Raman spectroscopic imaging for quantification of depth-dependent and local heterogeneities in native and engineered cartilage

(a) Raw spectra of native and engineered cartilage. Raman spectroscopic image (univariate analysis) of ECM heterogeneities in 56-day cultured large engineered cartilage tissue construct (？6？mm？×？3？mm) for (b) the full cross-section (10？μm spatial resolution) and (c) a localized peripheral region (1？μm resolution). Arrows represent media-exposed surfaces. (d) Raman spectroscopic image of natural depth dependent ECM heterogeneities in native articular cartilage (10？μm resolution). Arrow represents articular surfac