Biomimetic Synthesis Based On Gold Nanocomposites And Its Application In CT/MRI

Tumor especially malignancy has remained a malignant disease that plagues human health.Once cancers develop toward late,existing clinically treatments are almost impossible to heal.Therefore,it's particularly crucial to adopt early diagnoses and effective treatments without invasion for cancer.As a discipline combines medical imaging and molecular biology,molecular imaging integrates many technologies such as molecular biochemistry,nanotechnology and image processing.Due to its high specificity,sensitivity and image resolution,molecular imaging is widely applied to explore early biological changes in disease,metabolic levels and genetic abnormalities.In recent years,imaging contrast agents based on inorganic nanomaterials have been extensively studied in biomedical diagnostic and imaging applications.The purpose of this work is to synthesize a dual enhanced CT imaging of gold and iodine via modifying with iodine-containing small-molecule diatrizoic acid?DTA?on the surface of Au@BSA,which can overcome the shortcomings of traditional small molecule iodine contrast.Gd-Au NPs was synthesized to achieve the synergistic imaging between MRI and CT,improving the early diagnosis of tumors.In addition,Synthesis of dandelion-based gold nanomaterials and their X-ray attenuation property were studied.The major works are described as follows:1.A biomimetic Au@BSA-DTA nanocomposites-based contrast agent for computed tomography imagingHerein,we reported a facile one-pot synthesis process to obtain gold nanoparticles?Au@BSA?with bovine serum albumin?BSA?as a biotemplate following with conjugation of diatrizoic acid?DTA?for a potential X-ray computed tomography?CT?imaging contrast agent?Au@BSA-DTA?.The as-prepared biomimetic material was characterized systematically by several techniques.It was shown that the prepared biomaterial is colloid stable under the tested range of pH and temperature.The cell cytotoxicity assay,hemolytic assay and cell morphology observation showed that Au@BSA-DTA has low-cytotoxicity and good hemocompatibility at a concentration of Au even up to 80?g/m L.Besides,the biomimetic material Au@BSA-DTA with double radiodense elements of Au and iodine displayed much stronger CT imaging effect compared with the traditional small molecule contrast agents,which paves the potential clinical application in cancer early diagnosis.2.An albumin-based gold nanocomposites as potential dual mode CT/MRI contrast agentIn this study,biocompatible bovine serum albumin?BSA?-coated gold nanoparticles?Au NPs?containing Gd?III?as the contrast agent for both X-ray CT and T₁-weighted MR imaging is reported.Firstly,the Au NPs with BSA coating?Au@BSA?was prepared through a moderate one-pot reduction route in the presence of hydrazine hydrate as reducer.Sequentially,the BSA coating enables modification of diethylenetriaminepentaacetic acid?DTPA?as well as targeting reagent hyaluronic acid?HA?,and further chelation of Gd?III?ions led to the formation of biomimetic nanoagent HA-targeted Gd-Au NPs?HA-targeted Au@BSA-Gd-DTPA?.Several techniques were used to thoroughly characterize the formed HA-targeted Gd-Au NPs.As expected,the as-prepared nanoagent with mean diameter of 13.82 nm exhibits not only good colloid stablility and water dispersibility,but also satisfying low-cytotoxicity and hemocompatibility in the tested concentration range.Additionally,for the CT phantoms,the obtained nanocomplex shows an improved contrast in CT scanning than that of Au@BSA as well as small molecule iodine-based CT contrast agents such as iopromide.Meanwhile,for the T₁-weighted MRI images,there is a linear increase of contrast with concentration of Gd for the two cases of HA-targeted Gd-Au NPs and Magnevist.Strikingly,the nanoagent we explored displays a relatively higher r₁relaxivity than that of commercial MR contrast agents.Therefore,this newly-constructed nanoagent could be used as contrast agents for synergistically enhanced X-ray CT and MR phantoms,holding promising potential for future biomedical applications.3.Synthesis of dandelion-based gold nanomaterials and their CT imaging studiesBased on the dandelion root extract,a novel gold nanomaterial TO-Au was developed.The synthesis conditions are mild and the method is simple.That is,the method is obtained by one-pot method under alkaline conditions.Fluorescence and CT imaging results show that the TO-Au NPs have better fluorescence and CT imaging property.What's more,the root extract of dandelion has a certain effect on the apoptosis of cancer cells,so the development of TO-Au NPs offers new options for the theranostic of tumors.