Soutenance de Thèse de Doctorat en "Materials Science and Engineering" par Mr. Oluwatosin David ABODUNRIN

The Euromed University of Fez (UEMF) is pleased to inform the public of

the doctoral thesis defense in ” Materials Science and Engineering'”

The thesis defense will take place on Monday, June 23, 2025, at 2:30 p.m at l’UEMF 

Location: conference room Building 1

The thesis will be presented by Mr. Oluwatosin David ABODUNRIN

under the theme :

“ DEVELOPMENT AND ASSESSMENT OF ANTIMICROBIAL BORATE BIOACTIVE GLASSES “BBG” FOR OPTIMIZED GUIDED BONE REGENERATION”

Abstract 

Alveolar bone, or dental bone, is an important part of the oral cavity that forms sockets for tooth roots. It is highly susceptible to periodontitis affecting almost half of the global population in which severe cases constitute 24% and prevalence increases with age. Conventional bone graft types, including autografts, allografts, and xenografts, have serious drawbacks, like immunogenicity, infection risks, and donor-site morbidity. Moreover, non-resorbable barrier membranes utilized in guided bone regeneration require secondary procedures, lengthening the time of healing, increasing costs, discomfort, and complications. This limitation highlights the need for bioresorbable membranes that can facilitate recovery and eliminate the need for additional surgery. This research addresses these challenges by developing novel bioactive materials and bioresorbable membranes for guided bone and tissue regeneration. The first part investigates mesoporous borosilicate bioactive glass nanoparticles doped with silver and cerium ions to optimize bio-functional properties. These nanoparticles, synthesized via the Stober sol-gel method and characterized through various analytical techniques including TGA, FTIR, XRD, BET, NMR, ICP-AES, and SEM-EDX, exhibited an amorphous phase, mesoporosity, and enhanced bioactivity. Hydroxyapatite formation was dependent on borate concentration, with higher boron content reducing apatite formation and increasing degradation rates. Silver doping significantly improved antibacterial properties, with an optimal concentration of 1 wt% balancing antimicrobial efficacy and cytocompatibility. 0.5 wt% co-doping of silver and cerium demonstrated synergistic effects on antibacterial activity and bioactivity, though careful concentration balance was necessary to avoid cytotoxicity.

Multifunctional electrospun fibrous bioresorbable membranes were developed using blends of amoxicillin, polyvinylpyrrolidone, polyvinyl alcohol, polycaprolactone, and borosilicate bioactive glass nanoparticles. Their characterization was carried out through techniques described previously along with DSC for thermal properties, UV-vis for drug release, contact angle for wettability, and DMA for mechanical properties. Three variants were studied: S1 (PCL/PVP blend with amoxicillin); S2 (S1 + BG); and S3 (S1 + surface-functionalized BG). Their diameters varied from 110 to 550 nm. BG and SFBG enhanced fiber integrity, hydrophilicity, and hydroxyapatite production. The drug release followed a two-phase model including Fickian diffusion and class-II relaxations that favor the prolonged release of the drug for up to 63 days. Subsequent studies explored bi-layered nanofiber membranes incorporating ion-doped bioactive glasses (SBAg1, SBCe0.5, SBAgCe0.5). Bioactivity, antibiofilm, and antioxidants properties were assessed. The Ca/P ratios (2.06 for Ag1, 1.50 for Ce0.5, 1.80 for AgCe0.5) closely matched that of natural hydroxyapatite, which is 1.67. Ag1 exhibited the maximum inhibition of biofilm at 84% against S. aureus, 86% for E. coli, and 91% for P. aeruginosa, besides, AgCe0.5 also resulted in a substantial inhibition biofilm formation, indicative of silver and cerium synergistic action. Antioxidant activity was greatest in Ce0.5 (87%), followed by AgCe0.5 (70%) and Ag1 (66%), suggesting that co-doping could lead to a synergistic effect of antibiofilm and antioxidant properties. Overall, these findings highlight the potential of doped borosilicate bioactive glasses and multifunctional membranes in addressing the limitations of current regenerative therapies. These outcomes provide more evidence and suggest that these multifunctional nanofiber membranes have potential usage in GBTR applications.

General Summary 

This research focuses on developing advanced materials for guided bone and tissue regeneration (GBTR), particularly targeting issues related to alveolar bone loss from periodontitis. Conventional grafts and non-resorbable membranes have limitations, including immune reactions, infection risks, and the need for secondary surgeries. To overcome these, the study introduces bioresorbable membranes enhanced with mesoporous borosilicate bioactive glass nanoparticles doped with silver and cerium for improved antibacterial and bioactive properties. Electrospun nanofiber membranes incorporating these nanoparticles demonstrated controlled drug release, enhanced bioactivity, biofilm inhibition, and antioxidant effects. The results support their potential use in regenerative dentistry, offering a safer and more effective alternative to traditional methods.

This thesis will be presented to the jury members:

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