UROP Proceedings 2022-23

School of Engineering Department of Chemical and Biological Engineering 80 Rational Design of Wearable Device for Stress Assessment via Perspiration Analysis Supervisor: NYEIN, Hnin Yin Yin / CBE Co-supervisor: HSING, I-ming / CBE Student: SHAO, Heyan / CENG Course: UROP1000, Summer Urea, a vital component of human physiological fluids like sweat and urine, is formed from excess nitrogen via the urea cycle. Its measurement is crucial for diagnosing kidney and liver pathologies. Potentiometric biosensors are promising tools for urea quantification due to their economic viability, reduced sample volume requirements, and real-time analysis capabilities. These biosensors consist of a urease enzyme layer, an ammonium-selective membrane layer, and an ion-to-electron transducer layer. This study investigates the characterization of ion-selective electrodes and the performance of potentiometric urea sensors using two enzyme recipes. The importance of uniform and complete coverage for optimal sensor function is highlighted, and potential strategies for addressing this issue are discussed to enhance the reliability of urea biosensors in various applications. Neural Circuits for Visual Behaviors in Zebrafish Supervisor: SEMMELHACK, Julie / CBE Student: HO, Viet Duc / BCB-IRE Course: UROP1100, Spring Head-fixed behaviour assay of larvae zebrafish is a useful platform for studying the behaviour of larvae zebrafish. By head-fixing the larvae zebrafish, the visual stimuli can be precisely controlled and the fish behaviour can be quantitativly analyzed. Strike behaviour in zebrafish was used as assay to study distance estimation mechanism in zebrafish. Strike can be effectively triggered by a sweeping stimulus. However, most strike from the sweeping stimulus is J turn strike whereas in free swimming fish it is mostly forward swim strike and suction strike. By modifying the sweeping stimulus to a half sweep + flickering stimulus, some forward swim strike and suction strike was observed, however, at a very low frequency. Half sweep + flicker or only flicker stimuli at 2Hz or 4Hz is the better stimuli for triggering forward swim strike and suction strike. Neural Circuits for Visual Behaviors in Zebrafish Supervisor: SEMMELHACK, Julie / CBE Student: ZHAO, Yicheng / BCB Course: UROP2100, Fall Zebrafish is a powerful model for the study of neurobiology. We used zebrafish as a model to study an important part of its hunting behavior, strike. Prey captures of a zebrafish consist of 3 steps, J-turns, approaches, and capture strikes. Strike is the last step of prey capture, and usually appears when a strong prey capture occurs. Due to it being transparent at the larval stage, zebrafish’s neuroactivity can be visualized using techniques such as 2-photon calcium imaging. The visual circuit of zebrafish has been an interesting question to study, and the depth perception of zebrafish is an exciting area. How the fish integrated the vision of both eyes and what monocular cues they might use for depth perception remain to be studied.