Objectives: A polyelectrolyte (PE) based nano-walled reservoir (NwR) was developed using alternate deposition of natural polyions on a decomposable core (CaCO(3)). The system was charged with paclitaxel (PTX) using the trigger property of an organic solvent (NwR-PTX). In addition, the surface of the nano-walled reservoir was modified with PE-PEG2000 (NwR-PTX-PEG)) in order to investigate any changes in the interaction of surface-modified polyelectrolyte shells with breast cancer cells, since surface chemistry greatly influences the performance of microcapsules in the biological environment.
Methods: The surface modification was confirmed by differential scanning calorimetry studies, which showed a shifting of the endothermic peak after pegylation. Layer-by-layer (LBL) growth of the system was confirmed by the sequential change in the zeta-potential. The release of paclitaxel from the formulations followed first order kinetics (r(2) = 0.9), indicating matrix diffusion. The interaction of NwR-PTX with MCF-7 cell lines was investigated by coating the system with FITC-dextran (NwR-PTX-FITC) and quantitated using flow cytometry.
Key findings: Cellular uptake of positively charged NwR reached 56% after 4 h and 76% after 24 h. This was reduced significantly after pegylation. The negatively charged NwR reached only 49% after 24 h.
Conclusions: This study opens the possibility of specific targeting of tumour cells that can control the release of chemotherapeutic agent either by means of a physiological or chemical trigger. This suggests potential application of this system as a novel approach for the delivery of chemotherapeutic agents.