Abstract

Patterning of Cell Culture Inside an Exosome Gradient-Generating Microfluidic Device

Sara Micheli, PhD student , Università degli studi di Padova

In recent years, exosomes are being recognized as contributing factors in mediating cancer progression. The aim of this study is the optimization of a technique for the in vitro culture of patterned cells in an exosome gradient-generating microfluidic platform. The procedure uses two polydimethylsiloxane units: a stamp with embossed surface features to define the cell-adhesive and non-adhesive areas and a layer with the microfluidic circuit and culture chamber to complete the device. The patterned substrate will then guide selective attachment of cells. Both Neuroblastoma (NB) cancer cells and Mesenchymal Stem Cells, representative of its common metastatic target site, were used to test the effects of the NB-derived exosomes on protein expression using Immunofluorescences analyses. By applying a gradient of exosomes across cells, changes in the expression of proteins involved in invasiveness and stem cell maintenance are induced, both of which are graded and proportional to exosomes concentration. The microfluidic approach for the generation of controllable and stable concentration gradients coupled with the ability to micropattern the cell culture surface area enables fast screenings of induced concentration-dependent signals within a single culture chamber, surpassing several limitations of conventional cell culture techniques.