{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T16:51:50Z","timestamp":1786121510290,"version":"build-2736575974"},"reference-count":31,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T00:00:00Z","timestamp":1786060800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000072","name":"National Institute of Dental and Craniofacial Research","doi-asserted-by":"publisher","award":["R01DE032690"],"award-info":[{"award-number":["R01DE032690"]}],"id":[{"id":"10.13039\/100000072","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000072","name":"National Institute of Dental and Craniofacial Research","doi-asserted-by":"publisher","award":["DE030853"],"award-info":[{"award-number":["DE030853"]}],"id":[{"id":"10.13039\/100000072","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Bioeng. Biotechnol."],"abstract":"<jats:p>Organoids offer a novel platform to study developmental and reparative processes and hold promise as model systems for drug discovery and personalized medicine. To maximize their utility, we investigated the capacity of organoids, specifically tooth root organoids, to be scaled down in size. We previously established that dental pulp stem\/progenitor cells (DPSCs) and periodontal ligament (PDL) stem\/progenitor cells (PDLSCs) co-cultured using scaffold-free tissue engineering approaches, self-assemble into tooth root organoids with anatomically organized layers of pulp-, dentin-, cementum-, and PDL-like tissues. These organoids were originally formed in 6 well plates. To test the effects of scaling down construct size, DPSC-PDLSC constructs were now generated with fixed initial cell density in 6-, 12-, and 24-well plates. While construct diameter initially scaled linearly with culture surface area, over time samples generated in the larger wells condensed more than their smaller counterparts resulting in final construct sizes which deviated from the initial linear relationship. Furthermore, this differential size decrease coincided with altered mineralized tissue patterning, where samples generated in the smaller dishes had greater relative mineral deposition that lacked predictable patterning unlike the distinct anatomically patterned mineralized and soft tissue layers seen in constructs formed in the larger wells. Interestingly, samples formed in the smaller wells had increased apoptotic activity at the periphery, suggesting that cellular dynamics vary with initial construct size. These findings demonstrate that reducing initial cell number in scaffold-free DPSC-PDLSC constructs alters cellular behavior and tissue architecture, suggesting the existence of a critical cell mass required for consistent and proper tooth root organoid formation.<\/jats:p>","DOI":"10.3389\/fbioe.2026.1801110","type":"journal-article","created":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T05:28:35Z","timestamp":1786080515000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Effects of size scaling on cellular dynamics and tissue patterning in tooth root organoids"],"prefix":"10.3389","volume":"14","author":[{"given":"Tia C.","family":"Calabrese","sequence":"first","affiliation":[{"name":"Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh","place":["Pittsburgh, PA, United States"]},{"name":"Center for Craniofacial Regeneration, School of Dental Medicine, University of Pittsburgh","place":["Pittsburgh, PA, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristi","family":"Rothermund","sequence":"additional","affiliation":[{"name":"Center for Craniofacial Regeneration, School of Dental Medicine, University of Pittsburgh","place":["Pittsburgh, PA, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fatima N.","family":"Syed","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh","place":["Pittsburgh, PA, United States"]},{"name":"Center for Craniofacial Regeneration, School of Dental Medicine, University of Pittsburgh","place":["Pittsburgh, PA, United States"]},{"name":"Department of Oral and Craniofacial Sciences, School of Dental Medicine, University of Pittsburgh","place":["Pittsburgh, PA, United States"]},{"name":"McGowan Institute for Regenerative Medicine","place":["Pittsburgh, PA, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,7]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"42113","DOI":"10.1038\/srep42113","article-title":"Allometric scaling in-vitro","volume":"7","author":"Ahluwalia","year":"2017","journal-title":"Sci. Rep."