Characterization of human umbilical cord blood mesenchymal stem cell-derived exosomes by size and zeta potential analysis

Abstract

Background: Exosomes are cup-shaped lipid bilayer extracellular vesicles with a diameter of 30– 200 nm, secreted by various cell types, including mesenchymal stem cells (MSCs) [1–3]. MSC- derived exosomes (MSC-Exo) play an important role in tissue regeneration and show therapeutic potential in psoriasis and other inflammatory, autoimmune, and degenerative diseases [3,4]. For exosome characterization, measurement of their size and zeta potential is essential, as these parameters provide key information about their stability and biological interactions [5]. This study aimed to characterize exosomes derived from human umbilical cord blood mesenchymal stem cells (hUCBMSC-Exo) by measuring their size and zeta potential.

Materials and methods: Human umbilical cord blood MSC-derived exosomes (hUCB-MSC- Exo) were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). Particle size was measured using a NanoBrook 90Plus Zeta Analyzer (Brookhaven Instruments, USA) with three 15-minute runs at a 90° scattering angle. Zeta potential was determined using the same instrument equipped with a solvent-resistant electrode (BI-SREL) at 25 °C. For SEM, hUCB-MSC-Exo were coated with a 15 nm gold layer and examined using a Carl Zeiss Crossbeam 540 microscope (Carl Zeiss AG, Germany). High-resolution images were analyzed to determine particle size.

Results: The average diameter of hUCB-MSC-Exo was 85.34 nm by DLS and 95.93 nm by SEM, both within the characteristic exosome size range (30–200 nm). The zeta potential ranged from −21.24 to −25.16 mV, indicating stable dispersion in solution and suggesting favorable interactions with target cell membranes due to the negative surface charge.

Conclusion: The analyzed hUCB-MSC-Exo demonstrated size and surface charge consistent with typical exosomal characteristics, confirming the reliability of the applied methods for their physicochemical characterization.

Funding: This research was supported by the Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan, grant No. AP13068269.

Keywords: exosome, mesenchymal stem cell, characterization, size, zeta potential.

References:

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