Application Of Functional Nanomaterials In Biological Imaging

In recent years,burgeoning nanotechnology and nanomaterials has provided new chances and challenges for the biomedical field.Among them,inorganic nanomaterials in disease diagnosis and treatment have been paid much attention on account of high stability and excellent property.Unfortunately,the bio-distribution and metabolism of nanomaterials in organisms and environment is unclear which limit its clinical transformation and application vastly.Herein,in this master’s thesis,with the inorganic nanomaterials as core contents,the biodistributition and metabolism of magnetic Fe₃O₄ nanoparticles in vivo were studied systematically by means of susceptibility magnetic imaging（SWI）.In the meantime,the inorganic image probe was used to detect the microenvironment of reductive tumor with high sensitivity and precision based on fluorescence imaging technique.The main contents included:（1）The research of biodistribution and metabolism based on magnetic nanomaterials by mean of susceptibility weighted imaging（SWI）:the Fe₃O₄ nanoparticles with different sizes were synthesized by pyrolysis successfully.The experiments showed SWI possessed the advantages of more sensitive and semi-quantitative than conventional T₂WI,there are different critical concentration for the nanomaterials with different magnetic susceptibility:the critical concentration of Fe₃O₄ nanoparticles with 5.5 nm,13.1 nm and 18.0 nm is 8.0 ppm,4.0 ppm,2.0 ppm respectively.Experiments in vivo demonstrated SWI was more sensitive than T₂WI and the sensitive detection of biodistribution and metabolism of magnetic nanoparicles with different sizes was realized,which the metabolic pathways of Fe₃O₄ with5.5 nm is depended on kidney while Fe₃O₄ with 13.1 nm and 18.0 nm are through spleen and liver.The research lays the foundation of boosting clinical transformation of inorganic nanomaterial fleetly.（2）Highly sensitive fluorescence Detection of reducing tumor microenvironment with rare Earth Nanoprobe:the UCNP（NaYF₄:Tm/Yb@NaYF₄）and POM were synthesized with help of pyrolysis and one-pot method,then assembled to UCNP@POM nanoprobe by electrostatic interaction.UCNP possessed excellent luminescence properties and emitted the light of 350 nm and 808 nm with excitation of 980 nm.With response to reducibility,the POM with oxidation state can absorb the light of 808 nm and POM while reduction state can absorb the light of 350 nm and 808 nm simultaneously.The experiment of simulating tumor microenvironment showed fluorescence intensity of UCNP@POM changed with the transformation of POM with oxidation to reduction state and responsed the GSH sensitively.The research lays the foundation of subsequent experiment which the sensitive detection of true GSH in tumor microenvironment based on inorganic nanoprobe.