LOCALIZED SURFACE PLASMON RESONANCE BIOSENSOR DESIGN OPTIMIZATION WITH METAL–INSULATOR–METAL NANODISK/NANORING

• Main Author: Puspaduhita, Amilla
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/66637
• Institution: Institut Teknologi Bandung

ABSTRACT LOCALIZED SURFACE PLASMON RESONANCE BIOSENSOR DESIGN OPTIMIZATION WITH METAL–INSULATOR–METAL NANODISK/NANORING By Amilla Puspaduhita NIM: 18318015 (Undergraduate Program in Biomedical Engineering) In the recent years, research on optical biosensors and nanoparticles has been widely carried out with the aim of being applied to disease diagnosis development. One type of optical biosensors, namely Localized Surface Plasmon Resonance (LSPR) biosensor has also experienced significant development. LSPR biosensor has the same working principle as Surface Plasmon Resonance biosensor, and the difference between the two of them is LSPR utilize nanoparticles instead of thin films. Nanoparticles should be able to improve the detection performance because of its characteristic of high area to volume ratio. In addition, because surface plasmon polariton (SPP) would be localized, it's highly likely to cause the biosensor to be more sensitive, so that it has the potential to detect a very scarce sample. Even though LSPR biosensor has advantages mentioned above, LSPR biosensor still has several shortcomings that need to be improved, such as optimizing certain transducer design parameters, so that optimum detection performance could be achieved. Therefore, in this study, optimization of the biosensor transducer design parameters would be carried out. The basic design of the transducer is the metal-insulator-metal (MIM) nanodisk. From this basic design, there would be three parameters that would be optimized, namely diameter, aspect ratio, and the type of material used as a metal in the biosensor transducer nanoarray. This research was conducted by simulation using CST Studio Suite. This simulation aims to reduce the cycle of fabrication and analysis as well as to save fabrication costs. To determine the performance of the biosensor detection, there would be three parameters that are used as a reference, namely coefficient of determination, sensitivity, and figure of merit (FOM). The main result obtained in this research is that by modifying the three design parameters previously mentioned, the detection performance of LSPR biosensor will increase. The wider the diameter of gold nanodisk, the sensitivity value will increase. The narrower the diameter of gold nanodisk, the sensitivity would become stagnant, however, the full width at half maximum (FWHM) value would also decrease. In the end, it could possibly produce a high FOM value. In gold nanodisk's diameter variation, a stable coefficient of determination between 0.999 to 1 was found. The highest sensitivity of 4087.85 nm/RIU was found at diameter of 3200 nm, and the highest FOM of 3.22 was found at diameter of 25 nm. In the nanoring aspect ratio variation, the maximum sensitivity value of 2154 nm/RIU was obtained in this study when the aspect ratio is 0.25 and 0.275, while the highest FOM value was obtained when the nanoring aspect ratio was 0.167. Finally, when silver and palladium was used as metal in MIM instead of gold, there is a significant increase in sensitivity and FOM, which is 4343.67 nm/RIU using palladium with diameter of 3200 nm and 25 using silver with diameter of 50 nm, respectively. Keywords: localized surface plasmon resonance, transducer, metal-insulator-metal, coefficient of determination, sensitivity, figure of merit, CST studio suite.