Presentation PERCEL:Nano Particles for Imaging Probes

村山, 周平

Introduction We have developed a preparation method for polyethylene glycol-based nano particles that could contain various kinds of probe molecules by their mesh structure, as reported previously. 1 Because the encapsulated molecules are physically trapped by their mesh structure, there are no limitations to the types of molecules (protein, enzyme, siRNA, small molecular, and quantum dot (QD), etc.) that can be encapsulated using this technique.Here, we hypothesize that these properties of the nano particles could be affected by encapsulated molecules. To evaluate the pharmacokinetics of these nano particles in tumor bearing mouse, we prepared two different type nano particles. The soft nano particles with protein were labeled by fluorescent linker and MRI contrast agent, and the hard nano particle containing QD which show strong fluorescence.Material & Method These linkers of particles were synthesized and their structures were confirmed by NMR.1,2 These nano particles were prepared as previously described.1 After purification, nano particles were administrated to BALB/c nude mice (Japan SLC) with Colon-26. The pharmacokinetics of the nano particles in tumor bearing mouse were analyzed by using MRI (7-T, Bruker BioSpin), and fluorescence spectroscopy (Maestro, PerkinElmer). The physical properties of nano particles were characterized by DLS (Delsa Nano, Beckman Coulter), TEM(H-7000 electron microscope Hitachi), and AFM (NanoWizard II, JPK Instrument). All animals used for in vivo experiments were maintained in accordance with the guidelines of the NIRS, and all experiments were reviewed and approved by the institute's committee for care and use of laboratory animals.Result & Conclusion Analyzed by fluorescence spectroscopy, soft nano particles, which containing protein, rapidly excreted through urine. (Fig.1.a) TEM data also support this observation. (Fig.1. b) No nano particles were detected in liver by MRI imaging at 3h after injection, but the particles accumulated into the kidney and bladder. (Fig.1.c)3 Nano particles with QD, were not detected in urine, and they were delivered into tumor tissue and they excreted through liver.4 The study demonstrates that pharmacokinetics of nano particle depends on the properties of encapsulated molecule. If we achieve to control their pharmacokinetics in the body, such kind of nano particles will be a good tool for safety imaging probes and drug carriers.
(ICSB2016)International conference on Biomaterials Science in Tokyo に参加し、成果発表(ポスター)をする。

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