NANOPARTICLE FORMULATIONS OF DIAGNOSTIC AGENTS FOR MEDICAL IMAGING WANG YAN NATIONAL UNIVERSITY OF SINGAPORE 2007 NANOPARTICLE FORMULATIONS OF DIAGNOSTIC AGENTS FOR MEDICAL IMAGING WANG YAN (B Eng, Shanghai Jiao Tong University) A THESIS SUBMITTED FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE PROGRAMME IN BIOENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2007 Acknowledgements I would like to express my sincere appreciation to my supervisor, A/P Feng Si-Shen, for his wise guidance, effective support, and patient encouragement throughout this project His great passion to science and serious style of work give me a deep impression that will benefit me a lot in my future work I would also like to thank Dr Chen Yan, visiting scholar from Curtin University of Technology, Australia, my co-supervisor A/P Wang Shih-Chang and A/P Sheu Fwu-Shan, MRI specialist Shuter Borys, and all my colleagues in Chemotherapeutic Engineering Lab for their continuous guidance and useful advice Thanks also go to my parents, my husband and my friends Without their help and encouragement, this project would have been more difficult Finally, I wish to express my gratitude to National University of Singapore for providing me such a good chance to pursue my research in Singapore Being exposed to the frontier of bioengineering, I have thus enriched my knowledge and enhanced my ability for future work I Table of Contents Acknowledgements I Table of Contents II Summary VI List of Tables VIII List of Figures VIII List of Abbreviations XI Chapter Introduction 1.1 Background 1.2 Objectives 1.3 Thesis Organization Chapter 2.1 Literature Review Cancer 2.1.1 Introduction to cancer 2.1.2 Cancer diagnosis and therapy 2.2 Nanotechnology in Cancer Diagnosis 2.3 Magnetic Nanoparticles in Cancer Diagnosis 2.3.1 Basic principles of MRI 2.3.2 Important parameters of MRI 2.3.3 MRI contrast agent 11 2.3.4 Current research on magnetic polymeric nanoparticles in MRI 13 II 2.4 QDs in Cancer Diagnosis 18 2.4.1 Properties of QDs 18 2.4.2 Current research on QDs loaded polymeric nanoparticles in medical imaging 19 2.5 Nanoparticle Technology 21 2.5.1 Nanoparticle formulations 21 2.5.2 Characterization of nanoparticles 24 Chapter Materials and Methods 25 3.1 Superparamagnetic IOs Loaded PLGA-mPEG Nanoparticles 25 3.1.1 Materials 25 3.1.2 Preparation of IOs loaded PLGA-mPEG nanoparticles 26 3.1.3 Physicochemical characterization 27 3.1.4 MR characterization 31 3.2 QDs Loaded Polymeric Nanoparticles 32 3.2.1 Materials 32 3.2.2 Preparation of QDs loaded polymeric nanoparticles 33 3.2.3 Physicochemical characterization 33 3.2.4 Cellular and animal experiments 36 Chapter Superparamagnetic IOs Loaded PLGA-mPEG Nanoparticles as MRI Contrast Agent 39 4.1 4.1.1 Physicochemical Characteristics of the Nanoparticles 39 Characterization of the IOs 39 III 4.1.2 Particle size and size distribution 40 4.1.3 Surface morphology 42 4.1.4 TEM 43 4.1.5 Magnetic properties 43 4.1.6 Stability 48 4.1.7 In vitro release 49 4.2 MR Characteristics of the Nanoparticles 50 4.2.1 In vitro MRI 50 4.2.2 Ex vivo MRI 54 Chapter QDs loaded PLGA Nanoparticles as Fluorescent Probe 56 5.1 Physicochemical Characteristics of the Nanoparticles 56 5.1.1 Particle size and size distribution 56 5.1.2 Surface morphology 57 5.1.3 Localization of QDs in PLGA nanoparticles by TEM 58 5.1.4 Localization of QDs in PLGA nanoparticles by CLSM 59 5.1.5 Fluorescence emission spectrum 60 5.2 Cellular and Animal Experiments 61 5.2.1 Cell uptake 61 5.2.2 Ex vivo fluorescence imaging 62 Chapter Comparison of QDs Loaded Nanoparticles of Different Biocompatible and Biodegradable Polymers 64 6.1 Comparison of Physicochemical Properties of the Nanoparticles 64 IV 6.1.1 Particle size and size distribution 