Figure 7

(a) Scores and (b) loading plots from PCA of the ToF-SIMS positive-ion spectra acquired from HV-treated and dehydrated collagen fibril matrices. PCA was performed on all peaks with intensities of at least 100 counts (except Li⁺, Na⁺, and K⁺) to elucidate any minor spectral differences between the HV-treated and dehydrated fibrils, without bias, which may be present as a result in the change of fibrillar matrix state. Peaks were normalized to the total ion counts and mean-centered. The solid line ellipses and the dashed line ellipse represent the 95% confidence limit for each group and the entire PC model, respectively.