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Metal Oxo Containing Polymer Nanobeads As Potential Contrast Agents For Magnetic Resonance Imaging
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Book Synopsis Metal-Oxo Containing Polymer Nanobeads As Potential Contrast Agents for Magnetic Resonance Imaging by : Michele Huelar Pablico
Download or read book Metal-Oxo Containing Polymer Nanobeads As Potential Contrast Agents for Magnetic Resonance Imaging written by Michele Huelar Pablico and published by . This book was released on 2011 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most common MRI contrast agents that are in clinical use today are gadolinium chelates and superparamagnetic iron oxide nanoparticles, both of which have their own advantages in terms of contrast enhancement properties. In the past few years, however, there has been interest in utilizing metal-containing clusters for MRI contrast enhancement as these materials bridge the gap between the constrained structure and magnetic properties of the gadolinium chelates with the superparamagnetic behavior of the iron oxide nanoparticles. Recently, metallic clusters containing Mn and Fe metal centers have received increased attention mainly because of their potential for high spin states and benign nature.
Book Synopsis Metal-Oxo Polymer Nanobeads as Potential Multi-Modal Contrast Agents for Magnetic Resonance Imaging by : Vidumin Dahanayake
Download or read book Metal-Oxo Polymer Nanobeads as Potential Multi-Modal Contrast Agents for Magnetic Resonance Imaging written by Vidumin Dahanayake and published by . This book was released on 2018 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: The stability of these nanobeads in simulated biological conditions was extensively studied for potential use as contrast agents. Metal leaching, hydrodynamic diameter and relaxation were monitored over time. Hemo-compatibility, cellular uptake and viability in vitro was also investigated along with blood clearance and biodistribution in vivo. Finally the feasibility of these materials for MRI contrast enhancement and their integrity after opsonization was tested using live mouse models.
Book Synopsis Multifunctional Polymer Platform as Ligand and MRI Contrast Agent for Inorganic Nanocrystals by : Liang Du
Download or read book Multifunctional Polymer Platform as Ligand and MRI Contrast Agent for Inorganic Nanocrystals written by Liang Du and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique physical and optical properties of inorganic nanocrystals have generated tremendous interest over the past two decades. They have been extensively studied to prepare photovoltaic devices and diagnostic tools. Luminescent quantum dots, gold nanomaterials and iron oxide nanoparticles have found promising success in a broad range of areas including light-emitting diodes, therapeutic tomography, photodynamic therapy drug delivery and magnetic resonance imaging. However, most of the as-prepared nanoparticles are stabilized by hydrophobic coordinating ligands which impede their biological applications. In this dissertation, we summarize the application of poly(isobutylene-alt-maleic anhydride) (PIMA) polymer platform to prepare biocompatible nanomaterials as well as MRI contrast agents. In chapter 2, we designed a new set of multi-coordinating polymer ligands based on the phosphonate anchoring motif and applied them for the surface coating of luminescent quantum dots, gold nanoparticles and iron oxide nanoparticles alike. The ligand is synthesized via nucleophilic addition reaction between poly(isobutylene-alt-maleic anhydride) and amine-modified phosphonate derivatives and short polyethylene glycol hydrophilic blocks, which allows the flexibility to tune the architecture and stoichiometry of the final compound. We find that these phosphonate-based polymers exhibit strong coordinating affinity to ZnS-overcoated quantum dots (QDs), Au nanoparticles (AuNPs) as well as iron oxide nanoparticles (IONPs), yielding nanocrystal dispersions that exhibit good colloidal stability for all three systems. The affinity of these ligands is also preserved when additional coordinating groups are introduced, such as imidazoles. Furthermore, the resulting polymer-coated nanocrystals are easily functionalized with reactive groups, introduced along the polymer chain during synthesis. They are compact enough to allow implementation of resonance energy transfer coupling of luminescent QDs to proximal dyes. Affinity between the ligands and gold nanoparticle surfaces was compared to that of thiol groups using NaCN digestion tests. In Chapter 3, we designed a novel set of polymeric multicoordinating ligands based on the N-heterocyclic carbene (NHC) anchoring molecules and applied them for stabilizing luminescent quantum dots in aqueous media. The ligand is synthesized via nucleophilic addition reaction between amine-appended imidazole/poly(ethylene glycol) compounds and poly(isobutylene-alt-maleic anhydride) (PIMA), which yields coordinating ligands with tunable number of lateral motifs. We find that these NHC-based polymers exhibit fast and robust coordinating affinity to CdSe QDs overcoated with ZnS shells. The removal of pristine coating and the generation of carbene are demonstrated by NMR techniques. 