64 6.1.2 Zeta potential 67 6.1.3 Surface morphology 67 6.1.4 TEM 71 6.1.5 In vitro release 73 6.2 Cellular and Animal Experiemtns 76 6.2.1 Cell uptake 76 6.2.2 Cell viability 80 Chapter Conclusions and Recommendations 82 7.1 Conclusions 82 7.2 Recommendations 83 Reference 85 V Summary This project is to prepare and evaluate nanoparticles formulated by encapsulating diagnostic agents, superparamagnetic iron oxide (IOs) and quantum dots (QDs), into matrix of biocompatible and biodegradable polymers, which could potentially reduce the toxicity, and increase the imaging efficiency and cell uptake efficiency of the diagnostic agents The nanoparticles were prepared either by water-in-oil-in-water double emulsion method or oil-in-water solvent evaporation method Their physicochemical properties were characterized by various techniques including laser light scattering technique for particle size, zeta potential analysis for surface charge, field emission scanning electron microscopy and atomic force microscopy for surface morphology, transmission electron microscopy for qualitative determination of diagnostic agents encapsulated, inductively coupled plasma-mass spectrometry and micro-plate reader measurement for quantitative determination of the amount of the diagnostic agents loaded, vibrating sample magnetometer and superconducting quantum interference device for magnetization and magnetic resonance imaging (MRI) for contrast efficiency measurement of the IOs loaded nanoparticles, and micro-plate reader measurement for emission spectrum of the QDs loaded nanopartilces Furthermore, in vitro release of the diagnostic agents from the polymeric nanoparticles was studied and potential applications of these nanoparticles for medical imaging in vitro and ex vivo were also investigated using MCF-7 cell line and Sprague Dawley rat IOs loaded poly(lactide-co-glycolide)-methoxy poly(ethylene glycol) (PLGA-mPEG) nanoparticles are spherical, have a narrow size distribution and show slow IOs release in VI vitro Compared with the raw IOs (commercial contrast agent Resovist®), the prepared nanoparticles render increased saturation magnetization, r2 and r2* relaxivities, thus improved contrast effect for both in vitro and ex vivo MR images Therefore these nanoparticles could become a potential contrast agent for MRI QDs loaded poly(D, L-lactide-co-glicolide) (PLGA) and poly(lactide-co-glicolide)tocopheryl polyethylene glycol succinate (PLGA-TPGS) nanoparticles were formulated and evaluated Two emulsifiers: polyvinyl alcohol (PVA) and Vitamin E tocopheryl polyethylene glycol succinate (VE TPGS) were also compared The nanoparticles are spherical, relatively uniform, of low toxicity and show emission spectrum similar to that of free QDs Among all the formulations, nanoparticles made of PLGA-TPGS copolymer (emulsified by PVA) have the slowest QDs release in vitro, lowest cytotoxcity, highest cell uptake efficiency, which could be a potential fluorescent probe for cellular and biomolecular imaging VII List of Tables Table TR and TE for r2 and r2* relaxivity measurements 31 Table Properties of IOs and IOs loaded PLGA-mPEG nanoparticles 41 Table r2 and r2* relaxivities of IOs and IOs loaded PLGA-mPEG nanoparticles 52 Table Comparison of IOs and IOs loaded PLGA-mPEG Nanoparticles (TE = 7ms) 54 Table Properties of the QDs loaded polymeric nanoparticles 66 Table Zeta potential of QDs loaded polymeric nanoparticles 67 List of Figures Figure Chemical structures of PLGA-mPEG and PVA 25 Figure Schematic representation of the preparation of IOs loaded PLGA-mPEG nanoparticles by double emulsion method 26 Figure Chemical Structures of PLGA, VE TPGS and PLGA-TPGS 32 Figure Schematic representation of the preparation of QDs loaded polymeric