Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Fabrication of Aptamer Sensors Using by Plasmonically Engineered Nanoprobes" By Tae Hoo Chang Purdue MSE Ph.D. Preliminary Exam Advisor: Professors Alexander Wei and Lia A. Stanciu ABSTRACT As society is getting complicated and developed, people are easily stressed out. Cortisol is a well-known stress indicator hormone. Balancing this hormone in daily life is very important because it affects all our body such as metabolism, blood pressure, and physiological processes. Abnormal elevation of this hormone can be a cause of Cushing's syndrome and kidney disease. Hence, the detection of cortisol level in the body can be a key way to prevent related diseases. To detect cortisol level, we need to take cortisol from different sources. The best source for collecting cortisol is urine or saliva because of the requirement of 24 hour sample collection and non-invasive methods. However, these sources have limited amount of cortisol concentration. Therefore, a new highly sensitive nanosensor with low detection limits is needed. In this work, I will review the trends of cortisol sensors at first. Then, I will suggest a noble sensor platform called "Nano-brightener" sensor. This sensor platform has many benefits such as low cost, easy to sensing and non-invasive detection in urine. Moreover, the strongest point is that this sensor is suitable for the point-of-care monitoring systems because this sensor will be compatible with smart phone camera at the end of this project. This cortisol sensor composes four components: silver nanoparticle (AgNP), DNA aptamers, transducer core, and fluorescent dye. By using plasmon resonant AgNPs, the fluorescent dye can turn on/off due to the metal-enhanced fluorescence (MEF) effect. We will discuss not only the submerged fundamental principles of this aptamer sensor but also the roll of each component and how to fabricate it. At the end of presentation, preliminary results and future plans will be introduced. Date: Tuesday, November 21, 2017 Time: 8:30 A.M. Place: ARMS 1021