13C and HMBC NMR spectroscopy also confirm the existence of the carbene-carbon which is crucial for binding the transition-metals on QD surfaces. These QDs exhibit essentially identical absorption and emission features before and after the cap exchange, and their compact architecture is demonstrated by diffusion ordered NMR spectroscopy. Agarose gel electrophoresis measurements indicate that the polymer coating imparts the QDs good compatibility in different pH, and it prevents protein adsorption. Excellent colloidal stability of these QD samples is observed in a wide range of competitive conditions over extended period of time. In Chapter 4, we detail the design of a set of polymeric contrast agents used for 19F magnetic resonance imaging (19F MRI). The agent is synthesized via a nucleophilic addition reaction between poly(isobutylene-alt-maleic anhydride) and amine-appended fluorinated precursors and short polyethylene glycol (PEG) coils, which permits the tunability of the stoichiometric architecture. We find that introducing PEG moieties to ~70% of the repeating units on the polymers is essential for balancing the hydrophobic feature of fluorine groups. We show that the signal to noise ratio (SNR) of the contrast agents is highly dependent on the arm-length between the polymer scaffold and the magnetic responding CF3 groups. A series of lateral fluorinated chains with different lengths are installed onto the polymers, and extended transverse relaxation time (T2) is observed from the agents with long arm-lengths. Data from Diffusion-ordered NMR spectroscopy (DOSY) indicate that using a pegylated arm between the macromolecule and CF3 groups does not greatly increase the hydrodynamic size of the resulting contrast agents. The effectiveness of inserting the arm is also confirmed by phantom images collected from agent dispersions with different concentrations. In Chapter 5, we provide a summary of the versatility of PIMA platform and discuss the outlook of these multifunctional polymeric molecules.
Book Synopsis Polymeric Nanoparticle and Bioconjugate MRI Contrast Agents for In Vivo Imaging by : Clare Lee Matilda Le Guyader
Download or read book Polymeric Nanoparticle and Bioconjugate MRI Contrast Agents for In Vivo Imaging written by Clare Lee Matilda Le Guyader and published by . This book was released on 2017 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoparticles are the hallmark of nanomedicine, proving clinically relevant for the delivery of therapeutic and diagnostic drugs. Nanomaterials are highly versatile, with the ability for scientists to tailor composition and function to suit the desired application. Herein, two types of nanocarriers are investigated in the context of magnetic resonance imaging contrast agents: polymeric nanoparticles and protein carriers. A key research focus in applying nanoparticles for drug delivery is in understanding physicochemical properties affecting in vivo fate. Shape or morphology of a particle is a vastly underutilized property in the design of nanoparticles, and is difficult to predictably control in the context of polymeric nanoparticles. Investigations of block copolymer nanoassemblies evaluate effects of the polymer structure and the self-assembly process to form interesting and diverse structures. In this work, ring-opening metathesis polymerization is employed to prepare and study block copolymer amphiphile self-assembly. First, a small library of amphiphiles are prepared in which the hydrophobic block functionality is varied. In varying the polymer structure and the solvent for assembly, different morphologies are produced, including small and large spheres, cylinders, y-junctions, and rods. In several cases, one polymer can take on different morphologies depending on the organic cosolvent used during micellization, highlighting the importance of assembly conditions and dynamics in forming kinetically trapped structures versus thermodynamically stable structures. These are important considerations when designing, synthesizing, and formulating polymeric nanoparticles for in vivo applications. Next, direct incorporation of a gadolinium based contrast agent for magnetic resonance imaging is studied. A novel monomer and chain transfer agent of a gadolinium-chelate are used to directly incorporate the contrast agent in to a polynorbornene polymer backbone. The resulting spherical and fibrillar nanoparticles exhibited enhanced relaxivity and are studied as MRI contrast agents using live imaging in murine models. Finally, a fatty acid ligand is conjugated to a gadolinium-based contrast agent is prepared and formulated with human serum albumin. In formulation with HSA, the agent exhibits high relaxivity and prolonged blood circulation. In addition, therapeutic conjugates formulated with HSA are evaluated for in vitro cytotoxicity and found to be effective in tumor growth suppression in vivo.
