Mesoporous Bioactive Glass: Preparation, Characterisation, and Emerging Applications in Regenerative Medicine and Dentistry.

Biomimetic surfaces are increasingly needed to enhance the effectiveness of biomaterials in bone tissue repair. The Layer-by-Layer (LbL) technique is a particularly attractive method due to its versatility and ability to incorporate a wide range of bioactive molecules under mild conditions. While numerous LbL systems have been developed, those integrating glycosaminoglycans (GAG) are often reported to rapidly degrade, which limits their potential in tissue integration. To address this limitation, we investigated the incorporation of ReGeneraTing Agents® (RGTA®) into LbLs. RGTA® are glycanase-resistant analogues of heparan sulfate, designed to protect and stabilize growth factors. To date, their use is restricted to soluble formulations or adsorptions onto biomaterial surfaces. Here, we propose a novel approach to immobilize two RGTA® (OTR4120 and OTR4131) within LbL architectures to produce bone extracellular matrix-like microenvironments. We revealed that OTR4120 potentiated much more in vitro bone formation over OTR4131, with the synthesis of a mature mineralized hydroxyapatite-rich matrix only atop OTR4120 films. Subsequent in vivo translation of OTR4120 LbL films validated the osteogenic potentializing effect. This new strategy aimed at combining the regenerative potential of OTR4120 with the structural and functional advantages of the LbL assemblies, offering a new avenue for the development of biomimetic osteogenic materials.

The regeneration of bone tissue depends on the harmonious interaction between blood vessels and nerve fibers, both essential for various physiological and pathological functions in the skeletal system. The key to mimicking the structure and function of natural bone lies in integrating angiogenesis and neurogenesis processes to prepare vascular-nerve-tissue-engineered bone (TEB). Unlike traditional strategies for constructing vascular nerve TEB (such as adding growth factors or cells to scaffolds or preparing composite scaffolds), this study employs a bottom-up approach, using modular microtissue units to construct novel vascular nerve TEB. Initially, vascular-nerve-bone microtissues composed of bone marrow mesenchymal stem cells, endothelial progenitor cells (EPCs), and Schwann cells (SCs) were generated through three-dimensional coculture in microporous array plates. These vascular-neural-bone microtissues were then encapsulated as modular building blocks within gelatin methacrylate (GelMA) hydrogels to construct large-scale vascular-neural TEB. The microtissue-based vascular-neural-TEB construction protocol demonstrated feasibility at the molecular, cellular, and tissue/organ levels. Research findings indicate that the GelMA/MSC/EPC/SC vascular-neural-TEB possesses concurrent capabilities for angiogenesis, neurogenesis, and osteogenesis during bone repair. These findings provide novel insights for the construction of multifunctional bone grafts and lay the foundation for the clinical treatment of bone defects.

Repairing large bone defects is a significant clinical challenge. In this context, cellulose nanomaterials, such as bacterial nanocellulose (BNC), cellulose nanofibrils (CNF), and cellulose nanocrystals (CNC), have emerged as promising alternatives due to their natural origin and mechanical properties. Particularly noteworthy is their chemical malleability, which thereby confers specific functionalities. This comprehensive literature review evaluates the efficacy of nanocellulose scaffolds for the repair of critical bone defects, with a focus on the impact of surface modifications. The effects of inserting bioactive functional groups and adding metal ions are analyzed invitro and invivo models. The parameters evaluated include material mineralization (production and precipitation of biogenic apatite, Ca/P ratio), cell adhesion and proliferation, bioadsorption, degradation, and toxicity. The results discussed provide valuable insights into the chemical and biological processes of bone formation, supporting a new paradigm: cellulose is no longer just an "eco-friendly filler" but has become a programmable structural scaffold. The trends highlighted in this review open new avenues for the treatment of bone diseases and tissue regeneration.

Injectable composite gels containing magnesium phosphate for bone regeneration: Analysis of hydration and in vivo study.

