte microcapsules templated by microbubbles as potential hydrophilic or hydrophobic drug delivery system

Abstract

Giant polyelectrolyte microcapsules (GMs) with huge cavities and extremely low wall-to-diameter ratios have superior high loading ability and controlled permeability. However, the series of problems brought by template removal seriously impede their applications in biomedicine. In this work, a combination of microbubbles (MBs) as templates and layer-by-layer (LbL) self-assembly technology was used to fabricate GMs as potential hydrophilic or hydrophobic drug delivery system by depositing poly (allylamine hydrochloride) and poly(styrene sulfonate) onto monodispersity bovine serum albumin or liposome (Lipo) MBs. CLSM and AFM images showed that the GMs have a diameter of 100.4 ± 14.2 μm and a thickness of nearly 100 nm. Due to the difficulty in loading hydrophobic molecules into the hydrophilic structure of LbL capsules, we focused on encapsulating paclitaxel (PTX) into GMs based on PTX-loaded Lipo MBs, which presented high-drug loading and notable sustained-release effects. Collectively, these GMs have tremendous potential for drug delivery.