Book Synopsis Metal Oxide Nanoparticles as Potential MRI Contrast Agents by : Naomi E. Jones
Download or read book Metal Oxide Nanoparticles as Potential MRI Contrast Agents written by Naomi E. Jones and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Iron Oxide Nanoparticles for Biomedical Applications by : Sophie Laurent
Download or read book Iron Oxide Nanoparticles for Biomedical Applications written by Sophie Laurent and published by Elsevier. This book was released on 2017-10-20 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Iron Oxide Nanoparticles for Biomedical Applications: Synthesis, Functionalization and Application begins with several chapters covering the synthesis, stabilization, physico-chemical characterization and functionalization of iron oxide nanoparticles. The second part of the book outlines the various biomedical imaging applications that currently take advantage of the magnetic properties of iron oxide nanoparticles. Brief attention is given to potential iron oxide based therapies, while the final chapter covers nanocytotoxicity, which is a key concern wherever exposure to nanomaterials might occur. This comprehensive book is an essential reference for all those academics and professionals who require thorough knowledge of recent and future developments in the role of iron oxide nanoparticles in biomedicine. Unlocks the potential of iron oxide nanoparticles to transform diagnostic imaging techniques Contains full coverage of new developments and recent research, making this essential reading for researchers and engineers alike Explains the synthesis, processing and characterization of iron oxide nanoparticles with a view to their use in biomedicine
Book Synopsis Surface-modified Nanobiomaterials for Electrochemical and Biomedicine Applications by : Alain R. Puente-Santiago
Download or read book Surface-modified Nanobiomaterials for Electrochemical and Biomedicine Applications written by Alain R. Puente-Santiago and published by Springer Nature. This book was released on 2020-07-27 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.
Book Synopsis Synthesis of Biocompatible Nanoparticulate Coordination Polymers for Diagnostic and Therapeutic Applications by : Murthi S. Kandanapitiye
Download or read book Synthesis of Biocompatible Nanoparticulate Coordination Polymers for Diagnostic and Therapeutic Applications written by Murthi S. Kandanapitiye and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The combination of nanotechnology with medicinal chemistry has developed into a burgeoning research area. Nanomaterials (NMs) could be seamlessly interfaced with various facets in biology, biochemistry, medicinal chemistry and environmental chemistry that may not be available to the same material in the bulk scale. This dissertation research has focused on the development of nanoparticulate coordination polymers for diagnostic and therapeutic applications. Modern imaging techniques include X-ray computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) and positron emission tomography (PET). We have successfully developed several types of nanoparticulate diagnostics and therapeutics that have some potential usefulness in biomedicine. Synthesis and characterization of nanoparticulate based PET (Positron emission tomography)/SPECT (Single photon emission computed tomography) are discussed in chapter 3. For the preparation of 68Ga-radiopharmaceuticals, fast formation kinetics are required owing to the short half-life of 68Ga. Our accelerated synthesis involving the aqueous solution and efficient-easy purification of PB NPs would be highly desirable. In addition, easy preparation and fast purification allow physicians to gain considerable time for imaging even with relatively low concentration of radiopharmaceuticals. We demonstrate for the first time the use of Ga(III) doped colloidal solutions of Prussian blue (PB) as a novel radioactive Ga(III) delivering agent. The PET/SPECT imaging modalities provide information on molecular processes using radiolabeled imaging agents; on the other hand PET and SPECT gives limited anatomical details and spatial resolution as a major disadvantage, regardless of their high-sensitivity in tracking in vivo biomarkers. Also we have described for the first time a novel nanoparticulate solid-state compound that contains both Gd(III) (f7, S=7/2) and Ga(III) as dopants in the network structure. The dopant Gd(III) and radioactive Ga(III) render the T1- weighted MRI imaging active and PET-SPECT imaging active, respectively. Prussian blue nanoparticles are the smartest option as a scaffold material for the development of multimodal agent due to their biocompatibility, high water dispersability and easy with which its surface can be modified to get better pharmacokinetic properties. Such hybrid