A microfluidic lab-on-a-chip (LOC) device for in-situ synthesis of gold nano-particles was developed. The long term goal is to develop a portable hand-held diagnostic platform for monitoring water quality (e.g., detecting metal ion pollutants). The LOC consists of micro-chambers housing different reagents and samples that feed to a common reaction chamber. The reaction products are delivered to several waste chambers in a pre-defined sequence to enable reagents/ samples to flow into and out of the reaction chamber. Passive flow actuation is obtained by capillary driven flow (wicking) and dissolvable microstructures called ‘salt pillars’. The LOC does not require any external power source for actuation and the passive microvalves enable flow actuation at predefined intervals. The LOC and the dissolvable microstructures are fabricated using a combination of photolithography and soft lithography techniques. Experiments were conducted to demonstrate the variation in the valve actuation time with respect to valve position and geometric parameters. Subsequently, analytical models were developed using one dimensional linear diffusion theory. The analytical models were in good agreement with the experimental data. The microvalves were developed using various salts: polyethylene glycol, sodium chloride and sodium acetate. Synthesized in-situ in our experiments, gold nano-particles exhibit specific colorimetric and optical properties due to the surface plasmon resonance effect. These stabilized mono-disperse gold nano-particles can be coated with bio-molecular recognition motifs on their surfaces. A colorimetric peptide assay was thus developed using the intrinsic property of noble metal nano-particles. The LOC device was further developed on a paper microfluidics platform. This platform was tested successfully for synthesis of gold nano-particles using a peptide assay and using passive salt-bridge microvalves. This study proves the feasibility of a LOC device that utilizes peptide assay for synthesis of gold nano-particles in-situ. It could be highly significant in a simple portable water quality monitoring platform.

With device scaling, the current optical lithography technique is reaching its technological limit to print small features. Extreme Ultra-Violet (EUV) lithography has shown promise to print extremely thin lines reliably and cost-effectively. Many challenges remain before introducing EUV to large scale manufacturing. The main challenge addressed in this study is particle removal from EUV mask surfaces (CrON1, CrON2, and fused silica) and thermal oxide (SiO₂). Effective pre-clean procedures were developed for each surface. As chemical cleaning methods fail to meet SEMATECH criteria, addition of megasonic energy to EUV mask cleaning baths is seen as a promising cleaning methodology. As the requirement to print fine lines needs to be met, all materials used in EUV mask fabrication either absorb the incident EUV wavelength light or reflect it. Therefore, the masks used in the industry will be reflective instead of the conventional transmissive masks. Also, for the same reason, no protective pellicle can be used leading to all the surfaces unprotected from particle contamination. To avoid the detrimental effect of the particle contamination, a cleaning study for nano-particle removal was performed. A dark field microscope was utilized to study the removal of gold nano-particles from surfaces. The cleaning procedures utilized H₂SO₄ and NH₄OH chemistries with and without megasonic irradiation. The cleaning variables were bath concentration, temperature, and megasonic power. The contamination variables were the gold nanoparticles charge and size, from 40nm to 100nm. For 100 nm negatively charged gold nano-particles deposited on a CrON1 surface, a 1:10 H₂SO₄:DI bath at boiling temperature (101°C) without megasonics gave high particle removal efficiency (PRE) values as did a 1:10 H₂SO₄:DI bath at 35°C with 100W megasonics. Comparison of removal of poly diallyl-dimethyl ammonium chloride (PDAC) coated and uncoated gold nano-particles deposited on a CrON1 surface using dilute H₂SO₄ baths indicated that the coated, positively charged nano-particles were more difficult to remove. PRE trends for different baths indicate surface dissolution (shown to be thermodynamically favorable) as the particle removal mechanism. However, experimental etch rates indicated minimal surface etching in a 10 minute bath. Increased surface roughness indicated possible local galvanic corrosion at particle sites. Low surface etching results meet SEMATECH requirements. During the fused silica surface cleaning study, particle charge (negative) and size (100 nm) of the contamination source and cleaning bath chemistry (NH₄OH) were kept constant. Low PREs were obtained at room temperature for all NH₄OH bath concentrations; however, high PREs were obtained at an elevated temperature (78°C) without megasonics and at room temperature in more dilute chemistries with megasonic power applied. Similar PRE trends were demonstrated for thermal SiO₂ surfaces. The experimental etch rates of the thermal SiO₂ agree with published values.

