Date of Award

2017

Document Type

Thesis

Department

Biology

First Advisor

Andrea Goforth

Subjects

Radiographic contrast media, Nanoparticles -- Diagnostic use, Bismuth compounds, Transmission electron microscopy, Silica

DOI

10.15760/honors.456

Abstract

The development of novel X-ray contrast agents (XCAs) is being widely investigated. Nanoparticles for use as potential contrast agents is a heavily researched area because nanomaterials are able to generate a higher contrast image relative to a small molecule, have long blood circulation times, and allow for the addition of different functionalities such as a surface coating. Particularly bismuth nanoparticles are being considered as potential X-ray contrast agents because of bismuth’s high X-ray opacity and high biological tolerability. Furthermore, an SiO2 shell coating around bismuth nanoparticles can offer benefits in regards to nanoparticle colloidal stability in aqueous solution and in vivo biocompatibility. In this research, an aerobic synthesis of elemental bismuth nanoparticles and subsequent silicon dioxide coating protocol is examined in order to examine the reproducibility and feasibility of developing uniform silicon dioxide coated bismuth nanoparticles. TEM analysis was conducted and the images were analyzed for particle size distribution, shell thickness, and shape. The results of the elemental bismuth preparation trials show reproducibility in producing nanoparticles with narrow polydispersity within a range of 40-80 nm, but do not show reproducibility in producing size consistent bismuth nanoparticles. The average bismuth nanoparticle size was found to be 58.35 nm ± 13.47. The SiO2 procedure results showed that there was a positive association observed between silicon dioxide shell thickness and 25, 50, and 100 µL of Tetraethyl orthosilicate (TEOS) amounts with a limiting effect and that the procedure was effective in coating BiNPs uniformly with small variabilities. Both procedures could be improved and the limitations could be decreased to achieve highly monodisperse SiO2 BiNPs.

Comments

An undergraduate honors thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in University Honors and Biology.

Persistent Identifier

http://archives.pdx.edu/ds/psu/20512

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