Date of Award
Winter 2-24-2025
Document Type
Thesis (Undergraduate)
Department
Engineering
First Advisor
Ian Baker
Second Advisor
Emily Asenath-Smith
Abstract
Thermal hysteresis (TH) measurement techniques for ice binding proteins (IBPs) have historically lacked standardization, making cross-study comparisons challenging and potentially impeding development of these materials for practical applications. This study provides a comprehensive comparison of three measurement techniques: differential scanning calorimetry (DSC), microlitre osmometry, and cryostage microscopy. Through systematic experimentation with Wild Type III Antifreeze Protein (AFP) at varying concentrations (10μM, 100μM, 1mM), along with cell lysate AFP and Pseudomonas syringe ice nucleating protein (INP), mathematical relationships were established between measurement techniques, and cryostage microscopy was identified as the most reproducible and reliable method. Regression analysis revealed strong relationships between measurement techniques, with distinct mathematical relationships: a logarithmic relationship between cryostage microscopy and microlitre osmometry (y = 0.8241ln(x) + 0.8983, R² = 0.9949), and between DSC and microlitre osmometry (y = 0.4542ln(x) + 0.6029, R² = 1.0000). The relationship between cryostage microscopy and DSC also showed a strong logarithmic relationship (y = 0.6809ln(x) + 1.2083, R² = 0.9993. Factorial analysis revealed that both concentration (0.525) and measurement technique (0.167) had significant effects on TH values, exceeding the significance threshold of 0.153 (α=0.05). Cryostage microscopy consistently produced lower TH values (mean ~0.45 °C) compared to microlitre osmometry (0.6 °C TH), likely representing more accurate measurements due to guaranteed single crystal observation. The technique demonstrated perfect reproducibility across trials while maintaining high equipment precision (±0.01 °C). Additionally, cryostage microscopy was compatible with all sample types, while microlitre osmometry failed with cell lysate and Pseudomonas syringae samples, likely due to nucleating behavior. These findings establish cryostage microscopy as the most reliable and reproducible measurement technique due to its unique combination of direct visual observation, single crystal measurement capability, and high precision. The mathematical relationships discovered provide a framework for converting between measurement techniques while highlighting the importance of standardizing cryostage microscopy for future TH measurements. Such standardization would significantly improve the reliability and comparability of TH measurements across the field.
Recommended Citation
Barry, Hayden Calvert, "A Comparative Mathematical Analysis of Ice Modulation Measurement Techniques: Unifying Thermal Hysteresis, Freezing Point Depression, and Colligative Effects" (2025). Engineering Undergraduate Senior Theses. 2.
https://digitalcommons.dartmouth.edu/engineering_senior_theses/2
