Exosome Isolation: A Microfluidic TiO2-Based Approach with Liposome Modeling




Motamedi, Seyedeh Zahra

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Exosome isolation is the first challenge for any exosome research, often limited by extended processing times, high costs, and potential impurities. In exosome isolations, preserving particle integrity, recovery, and size distribution is paramount for clinical applications. This study aims to overcome the limitations of conventional techniques by taking advantage of the specific affinity between titanium dioxide (TiO_2) particles and exosomal lipid bilayers. To emulate exosomes, liposomes with a size of 100 nm, composed of a mixture of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol, were employed as exosome surrogates. These synthetic lipid vesicles closely replicate exosome attributes, rendering them suitable models for studying isolation methodologies due to their analogous size, density, and phospholipid bilayer composition. Using liposomes, which are more available and easier to work with, enables to explore the potential impact of our isolation method on exosome characteristics, offering insights into the adaptability of the developed approach for medical applications. We utilized TiO_2-based isolation for the attainment of efficient mixing and effective incubation with target particles to optimize their interaction. In assessing this methodology, we embraced two approaches: a conventional manual method and a microfluidic technique. We studied the effect of the incubation time and the amount of TiO_2 particles and the design and flowrate for the bulk and microfluidic approach respectively. A comprehensive evaluation incorporating dynamic light scattering (DLS) and zeta Potential Measurements, in conjunction with Fluorescence and Brightfield Imaging techniques, was conducted to carefully develop and evaluate the microfluidic TiO_2-based exosome isolation methodology using a liposome modeling. The analysis encompassed their effectiveness, recovery rates, and post-processed vesicle size distribution, affirming the method's reliability achieving a capturing efficiency of 94.49% and a recovery rate of 84.53%.



Exosome Isolation, Titanium Dioxide (TiO2) Affinity, Liposome Surrogates, Microfluidic Techniques