The discrimination of type I and type II collagen and the label-free imaging of engineered cartilage tissue.
Using excitation polarization-resolved second harmonic generation (SHG) microscopy, we measured SHG intensity as a function of the excitation polarization angle for type I and type II collagens. We determined the second order susceptibility (χ((2))) tensor ratios of type I and II collagens at each pixel, and displayed the results as images. We found that the χ((2)) tensor ratios can be used to distinguish the two types of collagen. In particular, we obtained χ(zzz)/χ(zxx) = 1.40 ± 0.04 and χ(xzx)/χ(zxx) = 0.53 ± 0.10 for type I collagen from rat tail tendon, and χ(zzz)/χ(zxx) = 1.14 ± 0.09 and χ(xzx)/χ(zxx) = 0.29 ± 0.11 for type II collagen from rat trachea cartilage. We also applied this methodology on the label-free imaging of engineered cartilage tissue which produces type I and II collagen simultaneously. By displaying the χ((2)) tensor ratios in the image format, the variation in the χ((2)) tensor ratios can be used as a contrast mechanism for distinguishing type I and II collagens.
Su
Ping-Jung
PJ
Department of Physics, National Taiwan University, Taipei 106, Taiwan.
Chen
Wei-Liang
WL
Li
Tsung-Hsien
TH
Chou
Chen-Kuan
CK
Chen
Te-Hsuen
TH
Ho
Yi-Yun
YY
Huang
Chi-Hsiu
CH
Chang
Shwu-Jen
SJ
Huang
Yi-You
YY
Lee
Hsuan-Shu
HS
Dong
Chen-Yuan
CY
D000818:Animals; D002356:Cartilage / Q000166:cytology / Q000502:physiology*; D024042:Collagen Type I / Q000378:metabolism*; D024043:Collagen Type II / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008954:Models, Biological; D051381:Rats; D013194:Staining and Labeling; D013710:Tendons / Q000166:cytology; D023822:Tissue Engineering / Q000379:methods*
D024042:Collagen Type I; D024043:Collagen Type II