The role of lithium in the osteogenic bioactivity of clay nanoparticles

Rapid closure and hemostasis of ruptured soft tissues using a modified human tropoelastin-based sealant in preclinical models

Treatment of injuries to soft elastic organs is often hindered by challenging anatomical features and limitations of existing sealant materials, which may lack adequate tissue adhesion, elasticity, biocompatibility, and effective hemostatic properties. To address these clinical challenges, we developed an injectable elastic sealant formulated with methacryloyl-modified human recombinant tropoelastin (MeTro) and Laponite silicate nanoplatelets (SNs). We optimized the hydrogel formulation for mechanical properties, adhesion, biocompatibility, and hemostatic properties and used visible light for cross-linking to improve safety. MeTro/SN hydrogels had increased tissue adhesion strength and burst pressure in vitro and ex vivo compared with MeTro alone or commercial sealants. The addition of SNs to the hydrogels facilitated faster blood clotting in vitro without increasing hemolysis. Applied to incisional injuries on rat lungs or aortas, MeTro/SN had burst pressures comparable to those of native tissue and greater than those of MeTro after a 7-day in vivo application. On porcine lungs, MeTro/SN also supported effective lung sealing and burst pressure similar to native lung 14 days after injury sealing. In a rodent tail hemostasis model, MeTro/SN reduced bleeding compared with MeTro. In an injured porcine lung model, early hemostasis was better than the tested commercial sealants. The results demonstrated that MeTro/SN provided effective tissue sealing and promoted hemostasis in a time frame that minimized blood loss without causing a major inflammatory response. These findings highlight the translational potential of our engineered sealant with biomimetic mechanics, durable tissue adhesion, and rapid hemostasis as a multipronged approach for the sealing and repair of traumatic injuries to soft organs.

The multifaceted roles of extracellular vesicles in osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a severe disease characterized by bone tissue necrosis due to vascular impairment, often leading to joint collapse and requiring surgical intervention. Extracellular vesicles (EVs) serve as crucial mediators of intercellular communication, influencing osteogenesis, angiogenesis, and immune regulation. This review summarizes the dual role of EVs in both the pathogenesis of ONFH and post-necrosis bone repair, highlighting the impact of various EV-mediated signaling pathways on bone regeneration and the potential crosstalk among these pathways. Additionally, EVs hold promise as diagnostic biomarkers or contrast agents to complement conventional imaging techniques for ONFH detection. By elucidating the role of EVs in osteonecrosis and addressing the current challenges, we aspire to establish a foundation for the timely identification and treatment of ONFH. The translational potential of this article: This review comprehensively discusses the role of EVs in ONFH, providing innovative and promising insights for its diagnosis and treatment, which also establishes a theoretical foundation for the future clinical application of EVs in ONFH.

Pre-vascularized bioactive scaffold driven by bidirectional cellular communication enhances bone repair

Bone, characterized by its extensive vascularization, relies on angiogenesis as a fundamental prerequisite for successful regeneration. However, conventional bone implant materials often exhibit limitations such as insufficient vascularization, leading to cellular necrosis and delayed host tissue infiltration. To address these challenges, this study integrates 3D printing and photo-crosslinking technologies to develop a pre-vascularized bioactive scaffold driven by endothelial cells (ECs)/ bone marrow mesenchymal stem cells (BMSCs) bidirectional cellular communication, aiming to facilitate the rapid reconstruction of vascular and bone networks. The results demonstrate that the scaffold not only enhances the vascularization of ECs, but also activates BMP-2 and TGF-β signaling of BMSCs through EC-secreted growth factors, thus synergistically enhancing the osteogenic differentiation of BMSCs. In a rat femoral defect model, this bioactive pre-vascularized scaffold exhibited robust matrix deposition and osteoinductive capacity, offering a promising strategy to enhance bone regeneration and address bone defects.

