Ultra-thin gold and its applications in biomedical sensing

Gold nanomaterials can be engineered into various shapes, which strongly influence their optical and catalytic behaviour. This thesis focuses on quasi‑one‑dimensional gold nanotapes (AuNT) and compares them with conventional gold nanoparticles and other morphological variants. Lower‑dimensional gold nanostructures with atomic‑level thickness, including AuNT, were synthesised using a simple aqueous‑based wet‑chemical soft‑template method. Among these, AuNT was shown to possess unique plasmonic properties and high surface reactivity.
To explore their practical use, AuNT were embedded into inkjet‑printed poly(vinyl alcohol) hydrogels, creating reusable catalytic platforms. These printed AuNT hydrogels degraded pollutants, such as 4‑nitrophenol, more rapidly and enabled phenol oxidation under mild conditions. Their printed mesh structure improved accessibility of active sites, offering higher catalytic efficiency and consistent reusability.
AuNT also demonstrated strong enzyme‑like activity, outperforming natural peroxidase in standard colourimetric and fluorometric assays. When integrated into a glucose‑sensing system, they achieved a detection limit of 9.5 µM, showing promise for low‑cost diagnostic applications.
Overall, this work establishes gold nanotapes as a versatile class of nanomaterials with applications in water purification, biosensing, and catalytic technologies, and presents inkjet printing as a scalable route for developing practical nanozyme‑based devices.