@misc{9232506,
  abstract     = {{Peptide therapeutics offer advantages in specificity and affinity, yet the potential propensity to self-associate and aggregate poses a challenge for the development of stable oral formulations. This master’s thesis evaluates the utility of the fluorescent dye Thioflavin T as a structural probe to monitor the aggregation of glucagon-like peptide-1 receptor agonists, specifically Liraglutide and Semaglutide. Using a multi-method analytical workflow, the self-association behavior of high-concentration (1 mM) peptide solutions was examined in a standard, neutral phosphate buffer and in biorelevant complex media simulating gastrointestinal environments. 

The results indicate that 1 mM Liraglutide immediately self-associate into oligomeric structures upon dissolution across all studied environments. Over 24 hours, the aggregation pathways diverge significantly depending on the medium. In neutral phosphate buffer, a correlated increase in Thioflavin T emission intensity, quenching of intrinsic Liraglutide tryptophan fluorescence, and a red-shifted absorbance in ultraviolet-viable spectroscopy absorbance suggest that Liraglutide forms stable, hydrophobic micellar structures. Comparative evaluations indicate, in the conditions studied, that Semaglutide remains relatively stable over 24 hours with no significant structural transitions. 

The complexity in evaluating Thiflavin T’s diagnostic results is concluded to be heavily dependent on the environment. While highly effective in simple buffers, Thioflavin T's detection capability is intricate in complex biorelevant media. In the fasted state simulated intestinal fluid, large aggregate clusters undergo physical sedimentation, artificially dropping the ThT signal. In low pH environments, fed state simulated intestinal and fasted state simulated gastric fluid, suspected high ordered β-sheet formation and precipitation trigger massive right-angle light scattering spikes and structural change that plateau or compromise the Thioflavin T emission signaling. Consequently, this study underlines the challenges in using the ThT assay in complex matrices but highlights the value and opportunity of combining them in a multi-method approach for oral peptide drug characterization.}},
  author       = {{Persson Skansjö, Elsa}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Thioflavin T as a Structural Probe for GLP-1 Analog Self-Association in Standard Buffer and Biorelevant Gastrointestinal Environments}},
  year         = {{2026}},
}