{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T21:03:45Z","timestamp":1789506225946,"version":"build-2803163510"},"reference-count":51,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2021,9,17]],"date-time":"2021-09-17T00:00:00Z","timestamp":1631836800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Extracellular calcium ion concentration levels increase in human osteoarthritic (OA) joints and contribute to OA pathogenesis. Given the fact that OA is a mechanical problem, the effect of the extracellular calcium level ([Ca2+]) on the mechanical behavior of primary human OA chondrocytes remains to be elucidated. Here, we measured the elastic modulus and cell\u2013ECM adhesion forces of human primary chondrocytes with atomic force microscopy (AFM) at different extracellular calcium ion concentration ([Ca2+]) levels. With the [Ca2+] level increasing from the normal baseline level, the elastic modulus of chondrocytes showed a trend of an increase and a subsequent decrease at the level of [Ca2+], reaching 2.75 mM. The maximum increment of the elastic modulus of chondrocytes is a 37% increase at the peak point. The maximum unbinding force of cell-ECM adhesion increased by up to 72% at the peak point relative to the baseline level. qPCR and immunofluorescence also indicated that dose-dependent changes in the expression of myosin and integrin \u03b21 due to the elevated [Ca2+] may be responsible for the variations in cell stiffness and cell-ECM adhesion. Scratch assay showed that the chondrocyte migration ability was modulated by cell stiffness and cell-ECM adhesion: as chondrocyte\u2019s elastic modulus and cell-ECM adhesion force increased, the migration speed of chondrocytes decreased. Taken together, our results showed that [Ca2+] could regulate chondrocytes stiffness and cell-ECM adhesion, and consequently, influence cell migration, which is critical in cartilage repair.<\/jats:p>","DOI":"10.3390\/ijms221810034","type":"journal-article","created":{"date-parts":[[2021,9,17]],"date-time":"2021-09-17T21:23:29Z","timestamp":1631913809000},"page":"10034","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Extracellular Calcium Ion Concentration Regulates Chondrocyte Elastic Modulus and Adhesion Behavior"],"prefix":"10.3390","volume":"22","author":[{"given":"Xingyu","family":"Shen","sequence":"first","affiliation":[{"name":"Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liqiu","family":"Hu","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhen","family":"Li","sequence":"additional","affiliation":[{"name":"School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liyun","family":"Wang","sequence":"additional","affiliation":[{"name":"Center for Biomechanical Research, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6365-3717","authenticated-orcid":false,"given":"Xiangchao","family":"Pang","sequence":"additional","affiliation":[{"name":"College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1949-7822","authenticated-orcid":false,"given":"Chun-Yi","family":"Wen","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bin","family":"Tang","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,9,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"16072","DOI":"10.1038\/nrdp.2016.72","article-title":"Osteoarthritis","volume":"2","author":"Barr","year":"2016","journal-title":"Nat. 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