{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T23:05:40Z","timestamp":1781564740895,"version":"3.54.5"},"reference-count":28,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2023,2,7]],"date-time":"2023-02-07T00:00:00Z","timestamp":1675728000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"French Agence Nationale de la Recherche","award":["ANR, convention 2009 CARN 003 01"],"award-info":[{"award-number":["ANR, convention 2009 CARN 003 01"]}]},{"name":"French Agence Nationale de la Recherche","award":["BMBF, funding reference number 01SF0804"],"award-info":[{"award-number":["BMBF, funding reference number 01SF0804"]}]},{"name":"German Bundesministerium f\u00fcr Bildung und Forschung","award":["ANR, convention 2009 CARN 003 01"],"award-info":[{"award-number":["ANR, convention 2009 CARN 003 01"]}]},{"name":"German Bundesministerium f\u00fcr Bildung und Forschung","award":["BMBF, funding reference number 01SF0804"],"award-info":[{"award-number":["BMBF, funding reference number 01SF0804"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Biomimetic nanocrystalline apatites analogous to bone mineral can be prepared using soft chemistry. Due to their high similarity to bone apatite, as opposed to stoichiometric hydroxyapatite for example, they now represent an appealing class of compounds to produce bioactive ceramics for which drug delivery and ion exchange abilities have been described extensively. However, immersion in aqueous media of dried non-carbonated biomimetic apatite crystals may generate an acidification event, which is often disregarded and not been clarified to-date. Yet, this acidification process could limit their further development if it is not understood and overcome if necessary. This may, for example, alter biological test outcomes, during their evaluation as bone repair materials, due to potentially deleterious effects of the acidic environment on cells, especially in in vitro static conditions. In this study, we explore the origins of this acidification phenomenon based on complementary experimental data and we point out the central role of the hydrated ionic layer present on apatite nanocrystals. We then propose a practical strategy to circumvent this acidification effect using an adequate post-precipitation equilibration step that was optimized. Using this enutralization protocol, we then showed the possibility of performing (micro)biological assessments on such compounds and provide an illustration with the examples of post-equilibrated Cu2+- and Ag+-doped nanocrystalline apatites. We demonstrate their non-cytotoxicity to osteoblast cells and their antibacterial features as tested versus five major pathogens involved in bone infections, therefore pointing to their relevance in the field of antibacterial bone substitutes. The preliminary in vivo implantation of a relevant sample in a rat\u2019s calvarial defect confirmed its biocompatibility and the absence of adverse reaction. Understanding and eliminating this technical barrier should help promoting biomimetic apatites as a genuine new class of biomaterial-producing compounds for bone regeneration applications, e.g., with antibacterial features, far from being solely considered as \u201claboratory curiosities\u201d.<\/jats:p>","DOI":"10.3390\/bioengineering10020220","type":"journal-article","created":{"date-parts":[[2023,2,7]],"date-time":"2023-02-07T03:24:13Z","timestamp":1675740253000},"page":"220","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Nanocrystalline Apatites: Post-Immersion Acidification and How to Avoid It\u2014Application to Antibacterial Bone Substitutes"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8471-8719","authenticated-orcid":false,"given":"Christophe","family":"Drouet","sequence":"first","affiliation":[{"name":"CIRIMAT, Universit\u00e9 de Toulouse, CNRS, Toulouse INP, 31000 Toulouse, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicolas","family":"Vandecandela\u00e8re","sequence":"additional","affiliation":[{"name":"CIRIMAT, Universit\u00e9 de Toulouse, CNRS, Toulouse INP, 31000 Toulouse, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anke","family":"Burger-Kentischer","sequence":"additional","affiliation":[{"name":"Fraunhofer IGB, 70569 Stuttgart, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Iris","family":"Trick","sequence":"additional","affiliation":[{"name":"Fraunhofer IGB, 70569 Stuttgart, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christina G.","family":"Kohl","sequence":"additional","affiliation":[{"name":"Fraunhofer IGB, 70569 Stuttgart, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tanja","family":"Maucher","sequence":"additional","affiliation":[{"name":"Fraunhofer IGB, 70569 Stuttgart, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0820-1742","authenticated-orcid":false,"given":"Michaela","family":"Mueller","sequence":"additional","affiliation":[{"name":"Fraunhofer IGB, 70569 Stuttgart, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1670-2296","authenticated-orcid":false,"given":"Franz E.","family":"Weber","sequence":"additional","affiliation":[{"name":"Center of Dental Medicine, Oral Biotechnology & Bioengineering, University of Zurich, 8006 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,2,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2593","DOI":"10.1007\/s10856-012-4719-y","article-title":"Biomimetic apatite-based biomaterials: On the critical impact of synthesis and post-synthesis parameters","volume":"23","author":"Vandecandelaere","year":"2012","journal-title":"J. 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