磁珠在临床以及生物科学与技术中的运用.ppt

Magnetic nano-and microparticles in bioscience and biotechnologyType of magnetic nano-and microparticlesMulti domain,single domain or superparamagnetic Magnetite(Fe3O4)Ferrites(MeO.Fe2O3;Me=Ni,Co,Mg,Zn,Mn)Maghemite(-Fe2O3)Greigite (Fe3S4)Iron,nickel Magnetic nano-and microparticlesInorganic material,but:Present in biological systems Usable for a variety of bio-applicationsImportant dates 1962-Lowenstam(biochemically-precipitated magnetite as a capping material in the radula(tongue plate)teeth of chitons(marine mollusks of the class Polyplacophora)1975-Blakemore(magnetotactic bacteria)Magnetic material in teeth of chitons hardening the tooth caps(enabling the chitons to extract and eat endolithic algae from within the outer few millimeters of rock substrates)Magnetotactic bacteria Various morphological types exist Gram-negative prokaryotes Magnetic nanoparticles present in magnetosomes Found in sediments in diverse aquatic environmentsMagnetotactic bacteriaProvided by Dr.D.Schler,GermanyMagnetosomes Composed from magnetite(Fe3O4)or greigite(Fe3S4)Ca 50 nm in diameter Covered with a lipidic membrane Important for navigation of the bacteria into oxic/anoxic layer Biocompatible character (phospholipid bilayer)Possible applications in biosciences Magnetosomes Provided by Dr.D.Schler,GermanyMagnetosomes Provided by Dr.D.Schler,GermanyBiogenic magnetic nanoparticles Magnetotactic bacteria Magnetotactic algae Protozoa Insect Fish Amphibians Reptiles Birds MammalsAnimal magnetite Magnetosome chains from the frontal tissues of chinook salmon S.Mann et al.:J.Exp.Biol.140(1988)35-49.Importance of animal magnetite Most probably involved in magnetoreception(what is the current position?,which direction to move?)interaction of magnetite nanoparticles(chains of magnetic nanoparticles?)with the sensing cellsNon-physiological presence of magnetic nanoparticles Found in human brain in case of neurodegenerative diseases Disruption of normal iron homeostasis in the brain Early detection of neurodegenerative diseases using MRI?Magnetic nanoparticles in meteorites from Mars Meteorite magnetic nanoparticles resemble magnetosomes from Earth magnetotactic bacteria Hypothesis:Was there a transfer of living systems from Mars to Earth?Lets return back to Earth!Magnetic nano-and microstructured materials for bioapplications Useful for many applications in biosciences,biotechnologies and environmental technologies Enable to label diamagnetic structures Enable separation or detection of magnetically labeled structures Both separation and non-separation applications are important Which nano-and microstructured magnetic materials?Three important bio-Biocompatible(in the broadest sense of this word)Biodegradable Biomimetic Biocompatible materialsBiocompatibility in the broadest sense of the word Minimal toxicity Stability of nanoparticles in body fluids Possibility for immobilization of biologically active compounds,cell organelles,cells(activated nanoparticles)Reproducible interaction with biosystems Enable labeling of biostructures(for magnetoassays)Biopolymer based particles,PEGylated structures,magnetoliposomes,biopolymer-based FFs,self-assembled magnetic structures Biodegradable materials Important from the point of view of possible clinical applications(e.g.,drug targeting)Nanoparticles formed by biodegradable(bio)polymer Magnetoliposomes and related structures Starch-based magnetic fluidsBiomimetic materials Analogues of bacterial magnetosomes Ferritin x magnetoferritin Important data 1960s Pappell(first ferrofluids,1000 hours of magnetite milling)1966-Magnetically controlled thrombosis of intracranial aneurysms 1970s increase of interest in biomagnetic research and technology 1980 Massart(chemical synthesis of aqueous ferrofluid without detergents)1980s commercially available magnetic particles Magnetic fluids examples of magnetic nanostructured materials ferrofluid can be influenced by the presence of external magnetic field Synthetic biocompatible magnetic nanoparticles and complexes containing them Biocompatible magnetic fluids Magnetoliposomes Magnetic nano-and microparticles MagnetoferritinMagnetic microparticlesDynabeads Homogeneous size distribution Simple recovery with small permanent magnets Magnetic nanoparticles present inside the beads Available in plain,activated and bioactive formExamples of of magnetic nano-and microparticles applications From molecular biology to environmental technologies Manipulation of microliters as well as million of liters Manipulation in suspension systems Both separation and non-separation techniques are importantImmobilization and modification of biologically active compoundsPossibility of simple removal of the immobilized molecules or cells from the system Immobilization of enzymes,antibodies,lectins,oligonucleotides,affinity ligands Modification of proteins via magnetic PEG Immobilization in magnetoliposomes Magnetosomes from genetically engineered magnetotactic bacteria carrying target pro