Innovative P(3HB)/carbon-based material composites for bone tissue regeneration: Biocompatibility, thermo-mechanical, and structural insights

Mesenchymal stem cells (MSCs) are multipotent progenitors that give rise to osteoblasts, which are essential for bone formation, remodeling, and skeletal homeostasis. MicroRNAs (miRNAs), small non-coding RNA molecules, have emerged as critical post-transcriptional regulators of gene expression that fine-tune MSC commitment, osteoblast proliferation, and matrix mineralization. In this review, we first summarize the physiological mechanisms of bone remodeling and the differentiation of MSCs into osteoblasts, with particular attention to the coordinated roles of osteoblasts, osteoclasts, and osteocytes. We then discuss how specific miRNAs regulate osteoblast growth and maturation by targeting key transcription factors such as Runx2 and osterix, as well as major signaling pathways including BMP and Wnt. Building on this mechanistic framework, we examine the contribution of dysregulated miRNAs to metabolic bone diseases, with a focus on osteoporosis, where alterations in age-related, hormonal, and inflammatory environments reshape miRNA networks and favor bone loss. Current and emerging clinical applications of miRNAs are also reviewed, including their use as minimally invasive circulating biomarkers for fracture risk assessment and treatment monitoring, and as therapeutic targets or tools through miRNA mimics and inhibitory agents. Finally, we highlight future perspectives that involve integrated analysis of miRNAs and other non-coding RNAs, advanced profiling approaches such as single-cell RNA sequencing, and miRNA-guided strategies for bone tissue regeneration. A comprehensive understanding of these regulatory networks is expected to support the development of more precise diagnostic tools and targeted therapies for osteoporosis and related skeletal disorders.

Multidrug-resistant bacterial infections pose a significant challenge in bone tissue engineering, primarily due to the formation of biofilms on implant surfaces, which can impede osteointegration. KR-12, a cationic antimicrobial peptide (AMP) with dual osteoinductive and biofilm-inhibitory properties, represents a promising strategy to address this issue. Poly(lactic-co-glycolic acid) (PLGA) electrospun nanofiber (NF) scaffolds offer biocompatibility, tunable morphology, and support for cell adhesion and proliferation, making them ideal for bone regeneration. While cold atmospheric plasma (CAP) treatment has been explored to enhance peptide functionalization, covalent conjugation of KR-12 to PLGA electrospun NFs has not yet been reported. In this study, KR-12 was incorporated into electrospun PLGA NFs to create a dual-functional scaffold that promotes osteogenic differentiation while inhibiting biofilm formation. Scaffold surface properties were characterized by scanning electron microscopy (SEM) and contact angle measurements, and peptide incorporation was confirmed via fluorescein isothiocyanate (FITC) labeling and FTIR spectroscopy. Human bone marrow-derived mesenchymal stem cells cultured on KR-12-functionalized NFs exhibited enhanced alkaline phosphatase (ALP) activity, calcium and collagen deposition, and upregulated expression of collagen type I (COL1), osteopontin (OPN), and osteocalcin (OCN), as well as positive immunofluorescence staining. Antibacterial and biofilm formation inhibition activities were evaluated against multidrug-resistant MRSA and P. aeruginosa, as well as non-MDR E. coli and S. aureus, demonstrating potent inhibition of biofilm formation. KR-12-functionalized PLGA NFs thus provide a dual-functional platform for infection-resistant bone tissue regeneration, combining osteogenic support with potent inhibition of biofilm formation.

3D-printed scaffolds with ROS-clearing capacity for critical-sized bone defect regeneration.

