University of Oulu

Awuniji Linus, Mohammadhossein Ebrahimi, Mikael J. Turunen, Simo Saarakkala, Antti Joukainen, Heikki Kröger, Arto Koistinen, Mikko A.J. Finnilä, Isaac O. Afara, Mika E. Mononen, Petri Tanska, Rami K. Korhonen, High-resolution infrared microspectroscopic characterization of cartilage cell microenvironment, Acta Biomaterialia, Volume 134, 2021, Pages 252-260, ISSN 1742-7061,

High-resolution infrared microspectroscopic characterization of cartilage cell microenvironment

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Author: Linus, Awuniji1; Ebrahimi, Mohammadhossein1,2; Turunen, Mikael J.1;
Organizations: 1Department of Applied Physics, University of Eastern Finland, POB 1627, 70211 Kuopio, Finland
2Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
3Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.
4Kuopio University Hospital, Kuopio, Finland
5SIB Labs, University of Eastern Finland, POB 1627, 70211 Kuopio, Finland
6School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.3 MB)
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Language: English
Published: Elsevier, 2021
Publish Date: 2021-11-10


The lateral resolution of infrared spectroscopy has been inadequate for accurate biochemical characterization of the cell microenvironment, a region regulating biochemical and biomechanical signals to cells. In this study, we demonstrate the capacity of a high-resolution Fourier transform infrared microspectroscopy (HR-FTIR-MS) to characterize the collagen content of this region. Specifically, we focus on the collagen content in the cartilage cell (chondrocyte) microenvironment of healthy and osteoarthritic (OA) cartilage. Human tibial cartilage samples (N = 28) were harvested from 7 cadaveric donors and graded for OA severity (healthy, early OA, advanced OA). HR-FTIR-MS was used to analyze the collagen content of the chondrocyte microenvironment of five distinct zones across the tissue depth. HR-FTIR-MS successfully showed collagen content distribution across chondrocytes and their environment. In zones 2 and 3 (10 - 50% of the tissue thickness), we observed that collagen content was smaller (P < 0.05) in early OA compared to the healthy tissue in the vicinity of cells (pericellular region). The collagen content loss was extended to the extracellular matrix in advanced OA tissue. No significant differences in the collagen content of the chondrocyte microenvironment were observed between the groups in the most superficial (0–10%) and deep zones (50–100%). HR-FTIR-MS revealed collagen loss in the early OA cartilage pericellular region before detectable changes in the extracellular matrix in advanced OA. HR-FTIR-MS-based compositional assessment enables a better understanding of OA-related changes in tissues. This technique can be used to identify new disease mechanisms enabling better intervention strategies.

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Series: Acta biomaterialia
ISSN: 1742-7061
ISSN-E: 1878-7568
ISSN-L: 1742-7061
Volume: 134
Pages: 252 - 260
DOI: 10.1016/j.actbio.2021.08.001
Type of Publication: A1 Journal article – refereed
Field of Science: 3111 Biomedicine
318 Medical biotechnology
Funding: Financial support from the Academy of Finland (grants 324529, 320135, 315820, 324994, 328920), Sigrid Juselius Foundation, Strategic Funding of the University of Eastern Finland, Finnish Cultural Foundation – Central fund (grant 191044), Finnish Cultural Foundation – North Savo regional fund (grant 65191841), Alfred Kordelin Foundation (#190317), Maire Lisko Foundation and Emil Aaltonen Foundation (grant 200016) are acknowledged. The funding sources had no role in the study design, collection, analysis, and interpretation of data; in the writing of the manuscript as well as the decision to submit the manuscript for publication.
Copyright information: © 2021 The Authors. Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY license (