Maria Inés Alvarez Echazú

Mesoporous silica particles (MSPs) are widely investigated in biomaterials due to their high surface area, tunable porosity, and potential for chemical functionalization. In this study, MSPs were modified with different anionic functional groups (carboxyl, phosphate, and sulfonate) and incorporated into Type I collagen hydrogels to evaluate their structural, biological, and drug‐loading behavior in the context of bone tissue engineering. A comprehensive set of analyses including FTIR, SEM/EDS, zeta potential, porosity, drug incorporation, cytocompatibility, in vitro mineralization, and short‐term in vivo response was conducted. While calcium phosphate deposition was not observed in functionalized composites, the study reveals key insights into how the surface chemistry of MSPs modulates particle–collagen interactions, drug loading efficiency, and biological responses. Phosphate‐modified MSPs showed higher cytotoxicity and interfered with collagen self‐assembly, whereas MSPs bearing hydroxyl or carboxyl groups maintained better cytocompatibility and distribution within the matrix. Interestingly, MSPs functionalized with sulfonate groups exhibited enhanced simvastatin loading, likely due to their reduced surface polarity resulting from the formation of siloxane bridges in the oxidation process. In vivo implantation of unloaded composites in a rat tibial defect model confirmed good biocompatibility without evidence of acute inflammation. However, no significant bone formation or biomineralization was detected after 14 days. These findings suggest that excessive negative surface charge may impair ion‐mediated mineralization and that the interplay between MSP chemistry and the biological environment must be carefully balanced. This work contributes to understanding the structure–function relationships in hybrid silica‐collagen systems and identifies key parameters to optimize in future designs of osteoinductive and drug‐eluting scaffolds.

Bone substitutes for tissue regeneration should provide an appropriate environment for cell attachment, differentiation, proliferation, and migration. 3D structure, degradability, swelling, porosity, and cytotoxicity have been highlighted as key points in their design. For this research, mesoporous silica‐biopolymer composites were synthesized from mesoporous silica (Mes‐Si) particles combined with either collagen (C/Mes‐Si) or chitosan (CS/Mes‐Si). The composites were evaluated for tissue engineering purposes, as bone substitutes intended to imitate features of the natural bone matrix, thereby providing an appropriate biochemical environment for bone repair. Physicochemical‐biological evaluation was performed to identify the features that would be useful for bone tissue engineering. For the Mes‐Si particles, the specific surface area was 750.95 m²/g and the average pore size was 3.47 nm. SEM images showed that Mes‐Si particles were distributed within the chitosan (CS) or collagen (C) matrix. Both composites swelled rapidly and had low cytotoxicity. Histologically, no acute inflammatory infiltrate or giant multinucleated cell was observed 14 days after implantation. In C/Mes‐Si, newly woven bone tissue and areas of osseointegration at the C/Mes‐Si‐tissue interface were observed. In CS/Mes‐Si, only reparative granulation tissue was observed. The physicochemical properties and biocompatibility of both composites were adequate for a bone scaffold. Moreover, Mes‐Si particles have a tunable surface area for chemical modifications and anchoring bioactive materials, which may enhance composite bioactivity or the delivery of bioactive materials.

Bone defects have prompted the development of biomaterial-based bone substitutes for restoring the affected tissue completely. Although many biomaterials have been designed and evaluated, the combination of properties required in a biomaterial for bone tissue engineering still poses a challenge. In this study, a chitosan–silica-based biocomposite was synthetized, and its physicochemical characteristics and biocompatibility were characterized, with the aim of exploring the advantages and drawbacks of its use in bone tissue engineering. Dynamic light scattering measurements showed that the mean hydrodynamic size of solid silica particles (Sol-Si) was 482 ± 3 nm. Scanning electron microscopy of the biocomposite showed that Sol-Si were homogenously distributed within the chitosan (CS) matrix. The biocomposite swelled rapidly and was observed to have no cytotoxic effect on the [3T3] cell line within 24 h. Biocompatibility was also analyzed in vivo 14 days post-implant using a murine experimental model (Wistar rats). The biocomposite was implanted in the medullary compartment of both tibiae (n = 12). Histologically, no acute inflammatory infiltrate or multinucleated giant cells associated to the biocomposite were observed, indicating good biocompatibility. At the tissue–biocomposite interface, there was new formation of woven bone tissue in close contact with the biocomposite surface (osseointegration). The new bone formation may be attributed to the action of silica. Free silica particles originating from the biocomposite were observed at the tissue–biocomposite interface. According to our results, the biocomposite may act as a template for cellular interactions and extracellular matrix formation, providing a structural support for new bone tissue formation. The CS/Sol-Si biocomposite may act as a Si reservoir, promoting new bone formation. A scaffold with these properties is essential for cell differentiation and filling a bone defect.