nanoparticles by solvent evaporation method 33 Figure XRD spectrum of the IOs 39 Figure Fe 2p XPS spectrum of the IOs 40 Figure Particle size distribution of IOs loaded PLGA-mPEG nanoparticles 41 Figure FESEM image of IOs loaded PLGA-mPEG nanoparticles (bar = 1µm) 42 Figure TEM images of (a) IOs (bar = 20 nm), and (b) IOs loaded PLGA-mPEG nanoparticles (bar = 50 nm) 43 VIII Chapter Conclusions and Recommendations 7.1 Conclusions This study demonstrates that the encapsulation of IOs into nanoparticles of biocompatible and biodegradable polymer PLGA-mPEG leads to an enhanced MRI contrast efficiency compared with Resovist®, the commercial IO contrast agent FESEM & TEM images and Fe content measured by ICP-MS show a strong evidence of the presence of IOs within the nanoparticles These nanoparticles render an increase in Ms and r2 & r2* relaxivities of the IOs, resulting in a strong enhancement in MRI contrast effect This suggests the nanoparticles be a promising formulation for MRI contrast agent QDs loaded PLGA and PLGA-TPGS nanoparticles using different emulsifiers (PVA and VE TPGS) were prepared and characterized by various techniques The experimental results show that all the three kinds of nanoparticles are spherical, uniform and stable TEM images indicate that the QDs have been successfully encapsulated into the polymer matrix In vitro release study shows that PLGA-TPGS nanoparticles (emulsified by PVA) have the slowest release in cell culture medium as well as in PBS This is very important to the biomedical applications of these nanoparticle formulations because the less the QDs released into the surrounding medium, the smaller the cytotoxicity of the nanoparticles, which agrees well with the cell viability results Moreover, the PLGATPGS nanoparticles attain the highest cell uptake efficiency among the three formulations Therefore, it could be concluded that polymer PLGA-TPGS performs well 82 for the encapsulation of raw QDs and the prepared nanoparticles have the potential as a fluorescent probe in cellular and biomolecular imaging 7.2 Recommendations In the study of superparamagnetic IOs loaded PLGA-mPEG nanoparticles as MRI contrast agent, due to time constraint, we only did some preliminary ex vivo MRI research on the nanoparticles A direct comparison of in vivo MR imaging of IOs and IOs loaded PLGA-mPEG nanoparticles in rats was unable to be done Thus, we suggest that in the future, in vivo MRI and further quantitative bio-distribution study of the nanoparticles in animals should be carried out to verify the efficiency of the developed nanoparticles as contrast agent In the study of QDs loaded polymeric nanoparticles as fluorescent probe, quantitative bio-distribution study of the nanoparticles is recommended Moreover, it is also good to conduct in vivo fluorescence imaging of the whole rats by using a macro-illumination system designed specifically for small animal studies (Gao X et al., 2004), to investigate the potential of the nanoparticles as biomedical fluorescent probe thus further study could be designed accordingly to improve the nanoparticle formulation In the field of drug delivery, therapeutic drugs together with the IOs or QDs can be encapsulated into the matrix of biocompatible and biodegradable polymers with certain ratio Thus quantification of the drug can be carried out by measuring the MRI or 83 fluorescence signal of the nanoparticles This way, the pathway of the drugs could be tracked and the amount of the drugs to be delivered could also be controlled In the field of surgery, there is an ongoing interest in the development of magneticfluorescent diagnostic agents, termed as multimodal imaging probes By correlating the ultrasensitive optical imaging capability of QDs with MRI, a