imaging techniques allow physicians to precisely co-register anatomical and functional information in a single scanning session without removing the patient from the bed, which would offer increased diagnostic accuracy. In chapter 4, preparation and potential utility of non-gadolinium based MRI contrast agent are reported for T1-weighted application. As far as the solely effectiveness of relaxation is concerned, Gd-based T1-weighted MRI contrast agents have excellent enhancement of image contrast but they have risks of biological toxicity. Consequently, the search for T1-weighted CAs with high efficacy and low toxicity has gained attention toward the Mn(II) and Fe(III). Fe(III) is considered to be more toxic to cells because free ferric or ferrous ions can catalyze the production of reactive oxygen species via the Fenton reactions. Paramagnetic chelates of Mn(II) could be employed as T1-weighted CAs. However, it is challenging to design and synthesize highly stable Mn(II) complexes that could maintain the integrity when administered to living system. Chapter 4 describes the synthesis and utility of nanoparticulate Mn analogue of Prussian blue (K2Mn3[FeII(CN)6]2) as an effective T1 MRI contrast agent for cellular imaging X-ray computed tomography is capable of delineating the 3-D images of soft tissues with superb quality. The variation of X-ray attenuation from one tissue to another is used to generate the well spatial resolved superb quality images. Exogenous radiopaque agents are necessary for the superb visualization of different types of soft tissues. Heavy metals with high atomic number are better suited for biomedical applications to enhance the image contrast due to their high mass attenuation coefficient. Bismuth (Z- 83) is the nonradioactive, heaviest, nontoxic element available among the other closest neighbors (Hg, Tl, Pb and Po) of the periodic table. We have set out to search for compounds that are hydrolytically stable, more efficient and more amenable in terms of biocompatibility. Moreover this new discovery can significantly reduce the average radiation dose in one CT scan. We have discovered a simple one-step aqueous solution route for preparing biocompatible and ultra-small bismuth oxyiodide BiOI nanoparticles and investigated their potential application as an efficient CT contrast agent. Our ultra-small monodisperse BiOI NPs have excellent water dispersability, thermodynamic stability, kinetic inertness, high biocompatibility and superior attenuation power, suggesting their potential as an organ-specific CT contrast agent that may fill the gap left by the other nanoparticulate and iodine-based CT contrasting agents. The chapter 6 of this dissertation discusses synthesis and characterization of novel nanoparticulate therapeutics and theranostics. D-penicillamine has the highest efficacy, and hence is currently the most widely used drug for WD across the world. We have prepared the D-PEN-conjugated Au NPs of the average size of 16 ± 2 nm with superb water dispersability, and examined the kinetics and selectivity of copper binding of such NPs in aqueous solution. We also studied the cellular uptake, cytotoxicity and intracellular copper removal of these NPs to demonstrate their potential as a novel cell-penetrable copper detoxifying agent. To the best of our knowledge, this is the first attempt to show that D-PEN can be tailor-made as a new-generation biocompatible intracellular copper detoxifying drug. Despite of its many adverse side effects, D-PEN remains as a treatment for WD because of its proven efficacy. It seems clear that there is an unmet clinical need for a novel WD drug with improved organ-specificity and reduced systemic toxicity. Our approach of tackling these problems focuses on the development of cell-permeable copper-depleting nanoparticles that can be surface-engineered to be potentially organ-specific when targeting agents are used to form new-generation drugs for WD. The latter part of chapter 6, we describe the synthesis, characterization of zinc analogue of Prussian blue (K2Zn3[Fe(CN)6]2-ZnPB) for intracellular copper detoxification. ZnPB NPs are highly water-dispersible, biocompatible and capable of penetrating cells and selectively remove the intracellular copper. Besides the copper detoxification ability of K2Zn3[Fe(CN)6]2, the concomitant copper sensing activity of ZnPB NPs was investigated owing to its selective copper ion exchange kinetics and the change in r1 relaxivity. Further, our K2Zn3[Fe(CN)6]2 NPs exhibit anti-angiogenic activity and such effect on HuVEC cells could easily be reversed by replenishing the copper supply. This observation suggested that our nanoparticles show their activity on angiogenesis inhibition by depleting copper which acts as a cofactor in a number of angiogenesis promoters.
