Independent Size and Fluorescence Emission Determination of Individual Biological Nanoparticles Reveals that Lipophilic Dye Incorporation Does Not Scale with Particle Size
Journal article, 2020

Advancements in nanoparticle characterization techniques are critical for improving the understanding of how biological nanoparticles (BNPs) contribute to different cellular processes, such as cellular communication, viral infection, as well as various drug-delivery applications. Since BNPs are intrinsically heterogeneous, there is a need for characterization methods that are capable of providing information about multiple parameters simultaneously, preferably at the single-nanoparticle level. In this work, fluorescence microscopy was combined with surface-based two-dimensional flow nanometry, allowing for simultaneous and independent determination of size and fluorescence emission of individual BNPs. In this way, the dependence of the fluorescence emission of the commonly used self-inserting lipophilic dye 3,3′-dioctadecyl-5,5′-di(4-sulfophenyl)oxacarbocyanine (SP-DiO) could successfully be correlated with nanoparticle size for different types of BNPs, including synthetic lipid vesicles, lipid vesicles derived from cellular membrane extracts, and extracellular vesicles derived from human SH-SY5Y cell cultures; all vesicles had a radius, r, of ∼50 nm and similar size distributions. The results demonstrate that the dependence of fluorescence emission of SP-DiO on nanoparticle size varies significantly between the different types of BNPs, with the expected dependence on membrane area, r2, being observed for synthetic lipid vesicles, while a significant weaker dependence on size was observed for BNPs with more complex composition. The latter observation is attributed to a size-dependent difference in membrane composition, which may influence either the optical properties of the dye and/or the insertion efficiency, indicating that the fluorescence emission of this type of self-inserting dye may not be reliable for determining size or size distribution of BNPs with complex lipid compositions.









Silver Jõemetsa

Chalmers, Physics, Biological Physics

Paul Joyce

Chalmers, Physics, Biological Physics

Quentin Lubart

Chalmers, Biology and Biological Engineering, Chemical Biology

Mokhtar Mapar

Chalmers, Physics, Biological Physics

Emanuele Celauro

Chalmers, Biology and Biological Engineering, Chemical Biology

Björn Agnarsson

Chalmers, Physics, Nano and Biophysics

Stephan Block

Chalmers, Physics, Biological Physics

Marta Bally

Chalmers, Physics, Biological Physics

Elin Esbjörner Winters

Chalmers, Biology and Biological Engineering, Chemical Biology

Gavin Jeffries

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Fredrik Höök

Chalmers, Physics, Nano and Biophysics


07437463 (ISSN) 15205827 (eISSN)

Vol. 36 33 9693-9700

Subject Categories

Materials Chemistry

Other Physics Topics

Nano Technology





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4/5/2022 9