YPIE Scientist: Maryam Aamir

Research: The concentration-dependent effects of non-nutritive sweeteners on the phase transition temperature and enthalpy of DOPC-based lipid membranes using Differential Scanning Calorimetry

Mentor: Dr. SungHee Lee

Awards: WESEF 2025 - 4th place in Biochemistry; SOMERS 2024 - 1st place in Animal Sciences; Participant - Envirothon 2025

Research Location: Iona University

Abstract:

Artificial sweeteners are a prevalent and accessible alternative to sucrose sugar. Increased incidences of obesity, diabetes, and metabolic syndrome, coupled with heightened consumer awareness, have led to a steady shift towards low-calorie artificial sweeteners. This has led to a longstanding controversy regarding the safety of using artificial sweeteners. The World Health Organization has advised against them, but the US Food and Drug Administration continues to recommend their use, claiming a lack of negative evidence. In this study, several artificial sweeteners were studied at a microbiological level. Tests were conducted in order to compare how they affect the phase transition temperature and enthalpy of DOPC-based lipid membranes at various concentrations using Differential Scanning Calorimetry. TA Universal Analysis software was used to ascertain the main phase temperature, the apex temperature for the endothermic peak, and the enthalpy of phase transition, the integrated area under the heat capacity curve, allowing for the data to be analyzed and interpreted. The Sucrose control showed stable peaks, with all concentrations following the same trend. As the concentrations increased (50:1 to 1:1) over intervals, the delta H decreased from about 0.6058 J/g to 0.5185 J/g. The phase transition temperature increased and then decreased, creating a steady peak, indicating that the Sucrose does not disrupt membrane fluidity and its biological processes. The Sorbitol seemed to follow similar trends as well, with smooth peaks; however, when concentration increased to 5mM, the peak was skewed, indicating some disruption. As the Sorbitol concentrations increased, the delta H increased steadily from 0.5058 J/g to 0.7675 J/g, with an outlier of a sharp decrease at the 20 mM concentration, as it dropped to 0.6445 J/g. The phase transition temperature also decreased steadily, staying within 17℃ to -18.6℃, closely reflecting that of the Sucrose control. Overall, Sorbitol and Mannitol do not seem to disrupt membrane permeability and functioning except at the 20 mM concentration. This shows that artificial sweeteners are not as harmful as expected to the cellular membrane on a molecular level.

Presentation Slides

About this Scientist:

Maryam Aamir is a junior at Yonkers High School. After college, she plans to enroll in an M.D program and become a pediatrician, pursuing her dream of helping children and saving lives worldwide.