Skin tissue engineering and regeneration aim at repairing defective skin injuries and progress in wound healing. Until now, even though several developments are made in this field, it is still challenging to face the complexity of the tissue with current methods of fabrication. In this review, short, state-of-the-art on developments made in skin tissue engineering using 3D bioprinting as a new tool are described. The current bioprinting methods and a summary of bioink formulations, parameters, and properties are discussed. Finally, a representative number of examples and advances made in the field together with limitations and future needs are provided.

Smart or stimuli-responsive materials are an emerging class of materials used for tissue engineering and drug delivery. A variety of stimuli (including temperature, pH, redox-state, light, and magnet fields) are being investigated for their potential to change a material’s properties, interactions, structure, and/or dimensions. The specificity of stimuli response, and ability to respond to endogenous cues inherently present in living systems provide possibilities to develop novel tissue engineering and drug delivery strategies (for example materials composed of stimuli responsive polymers that self-assemble or undergo phase transitions or morphology transformations). Herein, smart materials as controlled drug release vehicles for tissue engineering are described, highlighting their potential for the delivery of precise quantities of drugs at specific locations and times promoting the controlled repair or remodeling of tissues.

Skin wound healing presents a unique challenge because of its complex healing process. Herein, we developed a hydrophobic wound dressing to incorporate simvastatin, which has potential application in the treatment of ulcers and prevention of wound infection. For that matter, collagen hydrogels were grafted with dodecenylsuccinic anhydride (DDSA). The chemical modification was confirmed by FTIR and solid state ¹³C‐NMR spectroscopies while the ultrastructure was observed by scanning electron microscope (SEM) images. In contact angle measurements, a higher water droplet angle in DDSA‐collagen gels was observed. This was consistent with the swelling assay, in which water absorption was 5.2 g/g for collagen and 1.9 g/g for DDSA‐collagen. Additionally, viability and adhesion studies were performed. Cell adhesion decreased ~11% in DDSA‐collagen and the number of viable cells showed a tendency to decrease as DDSA concentration increased but it was only significantly lower above concentrations of 12%. Modified gels were loaded with simvastatin showing higher adsorption capacity and lower release. Lastly, the antimicrobial and anti‐inflammatory activity of DDSA‐collagen materials were assessed. DDSA‐collagen hydrogels, either unloaded or loaded with simvastatin showed sustained antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus for 72 hr probably due to the hydrophobic interaction of DDSA chains with bacterial cell walls. The antimicrobial activity was stronger against S. aureus. Collagen hydrogels also presented a prolonged antibacterial activity when they were loaded with simvastatin, confirming the antimicrobial properties of statins. Finally, it was observed that these materials can stimulate resident macrophages and promote an M2 profile which is desirable in wound healing processes.

Different materials have distinct surface and bulk characteristics; each of them potentially useful for the treatment of a particular wound or disease. By reviewing those materials that have reached a clinical stage the reader will have a broad panorama of the possibilities a particular material can offer, regarding its ability to support fast tissue regeneration. This review covers the most recent advances made towards the development of biomaterials aimed to support regenerative processes. Indeed, we highlight key examples, from basic research to clinical trials, of biomaterials for a specific biomedical application. In this context, the focus is made on collagen, chitosan and silica which are key representatives of a protein, a polysaccharide and an inorganic material usually employed as biomaterials. Particularly, this review article presents an overview of their potential therapeutics in the treatment of disorders within the oral mucosa and tooth supporting tissues. Finally, the importance of in vivo and in vitro studies, clinical evidence studies, systematic reviews and meta-analyses as an adequate guidance for biomaterial design and development is highlighted.

The impact of nanomaterials in the environment and human health is a cause of big concern and even though intensive studies are currently being carried out, there is still a lot to elucidate. The development of validated methods for the characterization and quantification of nanomaterials and their impact on the environment should be encouraged to achieve a proper, safe, and sustainable use of nanoparticles (NPs). Recently, CE emerged as a well‐adapted technique for the analysis of environmental samples. This review presents the application of NPs together with CE systems for environmental pollutants analysis, as well as the application of CE techniques for the analysis of various types of NPs.