NOVEL PLATFORM FOR BIOSENSING APPLICATION BASED ON CLUSTER-ASSEMBLED MATERIALS

Rapid methods to identify bacteria in biological samples are important for prompt antimicrobial therapy. The current detection methods are classical biological sample cultures and biochemical tests, which are however, time-consuming and not highly sensitive. A novel and highly performing approach is offered by aptamers acting as recognition elements able to detect epitopes on the surface of a bacterium. Aptamers interacting with specific bacteria are known and then could provide a solid base for developing promising solutions for this issue. With this PhD work I intended to tackle one drawback of aptamer-based biosensor: the lack of platforms for high density aptamers immobilization. Cluster-assembled thin films, have been optimized as supports to demonstrate that aptamers, targeting Staphylococcus aureus, well adhere on these substrates and keep their functionality. Moreover, the characteristics of the nanostructured zirconium oxide thin film: thermal stability, good reactivity towards -OH and -COOH groups and nano-morphology, make this material a suitable candidate for the realization of platforms for general screening and biosensing applications. This strategy will offer a promising way for the development of an user-friendly aptamer-based biosensors for screening biological samples. Furthermore, I focused on a technological problem, regarding the need of substrates to perform correlative light-electron microscopy(CLEM), designing, developing and testing a device which improve the feasibility of correlative fluorescence/confocal and scanning electron microscopy.