Self-assembled cationic biodegradable nanoparticles from a new family of pH-responsive amino acid-based poly(ester urea urethane) and their application as a doxorubicin delivery vehicle

Abstract

Event Abstract Back to Event Self-assembled cationic biodegradable nanoparticles from a new family of pH-responsive amino acid-based poly(ester urea urethane) and their application as a doxorubicin delivery vehicle Mingyu He1 and Chih-Chang Chu1 1 Cornell University, Department of Fiber Science and Apparel Design, United States Introduction: The objective of this study is to develop a new family of Arg-based biodegradable and biologically active copolymers (Arg-Leu PEUU) and their subsequent self-assembled cationic nanoparticles as a better delivery vehicle for anticancer drugs like doxorubicin (DOX) to achieve the synergism of cytotoxicity effect between the loaded drugs and macrophage inflammatory response of the delivery vehicle. This new strategy is expected to not only minimize severe cytotoxicity side effect of DOX upon conventional infusion administration but also enhance the cytotoxicity toward cancer cells via the synergism between the loaded DOX and the macrophage inflammatory response. Materials and Methods: Arginine-Leucine (Arg-Leu) based poly(ester urea urethane) (Arg-Leu PEUU) synthesized using a two-step solution polymerization[1]. Arg-Leu PEUU nanoparticles (NPs) and their DOX loading were performed by a facile dialysis method in water. Results and Discussion: The Arg-Leu PEUU copolymers have weight-average molecular weight from 13.4 to 16.8 KDa and glass-transition temperature from -3.4 to -4.6 oC. The self-assembled cationic nanoparticles (Arg-Leu PEUU NPs) were prepared by a facile dialysis method. The zeta potential of the Arg-Leu PEUU NPs ranged from +31.2 to +40.9 mV. The TEM images of the self-assembled 6-Arg-4-Leu-4 A/L-1/4 NPs and their DOX-loaded self-assemblies showed spherical morphology with a diameter ranging from 100 nm to 300 nm (Fig. 1). Arg-Leu PEUU NPs showed good biocompatibility toward 3T3 fibroblast and good bovine aortic endothelial cell (BAEC) proliferation and adhesion. DOX of 13.2~14.2 wt% could be physically incorporated into the Arg-Leu PEUU NPs. The merged fluorescence images provide a clear visual evidence (green fluorescent dots) of the blank Arg-Leu PEUU NPs engulfed by HeLa cells (Fig. 2A). The red fluorescence of the DOX-loaded Arg-Leu PEUU NP (Fig. 2B) was similarly distributed in the HeLa cells. While the free DOX treated HeLa cell (Fig. 2C) has red fluorescence concentrated around the cell nuclei. The quantified DOX fluorescence intensity data inside HeLa cells (Fig. 2D) show that the DOX-loaded Arg-Leu PEUU NPs have higher DOX fluorescence intensity than the free DOX. Arg-Leu PEUU NPs also enhanced the production of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) of RAW 264.7 macrophages, but relatively low interleukin-10 (IL-10) production, thereof anti-tumour activity of macrophages might be enhanced by the nanocarrier. The in vitro hemolysis assay showed the cationic Arg-Leu PEUU NPs increased their chance of endosomal escape at a more acidic pH. The DOX-loaded Arg-Leu PEUU NPs exhibited a pH-dependent drug release profile with accelerated release kinetics in a mild acidic condition. Free DOX showed the highest cytotoxicity potency at the shortest duration of treatment (i.e., 1 hr, Fig. 3 A), but the DOX-loaded Arg-Leu PEUU NPs caught up with the free DOX potency at the longer duration of treatment (4 and 24 hrs, Fig. 3 B & C). 6-Arg-4-Leu-4 A/L-2/1 NPs with encapsulated DOX showed a higher potency toward HeLa cell toxicity than the free DOX at the same concentration after 24 hours treatment (Fig 3. C). Conclusion: In this study, a new family of cationic Arg-Leu PEUU biomaterials and their self-assembled nanoparticles (NPs) were developed as an advanced nano-carrier for doxorubicin. The Arg-Leu PEUU biomaterials showed high macrophage-induced inflammatory cytokine production of TNF-α and NO but low IL-10, indicating the leaning toward the M-1 macrophages inflammatory response. By adjusting the chemical composition of the Arg to Leu feed ratio in the Arg-Leu PEUU NP system, the DOX release profile could be altered, hence an either enhanced or reduced DOX cytotoxicity against cancer cells could be achieved.