2021 Undergraduate Research Showcase

Document Type

Student Presentation

Presentation Date


Faculty Sponsor

Laxman Mainali


The lipid composition of the eye lens membrane differs between the species. In the lower life span animals, eye lenses have phosphatidylcholine as a major component, while lenses have sphingomyelins as a major phospholipid in higher life span animals. Here, we study the mechanical properties of model membrane made of mouse phospholipid composition with Chol/PL mixing ratio of 0 and 1, respectively using Atomic force microscopy (AFM). The model membrane's height image with 0 mol% Chol shows two phases: solid ordered (so) and liquid disordered (ld). The height difference between the two phases is ~ 1 nm. The model membrane with Chol/PL mixing ratio of 1 exhibit only a single-phase known as liquid-ordered phase (lo). Thus, the membrane roughness of Chol/PL mixing ratio of 1 is 152±8 pm which is significantly lower than the roughness of membrane with Chol/PL mixing ratio of 1, which is 241±36pm. Similarly, the average breakthrough force for the Chol/PL mixing ratio of 0 is 5.4±0.41 nN, while for Chol/PL mixing ratio of 1, the average breakthrough force is 4.88±0.58 nN. We speculate that this slight difference in the membrane breakthrough force may be due to two phases in the 0 mol% Chol-containing membrane.



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