Date of Completion


Embargo Period



Dr. Chen Xu, Dr. Patrick Kumavor, Dr. Guoan Zheng

Field of Study

Biomedical Engineering


Master of Science

Open Access

Open Access


Mimicking the body's natural healing process, which involves a variety of growth factors and cytokines produced by cells in a staged and sequential manner, has been shown to be a favorable technique in the field of tissue engineering. This project is focused on the fabrication and characterization of a polyelectrolyte multilayer (PEM) coating with and without a calcium phosphate (CaP) barrier layer capable of multiple growth factor delivery. The PEM coatings are created using a layer-by-layer (LBL) process in a dip coating machine in order to create uniform layers of oppositely charged material that can be used to deliver embedded growth factors. A custom sample holder was designed and fabricated using 3-D printing in order to minimize use of the expensive reagents. Diffusion and mixture of multiple growth factors through PEM-only coatings motivated the introduction of a CaP barrier layer. The CaP layer is precipitated using the simulated body fluid technique over the first growth factor followed by the PEM coating and additional growth factors. Confocal imaging of fluorescent model proteins was investigated as a means to assess the effectiveness of the CaP barrier layer in blocking diffusion of the model protein through poly L lysine/poly L Glutamic acid PEM coatings. Unfortunately, confocal imaging doesn’t have the resolution to discriminate the fluorescent model protein location within these nanometer thick PEM coatings, and the rough surface of the CaP further complicated the analysis. Cell-based bioassays are recommended to study ability of CaP to block diffusion of embedded factors within PEM coatings.

Major Advisor

Dr. Liisa Kuhn