surgeon could identify and remove the cancer cells completely during one operation (Jiang et al., 2004; Gao et al., 2005) 84 Reference Alivisatos AP, Semiconductor clusters, nanocrystals, and quantum dots, Science 1996; 271:933-937 Alyautdin RN, Petrov VE, Langer K, Berthold A, Kharkevich DA, Kreuter J, Delivery of loperamide across the blood-brain barrier with polysorbate 80-coated polybutylcyanoacrylate nanoparticles, Pharmaceutical Research, 1997; 14: 325-328 American Cancer Society, Cancer prevention & early detection, facts and figures 2002 Aronov O, Horowitz AT, Gabizon A, Gibson D, Folate-targeted PEG as a potential carrier for carboplatin analog, Synthesis and in vitro studies, Bioconjugate Chemistry 2003; 14: 563-574 Avgoustakis K, Beletsi A, Panagi Z, Klepetsanis P, Evangelatos G, Ithakissios DS, Effect of copolymer composition on the physicochemical characteristics, in vitro stability, and biodistribution of PLGA-mPEG nanoparticles, International Journal of Pharmaceutics 2003; 259: 115-127 Bies C, Lehr CM, Woodley JF, Lectin-mediated drug targeting: history and applications, Advanced Drug Delivery Reviews 2004; 56: 425-435 Bulte JW, Duncan ID, Frank JA, In vivo magnetic resonance tracking of magnetically labeled cells after transplantation, Journal of Cerebral Blood Flow and Metabolism 2002; 22: 899-907 85 Chambon C, Clement O, Blanche AL, Schouman-Claeys E, Frija G, Superparamagnetic iron oxides as positive MR contrast agents: in vitro and in vivo evidence, Magnetic Resonance Imaging 1993; 11: 509-519 Chan WCW, Maxell DJ, Gao X, Bailey RE, Han M, Nie S, Luminescent quantum dots for multiplexed biological detection and imaging, Current Opinion in Biotechnology 2002; 13: 40-46 Chatterjee J, Haik Y, Chen CJ, Polyethylene magnetic nanoparticle: A new magnetic material for biomedical applications, Journal of Magnetism and Magnetic Materials 2002; 246: 382-391 Chatterjee J, Haik Y, Chen CJ, Size dependent magnetic properties of iron oxide nanoparticles, Journal of Magnetism and Magnetic Materials 2003; 257: 113-118 Chen YF, Rosenzweig Z, Luminescent CdSe quantum dot doped stabilized micelles, Nano Letters 2002; 11: 1299-1302 Cornell RM, Schwertmann U, The in oxides, VCH publishers, New York, 1996 Derfus AM, Chan WCW, Bhatia SN, Probing the cytotoxicity of semiconductor quantum dots, Nano Letters 2004; 4: 11-18 Dong Y, Feng SS, Methoxy poly(ethylene glycol)-poly(lactide) (MPEG-PLA) nanoparticles for controlled delivery of anticancer drugs, Biomaterials 2004; 25: 28432849 86 Dresco PA, Zaitsev VS, Gambino RJ, Chu B, Preparation and properties of magnetite and polymer magnetite nanoparticles, Langmuir 1999; 15: 1945-1951 Dubertret B, Skourides P, Norris DJ, Noireaux V, Brivanlou AH, Libchaber A, In vivo imaging of quantum dots encapsulated in phospholipid micelles, Science 2002; 298: 1759-1762 Feng SS, Huang G, Effects of emulsifiers on the controlled release of paclitaxel (Taxol) from nanospheres of biodegradable polymers, Journal of Controlled Release 2001; 71: 53-69 Feng SS, Chien S, Chemotherapeutic engineering: Application and further development of chemical engineering principles for chemotherapy of cancer and other diseases, Chemical Engineering Science 2003; 58: 4087-4114 Gao X, Cui Y, Levenson R, Chung L, Nie S, In vivo cancer targeting and imaging with semiconductor quantum dots, Nature Biotechnology, 2004; 22: 969-976 Gao X, Yang L, Petros J, Marshall F, Simons J, Nie S, In vivo molecular and cellular imaging with quantum dots, Current Opinion in Biotechnology 2005; 16: 63-72 Gillis P, Moiny F, Brooks RA, On T2-shortening by strongly magnetized spheres: a partial refocusing model, Magnetic Resonance in Medicine 2002; 47: 257-263 87 Gomez-Lopera SA., Plaza RC, Delgado AV, Synthesis and