MICROFLUIDIC APPROACH FOR PRODUCTION OF LIPID NANOPARTICLES-BASED NANO MEDICINE M. Maeki 1* , T. SAITO 2 , Y. NODE 3 , Y. Sato 3 , T. Yasui 4,5 , N. Kaji 4,5 , A. Ishida 1 , H. Tani 1 , Y. Baba 4,5 , H. Harashima 3 , and M. Tokeshi 1,5* 1 Division of Applied Chemistry, Hokkaido University, JAPAN 2 Graduate School of Chemical Sciences and Engineering, Hokkaido University, JAPAN 3 Faculty of Pharmaceutical Sciences, Hokkaido University, JAPAN 4 Department of Applied Chemistry, Nagoya University, JAPAN 5 ImPACT Research Center for Advanced Nanobiodevices, Nagoya University, JAPAN ABSTRACT This paper described a simple preparation method for small-size and monodispersed lipid nanoparticles (LNPs) by using microfluidic devices. The fundamental role and importance of chaotic micromixer in the microfluidic device was demonstrated. The suitable cycle number of chaotic micromixer was confirmed for precise controlling LNPs size with narrow distribution under the any flow rate conditions. In addition, LNPs containing siRNA was synthesized for evaluation of penetration efficiency via in vivo experiment. The PEGylated LNPs containing siRNA with a diameter of 30 nm could penetrate to the mouse parenchymal liver cells rather than the LNPs with a diameter of 50 nm. KEYWORDS: Chaotic mixer, Lipid Nanoparticles, Nano Medicine INTRODUCTION Lipid nanoparticles (LNPs) are of the great interest as a nanometer-sized drug carriers. LNPs have remarkable features for drug delivery system such as a prolonged circulation time in the blood, low cytotoxicity, high accumulation efficiency into the tumor cells. In particular, LNPs in the size range of 30-100 nm are suitable for the cancer therapy. Therefore, precise control of the small-size LNPs with narrow distribution is a big challenge for the development of LNPs-based nanomedicine, because accumulation efficiency into the tumor cells strongly depends on the LNPs size [1]. Microfluidic device has been reported as a tool to produce monodispersed small-size LNPs[2]. However, the effect of fluid dynamics in the microfluidic device on the LNPs size has not been elucidated in detail. In this study, we investigated the role and importance of micromixer for the small size LNPs synthesis using the microfluidic device. Moreover, the LNPs containing siRNA was synthesized by using the microfluidic- based approach and was evaluated the penetration efficiency via in vivo experiment. EXPERIMENTAL Microfluidic devices were fabricated by double layer lithographic technique. The height of the first SU-8 layer was 79 µm and the second SU-8 layer was 31 µm. Figure 1 shows the schematic illustration of experimental system for producing the LNPs. To confirm the effect of the chaotic micromixer on LNPs formation behavior, the cycle number of chaotic micromixer was changed from 0, 6, 10, and 20 cycles. 1- palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) was dissolved in ethanol to obtain a concentration of 10 mg/mL lipid solution. Saline was used for the aqueous solution. These solutions were fed to the microfluidic device by using syringe pumps. The flow rate of the lipid solution was 0.1 mL/min and that of the aqueous solution was varied from 0.3 to 0.9 mL/min. The size of the LNPs was measured by dynamic light scattering. For in vivo experiment, we synthesized a multifunctional envelope-type nano device called MEND, which composed a pH-sensitive cationic lipid (YSK05), cholesterol, PEG-DMG by using microfluidic device. The PEGylated YSK-05 MEND was administered into the mouse liver cells to evaluate the effect of the LNPs size on the penetration and the gene knockdown efficiency. FITC-isolectin B4, Hoechst 33342, and Cy5-siRNA were used for staining the parenchymal liver cells, liver sinusoidal endothelial cells, and YSK-05 MEND, respectively. 838 978-0-9798064-8-3/μTAS 2015/$20©15CBMS-0001 19 th International Conference on Miniaturized Systems for Chemistry and Life Sciences October 25-29, 2015, Gyeongju, KOREA