Geometry-Dependent Spectroscopic Contrast in Deep Tissues

Xin Ge; Hongying Tang; Xianghong Wang; Xinyu Liu; Si Chen; Nanshuo Wang; Guangming Ni; Xiaojun Yu; Shufen Chen; Haitao Liang; En Bo; Lulu Wang; Cilwyn Shalitha Braganza; Chenjie Xu; Steven M Rowe; Guillermo J Tearney; Linbo Liu

doi:10.1016/j.isci.2019.08.046

Geometry-Dependent Spectroscopic Contrast in Deep Tissues

iScience. 2019 Sep 27:19:965-975. doi: 10.1016/j.isci.2019.08.046. Epub 2019 Aug 29.

Authors

Xin Ge¹, Hongying Tang², Xianghong Wang¹, Xinyu Liu¹, Si Chen¹, Nanshuo Wang¹, Guangming Ni³, Xiaojun Yu⁴, Shufen Chen¹, Haitao Liang¹, En Bo¹, Lulu Wang¹, Cilwyn Shalitha Braganza¹, Chenjie Xu⁵, Steven M Rowe⁶, Guillermo J Tearney⁷, Linbo Liu⁸

Affiliations

¹ School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Republic of Singapore.
² College of Information, Mechanical and Electrical Engineering, Shanghai Normal University, Shanghai 200234, China.
³ School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China.
⁴ School of Automation, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
⁵ School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Republic of Singapore.
⁶ Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA. Electronic address: smrowe@uab.edu.
⁷ Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02114, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA; Department of Pathology, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02114, USA. Electronic address: gtearney@partners.org.
⁸ School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Republic of Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Republic of Singapore. Electronic address: liulinbo@ntu.edu.sg.

Abstract

Nano-structures of biological systems can produce diverse spectroscopic effects through interactions with broadband light. Although structured coloration at the surface has been extensively studied, natural spectroscopic contrasts in deep tissues are poorly understood, which may carry valuable information for evaluating the anatomy and function of biological systems. Here we investigated the spectroscopic characteristics of an important geometry in deep tissues at the nanometer scale: packed nano-cylinders, in the near-infrared window, numerically predicted and experimentally proved that transversely oriented and regularly arranged nano-cylinders could selectively backscatter light of the long wavelengths. Notably, we found that the spectroscopic contrast of nanoscale fibrous structures was sensitive to the pressure load, possibly owing to the changes in the orientation, the degree of alignment, and the spacing. To explore the underlying physical basis, we further developed an analytical model based on the radial distribution function in terms of their radius, refractive index, and spatial distribution.

Keywords: Infrared Optics; Medical Imaging; Optical Imaging; Spectroscopy.

Abstract

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