In Situ Printing of Polylactic Acid/Nanoceramic Filaments for the Repair of Bone Defects Using a Portable 3D Device

In situ 3D printing is attractive for the direct repair of bone defects in underdeveloped countries and in emergency situations. So far, the lack of an interesting method to produce filament using FDA-approved biopolymers and nanoceramics combined with a portable strategy limits the use of in situ 3D printing. Herein, we investigated the osseointegration of new nanocomposite filaments based on polylactic acid (PLA), laponite (Lap), and hydroxyapatite (Hap) printed directly at the site of the bone defect in rats using a portable 3D printer. The filaments were produced using a single-screw extruder (L/D = 26), without the addition of solvents that can promote the toxicity of the materials. In vitro performance was evaluated in the cell differentiation process with mesenchymal stem cells (MSC) by an alkaline phosphatase activity test and visualization of mineralization nodules; a cell viability test and total protein dosage were performed to evaluate cytotoxicity. For the in vivo analysis, the PLA/Lap composite filaments with a diameter of 1.75 mm were printed directly into bone defects of Wistar rats using a commercially available portable 3D printer. Based on the in vitro and in vivo results, the in situ 3D printing technique followed by rapid cooling proved to be promising for bone tissue engineering. The absence of fibrous encapsulation and inflammatory processes became a good indicator of effectiveness in terms of biocompatibility parameters and bone tissue formation, and the use of the portable 3D printer showed a significant advantage in the application of this material by in situ printing.

LAPONITE® nano-silicates potentiate the angiogenic effects of FG-4592 and osteogenic effects of BMP-2

LAPONITE®-based drug delivery systems offer many advantages due to the unique ionic and physical properties of LAPONITE®. The high ionicity and large surface area of LAPONITE® nanoparticles enable the intercalation and dissolution of biomolecules. In this study, we explored the potential of LAPONITE® as a carrier for FG-4592 to support angiogenesis and as a carrier for bone morphogenic protein-2 (BMP-2) to support osteogenesis. Interestingly, we found that LAPONITE® promoted the FG-4592 induced upregulation of vascular endothelial growth factor (VEGF) gene expression of human umbilical cord endothelial cells (HUVECs). Additionally, we observed that LAPONITE® could provide a sustained release of BMP-2 and significantly potentiate the osteogenic effects of BMP-2 on adipose derived mesenchymal stem cells (AMSCs). Overall, current findings on the LAPONITE®-drug/protein model system provide a unique way to potentiate the angiogenic activities of FG-4592 on HUVECs and osteogenic effects of BMP-2 on AMSCs for tissue engineering application. Future studies will be directed towards gaining a deeper understanding of these effects on a co-culture system of HUVECs and AMSCs.

Highly disordered and resorbable lithiated nanoparticles with osteogenic and angiogenic properties

In this study, we have developed unique bioresorbable lithiated nanoparticles (LiCP, d50 = 20 nm), demonstrating a versatile material for bone repair and regeneration applications. The LiCPs are biocompatible even at the highest concentration tested (1000 μg mL-1) where bone marrow derived mesenchymal stem cells (BM-MSCs) maintained over 90% viability compared to the control. Notably, LiCP significantly enhanced the expression of osteogenic and angiogenic markers in vitro; collagen I, Runx2, angiogenin, and EGF increased by 8-fold, 8-fold, 9-fold, and 7.5-fold, respectively. Additionally, LiCP facilitated a marked improvement in tubulogenesis in endothelial cells across all tested concentrations. Remarkably, in an ectopic mouse model, LiCP induced mature bone formation, outperforming both the control group and non-lithiated nanoparticles. These findings establish lithiated nanoparticles as a highly promising material for advancing bone repair and regeneration therapies, offering dual benefits in osteogenesis and angiogenesis. The results lay the groundwork for future studies and potential clinical applications, where precise modulation of lithium release could tailor therapeutic outcomes to meet specific patient needs in bone and vascular tissue engineering.

Laponite nanoclay loaded microgel suspensions as supportive matrices for osteogenesis

Microscale carriers have emerged as promising materials for nurturing cell growth and as delivery vehicles for regenerative therapies. Carriers based on hydrogels have proved advantageous, where "microgels" can be formulated to have a broad range of properties to guide the behavior of adherent cells. Here we demonstrate the fabrication of osteogenic microgels through incorporation of laponite nanoclays. Forming a jammed suspension provides a scaffolding where cells can adhere to the surface of the microgels, with pathways for migration and proliferation fostered by the interstitial volume. By varying the content and type of laponite-RD and XLG-the degree of osteogenesis can be tuned in embedded populations of adipose derived stem cells (ADSCs). The nano- micro-structured composite materials enhance osteogenesis at the transcript and protein level, leading to increased deposition of bone minerals and an increase in the compressive modulus of the assembled scaffold. Together, these microgel suspensions are promising materials for encouraging osteogenesis with scope for delivery via syringe injection and stabilization to bone-mimetic mechanical properties after matrix deposition.

