Multiscale keratin assembly and mechanical characterizations using autofluorescence microscopy

Tsao-Chi Chuang^1*, Wen-Tau Juan^1,2

¹Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
²Department of Medical Research, China Medical University Hospital, Taichung, Taiwan

* Presenter:Tsao-Chi Chuang, email:Q6712084@hotmail.com

The interdisciplinary study of morphogenesis is vital for understanding the growth and functionality of tissues. The skin and its adaptable appendages, particularly avian feathers, serve as excellent models for investigating the development of keratin-based bioarchitecture due to their regenerative and multifunctional characteristics. Although recent biophysics studies employing microscopy have provided insights into cellular morphology, topology, and biomechanics, the intricate multiscale interactions that underlie tissue functionality are not yet fully understood. In this work, we harnessed autofluorescence (AF) microscopy to investigate avian feathers, unveiling cross-scale attributes of keratinized material that are imperceptible in conventional white-light-reflected microimaging. Our quantitative AF analyses of contour feather branches support modern theories regarding keratin integration within the rachis-barb-barbule hierarchy during feather development. Biomechanical characterizations conducted through tensile testing in relevant regions further establish a robust correlation between local AF intensity and the strength of materials, highlighting the potential of AF microscopy as a noninvasive method for cross-scale material assessment in keratinized structures [1]. This research presents an accessible method for uncovering keratin assembly in natural integuments across a wide range of length scales, offering interdisciplinary insights into the morphogenesis of functional tissues.

[1] T.C. Chuang, Jiun-Wei Cheng, Cheng-Ming Chuuong, Wen-Tau Juan*, “Autofluorescence microscopy as a non-invasive probe to characterize the complex mechanical properties of keratin-based integumentary organs: A feather paradigm”, Chin. J. Phys. (Accepted, 2023)

Keywords: autofluorescence, feather, keratin, biomechanics, morphogenesis