phaidra.vetmeduni.ac.at o:5604 DOI 10.1016/j.mtbio.2026.103225 A high-toughness, rare-earth-free magnesium alloy with excellent biocompatibility profile: Integrated in vitro and in vivo characterization Bioresorbable magnesium (Mg) alloys are promising alternatives to permanent implants in cardiovascular and orthopedic applications. Alloying with rare earth elements (REEs) can enhance corrosion resistance and mechanical strength, though their long-term biological behavior and biosafety are still being clarified. Herein, we compared the widely used REE-containing alloy WE43 with a previously self-designed REE-free alloy, ZX00 (Mg–0.6Zn–0.5Ca), focusing on biocompatibility, toxicity, degradation, and mechanical performance in vitro and in vivo. ZX00 demonstrated significantly higher fibroblast viability than WE43 in vitro (100.00% ± 9.30% vs. 43.00% ± 6.88%; p < 0.0001) and did not elicit inflammatory responses in primary human macrophages, while both alloys showed comparable hemocompatibility. After 5 months of subcutaneous implantation in rats, ZX00 and WE43 exhibited similar overall biocompatibility, with mild gas formation observed in X-ray imaging and histology. Although ZX00 degraded faster than WE43 according to micro-computed tomography and histological analyses, it retained markedly superior ductility after 5 months of implantation, due to uniform, non-localized corrosion. No systemic toxicity was detected for either alloy through histopathological assessment of multiple organs and hematological analyses. This study shows that the REE-free ZX00 alloy possesses the biological and mechanical requirements for demanding biomedical environments, positioning it as a promising candidate for cardiovascular applications and marking a first step toward a bioabsorbable material specifically designed for cardiac annuloplasty devices. eng Magnesium alloy Biocompatibility Inflammatory response Biodegradability Mechanical performance 2026-10-16T07:53:40.397Z LOMv1.0 Author BEGIN:VCARD VERSION:3.0 N:Weber;Lukas; FN:Lukas Weber X-ORCID:https://orcid.org/0009-0004-6775-5763 END:VCARD BEGIN:VCARD VERSION:3.0 N:Horky;Jelena; FN:Jelena Horky X-ORCID:https://orcid.org/0009-0001-6330-4883 END:VCARD BEGIN:VCARD VERSION:3.0 N:Riedmüller;Christopher; FN:Christopher Riedmüller X-ORCID:https://orcid.org/0009-0001-2696-2908 END:VCARD BEGIN:VCARD VERSION:3.0 N:Kampleitner;Carina; FN:Carina Kampleitner END:VCARD BEGIN:VCARD VERSION:3.0 N:Acar;Eylem; FN:Eylem Acar END:VCARD BEGIN:VCARD VERSION:3.0 N:Fedel;Mariangela; FN:Mariangela Fedel END:VCARD BEGIN:VCARD VERSION:3.0 N:Höchsmann;Claudia; FN:Claudia Höchsmann END:VCARD BEGIN:VCARD VERSION:3.0 N:Eskinja;Magdalena; FN:Magdalena Eskinja X-ORCID:https://orcid.org/0000-0002-8845-4351 END:VCARD BEGIN:VCARD VERSION:3.0 N:Mitsche;Stefan; FN:Stefan Mitsche END:VCARD BEGIN:VCARD VERSION:3.0 N:Mingler;Bernhard; FN:Bernhard Mingler END:VCARD BEGIN:VCARD VERSION:3.0 N:Sajti;Laszlo; FN:Laszlo Sajti END:VCARD BEGIN:VCARD VERSION:3.0 N:Mori;Gregor; FN:Gregor Mori END:VCARD BEGIN:VCARD VERSION:3.0 N:Bammer;Manfred; FN:Manfred Bammer END:VCARD BEGIN:VCARD VERSION:3.0 N:Walter;Ingrid; FN:Ingrid Walter X-ORCID:https://orcid.org/0000-0002-5038-188X END:VCARD BEGIN:VCARD VERSION:3.0 N:Tangl;Stefan; FN:Stefan Tangl X-ORCID:https://orcid.org/0000-0002-9023-4745 END:VCARD BEGIN:VCARD VERSION:3.0 N:Bergmeister;Helga; FN:Helga Bergmeister X-ORCID:https://orcid.org/0000-0003-3269-0168 END:VCARD BEGIN:VCARD VERSION:3.0 N:Podesser;Bruno K.; FN:Bruno K. Podesser X-ORCID:https://orcid.org/0000-0002-4641-7202 END:VCARD BEGIN:VCARD VERSION:3.0 N:Enayati;Marjan; FN:Marjan Enayati END:VCARD https://w3id.org/kim/hcrt/scheme https://w3id.org/kim/hcrt/text Textdokument Text LOMv1.0 yes https://creativecommons.org/licenses/by/4.0 application/pdf 17639909 https://phaidra.vetmeduni.ac.at/o:5604 https://phaidra.vetmeduni.ac.at/api/object/o:5604/thumbnail LOMv1.0 discipline