바이오 어레이칩을 위한 고SNR (Signal to Noise Ratio)광학특성을 갖는 금속박막에 대한 연구

Abstract

Well plate based ELISA is one of the most widely used immunoassay techniques for the detection of a target protein. However, this method has some technical limitations such as poor signal sensitivity, poor detection limit, large sample consumption, low signal/noise ratio (SNR) and poor quality images. In this work, we fabricated a high sensitive pre-patterned micro array chip by using semiconductor process where chips have a functional group and metal patterns down to 10 μm on a glass substrate. Metal thin film was used to achieve the seperation of each samples and the low background signal from the chip. In order to improve the signal to noise ratio by adapting the metal thin films, it should maximize the reflection of the light source. . The properties of metal thin films were simulated and optimized. The evaluation on optimized metal thin films was performed to lower background signals by measuring the fluorescence scan signals and Raman scanning after treating them with fluorescence labeled proteins. Fluorescent scanning was performed to measure the SNR of various metal thin films, various functional surface and AFP (α-fetoprotein) immunoassayed samples. All of metal thin films have high SNR over 45 dB. And all of functional surfaces have clear image and high SNR over 35 dB. Higher SNR and better quality images were obtained on pre-patterned micro array chips. In AFP immunoassay experiment, the fluorescence of AFP and background easily distinguished at lower concentration with high SNR over 45 dB. And the calibration curve shows the low limit of detection (LOD) to 1 ng/mL. Furthermore, coefficient of determination (R : 0.9868) indicated good fitting to the model. A novel fabrication method was suggested to make bio chip which has high optical SNR for bio analysis.