Figure 6.

Application examples of chain sizing natural, isolated GAG preparations. (a) Plot of the ΔD/− Δf ratio versus − Δf (i = 3; frequency shifts are normalised by i) for various polydisperse GAG-b polysaccharide preparations of HA and other GAG types (chondroitin sulfate – CS, CS-A, CS-C, CS-D and CS-E, chemically desulfated CS—CΔS, dermatan sulfate – DS, heparan sulfate – HS; symbols and colour codes as indicated). Original QCM-D data are shown in Fig. S9. The inset shows the ΔD/− Δf values at − Δf = 2.5 Hz, as mean ± standard deviations for − Δf values ranging between 2 and 3 Hz. (b) Comparison of the effective size (in number of disaccharides n_ds) of surface-grafted GAG-b polysaccharides (as determined by QCM-D; filled bars) with the effective size distribution of GAG-b polysaccharides in solution (as determined by PAGE; unfilled bars) and the size estimates of the original GAGs given by the provider (bars with diagonal lines; taking disaccharide masses to be 400 Da for HA, and 500 Da for all sulfated GAGs). To calculate GAG sizes from QCM-D data, the ΔD/− Δf values at − Δf = 2.5 Hz of the polydisperse GAG-b preparations were compared with the standard curve (Fig. 4 and Eq. 1). To calculate the effective size distribution from PAGE data, the migration distances of the peak intensity and the half-maximal intensities above background were compared to the migration distances of size-defined HA standards (Fig. S8). The effective molecular masses of surface-grafted GAGs (in kDa) are given below the GAG names, and were derived from n_ds with disaccharide masses of 400 Da for HA and CΔS, and 500 Da for all sulfated GAGs.