Search

Chia-Liang Tsai,1 Ching-Yun Huang,2 Yi-Ching Lu,1 Li-Mei Pai,3,4 Daniel Horák,5 Yunn-Hwa Ma1,6 1Department of Physiology and Pharmacology, Chang Gung University, Taoyuan, 33302, Taiwan, Republic of China; 2Institute of Biomedical Sciences, Chang Gung University, Taoyuan, 33302, Taiwan, Republic of China; 3Department of Biochemistry & Molecular Biology, College of Medicine, Chang Gung University, Taoyuan, 33302, Taiwan, Republic of China; 4Liver Research Center, Chang Gung Memorial Hospital, Taoyuan, 33305, Taiwan, Republic of China; 5Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague 6, 162 06, Czech Republic; 6Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Taoyuan, 33305, Taiwan, Republic of ChinaCorrespondence: Yunn-Hwa Ma, Department of Physiology and Pharmacology, Chang Gung University, Guishan, Taoyuan, 33302, Taiwan, Republic of China, Email yhma@mail.cgu.edu.twBackground: Intravascular delivery of nanoparticles for theranostic application permits direct interaction of nanoparticles and vascular cells. Since vascular smooth muscle cells (VSMCs), the major components of the vascular wall, are constantly subjected to mechanical stimulation from hemodynamic influence, we asked whether cyclic strain may modulate internalization of magnetic nanoparticles (MNPs) by cultured VSMCs.Methods: Cyclic strain (1 Hz and 10%) was applied with Flexcell system in cultured VSMCs from rats, with cell-associated MNPs (MNPcell) determined by a colorimetric iron assay. Transmission and scanning electron microscopy were used for morphology studies. Confocal microscopy was used to demonstrate distribution of actin assembly in VSMCs.Results: Incubation of poly(acrylic acid) (PAA)-coated MNPs with VSMCs for 4 h induced microvilli formation and MNP internalization. Application of cyclic strain for 4– 12 h significantly reduced MNPcell by up to 65% (p < 0.05), which was associated with blunted microvilli and r

Wei Xiong Siow,1,2 Yi-Ting Chang,1,2 Michal Babič,3 Yi-Ching Lu,2 Daniel Horák,3 Yunn-Hwa Ma1,2,4 1Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Guishan, Taoyuan, Taiwan, Republic of China; 2Department of Physiology and Pharmacology and Healthy Aging Research Center, College of Medicine, Chang Gung University, Guishan, Taoyuan, Taiwan, Republic of China; 3Institute of Macromolecular Chemistry, Czech Academy of Sciences, Prague, Czech Republic; 4Department of Neurology, Chang Gung Memorial Hospital, Guishan, Taoyuan, Taiwan, Republic of China Background: Poly-L-lysine (PLL) enhances nanoparticle (NP) uptake, but the molecular mechanism remains unresolved. We asked whether PLL may interact with negatively charged glycoconjugates on the cell surface and facilitate uptake of magnetic NPs (MNPs) by tumor cells.Methods: PLL-coated MNPs (PLL-MNPs) with positive and negative ζ-potential were prepared and characterized. Confocal and transmission electron microscopy was used to analyze cellular internalization of MNPs. A colorimetric iron assay was used to quantitate cell-associated MNPs (MNPcell).Results: Coadministration of PLL and dextran-coated MNPs in culture enhanced cellular internalization of MNPs, with increased vesicle size and numbers/cell. MNPcell was increased by eight- to 12-fold in response to PLL in a concentration-dependent manner in human glioma and HeLa cells. However, the application of a magnetic field attenuated PLL-induced increase in MNPcell. PLL-coating increased MNPcell regardless of ζ-potential of PLL-MNPs, whereas magnetic force did not enhance MNPcell. In contrast, epigallocatechin gallate and magnetic force synergistically enhanced PLL-MNP uptake. In addition, heparin, but not sialic acid, greatly reduced the enhancement effects of PLL; however, removal of heparan sulfate from heparan sulfate proteoglycans of the cell surface by heparinase III significantly reduced MNPcell.Con

Yunn-Hwa Ma,1 Si-Yi Chen,1 Shu-Ju Tu,2 Hung-Wei Yang,3 Hao-Li Liu41Department of Physiology and Pharmacology and Healthy Aging Research Center, 2Department of Medical Image and Radiological Sciences, 3Department of Chemical and Material Engineering, 4Department of Electrical Engineering, College of Medicine and College of Engineering, Chang Gung University, Kuei-Shan, Tao-Yuan, Taiwan, ROCAbstract: Magnetic nanoparticles (MNPs) have been proposed for targeted or embolization therapeutics. How MNP retention occurs in circulation may critically determine local hemodynamics, tissue distribution of MNPs, and the therapeutic effects. We attempted to establish a microcirculation model to study the magnetic capture of MNPs in small vessels and to determine the factors affecting MNP retention. Two-dimensional hemodynamic changes in response to magnet-induced MNP retention in the microvessels of the cremaster muscle in vivo were observed in a real-time manner using a laser speckle imaging technique. Changes in tissue perfusion of the cremaster muscle appeared to be closely correlated with the location of the magnet placement underneath the muscle in response to intra-arterial administration of dextran-coated MNPs. Magnet-related retention was observed along the edge of the magnet, as corroborated by the results of histology analysis and microcomputed tomography. In these preparations, tissue iron content almost doubled, as revealed by inductively coupled plasma optical emission spectroscopy. In addition, MNP retention was associated with reduced downstream flow in a dose-dependent manner. Dissipation of MNPs (5 mg/kg) occurred shortly after removal of the magnet, which was associated with significant recovery of tissue flow. However, MNP dissipation did not easily occur after administration of a higher MNP dose (10 mg/kg) or prolonged exposure to the magnetic field. An ultrasound after removal of the magnet may induce the partial dispersion of MNPs and thus partially improve