Bioinspired Fabrication Strategies of Biomaterials for Bone Tissue Repair and Regeneration

Magnesium (Mg) biodegradable implants are emerging as a new generation of implantable materials due to their excellent biocompatibility, mechanical properties similar to bone, and the potential to release bioactive byproducts like magnesium ions (Mg2+) and hydrogen gas (H2). This review article investigates the synergistic effects of these two corrosion products on bone and vascular tissue regeneration, immune modulation, and the reduction of oxidative stress. Under controlled conditions, H2 demonstrates anti-inflammatory effects by inhibiting the NF-κB pathway and activating Keap1-Nrf2. Concurrently, Mg2+ activates the Wnt and TRPM7 pathways to stimulate osteogenesis and angiogenesis. However, excessive release of these compounds can lead to detrimental effects. The article further addresses the challenges in modeling, clinical translation, and real-time monitoring. It also proposes future research directions, including reactive design, implantable sensors, and trials in high-risk populations. This comprehensive review provides a foundation for developing smart and personalized implants for tissue regeneration.

This study focuses on the fabrication and comprehensive characterization of electrospun nanofibrous scaffolds composed of polylactic acid (PLA), chitosan (CH), gelatin methacryloyl (GelMA), and varying concentrations of hydroxyapatite (HAP) nanoparticles (0.1, 0.3, and 0.5% w/v) for potential applications in bone tissue engineering. Unlike previous studies utilizing binary or ternary systems, this work introduces a novel quadri-composite scaffold designed to overcome individual material limitations through synergistic effects: PLA provides the mechanical backbone, chitosan ensures hydrophilicity and antimicrobial potential, GelMA enhances cell adhesion via RGD motifs, and HAP serves as the osteoconductive mineral phase. The structural, thermal, mechanical, swelling, degradation, and biological properties of the nanofibers were investigated using SEM, FT-IR, DSC, and tensile testing. Among the tested formulations, the nanofibers containing 0.3% HAP exhibited the most balanced properties, with a tensile strength of 0.50 ± 0.18 MPa and elongation at break of 14.82 ± 6.93%, indicating optimal mechanical flexibility. These fibers also demonstrated improved thermal stability, controlled swelling behavior, and a degradation profile suitable for bone healing. In vitro biocompatibility studies using human osteoblast (hFOB) cells showed that while lower HAP content supported initial attachment, significantly higher cell viability was observed on the 0.3% HAP scaffolds at day 7 (p < 0.0365), supporting their superior long-term osteoblast proliferation. Overall, PLA/CH/GelMA nanofibers containing 0.3% HAP offer a promising strategy for bone regeneration due to their ECM-mimetic structure, tunable biodegradability, mechanical resilience, and bioactivity. Future studies will focus on in vivo evaluation of these scaffolds for bone defect repair.

With the growing population and increased life expectancy, there has been a significant rise in orthopedic fractures and pathologies, leading to a heightened demand for effective orthopedic solutions. Bone tissue engineering (BTE) has emerged as a promising approach, employing scaffolds to regenerate bone tissue. This review highlights that successful material design for BTE requires a comprehensive understanding of the composition, structure, and biomechanics of natural bone. It also necessitates the careful selection of biomimetic natural or tunable synthetic materials, including polymers, bioceramics, metals, and composites. Furthermore, optimizing the physical, mechanical, and chemical properties of scaffolds is crucial, as these factors influence cell adhesion, proliferation, and differentiation. Special attention is given to the interaction between scaffolds and the host immune system, including the strategic incorporation of bioactive molecules and immunoregulatory cells. This holistic approach aims to engineer scaffolds that not only meet structural and functional demands but also foster an immune-compatible environment to enhance bone regeneration effectively. Careful selection of effective immunomodulation strategies for 3D scaffolds is crucial for creating a supportive immune microenvironment without negative effects. Various approaches can enhance the immune response, including incorporating smart nanomaterials into the surface of scaffolds, which contribute to immunomodulation, angiogenesis, and osteogenesis. Using stem cells for regenerating damaged bone tissue also improves the scaffold's immune response. Moreover, ionic and molecular doping are effective methods used to enhance immune response of scaffold in (BET), where specific ions like magnesium, zinc, and silicon are added to improve bioactivity and immune modulation capabilities. Finally, Wnt/β-catenin signaling pathway can be activated by integrating lithium into the scaffold surface, as lithium has anti-inflammatory properties and promotes bone formation by activating these pathways.