},{"key":"B2","doi-asserted-by":"publisher","first-page":"422","DOI":"10.3389\/fphys.2019.00422","article-title":"Self-assembly of an organized cementum-periodontal ligament-like complex using scaffold-free tissue engineering","volume":"10","author":"Basu","year":"2019","journal-title":"Front. Physiol."},{"key":"B3","doi-asserted-by":"publisher","first-page":"499","DOI":"10.1016\/j.ydbio.2007.01.002","article-title":"Patterning the size and number of tooth and its cusps","volume":"304","author":"Cai","year":"2007","journal-title":"Dev. Biol."},{"key":"B4","doi-asserted-by":"publisher","first-page":"404","DOI":"10.1089\/ten.tea.2023.0219","article-title":"Self-assembly of tooth root organoid from postnatal human dental stem cells","volume":"30","author":"Calabrese","year":"2023","journal-title":"Tissue Eng. Part A"},{"key":"B5","doi-asserted-by":"publisher","first-page":"13","DOI":"10.1177\/154411130401500103","article-title":"Cells and extracellular matrices of dentin and pulp: a biological basis for repair and tissue engineering","volume":"15","author":"Goldberg","year":"2004","journal-title":"Crit. Rev. Oral Biol. Med."},{"key":"B6","doi-asserted-by":"publisher","first-page":"711","DOI":"10.2741\/e281","article-title":"Dentin: structure, composition and mineralization","author":"Goldberg","year":"2011","journal-title":"Front. Biosci. - Elite"},{"key":"B7","doi-asserted-by":"publisher","first-page":"387","DOI":"10.3390\/biomedicines11020387","article-title":"The role and involvement of stem cells in periodontology","volume":"11","author":"Goriuc","year":"2023","journal-title":"Biomedicines"},{"key":"B8","doi-asserted-by":"publisher","first-page":"13625","DOI":"10.1073\/pnas.240309797","article-title":"Postnatal human dental pulp stem cells (DPSCs) in vitro and in vivo","volume":"97","author":"Gronthos","year":"2000","journal-title":"Proc. Natl. Acad. Sci. U. S. A."},{"key":"B9","doi-asserted-by":"publisher","first-page":"3253","DOI":"10.1002\/adma.201304995","article-title":"Developmentally-inspired shrink-wrap polymers for mechanical induction of tissue differentiation","volume":"26","author":"Hashmi","year":"2014","journal-title":"Adv. Mater."},{"key":"B10","doi-asserted-by":"publisher","first-page":"402","DOI":"10.1038\/s41578-021-00279-y","article-title":"Engineering organoids","volume":"6","author":"Hofer","year":"2021","journal-title":"Nat. Rev. Mat."},{"key":"B11","doi-asserted-by":"publisher","first-page":"427","DOI":"10.1038\/nature06153","article-title":"Predicting evolutionary patterns of Mammalian teeth from development","volume":"449","author":"Kavanagh","year":"2007","journal-title":"Nature"},{"key":"B12","doi-asserted-by":"publisher","first-page":"299","DOI":"10.1038\/s42003-023-04694-5","article-title":"Gradient to sectioning CUBE workflow for the generation and imaging of organoids with localized differentiation","volume":"6","author":"Koh","year":"2023","journal-title":"Commun. Biol."},{"key":"B13","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3390\/ijms22020539","article-title":"Inflammation in the human periodontium induces downregulation of the \u03b11-and \u03b21-subunits of the sgc in cementoclasts","volume":"22","author":"Korkmaz","year":"2021","journal-title":"Int. J. Mol. Sci."},{"key":"B14","doi-asserted-by":"publisher","DOI":"10.1242\/dmm.039347","article-title":"Disease modelling in human organoids","volume":"12","author":"Lancaster","year":"2019","journal-title":"DMM Dis. Models Mech."},{"key":"B15","doi-asserted-by":"publisher","first-page":"1","DOI":"10.3389\/fphar.2018.00006","article-title":"Three-dimensional in vitro cell culture models in drug discovery and drug repositioning","volume":"9","author":"Langhans","year":"2018","journal-title":"Front. Pharmacol."},{"key":"B16","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1101\/cshperspect.a025668","article-title":"The self-assembling process and applications in tissue engineering","volume":"7","author":"Lee","year":"2017","journal-title":"Cold Spring Harb. Perspect. Med."},{"key":"B17","doi-asserted-by":"publisher","first-page":"40","DOI":"10.1186\/s12967-020-02677-2","article-title":"Patient-derived organoid (PDO) platforms to facilitate clinical decision making","volume":"19","author":"Liu","year":"2021","journal-title":"J. Transl. Med."