AVS 57th International Symposium & Exhibition
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThP

Paper BI-ThP13
Univariable Synthetic Material for the Study of Cell Response to Substrate Rigidity

Thursday, October 21, 2010, 6:00 pm, Room Southwest Exhibit Hall

Session: Biomaterial Interfaces Poster Session
Presenter: A.T. Leonard, University of New Mexico
Authors: A.T. Leonard, University of New Mexico
J.R. Funston, University of New Mexico
K.N. Cicotte, Sandia National Laboratories
M.N. Rush, University of New Mexico
E.L. Hedberg-Dirk, University of New Mexico
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There is a strong indication that the mechanics of a substrate plays an important role in many cellular functions. Native human soft tissue has elastic modulus in the range of 0.01 to 1000 kPa. The synthetic materials commonly used to fabricate cell culture platforms with varied moduli, including polyacrylamide and polydimethylsiloxane, are limited in applicability due to a restricted range of achievable moduli and/or surface chemistry instabilities. The copolymer network of n-octyl methacrylate (nOM) and diethylene gycol dimethacrylate (DEGDMA) offers attractive material properties that overcome these limitations. In our laboratory, co-polymer networks were fabricated with 3 to 33 wt% DEGDMA. The compressive modulus was 25±2 kPA for the 3% DEGDMA network and increased with increasing DEGDMA fraction to 4700±300 kPa at 33 wt%. The networks demonstrated consistent surface wettability over the range of gel formulations examined as determined by goiniometry. Surface interrogation with x-ray photoelectric spectroscopy (XPS) at the two extremes of formulations, 3 and 33 wt.% DEGDMA, showed similar elemental and chemical bond compositions. The formulation 3% DEGDMA had elemental composition of 82.1±2.0 % Carbon 1s and 16.8±0.7 % Oxygen 1s. The higher DEGDMA composition of 33 wt% DEGDMA showed 83.2±0.8 % Carbon 1s, 15.4±0.2 % Oxygen 1s. High resolution carbon XPS indicated similar ratios of ether, ester and alkyl groups at the two extremes of DEGDMA compositions. The murine osteoblastic cell line MC-3T3 was used as a model for cell attachment and viability at six and 72 hours, respectfully. Scanning electron spectroscopy was used to visualize the long range nano and micro surface topology. Atomic force microscopy was used to map as well as quantify the surface roughness for each of the formulations. Our results indicate nOM/DEGDMA substrates can vary in modulus over three orders of magnitude while maintaining comparable chemical and topographical surface features. These networks are the first that allow for the study of the effects of material mechanics without the interference of other material properties.