Three-dimensional (3D) (bio)printing has emerged as a relevant approach in bone tissue regeneration, enabling the precise fabrication of biomimetic scaffolds. The incorporation of extracellular vesicles (EVs) into 3D-(bio)printed constructs represents a promising cell-free strategy to enhance bone regeneration. EVs, as natural mediators of intercellular communication, contribute to osteogenesis, angiogenesis, and immune modulation. This review aims to evaluate current evidence on the use of EVs-enhanced 3D (bio)printing for bone regeneration. The literature search was conducted across different databases. In vitro and invivo studies using EVs-containing (bio)printed constructs to assess osteogenic differentiation and/or bone regeneration were included. Out of 552 articles, 35 met the inclusion criteria. Most EVs were derived from bone marrow mesenchymal stem cells and were incorporated into scaffolds either before or after printing. Extrusion-based bioprinting was the most commonly used method. Nearly all studies reported enhanced osteogenic differentiation and bone formation in EV-treated groups, underscoring their therapeutic potential. EVs-based bioinks retain the regenerative benefits of stem cells while avoiding challenges associated to cell-based therapies. Despite encouraging results, standardization in EV isolation, storage, and delivery remains crucial for clinical translation. This review highlights the growing significance of EVs in regenerative medicine and identifies key areas for future research and development.

Abstract to be supplied.

Bone regeneration remains a major clinical challenge due to the limited healing capacity of large bone defects and the limitations of conventional grafting or cell-based therapies. Exosomes, nanosized extracellular vesicles secreted by diverse cell types, have emerged as promising cell-free mediators of osteogenesis, angiogenesis, and immune regulation. However, the therapeutic efficacy of native exosomes is constrained by low yield, rapid clearance, and limited targeting. Because effective bone regeneration is inherently multi-factorial-requiring biomechanical stability, vascularization, and an instructive ECM and cellular microenvironment-engineered exosomes should be regarded as enabling components within integrated regenerative systems rather than a standalone solution. Recent advances in engineered exosomes (EExos) have opened new frontiers in bone tissue regeneration by enabling precise design, biofunctionalization, and targeted delivery. Engineering strategies-ranging from genetic modification of donor cells to chemical conjugation, hybrid nanocarrier formation, and controlled cargo loading-have been employed to enhance the osteoinductive and osteoconductive potential of exosomes. Furthermore, incorporation of EExos into smart delivery systems, such as hydrogel scaffolds, 3D-printed matrices, and bone-targeting ligands, offers sustained release and localized therapeutic effects within the bone microenvironment. This review comprehensively summarizes the latest developments in the design, delivery, and functional optimization of EExos for bone regeneration. Mechanistic insights into their roles in promoting bone remodeling, angiogenesis, and immune modulation are discussed alongside current translational progress, manufacturing challenges, and regulatory considerations. Finally, emerging directions-such as AI-assisted exosome engineering, CRISPR-based programming, and bioprinting-integrated therapies-are highlighted as transformative pathways toward personalized and clinically translatable bone regenerative medicine.

