Quantitative results of tendon-derived stem cells proliferation (A) by MTS test. (Bi–Ei) Fluorescence microscopy images of attached cells on the surface of P2L8 (Bi), P2L8-S3 (Ci), P2L8-S5 (Di), and P2L8-S15 (Ei) after 3 days culture. (Bii-Eii) SEM images of attached cells on the surface of P2L8 (Bii), P2L8-S3 (Cii), P2L8-S5 (Dii), and P2L8-S15 (Eii) after 72 h culture. Data are expressed as mean ± SD (n = 3). Statistical difference between groups is indicated (*p < 0.05; **p < 0.01). Scale bar = 100 μm.