Jyh-Ping Chen,1 Pei-Ching Yang,1 Yunn-Hwa Ma,2 Su-Ju Tu,3 Yu-Jen Lu1,41Department of Chemical and Materials Engineering, 2Department of Physiology and Pharmacology, 3Department of Medical Imaging and Radiological Sciences, Chang Gung University, Kwei-San, Taoyuan, Taiwan, Republic of China; 4Department of Neurosurgery, Chang Gung Memorial Hospital, Kwei-San, Taoyuan, Taiwan, Republic of ChinaBackground and methods: Silica-coated magnetic nanoparticle (SiO2-MNP) prepared by the sol-gel method was studied as a nanocarrier for targeted delivery of tissue plasminogen activator (tPA). The nanocarrier consists of a superparamagnetic iron oxide core and an SiO2 shell and is characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, superconducting quantum interference device, and thermogravimetric analysis. An amine-terminated surface silanizing agent (3-aminopropyltrimethoxysilane) was used to functionalize the SiO2 surface, which provides abundant —NH2 functional groups for conjugating with tPA.Results: The optimum drug loading is reached when 0.5 mg/mL tPA is conjugated with 5 mg SiO2-MNP where 94% tPA is attached to the carrier with 86% retention of amidolytic activity and full retention of fibrinolytic activity. In vitro biocompatibility determined by lactate dehydrogenase release and cell proliferation indicated that SiO2-MNP does not elicit cytotoxicity. Hematological analysis of blood samples withdrawn from mice after venous administration indicates that tPA-conjugated SiO2-MNP (SiO2-MNP-tPA) did not alter blood component concentrations. After conjugating to SiO2-MNP, tPA showed enhanced storage stability in buffer and operation stability in whole blood up to 9.5 and 2.8-fold, respectively. Effective thrombolysis with SiO2-MNP-tPA under magnetic guidance is demonstrated in an ex vivo thrombolysis model where 34% and 40% reductions in blood clot lysis time were observed compared with runs without magnetic

Hung-Wei Yang,1,* Mu-Yi Hua,1,* Kun-Ju Lin,2,* Shiaw-Pyng Wey,3 Rung-Ywan Tsai,4 Siao-Yun Wu,5 Yi-Ching Lu,5 Hao-Li Liu,6 Tony Wu,7 Yunn-Hwa Ma5 1Chang Gung Molecular Medicine Research Center, Department of Chemical and Materials Engineering, 2Molecular Imaging Center, Department of Nuclear Medicine, Chang Gung Memorial Hospital, Kuei-Shan, Tao-Yuan, Taiwan, Republic of China; 3Department of Medical Imaging and Radiological Sciences, 4Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsin-chu, Taiwan, Republic of China; 5Department of Physiology and Pharmacology and Healthy Aging Research Center, 6Department of Electrical Engineering, Chang Gung University, Kuei-Shan, Tao-Yuan, Taiwan, Republic of China; 7Department of Neurology, Chang Gung University College of Medicine and Memorial Hospital, Tao-Yuan, Taiwan, Republic of China*These authors contributed equally to this workAbstract: Low-toxicity magnetic nanocarriers (MNCs) composed of a shell of poly [aniline-co-N-(1-one-butyric acid) aniline] over a Fe3O4 magnetic nanoparticle core were developed to carry recombinant tissue plasminogen activator (rtPA) in MNC-rtPA for targeted thrombolysis. With an average diameter of 14.8 nm, the MNCs exerted superparamagnetic properties. Up to 276 µg of active rtPA was immobilized per mg of MNCs, and the stability of the immobilized rtPA was greatly improved during storage at 4°C and 25°C. In vitro thrombolysis testing with a tubing system demonstrated that magnet-guided MNC-rtPA showed significantly improved thrombolysis compared with free rtPA and reduced the clot lysis time from 39.2 ± 3.2 minutes to 10.8 ± 4.2 minutes. In addition, magnet-guided MNC-rtPA at 20% of the regular rtPA dose restored blood flow within 15–25 minutes of treatment in a rat embolism model without triggering hematological toxicity. In conclusion, this improved system is based on magnetic targeting