The application of ICP-MS to the fields of proteomics and genomics has arisen in part due to its ability to detect and quantify trace levels of S and P, which are major constituents in proteins and nucleic acids respectively. The development of collision/reaction cell technology and high resolution instruments has enabled these biologically important elements to be measured and quantified at the pg - ng ml-1 level. Despite these advances, the detection limits of P and S are still inferior compared to other elements. Oligonucleotides containing biotin functionality were labelled with Au nano-particles attached to a streptavidin protein to achieve site specific labelling, with 100% labelling efficiency. Each nano-particle contained ~86 Au atoms, resulting in an 882 fold signal enhancement for 24 base length oligonucleotides. However, this enhancement factor was only observed when one oligonucleotide bound to one nano-particle in a 1:1 ratio. Much lower Au labelling efficiencies and signal enhancements were observed when thiolated oligonucleotides were labelled with maleimide functionalised gold nano-particles. This was attributed to the extensive and difficult sample preparation steps that were required prior to labelling. The detection and quantification of adducts formed between DNA and the Pt anti-cancer drugs cisplatin and oxaliplatin were also investigated with ICP-MS. Acid digestion of the carbon based DNA matrix enabled Pt adducts to be quantified at low dose rates of 1 Pt atom per 1 500 000 nucleotides in ~12 μg DNA. Such sensitive mass spectrometric determinations could be employed in clinical tests to detect and quantify low level adducts formed in patients in-vivo. To complement ICP-MS analysis, electrospray ionisation linear ion trap mass spectrometry was employed to study the interaction of oxaliplatin with the four DNA nucleobases. Multiple stage mass spectrometry enabled detailed Pt-nucleobase adduct fragmentation pathways to be established. The method of DNA detection using P in conjunction with the collision cell, or cool plasma to form PO+ was also demonstrated and the limitations of the method, namely, polyatomic interferences and severe matrix effects were highlighted.

The head and neck cancers (HNC) are a group of cancers that begin in the squamous cells that line the mucosal surfaces of the head and neck. Therefore, they are commonly known as squamous cell carcinoma of the head and neck. Squamous cell carcinoma of the maxillary sinus (MC) is a rare type of HNC, and it is a very aggressive tumour. This cancer is typically diagnosed at a very advanced stage and most patients have a poor survival rate and prognosis. This study is based on the synthesis and applications of gold nanoparticles (AuNPs) conjugated with hesperidin (Hsp) as a targeted drug delivery system. AuNPs are ideal for loading different drugs and delivering them to targets sites due to their stability, small size, substantial surface area, non-cytotoxic and inert nature. Hsp is a naturally occurring substance with anti-inflammatory and antioxidant capabilities. The main aim of this research was to develop a highly efficient and safer method to deliver Hsp to the target sites. The Hsp with poor solubility and bioavailability render it only slightly absorbed, requiring a delivery system to reach its therapeutic target. This study focused on the effects of 15μg/ml Hsp loaded on gold nanoparticles (Hsp-AuNPs) on 20 healthy individuals’ lymphocytes as compared to 20 HNC patients’ lymphocytes using the alkaline Comet assay. While enzyme-based Comet repair was performed on 5 healthy individuals’ lymphocytes as compared to 5 HNC patients’ lymphocytes. The Hsp-AuNPs reduced the DNA damage in HNC patients’ lymphocytes compared to the healthy lymphocytes (***p<0.001). Furthermore, the 15μg/ml of Hsp-AuNPs significantly reduced the oxidative stress caused by H2O2 and appeared to be effective in both groups using the Comet and Comet repair assay. Results from Comet and Comet repair assay were consistent. The human squamous cells of maxillary sinus (MC) were also treated with 5μg/ml of Hsp-AuNPs. The alkaline Comet assay results showed that Hsp-AuNPs induced DNA damage in MC cells (***p<0.001). Therefore, Hsp-AuNPs demonstrated the most substantial genotoxic effects and confirmed a possible anticancer agent. The Hsp was also used to treat lymphocytes from healthy individuals as compared to HNC patients’ lymphocytes they reduced the DNA damage, but they were less effective as compared to Hsp-AuNPs. Published data shows that using the AuNPs as a drug carrier has a more potent therapeutic effect against different diseases including cancer. Also, this study investigated the gene protective and genotoxic impact of bulk Hsp in Maxillary sinus carcinoma cells. The data obtained indicated that Hsp-AuNPs might possibly be effective for the treatment of MC and demonstrated the ability of Hsp-AuNPs to increase the DNA damage more than the bulk form of Hsp (***p<0.001). The outcomes of this study are consistent with the viewpoint that the Hsp-AuNPs might have a substantial role in cancer treatment, including MC. The concentration of 5μg/ml Hsp-AuNPs was used to treat the MC cells in Western blotting, and real-time polymerase chain reaction (qPCR) was based on a preliminary test for the optimal dose. The data obtained indicated that Hsp-AuNPs might potentially be effective for the treatment of HNC and showed the ability of Hsp-AuNPs to reduce DNA damage more than the bulk form of Hsp. Hsp-AuNPs has also shown anti-cancer potential in the MC cells by up-regulating the expression of p53, p21, PPAR gamma, and Caspase 3, at mRNA and protein levels by up-regulating the p53, PPAR gamma, Caspase 3, and p21 to mediate apoptosis and DNA repair in MC cells. The findings of this study are consistent with the view that the Hsp-AuNPs could have a significant role in cancer treatment, including HNC and MC.