Investigation of LSPR sensor chips as biosensor transducers

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Supervisor:
Dr. Bonyár Attila
Department of Electronics Technology

During my work I reviewed the operating principles of localized surface plasmon resonance (LSPR) sensors based on literature data, and the potential applications of these tools, especially in biosensors.

I selected the most suitable fabrication technology for LSPR sensor elements, keeping in mind the expectations and the possibilities at the department. Expectations are: smaller size, portability, better sensitivity, good imaging capabilities, possibility of multiple measurements, disposable and the most important is: cost- and time efficient. Based on these, two nanoparticle fabrication technologies were selected and experimentally tested, one is the binding of colloidal gold nanoparticles to glass surfaces via surface chemistry (silanization), the second is the thermal annealing of gold thin films on glass substrates. In my experiments the purity of the glass substrates is found to be most important, because the presence of any contamination on the surface could obstruct either the formation of gold nanoparticles (annealing) or their binding to the surface (silanization) or cause unwanted aggregation (silanization). Hence, one focus of my work was the optimization of cleaning processes and fabrication technologies to avoid these effects and produce LSPR sensor elements with the highest possible quality and sensitivity.

My research also covered the characterization of these sensor elements, which were fabricated by different technologies, regarding their bulk refractive index sensitivity and also regarding their biosensitivity. The latter was performed by using DNA based receptor-target molecule pairs. The sensitivity, reliability, stability and other characteristics of the two methods were compared and discussed in detail.

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