Measuring Vesicle Loading with Holographic Microscopy and Bulk Light Scattering

Lan Hai Anh Tran; Lauren A Lowe; Yaam Deckel; Matthew Turner; James Luong; Omar Abdullah A Khamis; Megan L Amos; Anna Wang

doi:10.1021/acsphyschemau.4c00011

Measuring Vesicle Loading with Holographic Microscopy and Bulk Light Scattering

ACS Phys Chem Au. 2024 May 20;4(4):400-407. doi: 10.1021/acsphyschemau.4c00011. eCollection 2024 Jul 24.

Authors

Lan Hai Anh Tran¹, Lauren A Lowe^{1

2}, Yaam Deckel^{1

2}, Matthew Turner^{1

3}, James Luong^{1

4}, Omar Abdullah A Khamis¹, Megan L Amos^{1

2}, Anna Wang^{1

2

5

6}

Affiliations

¹ School of Chemistry, UNSW, Sydney 2052, NSW, Australia.
² Australian Centre for Astrobiology, UNSW, Sydney 2052, NSW, Australia.
³ School of Physics, The University of Sydney, Sydney 2006, NSW, Australia.
⁴ School of Chemistry, The University of Sydney, Sydney 2006, NSW, Australia.
⁵ ARC Centre of Excellence in Synthetic Biology, UNSW, Sydney 2052, NSW, Australia.
⁶ RNA Institute, UNSW, Sydney 2052, NSW, Australia.

Abstract

We report efforts to quantify the loading of cell-sized lipid vesicles using in-line digital holographic microscopy. This method does not require fluorescent reporters, fluorescent tracers, or radioactive tracers. A single-color LED light source takes the place of conventional illumination to generate holograms rather than bright field images. By modeling the vesicle's scattering in a microscope with a Lorenz-Mie light scattering model and comparing the results to data holograms, we are able to measure the vesicle's refractive index and thus loading. Performing the same comparison for bulk light scattering measurements enables the retrieval of vesicle loading for nanoscale vesicles.