This study describes the use of human serum albumin (HSA)-modified gold nanoparticles (HSA-AuNPs) for the selective extraction and enrichment of high-pI protein, lysozyme (Lyz) prior to analysis by capillary electrophoresis (CE) with UV detection. HSA-AuNPs are capable of extracting Lyz from a complicated matrix because a HSA capping layer not only stabilizes gold nanoparticles in a high-salt environment but also exhibits strong electrostatic attraction with Lyz under neutral pH condition. Efficient separation of Lyz and other high-pI proteins has been successfully achieved by the filling of cationic polyelectrolyte, poly(diallydimethylammonium chloride) (PDDAC), to the background electrolyte. After capturing Lyz with HSA-AuNPs, PDDAC-filled CE can be directly used for the analysis of the extracted Lyz without the addition of the releasing agent into the extractor. The extraction efficiency relied on the pH of the solution and the concentration of HSA-AuNPs. Under optimal extraction conditions, the limits of detection at a signal-to-noise ratio of 3 for Lyz were down to 8 nM. The combination of HSA-AuNP extraction and PDDAC-filled CE has been applied the analyses of lysozyme in chicken egg white, white wine and human tear. Also, we reveal that this NP-based extraction can be coupled to matrix-assisted desorption/ionization time-of-flight mass spectrometry.

This study presents a simple process for producing resistance-based humidity sensors utilizing dopamine (DA) coated gold nano-particles (AuNPs) as the sensing material. The sensing material for typical humidity sensors are solid state metal oxides, graft-polymers or salt-doped polymers. However, these humidity sensors may suffer from low sensing response or slow time response since water molecules have to diffuse into the sensing materials to induce the electrical property changes. Alternatively, AuNPs have large surface area for water molecule absorption and can be potentially for high performance humidity sensing. Nevertheless, the surface property of AuNPs is hydrophobic and needs to be modified. In this regards, this work uses a highly hydrophilic molecule of dopamine to modify the surface of AuNP into hydrophilic to enhance the humidity sensing performance. Highly hydrophilic bio-molecule of dopamine is physically bonded onto 4-6 nm AuNPs to enhance the humidity sensing performance. Results show that the DA coated AuNPs have nice humidity sensing responses in the measuring range of 20-90%RH. The measured resistance response shows >1500 times greater than the sensor using the same AuNPs without DA coating. The developed humidity sensor shows rapid time responses for water absorption (13 s) and desorption (30 s), respectively. Moreover, a 3-day long-term measurement at low, medium and high humidity ranges also shows the good stability of the developed sensor. The method developed in this study provides a simple and low-cost method to produce high-performance humidity sensors with DA-coated AuNPs.

