The Design And Investigation Of Novel Targeting Nanomaterials And Biological Interactions

Nanotechnology is a rising branch of science and technology developing rapidly in the past two decades.It is interdisciplinary founded on a variety of modern sciences and technologies.Related research and products covered all the aspects of human life,including machinery manufacturing,product processing,environmental monitoring,food hygiene and health care.In these fields,nanotechnology biomedical applications spawned a new technology,nanomedicine.The introduction of nanotechnology into the traditional biomedicine resolved some of the existed problems which troubled researchers for a long time.For example,based on the nanotechnology,researchers have developed numerous novel analytical methods and instruments to facilitate the rapid detection of certain deadly diseases related biomarkers.These approaches allow doctors realizing early diagnosis of disease through a simple way,greatly improved the cure rate of patients and released their pains.The combination of nanomaterials and traditional drugs provided targeted drug delivery against certain diseases or abnormal organs and tissues.The targeting nanodrugs significantly reduced side effects and improved therapeutic efficiency simultaneously.However,the nanotechnology's biomedical applications also have huge challenges and difficulties.Physiological environment and biological samples possess the unique diversity of biosystems.The use of nanomaterials in organisms or the detection of biological samples will face a variety of effects on the biological environment.In the physiological environment,large from organs,small to cells,cytokines,will influence the nanomaterials which entered the biosystem.The body's extracellular fluid,including plasma,tissue fluid and lymph,constitute the cells living body fluid environment.When we apply nanomaterials into biological applications,the humoral environment is the first encounter.The interactions between physiological environments and nanomaterials will alter the physical and chemical properties of nanomaterials,such as size,morphology,surface chemistry,and so on.And the corresponding changes of the nature will also affect the nanomaterials bio behaviors leading to the deviation of the designed bio-functions.Therefore,it is important to study the effects of physiological environment when it interacted with(targeted)nanomaterials,and consider the influence of special physiological environments on materials.It is of great significance for the future development of nano-biotechnology.In this thesis,we functionalized the most commonly used gold nanoparticles with different targeting molecules,which allowed them specifically targeting cancer cells.Next,we studied the targeting nanomaterials bio-distribution in animal model and investigated the physiological environment impacts on nanomaterials.Later,we built a graphite coated metal nanocapsules(GIAN)through chemical vapor deposition and studied the GIAN's cellular uptake route.Taking advantages of the graphite coating,we developed graphite coated magnetic nanocapsules and targeting functionalized for the H.pylori MRI and Raman detection within stomach.The details are as follows:(1)In Chapter 2,we used Herceptin,which targets the ErbB2 receptor,targeting functionalized three different sizes gold nanoparticles,and labeled the nanoparticles with fluorophore.The physicochemical properties of the functionalized nanoparticles were confirmed by a variety of characterization methods and confirmed the truth that they could specifically target the ErbB2 receptors overexpressed SKOV-3 cell line at cellular level.The biodistribution of Herceptin or non(active/passive targeting)functionalized gold nanoparticles in the organs and tumor sites were studied in a mice model.This study provides a basis for studying the distribution of targeted nanoparticles in vivo.(2)In Chapter 3,we used another targeting molecular aptamer instead of the antibody to targeting functionalization of four different sizes gold nanoparticles.Nucleic acid aptamers have similar antibody-specific binding capacity but cheaper and more stable.It plays an important role in future targeting nanomedicine development.We firstly validated the specific binding ability of the nucleic acid aptamer itself and aptamer modified gold nanoparticles against its target CEM cells.The fabrication of this targeting nanomaterials provides a research model for further study of the interaction between targeted nanoparticles and physiological environment.(3)When the nano-materials enter human body,the first interaction is happened between them with the blood.In Chapter 4 we simulated physiological blood environment with human serum.The interactions between aptamers,aptamers modified nanoparticles with serum were studied.First,the variation of targeting ability in the presence of serum were investigated.Then,the interaction between serum and aptamers,aptamers modified nanoparticles was investigated through physicochemical characterization,gel electrophoresis and label-free liquid chromatography-mass spectrometry/mass spectrometry(LC-MS/MS).This approach sheds lights on the possible problems which targeting nanomaterials may come across when they were administrated into body.It also provides useful guidance for the future development of targeted nanomaterials.(4)In Chapter 5 we have prepared a graphite-isolated Au nanocapsules(GIAN).It has the unique Raman signal of graphite,noble metal induced surface enhanced Raman resonance,and has two-photon fluorescence properties.Using these properties,we successfully studied the endocytosis pathway of GIAN and aptamers targeting functionalized GIAN by dual-modal imaging.The changes of the interaction between nanoparticles and cells in the presence of targeted molecules were elucidated.(5)In the last chapter,we developed a novel targeting nano-contrast agent for some extreme conditions in the physiological environment.In the strong acidic environment like stomach,most of the targeting nanomaterials properties will largely change and thus affecting their performance.So far,it is difficult to realize real-time in situ monitoring abnormal regions within stomach.Thus,we fabricated a nano magnetic resonance contrast agent which could target Helicobacter pylori by modifying the graphite coated magnetic nanocapsules with boron functionalized PEG molecules.This nano MRI contrast agent can specifically target bacterial cell walls and bind tightly.Graphite coating also ensures that its magnetic core will not corroded and provides stable MRI signal.The development of this special targeted nanomaterials addresses the degradation of nanomaterials under extreme conditions in physiological environments.