Analysis of protein expression, deposition, and ECM mechanical properties. (A) Representative images of immunofluorescence detection of several ECM components in DF-derived decellularized WT and TSP2 KO ECM (Zeiss). (B-C) Representative SEM images of WT (B) and TSP2 KO (C) decellularized ECM deposited on tissue-culture plastic. Collagen fibril arrangement appeared less aligned in the latter (Hitachi). (D) PCR analysis of several ECM proteins expressed by WT and TSP2 KO DFs revealed similar levels of expression. (E) Determination of ECM Young Modulus by AFM. A 2-μm bead affixed to the end of an AFM cantilever was used to perform nanoindentation studies on WT and TSP2 KO ECM. After force curves were collected, Young Modulus was determined using NanoScope Analysis software. n = 8. Col, collagen.