Book Synopsis Advancements in Branched Bottlebrush Polymers for Responsive, Targeted Imaging by : Molly Ann Sowers
Download or read book Advancements in Branched Bottlebrush Polymers for Responsive, Targeted Imaging written by Molly Ann Sowers and published by . This book was released on 2015 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-modality and stimuli responsive nanoparticles are promising platform materials for medical imaging and diagnostics. Specifically magnetic resonance imaging (MRI) and nearinfrared (NIR) fluorescent probes can be used in combination to visualize biodistribution and in vivo clearance rates. We reasoned that through the use of a nitroxide radical MRI contrast agent along with a NIR fluorophore it would be possible to study these phenomena along with nitroxide reduction in vivo. Thus, we have developed branched bottlebrush copolymers that display compensatory fluorescence response to nitroxide reduction that enables correlation of MRI contrast, fluorescence intensity, and spin concentration in tissues. These polymers were synthesized by ring-opening metathesis copolymerization of two new branched macromonomers: one carries a bis-spirocyclohexyl nitroxide and the other the NIR dye Cy5.5. Promising preliminary results with the resulting polymers in solution MRI and NIR imaging studies as well as in vitro toxicity led us to explore the potential of these materials for in vivo applications. Though nitroxide agents are promising organic agents for MRI applications, clinically, gadolinium-based MRI contrast agents are most common due to their high relaxivity and relatively low toxicity when bound to chelating ligands. We have also explored the idea of incorporation of gadolinium agents into our branched bottlebrush copolymer platform through the design of Gd-based branched macromonomers. While the fluorescence redox effects described in the nitroxide system above would not be applicable, chelated Gd could be used in much smaller concentration to provide similar MRI contrast. In this way, a small percentage of Gd could be added as an MRI tag to any polymer synthesized by ROMP. A natural extension of the work described above is the incorporation of cellular targeting moieties for tissue-selective imaging. Toward this end, we propose the incorporation of known cellular targeting ligands onto the surface of branched bottlebrush polymers through the synthesis of end-functionalized branched macromonomers. The synthesis of several targeting ligands is described, alongside synthesis and characterization of positively charged nanoparticles for improved cellular uptake and ionic coordination of hyaluronic acid or other negatively charged polymers.
Download or read book Nanomedicine written by Marc J. Williams and published by Elsevier Inc. Chapters. This book was released on 2013-09-19 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past two decades have seen a surge in the development and application of nanoparticles for biomedical uses, with a focused effort on engineering particles for ‘theranostic’ applications where diagnosis and disease treatment are possible using a single platform. Magnetic nanoparticles, in particular, are ideal candidates for this kind of multimodal action, given their potential use spans magnetic resonance (MR) imaging, magnetic hyperthermia and targeted drug delivery. This is due to unique properties their size bestows on them. Here, we examine these properties of magnetic nanoparticles and how they govern the particle efficacy for a desired application. Given the intimate link between synthetic approach chosen and subsequent properties, we will also discuss typical and emerging routes to magnetic nanoparticle preparation. We will, in detail, describe the uses of magnetic nanoparticles as diagnostic and therapeutic tools, with particular emphasis on their use as MR contrast agents and the most recent developments in targeted drug delivery. Finally, we will present an outlook for the future of these important materials.
Book Synopsis Applications of Theranostic Nanoparticles as Contrast Agents in Magnetic Resonance Imaging by : Richard Aaron Revia
Download or read book Applications of Theranostic Nanoparticles as Contrast Agents in Magnetic Resonance Imaging written by Richard Aaron Revia and published by . This book was released on 2020 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in materials science that have allowed for the engineering of nanoscale structures represent a revolutionary paradigm shift for the detection and remediation of diseases such as cancer. Worldwide research efforts are currently leveraging the tools of nanotechnology to aid the fight against cancer by developing novel material architectures that are designed to provide quicker diagnoses of disease at earlier time points than are currently available and improved therapeutic responses by efficiently killing cancer tissue while minimizing off-target side effects. One nanotechnology in particular, iron oxide nanoparticles (NPs), has received intense interest due to its many beneficial attributes: biodegradability, chemical surface properties, and superparamagnetism. Unlike other metal-core NPs, iron oxide NPs are nontoxic when decomposed and prepared for excretion by the body as the iron in their cores may be used by the body in iron-containing proteins (e.g., hemoglobin and ferritin). Additionally, the chemical composition of iron oxide lends itself for use in chemical passivation techniques that seek to coat the iron oxide cores in polymers that confer advantageous qualities of biocompatibility and ligation of functional moieties. Finally, the magnetic properties of iron oxide particles of nanoscale proportions allow the NPs to serve as contrast enhancing agents in magnetic resonance imaging (MRI), a tool that is widely used to image the soft tissue of the body for cancer detection. This dissertation details the use of iron oxide NPs as contrast agents for MRI and as therapeutic agents targeting an insidiously aggressive brain cancer: glioblastoma. First, noninvasive MRI is used to determine the biodistribution of iron oxide NPs in both mice and nonhuman primates in a first-of-its-kind, cross-species comparison of iron oxide NP pharmacokinetics. It was found that the pharmacokinetics of iron oxide NPs between the two species were similar in some organs (i.e., blood, liver, spleen, and muscle) but distinct in others (i.e., kidneys, brain, and bone marrow). Next, iron oxide NPs are directly delivered to brain tumors in mice via convection-enhanced delivery (CED), and their distribution throughout the tumor volume is tracked in real-time using MRI. The distribution of iron oxide NPs ligated with a glioblastoma-targeting peptide, chlorotoxin, is compared to the distribution of bare NPs; results show that NPs attached to chlorotoxin are better able to suffuse throughout the tumor volume than NPs lacking the tumor-targeting moiety. Following these research efforts that display the ability of iron oxide NPs to serve as contrast agents in MRI, a therapeutic example of iron oxide NPs in oncology is provided as these NPs are used to enhance the radiation dose delivered to mice-bearing orthotopic glioblastoma tumors. Mice treated with NPs prior to receiving radiotherapy exhibited a 2-fold increase in median survival compared to mice receiving only radiotherapy. Finally, a novel nanotechnology platform, boron-doped graphene quantum dots, is explored for use as a nontoxic MRI contrast agents.