Gold¡¦s reputation as an inactive catalyst has been changed since the discoveries made by pioneers, including Bond, Hutchings, and Haruta. Today, exploring gold¡¦s potential to catalyze a range of heterogeneous and homogeneous reactions has been a hot topic. In this dissertation, reaction of CO and hydroxyl groups and cyclotrimerization of propanal (C2H5CHO) catalyzed by gold were studied by using temperature-programmed desorption (TPD), reflection absorption infrared spectroscopy (RAIRS), X-ray photoemission spectroscopy (XPS), low energy electron diffraction (LEED) and density functional theory (DFT) calculations. keywords: LEED, XPS, RAIRS,TPD, Gold, cyclotrimerization, propanal, CO oxidation In the first topic, CO oxidation by hydroxyl groups prepared by electron beam bombardment of physisorbed water was performed on Au(110) and Au(531). The formation of hydroxyl groups was evidenced by the observation of the desorption of D2O at 175 K and D2 at 230 K in TPD, in conjunction with the O 1s peak at 531.32 eV in XPS. The adsorption of CO on the hydroxyl-covered surface resulted in CO2 desorption at 110 K and 150 K on Au(110), and 105 K, 140 K and 180 K on Au(531). In the investigation of various D2O and CO coverages, the adsorption of CO and D2O was found to be preferred on low-coordinated Au atoms. Additionally, D2O on low-coordinated Au atoms required lower dissociation energy. This site effect was correlated with the high activity of smaller gold nanoparticles. Moreover, the mechanism for reaction of CO and hydroxyl groups was suggested to be similar to the water-gas-shift reaction due to the observation of the enhancement of D2 desorption after reaction. The second topic studied the cyclotrimerization of propanal catalyzed by gold. After exposing Au(110) to propanal at 180 K, the desorption of 2,4,6-triethyl-1,3,5-trioxane ((C2H5CHO)3) was observed at 340 K. The RAIRS and XPS studies showed that the cyclotrimerization of propanal was completed at 180 K. The same results were also detected on Au(531). However, only propanal molecular desorption was found on Au(111) suggesting that the low coordination Au atoms and the trench-like structure on Au(110) and Au(531) play key roles. On Ag(110) and Cu(110), no reaction was found indicating that the intrinsic nature of gold is also an important factor for the reaction. Investigation on Pt(110) inherited with the same (1x2) missing-row structure revealed that the decarbonylation of propanal occurred due to the stronger £b2(C,O) bonding mode. The reactions observed on Au(110), Au(531), and Pt(110) strongly suggest that the activity for the reactions may result from the relativistic effect of gold. The DFT calculations further showed the interactions between hydrogen in carbonyl groups and low-coordinated Au atoms (O=C-H¡KAu) help to gather propanal molecules and preorganize them at specific surface sites while an intracomplex reaction takes place.

This study presents studies on camptothecin (CPT), a potent antitumor agent in order to improve its stability and solubility without reducing its activity. The work describes the modification of camptothecin at 20-OH position a new strategy to overcome the stability and solubility problems of the free drug. Camptothecin is conneted to linker that could be processed to a terminal thiol group and this thiol group was connected to gold surface, to obtain CPT-gold nanoparticles. In the first part of the study / undecenol was chosen as the starting material and reacted with azobisisobutylonitrile to obtain S-11-hydroxyundecyl ethanethioate. 11-hydroxyundecyl ethanethioate was reacted with NaOMe to synthesize the target linker 11, 11&rsquo / -disulfanediyldiundecan. After synthesis of the target linker, the 20- OH functional group of CPT was replaced with this linker to obtain 20- (11, 11&rsquo / -disulfanediyldiundecan) - captothecin. The second part of the study, gold nanoparticles were synthesized by using HAuCl4 solution and the camptothecin derivative containing thiol group at 20-OH position was connected to the gold surface.

Metal nanoparticles have recently gained popularity in many research areas due to their nanosize-related properties. Depending on the size of the metal nanoparticle, their mode of interaction with electromagnetic radiation and the outcome of this interaction vary; in turn the effect exerted on a protein which is conjugated to a nanoparticle varies, because different sized nanoparticles demonstrate different modes of energy transfer with electromagnetic radiation and molecules conjugated to them. Very small cluster with sizes around 1 – 1.2 nm tend to get excited by incident light and emit fluorescence, whereas larger nanoparticles absorb the incoming light very strongly due to their LSPR. In this study we observed the outcomes of the interaction between two types of nanoparticles, namely gold and gold/silver alloyed nanoparticles with the fluorescence emission of two fluorophores, namely eGFP and rPhiYFP; and demonstrated a bioassay where the fluorescence modulation by gold nanoparticles can be used as the sensing strategy. Lastly, we demonstrated the potential of autofluorescent gold nanoparticles as intracellular reporters.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 263-285).

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 68-77). Also available on the Internet.

Thesis (B.S.)--University of Alaska, 1940. / Alaska "Territorial Department of Mines reports" or "TDM reports" are a collection of reports, notes and maps written by Dept. employees working out of several field offices throughout the territory. Series titles and numbers within the collection were retrospectively assigned with the exception of the few written after statehood (1959). Report contains information on the Yukon River Mining Region, Circle Quadrangle. Includes bibliographical references (leaf 80). Also available in electronic format via Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 68-77). Also available on the Internet.

Thesis (M.A.)--University of Alberta, 1963. / Includes bibliographical references (p. [135]-149).