Droplet-based microfluidic systems to incorporate nucleic acids into cationic liposomes and to transfect mammalian cells in vitro

Micaela Tamara Vitor

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Author(s):	Micaela Tamara Vitor Total Authors: 1
Document type:	Doctoral Thesis
Press:	Campinas, SP.
Institution:	Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
Defense date:	2017-04-26
Examining board members:	Lucimara Gaziola de la Torre; Stéphanie Descroix; Rosiane Lopes da Cunha; Hernandes Faustino de Carvalho
Advisor:	Lucimara Gaziola de la Torre; Charles Baroud
Abstract
This work aimed at using one droplet-based microfluidic systems to incorporate nucleic acids into cationic liposomes and another one to study the mammalian cell transfection process. In the first part of this study we used a droplet-based microfluidic system to complex cationic liposomes with pDNA in order to obtain reproducible and suitable lipoplexes to dendritic cells (DCs) transfection. For this purpose, some experimental parameters were investigated, such as inlet flow rates, the maintenance of liposomes¿ properties after microfluidic processing, lipoplex characteristics (size, polydispersity and zeta potential) as function of molar charge ratio (R+/-) and microchip design. Lipoplexes produced in a microchip with large serpentine channel and split region, which decreases lipoplex polydispersity, operating at ratio aqueous/oil flow rate 0.25 and R+/- 1.5, 3, 5, 7 and 10 were used to transfect DCs in vitro. All lipoplexes transfected DCs and resulted in cell activation. In the second part of this study we used a single-cell microfluidic platform to investigate and control transfection conditions, in view of optimizing the recombinant protein production by transfected cells. Chinese hamster ovary cells (CHO-S) were transfected in microchip with different types of lipoplexes (R+/- 1.5, 3, 5) and monitored by green fluorescent protein (GFP) production and cell viability. The single-cell platform enables to assess the heterogeneities of CHO-S population, revealing the presence of a subpopulation producing significantly high levels of GFP. These high producers (HP) showed increased cell size in comparison to the average population. Moreover, the charge of lipoplexes shows an important role to transfect CHO-S, since the unique positive charged lipoplex R+/- 5 produced more HPs. Additionally, the amount of pDNA delivered affects protein production, since R+/- 1.5 with more pDNA increased GFP specific productivity of HPs. This thesis was developed under the joint graduate program of the University of Campinas, Brazil and École Polytechnique, France. In general, this work presents original contributions in the areas of microfluidics and gene delivery (AU)

FAPESP's process:	12/24797-2 - Microfluidic droplets devices to incorporate nucleic acids into cationic liposomes and chitosan nanoparticles and to transfect mammalian cells in vitro
Grantee:	Micaela Tamara Vitor
Support Opportunities:	Scholarships in Brazil - Doctorate

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