Red blood cells and polyelectrolyte multilayer capsules: natural carriers versus polymer-based drug delivery vehicles.

INTRODUCTION: Red blood cells (RBCs) and lipid-based carriers on the one hand and polymeric capsules on the other hand represent two of the most widely used carriers in drug delivery. Each class of these carriers has its own set of properties, specificity and advantages. Thorough comparative studies of such systems are reported here for the first time. AREAS COVERED: In this review, RBCs are described in comparison with synthetic polymeric drug delivery vehicles using polyelectrolyte multilayer capsules as an example. Lipid-based composition of the shell in the former case is particularly attractive due to their inherent biocompatibility and flexibility of the carriers. On the other hand, synthetic approaches to fabrication of polyelectrolyte multilayer capsules permit manipulation of the permeability of their shell as well as tuning their composition, mechanical properties, release methods and targeting. EXPERT OPINION: In conclusion, properties of RBCs and polyelectrolyte multilayer capsules are reported here highlighting similarities and differences in their preparation and applications. In addition, their advantages and disadvantages are discussed.