AVS 53rd International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI-TuA

Paper BI-TuA8
Tunable Biomimetic Artificial Extracellular Matrix Coatings

Tuesday, November 14, 2006, 4:20 pm, Room 2001

Session: Cells at Surfaces
Presenter: E.F. Irwin, UC Berkeley
Authors: E.F. Irwin, UC Berkeley
K. Saha, UC Berkeley
K.E. Healy, UC Berkeley
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In this work we have designed an artificial extracellular matrix that can be utilized for both in vitro cell culture and biomaterial coatings. In our system, we can modulate both ligand density and the mechanical properties of the coating. The base coating is a greater than 100 +AEA-micron+AEA- thick acrylamide (AAm) gel in which the crosslinker density is varied in order to modulate stiffness. Next, this surface is modified with a 4 nm thick poly(ethylene glycol) (pEG) based interpenetrating gel which prevents non-specific protein and cell attachment. Finally, the surface is functionalized with RGD peptides from bone sialoprotein via a 3400MW pEG spacer arm, where the surface density can be controlled by varying input peptide concentration. The mechanical properties of these coatings were measured using force-mode atomic force microscopy (AFM) and analyzed with a Hertzian mechanics model. According to the model, the Young's modulus varied linearly in the range of crosslinker used (0.3-0.03 wt percent) from 1.16 +AEAAKwBA- 0.32 kPa to 9.03 +AEAAKwBA- 1.02 kPa. The immune response to these coatings of varying ligand density and mechanical stiffness is currently being assayed by culturing THP-1 cells, a monocytic leukemia cell line, on our system. It is anticipated that softer surfaces will exhibit a reduced immune response, as macrophages will not be able to spread and activate as readily. Preliminary experiments indicate that the softer surfaces allow less THP-1 cell attachment and spreading. In summary, we have designed a tunable artificial extracellular matrix coating to modulate cell behavior.