DISSERTATION DEFENSE
Rabeb Layouni, Chemical & Biomolecular Engineering
*under the direction of Sharon Weiss & Paul Laibinis
“Investigation of Design and Surface Treatment of Porous Silicon for Robust, Selective, and Sensitive Optical Biosensing”
05.02.23 | 1:00PM CST | 306 Featheringill Hall
Porous silicon (PSi) has attracted interest as a nanomaterial with potential for optical biosensing, due to its high internal surface area, ease of fabrication, and versatile surface chemistry. Despite successful applications of PSi in the capture of various target analytes, few studies have investigated its use in multi-protein complex media such as blood and serum, hindering its implementation in clinical diagnostics. Challenges such as material corrosion, non-specific adsorption of foulants, and mass transport limitations have impeded PSi-based biosensors. This dissertation examines several strategies to overcome these issues and achieve robust, selective, and sensitive porous silicon optical biosensing. To detect DNA oligonucleotides without inducing corrosion, highly stable thermally carbonized PSi was developed. The advantages of peptides as capture probes over antibodies were also demonstrated, and the porous silicon surface was engineered to detect the malaria biomarker plasmodium falciparum histidine-rich protein II (PfHRPII) in human serum while minimizing fouling by adding a zwitterionic antifouling coating. Additionally, a novel PSi-on-paper structure was designed and fabricated to enhance mass transport for rapid target detection. Overall, this work has led to more robust, selective, and sensitive porous silicon optical biosensors for applications in complex biological media. With further research and development, porous silicon may become a valuable tool in clinical and point-of-care diagnostics, allowing for rapid and accurate detection of various diseases and pathogens.