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. Author manuscript; available in PMC: 2012 Feb 1.
Published in final edited form as: Biomaterials. 2010 Oct 28;32(4):969–978. doi: 10.1016/j.biomaterials.2010.09.075

Figure 6.

Figure 6

Adsorbent capacity of a hydrophobized sensor surface measured by the quartz-crystal microbalance method (QCM, ordinate) compared to theoretical capacity (abscissa), corresponding to cubic packing (Panel A) of hydrated proteins (see Fig. 1) or face-centered-cubic packing (FCC, Panel B). The 45° bisecting line represents perfect correlation of experiment and theory, with under prediction falling in the upper quadrant and over prediction falling in the lower quadrant (see annotations). Assumption of one adsorbed layer under predicted measurement for proteins larger than HSA (filled circles) whereas a three-layer model over predicted measurement for all proteins (with the exception of IgG in the FCC packing model). For cubic packing (Panel A), judicious combination of layer models, one layer for HSA and two layers for IgG, and three of Fib predicts adsorbent capacity nearly exactly (open squares). The FCC packing case (Panel B) required one layer for HSA, three layers for IgG, and four Fib layers to accommodate experimental data. Dotted lines through experimental data are guides to the eye. In contrast to modeling of solution-depletion measurements (Fig. 3), outcomes for cubic packing (Panel A) were quite different from that of FCC packing (Panel B). Error bars represent experimental uncertainty in QCM measurements.