characterization of spherical magnetite/biodegradable polymer composite particles, Journal of Colloid and Interface Science 2001; 240: 40–47 Guo G, Liu W, Liang J, Xu H, He Z, Yang X, Preparation and characterization of novel CdSe quantum dots modified with poly (D, L-lactide) nanoparticles, Materials Letters 2006; 60:2565-2568 Gupta AK, Gupta M, Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications, Biomaterials 2005; 26: 3995-4021 Gupta RB, Kompella UB, Nanoparticle Technology for Drug Delivery, Vol 162, 2006 Hornak JP, The basics of MRI, http://www.cis.rit.edu/htbooks/mri/ Jiang W, Papa E, Fischer H, Mardyani S, Chan WC, Semiconductor quantum dots as contrast agents for whole animal imaging, Trends in Biotechnology 2004; 22: 607-609 Jeong JR, Lee SJ, Kim JD, Shin SC, Magnetic properties of Fe3O4 nanoparticles encapsulated with poly(D,L lactide-co-glycolide), IEEE Transactions on Magnetics 2004; 40: 3015-3017 Jordan A, Scholz R, Maier-Hauff K, Johannsen M, Wust P, Nadobny J, Schirra H, Deger S, Loening S, Lanksch W, Felix R Presentation of a new magnetic field therapy system for the treatment of human solid tumors with magnetic fluid hyperthermia, Journal of Magnetism and Magnetic Materials 2001; 225: 118-126 88 Keevil SF, Magnetic resonance imaging in medicine, Physics Education 2001; 36: 476485 Kirchin MA, Runge VM, Contrast agents for magnetic resonance imaging: safety update, Topics in Magnetic Resonance Imaging 2003; 14: 426-435 Krachler M, Radner H, Irgolic KJ Microwave digestion methods for the determination of trace elements in brain and liver samples by inductively coupled plasma mass spectrometry, Fresenius' Journal of Analytical Chemistry 1996; 355: 120-128 Kreuter J, Ramge P, Petrov V, Hamm S, Gelperina SE, Engelhardt B, Alyautdin R, von Briesen H, Begley DJ, Direct evidence that polysorbate-80-coated poly(butylcyanoacrylate) nanoparticles deliver drugs to the CNS via specific mechanisms requiring prior binding of drug to the nanoparticles, Pharmaceutical Research 2003; 20: 409-416 Kreuter J, Application of nanoparticles for the delivery of drugs to the brain, International Congress Series 2005; 1277: 85-94 Kwon GS, Okano T, Polymeric micelles as new drug carriers, Advanced Drug Delivery Reviews, 1996; 21:107-116 Lang P, Yeow K, Nichols A, Scheer A, Cellular imaging in drug discovery, Nature Reviews Drug Discovery 2006; 5:343-356 89 Lanza GM, Abendschein DA, Yu X, Winter PM, Karukstis KK, Scott MJ, Fuhrhop RW, Scherrer DE, Wickline SA Molecular imaging and targeted drug delivery with a novel, ligand-directed paramagnetic nanoparticle technology, Academic Radiology 2002; 9:S330-331 Lee SJ, Jeong JR, Shina SC, Kim JC, Changa YH, Chang YM, Kim JD, Nanoparticles of magnetic ferric oxides encapsulated with poly(D,L latide-co-glycolide) and their applications to magnetic resonance imaging contrast agent, Journal of Magnetism and Magnetic Materials 2004; 272: 2432-2433 Lefevre ME, Vanderhoff JW, Laissue JA, Joel DD, Accumulation of 2-micron latex particles in mouse Peyer's patches during chronic latex feeding, Experientia 1978; 34: 120-122 Lim JH, Choi D, Cho SK, Kim SH, Lee WJ, Lim HK, Park CK, Paik SW, Kim YI, Conspicuity of hepatocellular nodular lesions in cirrhotic livers at ferumoxides-enhanced MR imaging: importance of Kupffer cell number, Radiology 2001; 220:669-676 Lin CR, Chiang RK, Wang JS, Sung TW, Magnetic properties of monodisperse iron oxide nanoparticles, Journal of Applied Physics 2006; 99: 1-3 Liu C, Rondinone AJ, Zhang ZJ, Synthesis of magnetic spinel ferrite CoFe2O4 nanoparticles from ferric salt and characterization of the size-dependent superparamagnetic properties, Pure and Applied Chemistry 2000; 72: 37-45 90 Mareda H, The enhanced permeability and retention (EPR) effect