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Synthesis, Characterization and Application of Bi2S3Nanoparticles with High X-ray Absorption

Author: HuangHuanHuan
Tutor: ZhaoYuanDi
School: Huazhong University of Science and Technology
Course: Biochemistry and Molecular Biology
Keywords: Bismuth sulphide CT contrast agent nanoparticles
CLC: R318.08
Type: Master's thesis
Year: 2013
Downloads: 8
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Abstract


X-ray computed tomography （CT） is regarded as one of the most powerful diagnosticimaging technique with the help of contrast agents. Currently, the CT contrast agentsapproved for clinical use are small iodinated molecules. For many years’ use as CTcontrast agents in vivo, these iodinated molecules exposed some shortages gradually.The appearance of nanobiotechnology provides a potential solving method for thedeficiency of iodine contrast agents. Bi2S3nanomaterials maybe is the most promisingcontrast agents, because Bi has the large atomic number （Bi,83） and X-ray attenuationcoefficient （Bi,5.74cm2g-1at100keV）, while the atomic number and X-ray attenuationcoefficient of iodine are53and1.94cm2g-1respectively. In this paper, we had prepareddifferent hydrophilic Bi2S3nanorods via a hot injection method, and modified one of themthe biological utility. We characterized the nanomaterials with X-ray diffraction （XRD）,fourier transform infrared spectrometer （FT-IR）, transmission electron microscopy（TEM）, and detected their CT contrast with a high-resolution CT system. Next, thecytotoxicity of hydrophilic Bi2S3nanomaterials was examined through an MTT assay andan extensive TEM analysis of hydrophilic Bi2S3nanomaterials taken up in RAW264.7cells was carried out to confirm the validity of the above cytotoxicity experiments. Themain work includes:（1） Bi2S3nanorods were synthesized through a hot injection method using BiCl3as abismuth precursor and elemental sulfur as a sulfur source. When the ratio of the precursors（ρ=[S]/[Bi]） was2:1, the nanorods were allowed to grow at170°C. If the ratio of theprecursors was1:5, the reaction was happened at130°C. In addition, hydrophilic Bi2S3nanorods were prepared by another strategy, using BiCl3as a bismuth precursor andthioacetamide as a sulfur source. The characterization of the nanocrystals suggests that thenanorods synthesized with the first strategy have an orthorhombic structure, the length anddiameter was14nm and7nm respectively. Next, we use these Bi2S3nanoparticles for thesurface modification.（2） Hydrophobic Bi2S3nanorods were surface modified for the hydrophilicity. Thereare two different strategies: Bi2S3nanorods were surface modified with tetraethylorthosilicate （TEOS） and2-[methoxy（polyethyleneoxy）propyl]yrimethoxysilane （PEG-silane）to yield Bi2S3@SiO2-PEG nanoparticles; Pluronic F127, triblock copolymer of PEO-PPO-PEO,coated the Bi2S3nanorods to obtain the hydrophilic Bi2S3-PF127nanoparticles. The resultsof transmission electron microscopy （TEM） and fourier transform infraredspectrometer （FT-IR） results show that the resulting Bi2S3@SiO2-PEG and Bi2S3-PF127have great hydrophilicity. X-ray phantom images were acquired using variousconcentration of Bi2S3@SiO2-PEG and Bi2S3-PF127dispersed in water. It was found thatthe CT number, called Hounsfield units （HU）, increased linearly as the concentration ofthe nanoparticles increased. In other words, at the same X-ray absorption, the dosage ofBi2S3@SiO2-PEG and Bi2S3-PF127is much less than iobitridol. The dose reduction meansit can significantly reduce the potential for adverse reactions in patients in clinicalapplications.（3） Next, the cytotoxicity of Bi2S3@SiO2-PEG and Bi2S3-PF127were examinedthrough an MTT assay using murine macrophage （RAW264.7） cells. We carried out anextensive TEM analysis of Bi2S3@SiO2-PEG taken up in RAW264.7cells to confirm theviability of the above cytotoxicity experiments. The cell viability was not hindered byBi2S3@SiO2-PEG up to a concentration of2.1mg/mL and Bi2S3-PF127up to aconcentration of3.2mg/mL of Bi, which was an extremely high concentration. Probeswere directly in contact with tissue fluid and without visible harm to cell.

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CLC: > Medicine, health > Basic Medical > Medical science in general > Biomedical Engineering > General issues > Biomaterial
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