Red Blood Cell-Shaped Microparticles with a Red Blood Cell Membrane Demonstrate Prolonged Circulation Time in Blood

Prolonging the circulation time (CT) of microparticles (MPs) in the blood is key for a successful microparticle-based medicinal approach to serve as drug delivery systems (DDSs). Previously, we reported that MPs that mimic the shape of red blood cells (RBCs) avoid accumulation in the spleen and lungs. We now describe the effectiveness of mimicking not only the shape of RBCs but also their surface structure for the prolongation of CT. RBC-shaped MPs (RBC-MPs) were electrosprayed with cellulose and covered with a native RBC membrane (RBCM) collected from mouse blood. Seven hours after intravenous injection, approximately twice as many RBCM-covered RBC-MPs (RBC-MPs@RBCM) were present in the blood of mice compared to unmodified RBC-MPs. Twenty-four hours postinjection, the concentration of RBC-MPs@RBCM in the blood was 4 times higher. These findings suggest that an RBCM covering the MPs contributed to significant CT prolongation, which may positively impact their applications as DDSs.