Book Synopsis Optimization and Characterization of Multifunctional Polymer-based Nanoparticles Containing DTPA-Gd Contrast Agent for MRI Enhancement by : Xinyu Wu
Download or read book Optimization and Characterization of Multifunctional Polymer-based Nanoparticles Containing DTPA-Gd Contrast Agent for MRI Enhancement written by Xinyu Wu and published by . This book was released on 2015 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies of Catechol-functionalized Multidentate Block Copolymer Strategy to Stabilize Superparamagnetic Iron Oxide Nanoparticles for Magnetic Resonance Imaging by : Puzhen Li
Download or read book Studies of Catechol-functionalized Multidentate Block Copolymer Strategy to Stabilize Superparamagnetic Iron Oxide Nanoparticles for Magnetic Resonance Imaging written by Puzhen Li and published by . This book was released on 2016 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) contrast agents play important roles in diagnosis and clinical applications. Particularly, superparamagnetic iron oxide nanoparticles (SNPs) with appropriate surface modification hold enormous promise as MRI contrast agents owning to their excellent biocompatibility. This thesis describes novel catechol-functionalized multidentate block copolymer (Cat-MDBC) strategy that enables the stabilization of SNPs with diameter ≤3.5 nm as effective MR bright imaging (T1-weighted) contrast agents. Atom transfer radical polymerization and post-modification methods allow for the synthesis of well-controlled Cat-MDBCs. They enable the stabilization of ultrasmall SNPs with diameter ≈3.5 nm (i.e. USNPs) through a biphasic ligand exchange process. The results from surface characteristics, colloidal stability in physiological properties, relaxivity properties, and in vitro MRI suggest that the USNPs coated with Cat-MDBC (Cat-MDBC/USNPs) can be a promising candidate for T1-MRI application. Further, extremely small SNPs with diameter ≈2 nm (i.e. ESNPs) coated with Cat-MDBC (Cat-MDBC/ESNPs) have better relaxivity properties as T1-MRI contrast agents, compared with the Cat-MDBC/USNP colloids; and more promisingly, they have the r2/r1 value comparable to clinically-used Gd3+-based contrast agents.