in tumour vasculature: the key role of tumor-selective macromolecular drug targeting, Advances in Enzyme Regulation 2001; 41: 189-207 Massoud TF, Gambhir SS, Molecular imaging in living subjects: seeing fundamental biological processes in a new light, Genes & Development, 2003; 17: 545–580 Mauduit J, Bukh N, Vert M, Gentamycin/poly(lactic acid) blends aimed at sustained release local antibiotic therapy administered per-operatively I The case of gentamycin base and gentamycin sulfate in poly(DL-lactic acid) oligomers, Journal of Controlled Release 1993a; 23: 209-220 Mauduit J, Bukh N, Vert M, Gentamycin/poly (lactic acid) blends aimed at sustained release local antibiotic therapy administered per-operatively II The case of gentamycin sulfate in high molecular weight poly (DL-lactic acid) and poly (L-lactic acid), Journal of Ccontrolled Release 1993b; 23: 221-230 Mauduit J, Bukh N, Vert M, Gentamycin/poly (lactic acid) blends aimed at sustained release local antibiotic therapy administered per-operatively III The case of gentamycin sulfate in films prepared from high and low molecular weight poly (DL-lactic acids), Journal of Controlled Release 1993c; 25: 43-49 Medintz IL, Uyeda HT, Goldman ER, Mattoussi H, Quantum dot bioconjugates for imaging, labeling and sensing, Nature Materials, 2005; 4: 435-446 91 Moghimi SM, Hunter AC, Murray JC, Long-circulating and target-specific nanoparticles: theory to practice, Pharmacological Reviews 2001; 53: 283-318 Mornet S, Vasseur S, Grasset F, Veverka P, Goglio G, Demourgues A, Portier J, Pollert E, Duguet E, Magnetic nanoparticle design for medical applications , Progress in Solid State Chemistry 2005; 34: 237-247 Mu L, Feng SS, A novel controlled release formulation for anticancer drug paclitaxel (Taxol®): PLGA nanoparticles containing vitamin E TPGS, Journal of Controlled Release 2003; 86: 33-48 Muller RH, Maassen S, Weyhers H, Specht F, Lucks JS, Cytotoxicity of magnetiteloaded polylactide, polylactide/glycolide particles and solid lipid nanoparticles, International Journal of Pharmaceutics 1996; 138: 85–94 Neuberger T, Schopf B, Hofmann H, Hofmann M, von Rechenberg B, Superparamagnetic nanoparticles for biomedical applications: Possibilities and limitations of a new drug delivery system, Journal of Magnetism and Magnetic Materials 2005; 293: 483-496 Ngaboni Okassa L, Marchais H, Douziech-Eyrolles L, Cohen-Jonathan S, Souce M, Dubois P, Chourpa I, Development and characterization of sub-micron poly(D,L-lactideco-glycolide) particles loaded with magnetite/maghemite nanoparticles, International Journal of Pharmaceutics 2005; 302: 187-196 92 Pankhurst QA, Connoly J, Jones SK, Dobson J, Applications of magnetic nanoparticles in biomedicine, Journal of physics D: Applied physics, 2003; 36:R167-181 Pereira E, Marzola P, Podio V, Aime S, Sbarbati A, Gasco MR, In vitro and in vivo study of solid lipid nanoparticles loaded with superparamagnetic iron oxide, Journal of Drug Targeting, 2003; 11: 19-24 Pich A, Bhattacharya S, Ghosh A, Adler HJP, Composite magnetic particles: Encapsulation of iron oxide by surfactant-free emulsion polymerization, Polymer 2005; 46: 4596-4603 Pinaud F, Michalet X, Bentolila LA, Tsay JM, Doose S, Li JJ, Tyer G, Weiss S, Advances in fluorescence imaging with quantum dot bio-probes, Biomaterials 2006; 27:1679-1687 Pouliquen D, Perdrisot R, Ermias A, Akoka S, Le Jeune JJ, Superparamagnetic iron oxide nanoparticles as liver MRI contrast agent: Contribution of microencapsulation to improved biodistribution, Magnetic Resonance Imaging 1989; 7: 619-627 Ranade VV, Hollinger MA, Drug Delivery Systems, Second Edition, Boca Raton, FL: CRC Press 2004 Ruan G, Feng SS, Li QT, Effects of material hydrophobicity on physical properties of polymeric microspheres