Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Natural Biopolymeric Materials for Aptamer-based Whole Bacterial Cell Detection" By Lixby Susana Diaz Amaya Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Lia A. Stanciu ABSTRACT With a number close to 108 million people facing critical food insecurity during last year according to the FAO, Food safety becomes a real priority. Although several efforts have been made to improve the productivity of the crops, biosensors for on-site phytopathogen early detection still a research field marginally explored. Lateral flow devices represent a cost-effective promising alternative for on-site detection, but there still some concerns regarding their low sensitivity and limited range of applications. To overcome these drawbacks, the combination of gold decorated core nanoparticles coated with natural biopolymers and their application to the detection of phytopathogens could lead to a new generation of detection devices. On the other hand, aptamers' outstanding advantages as detection biomolecules over antibodies, make possible to explore virtually any target and potentially any chemical modification for its proper immobilization on the surface of label nanoparticles. All these facts together bring up promising conditions to design and develop a cost-effective and instrument-free on-site platform for the early detection of critical phytopathogens. Here, we propose the surface modification or core materials by positively charged biopolymers using layer by layer self-assembling approach and following an aptamer-based detection strategy, that will enhance the stability of gold nanoparticles and provide augmented surface contact area for higher sensitivity. Date: Wednesday, November 8, 2017 Time: 10:00 A.M. Place: ARMS 1028