Book Synopsis Magnetic and Surface Interactions of Functionalized Polydopamine Nanoparticles for Biomedical Applications by : Yijun Xie
Download or read book Magnetic and Surface Interactions of Functionalized Polydopamine Nanoparticles for Biomedical Applications written by Yijun Xie and published by . This book was released on 2019 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polydopamine (PDA) materials have provoked great attention in chemistry and materials science since 2007 due to their versatile properties including metal-ion chelation, easy functionalization, adhesion, and free radical scavenging ability. Produced via mild oxidation of dopamine monomer to form a colloidally-suspendable nanomaterial, polydopamine was initially developed as a versatile, biomimetic coating material, similar to the foot protein of mussels. Subsequently, PDA nanoparticles were developed as free radical scavengers and biomedical contrast agents amongst an ever-expanding list of applications. Currently, PDA nanoparticles are tunable in size within the range from tens to several hundred nanometers, and they can be easily loaded with metal ions and functionalized with different types of molecules. Therefore, PDA materials have great potentials in applications such as biomedicine, catalysis, and environmental remediation. In chapter 2, Fe3+-loaded PDA materials were studied as magnetic resonance imaging (MRI) contrast agents. An amorphous metal-chelated polymer nanoparticle presents a significant challenge for characterizing the source of MRI contrast as structural data is complex and characterization methods limited. Tunable concentrations of Fe3+ were achieved and the structure and magnetic interaction were analyzed comprehensively by magnetometry and electron paramagnetic resonance. These characterizations indicate the antiferromagnetic coupling in Fe3+ centers and optimal Fe3+ concentrations can be predicted to improve the contrast performance of PDA materials. In chapter 3 and 4, fluorocarbon-functionalized PDA and Fe3+-loaded PDA NPs were investigated as ultrasound contrast agents. Traditional ultrasound imaging uses microbubbles with perfluorocarbon core and lipid shell to enhance an ultrasound signal. Herein, a balance between polarity and fluorophilicity is achieved to generate water-dispersible nanomaterials that also stabilize perfluorocarbon liquids. Results show strong and long-term US imaging capability, with chelation of Fe3+ introducing enhanced photoacoustic imaging capability. In chapter 5, a facile method to generate magnetic exchange-bias between ferromagnetic and antiferromagnetic nanomaterials using nanoparticle emulsion clusters is developed. Magnetic CoFe2O4/CoO nanoclusters are studied as proof-of-concept for exchange-bias behavior. This system shows a record exchange bias field (3200 Oe; 5K) for a nanoparticle-based system. This study gives a roadmap for extending synthetic methods beyond the superparamagnetic range and into composite single-domain materials for high-temperature magnetic materials with exchange-bias behavior.
Book Synopsis Investigations Into Building Block Structure and Method of Preparation on the Properties of Nanomaterials by : Zicheng Li
Download or read book Investigations Into Building Block Structure and Method of Preparation on the Properties of Nanomaterials written by Zicheng Li and published by . This book was released on 2009 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation research is primarily focused on the preparation of polymer-based nanostructures as potential diagnostic agents and therapeutics delivery vehicles. Various polymers, nanoparticles and conjugation techniques were developed to meet the specific requirements of each application. Shell crosslinked nanoparticles (SCKs) are characterized by their structural integrity and available functionality to attach multiple agents on the shell, such as receptor-recognizing or receptor-specific ligands, .imaging agents, Cell transduction components, etc. In this work, SCKs derived from amphiphilic poly(acrylic acid)-block-polystyrene (PAA-b-PS) have been studied as potential diagnostic and therapeutic agent delivery vehicles (Chapters 2 and 4). SCK nanoparticles bearing a cyclic KCRGDC peptide which specifically binds to avb3 integrin receptor were developed as potential delivery system for treatment of acute vascular injuries. Methods were developed to afford "clean" nanoparticles with significant binding abilities. Nanoscale contrast agents for magnetic resonance imaging were also developed based on SCKs derived from PAA-b-PS and a Gadolinium-DOTA complex to achieve high relaxivity contrast agents. Our results showed that SCKs may serve well as potential diagnostic and therapeutic agent delivery vehicles Meanwhile, these SCKs were also studied as the template for mineralization of silver nanoparticles, along with a nuleating peptide, AG-P35, as a co-template (Chapter 5). Various morphologies of silver nanoparticles were obtained and it's found that the morphology was highly dependent on polymer and peptide concentrations and incubation time. Micelles from a novel hyperbranched fluoropolymer with small sizes able to pass the blood brain barrier were synthesized (Chapter 3). After conjugation with F3 peptide which targets to nucleolin in most tumor cells, and loaded with doxorubicin as the drug to kill the tumor cells, both in vitro and in vivo studies were performed. It was found that F3-peptide conjugated nanoparticle not only specifically bind to the tumor-associated angiogenic endothelial cells, doxorubicin carried by these nanoparticles also caused apoptotic effects on the targeted tumor cells.
