Comparison of Nanostructure Arrangement with Combination of Thin Film of Gold and Silver as an Optical Leukemia Biosensor: Simulation Study

Combinations of various types and structures of materials were developed to obtain highest sensitivity of biosensor. The optical analysis of the electric field simulation results was used to determine the best arrangement of thin layer and nanostructures Au and Ag electrodes as an optical biosensor for blood cancer detection. This study used a finite difference time domain (FDTD) to simulate the electric field distribution and analyze the optical properties of the biosensor. This research was conducted by making an anodic aluminum oxide (AAO) as mold of a nanostructure whose hole dimensions will be used as a model of the nanostructure in the simulation. The holes in AAO are circles with a diameter of 90 nm and the distance between holes is 25 nm. The structural model for electric field simulation is a glass substrate coated with an Ag thin film/Au nanostructure, Au thin film/Ag nanostructures, arrays of Ag/Au nanostructures, and arrays of Au/Ag nanostructures. The top side of the nanostructure arrangement and thin film will be deposited with normal blood cells and leukocytes. The electric field distribution shows that the Ag thin film/Au nanostructure is the best combination electrode of nanostructures and thin film of Ag and Au for the detection of blood cancer because of the highest difference of absorbance intensity and absorbance peak wavelength, which is 8.66 nm. These results provide a preliminary interpretation of the arrangement of nanostructures and thin film of gold and silver for optical blood cancer detection as biomedical device.