formed by double emulsion process, Journal of Controlled Release 2002; 84: 151-160 93 Sah H, Chien YW, Effects of H+ liberated from hydrolytic cleavage of polyester microcapsules on their permeability and degradability, Journal of Pharmaceutical Sciences 1995; 84: 1353-1359 Sahoo SK, Panyam J, Prabha S, Labhasetwar V, Residual polyvinyl alcohol associated with poly (D,L-lactide-co-glycolide) nanoparticles affects their physical properties and cellular uptake, Journal of Controlled Release 2002; 82:105-114 Savic R, Luo LB, Eisenberg A, Maysinger D, Micellar nanocontainers distribute to defined cytoplasmic organelles, Science 2003; 300: 615-618 Stark DD, Weissleder R, Elizondo G, Hahn PF, Saini S, Todd LE, Wittenberg J, Ferrucci JT, Superparamagnetic iron oxide: clinical application as a contrast agent for MR imaging of the liver, Radiology 1988; 168:297-301 Stolnik S, Garnett MC, Davies MC, Illum L, Bousta M, Vert M, Davis SS, The colloidal properties of surfactant-free biodegradable nanospheres from poly(β-malic acid-cobenzyl malate)s and poly(lactic acid-co-glycolide), Colloids surfaces A: Physicochem Eng Aspects1995; 97: 235-245 Sun WQ, Xie C, Wu H, Hu Y, Specific role of polysorbate 80 coating on the targeting of nanoparticles to the brain, Biomaterials 2004; 25: 3065-3071 Tartaj P, Morales MP, Veintemillas-Verdaguer S, Gonzalez-Carreno T, Serna CJ, The preparation of magnetic nanoparticles for application in biomedicine, Journal of Physics D: Applied Physics 2003; 36: R182-197 94 Wang DS, He JB, Rosenzweig N, Rosenzweig Z, Superparamagnetic Fe2O3 beadsCdSe/ZnS quantum dots core-shell nanocomposite particles for cell separation, Nano Letters 2004; 4: 409-413 Weissleder R, Scaling down imaging: molecular mapping of cancer in mice, Nature Reviews Cancer 2002; 2:11-18 Weissleder R, Mahmood U, Molecular imaging, Radiology 2001; 219: 316-333 Win KY, Feng SS, Effects of particle size and surface coating on cellular uptake of polymeric nanoparticles for oral delivery of anticancer drugs, Biomaterials 2005; 26: 2713-2722 Win KY, Feng SS, In vitro and in vivo studies on vitamin E TPGS-emulsified poly(D,Llactic-co-glycolic acid) nanoparticles for paclitaxel formulation, Biomaterials 2006; 27: 2285-2291 Yang X, Zhang Y, Encapsulation of quantum nanodots in polystyrene and silica micro/nanoparticles, Langmuir 2004; 20:6071-6073 Zhang Z, Feng SS, The drug encapsulation efficiencies, in vitro drug release, cellular uptake and cytotoxicity of Paclitaxel-loaded poly(lactide)-tocopheryl polyethylene glycol succinate nanoparticles, Biomaterials 2006; 27: 4025-4033 Zheng W, Gao F, Gu H, Magnetic polymer nanospheres with high and uniform magnetite content, Journal of Magnetism and Magnetic Materials 2005; 288: 403-410 95 Zhitomirsky I, Niewczas M, Petric A, Electrodeposition of hybrid organic-inorganic films containing iron oxide, Materials Letters 2003; 57: 1045-1050 96 [...]... development of efficient diagnostic agents 1.2 Objectives To develop stable, efficient and low-toxic diagnostic agents for MRI and fluorescence imaging, superparamagnetic iron oxides (IOs) and quantum dots (QDs) were encapsulate within matrix of biocompatible and biodegradable polymers Experiments were carried out to investigate the feasibility of the obtained nanoparticles for delivery of diagnostic agents. .. multicolor imaging in living animals 20 2.5 Nanoparticle Technology 2.5.1 Nanoparticle formulations There are quite a number of methods to formulate nanoparticles In general, nanoparticles can be formed either by dispersion of polymers or by polymerization of monomers These methods include: solvent evaporation/extraction, solvent diffusion/nanoprecipitation, supercritical fluid spraying, and polymerization of. .. vitro release of IOs