Book Synopsis Iron Oxide Nanoparticles for Targeted Cellular Imaging and Drug Delivery by : Mike Jeon
Download or read book Iron Oxide Nanoparticles for Targeted Cellular Imaging and Drug Delivery written by Mike Jeon and published by . This book was released on 2019 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Iron oxide nanoparticles (IONPs) have drawn significant interest in the field of biomedicine due to their intrinsic magnetic properties that allow contrast under magnetic resonance imaging (MRI). With proven biocompatibility, biodegradability, and flexible surface chemistry for a variety of applications, IONPs have been used as theranostic agents, combining therapy and diagnosis in a single formulation. Despite their potential, few IONPs have transitioned to the clinic due to the challenges of achieving high drug loading while maintaining proper size and stability to bypass biological barriers, minimizing off-target drug release to prevent side effects, and increasing specificity to minimize non-specific uptake for increased efficacy. Many strategies can overcome these limitations. To increase specificity, incorporating active targeting by conjugating targeting agents onto IONPs can specifically bind and label intended sites. This approach can open up labeling and imaging of novel sites, such as neurons, when using MRI for diagnostic purposes. For drug delivery purposes, chemotherapeutics can be loaded onto IONPs with controlled release to prevent drug leakage and the consequent side effects. Incorporating targeting agents can further reduce off-target drug release. While IONPs have historically seen great utility as T2 contrast agents, these applications could be further expanded by designing IONPs for T1 contrast enhancement. This dissertation documents the development of iron oxide nanoparticle systems intended to overcome the shortcomings of various iron oxide nanoparticle applications with novel applications. First, we used IONPs conjugated with a dopaminergic neurolabeler to actively target the dopamine transporter to label and image dopaminergic neurons under MRI. The neurolabeler enhanced targeting and uptake of IONPs 3-fold over control IONPs. Labeling and imaging the brain using PET/SPECT is a tool to diagnose neurological disorders, such as Parkinson's disease. By using IONPs, this technique can be expanded to MRI to improve upon the shortcomings of PET/SPECT. Next, IONPs were loaded with paclitaxel to treat breast cancer cells. Due to their severe hydrophobicity, paclitaxel were bound close to the core of the IONP via an acid-cleavable ester bond, with longer chain PEG providing steric stabilization and hydrophilicity to stabilize the IONP. The paclitaxel loaded IONPs were further modified with folic acid, used as a targeting agent to bind to the folate receptors that are commonly over-expressed in breast cancer cells. The folic acid labeled and paclitaxel loaded IONP enhanced uptake by 2-fold, demonstrated controlled release of paclitaxel, and produced significantly higher cytotoxicity in breast cancer cells compared to free paclitaxel. Despite their proven efficacy as T2 contrast agents, IONPs have been hindered in their translation to clinical imaging applications due to the inherent limitations of T2 contrast agents. The benefits of T1 contrast has led to gadolinium-based contrast agents (GBCAs) serving as the dominant contrast agents in the clinic, while their severe side effects have highlighted the need for a biocompatible alternative. IONPs have the ability to serve as an alternative T1 contrast agent to GBCAs, but their potential has not been fully explored. Using the fundamentals of T1 contrast, we developed and characterized a T1 IONP. It demonstrated excellent physiological properties ideal for biological applications, with T1 contrast capabilities confirmed through phantom MR imaging. Finally, with clinical translation in mind, we investigated optimization of freeze-drying methods to prolong the stability of IONPs. Aqueous solutions can hydrolyze and degrade NPs, prohibiting long-term stability in solutions. Freeze-drying offers means of removing water to prevent degradation, yet freeze-drying stresses can cause irreversible damage to NPs. Cryoprotectants have been used to minimize or rid these freeze-drying stresses, yet their effects on IONPs have not been explored. A variety of cryoprotectants were tested for their effects on maintaining size, stability, zeta potential, and magnetic properties after freeze-drying on IONPs produced by the Zhang group and commercially available IONPs. Sucrose was the most effective cryoprotectant, with 10 wt.% sucrose offering IONPs great stability up to 6 months while preserving size, zeta potential, and magnetic properties.
Book Synopsis Single-Chain Polymer Nanoparticles by : José A. Pomposo
Download or read book Single-Chain Polymer Nanoparticles written by José A. Pomposo and published by John Wiley & Sons. This book was released on 2017-08-18 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first book on this important and emerging topic presents an overview of the very latest results obtained in single-chain polymer nanoparticles obtained by folding synthetic single polymer chains, painting a complete picture from synthesis via characterization to everyday applications. The initial chapters describe the synthetics methods as well as the molecular simulation of these nanoparticles, while subsequent chapters discuss the analytical techniques that are applied to characterize them, including size and structural characterization as well as scattering techniques. The final chapters are then devoted to the practical applications in nanomedicine, sensing, catalysis and several other uses, concluding with a look at the future for such nanoparticles. Essential reading for polymer and materials scientists, materials engineers, biochemists as well as environmental chemists.
