The main objective was to produce 3D printable hydrogels based on GelMA and hydroxyapatite doped with cerium ions with potential application in bone regeneration. The first part of the study regards the substitution of Ca²⁺ ions from hydroxyapatite structure with cerium ions (Ca_10-xCe_x(PO₄)₆(OH)₂, xCe = 0.1, 0.3, 0.5). The second part followed the selection of the optimal concentration of HAp doped, which will ensure GelMA-based scaffolds with good biocompatibility, viability and cell proliferation. The third part aimed to select the optimal concentrations of GelMA for the 3D printing process (20%, 30% and 35%). In vitro biological assessment presented the highest level of cell viability and proliferation potency of GelMA-HC5 composites, along with a low cytotoxic potential, highlighting the beneficial effects of cerium on cell growth, also supported by Live/Dead results. According to the 3D printing experiments, the 30% GelMA enriched with HC5 was able to generate 3D scaffolds with high structural integrity and homogeneity, showing the highest suitability for the 3D printing process. The osteogenic differentiation experiments confirmed the ability of 30% GelMA-3% HC5 scaffold to support and efficiently maintain the osteogenesis process. Based on the results, 30% GelMA-3% HC5 3D printed scaffolds could be considered as biomaterials with suitable characteristics for application in bone tissue engineering.

As bone diseases and defects are constantly increasing, the improvement of bone regeneration techniques is constantly evolving. The main purpose of this scientific study was to obtain and investigate biomaterials that can be used in tissue engineering. In this respect, nanocomposite inks of GelMA modified with hydroxyapatite (HA) substituted with Mg and Zn were developed. Using a 3D bioprinting technique, scaffolds with varying shapes and dimensions were obtained. The following analyses were used in order to study the nanocomposite materials and scaffolds obtained by the 3D printing technique: Fourier transform infrared spectrometry and X-ray diffraction (XRD), scanning electron microscopy (SEM), and micro-computed tomography (Micro-CT). The swelling and dissolvability of each scaffold were also studied. Biological studies, osteopontin (OPN), and osterix (OSX) gene expression evaluations were confirmed at the protein levels, using immunofluorescence coupled with confocal microscopy. These findings suggest the positive effect of magnesium and zinc on the osteogenic differentiation process. OSX fluorescent staining also confirmed the capacity of GelMA-HM5 and GelMA-HZ5 to support osteogenesis, especially of the magnesium enriched scaffold.

Bioglass (BG) is a class of biomaterials increasingly approached in biomedical applications, such as in regeneration of hard tissues, due to the properties of bioactivity, osteoinductivity, osteoconductivity, but also the high rate of biodegradation, both in vitro and in vivo. The present paper addresses the obtaining of bioglasses from the ZnO(MgO)-CaO-SiO₂-P₂O₅ system by the sol-gel method and the use of a surfactant to ensure a specific surface or high open porosity, starting from S53P4 bioglass (53% SiO₂, 23% Na₂O, 20% CaO, 4% P₂O₅), also known as BoneAlive^®. The precursor powders were analyzed from the phase composition point of view by complex thermal analysis and X-ray diffraction, the vitreous powders were assessed from the compositional point of view by X-ray diffraction, morpho-structural by scanning electron microscopy, specific surface area and the pore size dimension by the Brunauer–Emmett–Teller (BET) analysis, dispersion by laser granulometry, and also cell biology and surface mineralization tests were performed by immersion in SBF (simulated body fluid). The system proposed in this paper ZnO(MgO)-CaO-SiO₂-P₂O₅ was successfully obtained by sol-gel method. The results showed the higher interaction between the samples and the SBF medium for samples containing magnesium (M2) and the lowest degree of mineralization after immersion in SBF was noticed for samples containing zinc (M1). The results also prove that by incorporating different ionic species in bioglass composition—Zn²⁺ and Mg²⁺, biocompatibility and antibacterial properties will be significantly enhanced.

In this paper, ZnO and Co²⁺/Mg²⁺-doped ZnO thin films on TiAlV alloy substrates were obtained. The films were deposited by spin coating of sol-gel precursor solutions and thermally treated at 600 °C for 2 h, in air and slow cooled. The doping ions concentration was 1.0 mol%. The study’s aim was to obtain implantable metallic materials with improved biocompatibility and antibacterial qualities. The characteristics of the thin films were assessed from the point of view of microstructure, morphology, wetting properties, antibacterial activity and biological response in the presence of amniotic fluid stem cells (AFSC). The results proved that all deposited samples were nanostructured, suggesting a very good antibacterial effect and proving to be suitable supports for cellular adhesion and proliferation. All properties also depended on the doping ion nature.

Mesoporous bioactive glass nanoparticles (MBGNs) are widely recognized for their ability to bond to hard tissue, while the ions released from the BG structure enhance specific cellular pathways. In this study, the SiO₂-P₂O₅-CaO-MgO-ZnO system was used to successfully synthesize MBGNs by a microemulsion-assisted sol-gel method. The MBGNs calcinated at 600 °C/3 h had a typical phosphosilicate structure together with a poorly crystalline hydroxyapatite (HAp). The addition of ZnO not only led to a higher degree of crystallinity of HAp but also induced a higher porosity of the particles. All MBGNs had a mesoporous structure with an interconnected network of slit shape pores. For each type of composition, two families of highly dispersed spherical nanoparticles could be identified. In vitro tests in simulated body fluid (SBF) proved that after only 3 days of immersion all the materials were covered with a layer of brushite whose degree of crystallinity decreases in the presence of Zn²⁺. The antibacterial assay revealed a strong inhibitory effect for all samples after 40 h of contact. Simultaneously, MBGNs did not increase the intracellular oxidative stress while it stimulated the cell proliferation process.

Bioactive glasses in the SiO₂-CaO-P₂O₅ system represent emerging materials for hard-tissue-regeneration applications. This article focuses on the synthesis, characterization, and biological interaction of glasses doped with Mg²⁺ and/or Zn²⁺, with an emphasis on their effects on biomineralization, antibacterial behavior, and interactions with preosteoblasts from the MC3T3-E1 cell line. The bioglasses were synthesized using the sol-gel method, and the vitreous nature remained predominant even after thermal treatment at 600 °C for 2 h. From an in vitro perspective, the synthesized bioglasses demonstrated strong cell adhesion and proliferation (notably in the case of Mg²⁺ doping), low cytotoxicity, and antibacterial properties (especially in Zn²⁺-doped samples). Additionally, the simultaneous doping with Mg²⁺ and Zn²⁺ of the bioactive glass matrix is a prospective strategy for developing biomaterials with a “dual” biological characteristics–both osteoinductive and antibacterial.