loaded PLGA-mPEG nanoparticles in PBS 49 Figure 15 r2 and r2* relaxativities of IOs and IOs loaded PLGA-mPEG nanoparticles 51 Figure 16 Relaxation rate 1/T2 and 1/T2* of IOs, empty PLGA-mPEG nanoparticles, and mixtures of them at different nanoparticle concentrations 53 Figure 17 MR imaging of the livers of the rats: upper is the control, and bottom is that of the rat injected... images of QD loaded PLGA nanoparticles in SD rat 1h after tail vein injection (bar = 5µm) 63 Figure 26 Size distribution of QDs loaded polymeric nanoparticles 65 Figure 27 FESEM images of QDs loaded polymeric nanoparticles 70 Figure 28 AFM images of QDs loaded polymeric nanoparticles: zoom-in 3D image and 5µm x 5µm 2D image 71 Figure 29 TEM images of QDs loaded polymeric nanoparticles... magnetic resonance imaging (MRI) also has a wide range of applications in cellular and biomolecular imaging (Weissleder, 2002; Lanza et al., 2002; Massoud & Gambhir, 2003) 1 However, some factors have become the bottle-necks for the further applications of cellular imaging, one of which is the unstable, ineffective, toxic, and high-cost diagnostic agents (Bulte et al., 2002) One of the future improvements... injected with IOs loaded PLGA-mPEG nanoparticles 55 Figure 18 Particle size distribution of QDs loaded PLGA nanoparticles 56 Figure 19 FESEM image of QDs loaded PLGA nanoparticles 57 Figure 20 AFM image of QDs loaded PLGA nanoparticles 58 Figure 21 TEM images: (a) QDs, (b) QDs loaded PLGA nanoparticles 59 Figure 22 Confocal microscopic images of red emission hydrophobic and green...Figure 10 Magnetizations of IOs and IOs loaded PLGA-mPEG nanoparticles at 300K 44 Figure 11 Magnetization as a function of temperature for IOs and IOs loaded PLGAmPEG nanoparticles (Applied field = 20 kOe) 45 Figure 12 ZFC and FC curves of IOs and IOs loaded PLGA-mPEG nanoparticles (Applied field = 100Oe) 47 Figure 13 Stability of IOs loaded PLGA-mPEG nanoparticles in saline solution... investigated physicochemical properties of the formulated particles such as particle size, surface morphology and magnetization Magnetization of the nanoparticles is important but it is not a direct indication of the contrast efficacy Releasing of the IOs from the nanoparticles also plays a crucial role in their diagnostic efficiency in vitro and in vivo So far, none of the research groups have measured... photosensitizing agents (photosensitizers) in photodynamic therapy (PDT) (Gao et al., 2005) When exposed to a specific wavelength of light, QDs can induce the formation of peroxide and other free forms of radicals which can kill nearby cells This is especially useful if QDs could de designed to target cancer cells 2.4.2 Current research on QDs loaded polymeric nanoparticles in medical imaging QDs have... cancer diagnosis and therapy In order to understand the mechanisms of various cancers and realize early detection, great efforts have been put towards the development of reliable, noninvasive and high-resolution medical imaging technology Traditional medical imaging focuses on the final manifestation of diseases, while modern cellular imaging targets the cellular abnormalities that underlie diseases .. .NANOPARTICLE FORMULATIONS OF DIAGNOSTIC AGENTS FOR MEDICAL IMAGING WANG YAN (B Eng, Shanghai Jiao Tong University) A THESIS SUBMITTED FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE... 20 2.5 Nanoparticle Technology 2.5.1 Nanoparticle formulations There are quite a number of methods to formulate nanoparticles In general, nanoparticles can be formed either by dispersion of polymers... used emulsifier in nanoparticle formulations, often resulting in nanoparticles that are small and uniform VE TPGS was chosen because of its masking effect that allowed the nanoparticles to be