Visualizing anatomical and functional features of hair follicle development in their unperturbed environment is key in understanding complex mechanisms of hair pathophysiology and in discovery of novel therapies. Of particular interest is in vivo visualization of the intact pilosebaceous unit, vascularization of the hair bulb, and evaluation of the hair cycle, particularly in humans. Furthermore, noninvasive visualization of the sebaceous glands could offer crucial insight into the pathophysiology of follicle-related diseases and dry or seborrheic skin, in particular by combining in vivo imaging with other phenotyping, genotyping, and microbial analyses. The available imaging techniques are limited in their ability for deep tissue in vivo imaging of hair follicles and lipid-rich sebaceous glands in their entirety without biopsy. We developed a noninvasive, painless, and risk-free volumetric multispectral optoacoustic tomography method for deep tissue three-dimensional visualization of whole hair follicles and surrounding structures with high spatial resolution below 80 μm. Herein we demonstrate on-the-fly assessment of key morphometric parameters of follicles and lipid content as well as functional oxygenation parameters of the associated capillary bed. The ease of handheld operation and versatility of the newly developed approach poise it as an indispensable tool for early diagnosis of disorders of the pilosebaceous unit and surrounding structures, and for monitoring the efficacy of cosmetic and therapeutic interventions.
Bibliographical noteFunding Information:
DR recognizes funding from the European Research Council under grant agreement ERC-2010-StG-260991. MO and PLB recognize funding from the Agency for Science, Technology and Research, in particular the Institute of Medical Biology and Singapore Bioimaging Consortium. The hematoxylin and eosin slide from the scalp hair was generously provided by Dr. Graham Wright and Declan Lunny from IMB, ASTAR. We thank Chris Ho and Amalina Attia for assistance in vMSOT imaging and Yuri Dancik and Bryan Siu-Yin Ho for assistance in providing the microscope images from the follicular unit extractions. SJF PLB, MO, and DR conceived the study. AU and MK constructed the system. SJF, TCPS, AU, NCB, and MK designed and performed experiments. SJF and TCPS analyzed the data. AU, MC, and MB developed analytical tools. MO, PLB, and DR supervised the project. SJF and DR wrote the paper. All authors discussed the results and implications and commented on the manuscript at all stages.
© 2015 The Authors