Polymeric biomaterials and their composites have been extensively explored for orthopaedic applications; however, their inadequate mechanical performance significantly restricts their use in load‐bearing environments. Metallic biomaterials, by contrast, offer superior mechanical strength and structural stability. Among them, magnesium (Mg) has emerged as a particularly attractive candidate for temporary orthopaedic implants owing to its elastic modulus and density being close to those of natural bone, thereby minimising stress shielding. In addition, Mg inherently fulfils two critical requirements for orthopaedic implants—biocompatibility and biodegradability. In this study, a bioactive magnesium‐alloy‐based nanocomposite scaffold was engineered to overcome the limitations of conventional biomaterials while closely replicating the porous microarchitecture of human bone. A novel bioactive glass–ceramic, nano‐fluorcanasite (n‐FC), was incorporated into the Mg‐alloy matrix to enhance osteogenic activity and accelerate bone tissue regeneration. The introduction of an interconnected porous structure was designed to promote efficient nutrient diffusion, facilitate metabolic waste removal and reduce implant density. Furthermore, the controlled addition of selected alloying elements in specific weight fractions effectively moderated the degradation kinetics of the Mg‐based scaffold. The nanocomposite scaffolds were fabricated using a powder metallurgy route followed by sintering. Tailored porosity was achieved through the controlled incorporation of carbamide particles as a space‐holding agent. The in vitro degradation behaviour of the scaffolds was systematically evaluated using a weight‐change method after immersion in phosphate‐buffered saline (PBS) for predetermined durations. The results demonstrate that, compared with unalloyed magnesium, the degradation rate of the nanocomposite scaffolds can be precisely and consistently regulated, highlighting their potential as mechanically competent, bioactive and biodegradable candidates for orthopaedic implant applications.

Bone tissue regeneration for large defects presents a significant challenge, demanding scaffolds that combine robust mechanical support alongside a bioactive environment. Hydrogels represent a promising solution for bone regeneration due to their biocompatibility, tunable properties, and crosslinked three-dimensional (3D) networks mimicking the natural extracellular matrix (ECM). However, their mechanical properties remain suboptimal for restoring bone defects effectively. This study introduces a novel bilayer laminate scaffold, integrating a biostable fiber-reinforced composite (FRC) with a biodegradable, 3D-printed hyaluronic acid (HA)-based hydrogel. To enhance bioactivity, bioactive glass (BAG) was incorporated into the hydrogel layer. Comprehensive characterization confirmed the scaffold's chemical and morphological properties, as well as its controlled degradation, sustained ion release, and bioactivity. Additionally, the study revealed that the BAG-induced alkaline pH shift (up to 9.24) affected hydrazone crosslinking efficiency, resulting in reduced hydrogel stiffness (86 ± 8 Pa versus 150 ± 4 Pa in control). The system showed excellent cytocompatibility, supporting high viability and proliferation of human bone marrow stem cells (BMSCs) embedded within the hydrogel component. The developed scaffolds promoted osteogenic differentiation, as evidenced by increased ALP activity and upregulated expression of osteogenic marker genes. Nevertheless, BAG incorporation did not enhance early osteogenic differentiation compared to control scaffolds. In conclusion, this bilayer scaffold offers a promising platform for bone tissue engineering (TE), providing some insights into the chemical interplay between inorganic fillers and hydrogel matrix foroptimizing future scaffold designs.

Antheraea mylitta silk sericin grafted polyaniline/Polyvinyl Alcohol based scaffolds as emerging biomaterials for bone tissue regeneration

The development of biomaterials capable of promoting bone tissue regeneration while simultaneously exhibiting antimicrobial activity is a highly relevant and timely topic, both in healthcare and economic terms. The present study aimed to produce scaffolds based on a composite of hydroxyapatite (HA) and calcium carbonate (CaCO3) loaded with 2.5 and 5wt% of gallium, known for its antimicrobial activity and only recently investigated for its potential to modulate bone metabolism. The characterization of the scaffolds, performed by X-ray powder diffraction, field emission scanning electron microscopy, and attenuated total reflectance Fourier transform infrared spectroscopy, shows a homogeneous distribution of gallium at the nanoscale and presence of tetracalcium diphosphate oxide beside HA and CaO. In vitro bioactivity test proved the growth of the new HA on the scaffolds after three days. Scaffolds were tested for their antibacterial activity against the gram-positive Staphylococcus aureus and Staphylococcus epidermidis, as well as for their ability to inhibit osteoclastogenesis. The results showed that released gallium interferes with the differentiation of precursor cells into mature bone-resorbing osteoclasts and showed moderate antibacterial effects against the tested strains.