},{"key":"B18","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1038\/s41598-019-48347-2","article-title":"Allometric scaling of physiologically-relevant organoids","volume":"9","author":"Magliaro","year":"2019","journal-title":"Sci. Rep."},{"key":"B19","doi-asserted-by":"publisher","first-page":"758","DOI":"10.1016\/j.devcel.2011.07.006","article-title":"Mechanochemical control of mesenchymal condensation and embryonic tooth organ formation","volume":"21","author":"Mammoto","year":"2011","journal-title":"Dev. Cell."},{"key":"B20","doi-asserted-by":"publisher","first-page":"713","DOI":"10.1002\/dvdy.24264","article-title":"Mesenchymal condensation-dependent accumulation of collagen VI stabilizes organ-specific cell fates during embryonic tooth formation","author":"Mammoto","year":"2015","journal-title":"Dev. Dyn."},{"key":"B21","volume-title":"Ten Cate\u2019s Oral Histology","author":"Nanci","year":"2013"},{"key":"B22","doi-asserted-by":"publisher","first-page":"100779","DOI":"10.1016\/j.crmeth.2024.100779","article-title":"Bioengineering methods for vascularizing organoids","volume":"4","author":"Nwokoye","year":"2024","journal-title":"Cell. Rep. Methods"},{"key":"B23","doi-asserted-by":"publisher","first-page":"2729","DOI":"10.1042\/BST20200514","article-title":"Exploiting teeth as a model to study basic features of signaling pathways","volume":"48","author":"Pagella","year":"2020","journal-title":"Biochem. Soc. Trans."},{"key":"B24","doi-asserted-by":"publisher","first-page":"671","DOI":"10.1038\/s41576-018-0051-9","article-title":"Progress and potential in organoid research","volume":"19","author":"Rossi","year":"2018","journal-title":"Nat. Rev. Genet."},{"key":"B25","doi-asserted-by":"publisher","first-page":"1378","DOI":"10.1016\/j.joen.2022.08.010","article-title":"Differential effects of Escherichia coli versus porphyromonas gingivalis-derived lipopolysaccharides on dental pulp stem cell differentiation in scaffold-free engineered tissues","volume":"48","author":"Rothermund","year":"2022","journal-title":"J. Endod."},{"key":"B26","doi-asserted-by":"publisher","first-page":"149","DOI":"10.1016\/S0140-6736(04)16627-0","article-title":"Investigation of multipotent postnatal stem cells from human periodontal ligament","volume":"364","author":"Seo","year":"2004","journal-title":"Lancet"},{"key":"B27","doi-asserted-by":"publisher","first-page":"1899","DOI":"10.1152\/physrev.00019.2022","article-title":"Mesenchymal condensation in tooth development and regeneration: a focus on translational aspects of organogenesis","volume":"103","author":"Sui","year":"2023","journal-title":"Physiol. Rev."},{"key":"B28","doi-asserted-by":"publisher","first-page":"187","DOI":"10.1089\/ten.tea.2007.0140","article-title":"Three-dimensional engineered bone from bone marrow stromal cells and their autogenous extracellular matrix","volume":"15","author":"Syed-Picard","year":"2009","journal-title":"Tissue Eng. Part A"},{"key":"B29","doi-asserted-by":"publisher","first-page":"3763","DOI":"10.1016\/j.biomaterials.2013.01.095","article-title":"Osteoinductivity of calcium phosphate mediated by connexin 43","volume":"34","author":"Syed-Picard","year":"2013","journal-title":"Biomaterials"},{"key":"B30","doi-asserted-by":"publisher","first-page":"250","DOI":"10.1177\/0022034513517901","article-title":"Scaffoldless tissue-engineered dental pulp cell constructs for endodontic therapy","volume":"93","author":"Syed-Picard","year":"2014","journal-title":"J. Dent. Res."},{"key":"B31","doi-asserted-by":"publisher","first-page":"102810","DOI":"10.1016\/j.copbio.2022.102810","article-title":"Creating artificial signaling gradients to spatially pattern engineered tissues","volume":"78","author":"Zheng","year":"2022","journal-title":"Curr. Opin. Biotechnol."}],"container-title":["Frontiers in Bioengineering and Biotechnology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fbioe.2026.1801110\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T05:28:36Z","timestamp":1786080516000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fbioe.2026.1801110\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,7]]},"references-count":31,"alternative-id":["10.3389\/fbioe.2026.1801110"],"URL":"https:\/\/doi.org\/10.3389\/fbioe.2026.1801110","relation":{},"ISSN":["2296-4185"],"issn-type":[{"value":"2296-4185","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,7]]},"article-number":"1801110"}}