Polyelectrolyte-Clay-Protein Layer Films on Microfluidic PDMS Bioreactor Surfaces for Primary Murine Bone Marrow Culture


  • We thank Dr Brian Johnson and Prof. Mark Burns, Department of Chemical Engineering, Univ. of Michigan for use of clean room facilities. We also thank Dr. Sean Morrison (Life Sciences Institute, University of Michigan) for the use of his lab space, access to animal facilities, and for his helpful suggestions throughout this work. We also thank Dr. Anish Tuteja for help with AFM pictures. This material is based upon work supported by the U.S. Army Research Laboratory and the U.S. Army Research Office under contract/grant number DAAD19-03-1-0168 and the National Science Foundation (BES-0238625). Supporting Information is available online from Wiley InterScience or from the authors.


Poly(dimethylsiloxane) (PDMS) microbioreactors with computerized perfusion controls would be useful for engineering the bone marrow microenvironment. However, previous efforts to grow primary bone marrow cells on PDMS substrates have not been successful due to the weak attachment of cells to the PDMS surface even with adsorption of cell adhesive proteins such as collagen or fibronectin. In this work, modification of the surface of PDMS with biofunctional multilayer coatings is shown to promote marrow cell attachment and spreading. An automated microfluidic perfusion system is used to create multiple types of polyelectrolyte nanoscale coatings simultaneously in multiple channels based on layer-by-layer deposition of PDDA (poly(diallyldimethyl ammonium chloride)), clay, type IV collagen and fibronectin. Adherent primary bone marrow cells attached and spread best on a surface with composition of (PDDA/clay)5 (Collagen/Fibronectin)2 with negatively charged fibronectin exposed on the top, remaining well spread and proliferating for at least two weeks. Compared to traditional more macroscopic layer-by-layer methods, this microfluidic nanocomposite process has advantages of greater flow control, automatic processing, multiplexed fabrication, and use of lesser amounts of polymers and protein solutions.