Nanoclay Hydrogel Microspheres with a Sandwich-Like Structure for Complex Tissue Infection Treatment

Addressing complex tissue infections remains a challenging task because of the lack of effective means, and the limitations of traditional bioantimicrobial materials in single-application scenarios hinder their utility for complex infection sites. Hence, the development of a bioantimicrobial material with broad applicability and potent bactericidal activity is necessary to treat such infections. In this study, a layered lithium magnesium silicate nanoclay (LMS) is used to construct a nanobactericidal platform. This platform exhibits a sandwich-like structure, which is achieved through copper ion modification using a dopamine-mediated metallophenolic network. Moreover, the nanoclay is encapsulated within gelatin methacryloyl (GelMA) hydrogel microspheres for the treatment of complex tissue infections. The results demonstrate that the sandwich-like micro- and nanobactericidal hydrogel microspheres effectively eradicated Staphylococcus aureus (S. aureus) while exhibiting excellent biocompatibility with bone marrow-derived mesenchymal stem cells (BMSCs) and human umbilical vein endothelial cells (HUVECs). Furthermore, the hydrogel microspheres upregulated the expression levels of osteogenic differentiation and angiogenesis-related genes in these cells. In vivo experiments validated the efficacy of sandwich-like micro- and nanobactericidal hydrogel microspheres when injected into deep infected tissues, effectively eliminating bacteria and promoting robust vascular regeneration and tissue repair. Therefore, these innovative sandwich-like micro- and nanobacteriostatic hydrogel microspheres show great potential for treating complex tissue infections.

Nanoclay-Modified Hyaluronic Acid Microspheres for Bone Induction by Sustained rhBMP-2 Delivery

Microspheres (MSs) are ideal candidates as biological scaffolds loading with growth factors or cells for bone tissue engineering to repair irregular alveolar bone defects by minimally invasive injection. However, the high initial burst release of growth factor and low cell attachment limit the application of microspheres. The modification of microspheres often needs expensive experiments facility or complex chemical reactions, which is difficult to achieve and may bring other problems. In this study, a sol-grade nanoclay, laponite XLS is used to modify the surface of MSs to enhance its affinity to either positively or negatively charged proteins and cells without changing the interior structure of the MSs. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is used as a representation of growth factor to check the osteoinduction ability of laponite XLS-modified MSs. By modification, the protein sustained release, cell loading, and osteoinduction ability of MSs are improved. Modified by 1% laponite XLS, the MSs can not only promote osteogenic differentiation of MC3T3-E1 cells by themselves, but also enhance the effect of the rhBMP-2 below the effective dose. Collectively, the study provides an easy and viable method to modify the biological behavior of microspheres for bone tissue regeneration.

Laponite for biomedical applications: An ophthalmological perspective

Clay minerals have been applied in biomedicine for thousands of years. Laponite is a nanostructured synthetic clay with the capacity to retain and progressively release drugs. In recent years there has been a resurgence of interest in Laponite application in various biomedical areas. This is the first paper to review the potential biomedical applications of Laponite in ophthalmology. The introduction briefly covers the physical, chemical, rheological, and biocompatibility features of different routes of administration. After that, emphasis is placed on 1) drug delivery for antibiotics, anti-inflammatories, growth factors, other proteins, and cancer treatment; 2) bleeding prevention or treatment; and 3) tissue engineering through regenerative medicine using scaffolds in intraocular and extraocular tissue. Although most scientific research is not performed on the eye, both the findings and the new treatments resulting from that research are potentially applicable in ophthalmology since many of the drugs used are the same, the tissue evaluated in vitro or in vivo is also present in the eye, and the pathologies treated also occur in the eye. Finally, future prospects for this emerging field are discussed.

Lithiated porous silicon nanowires stimulate periodontal regeneration

Periodontal disease is a significant burden for oral health, causing progressive and irreversible damage to the support structure of the tooth. This complex structure, the periodontium, is composed of interconnected soft and mineralised tissues, posing a challenge for regenerative approaches. Materials combining silicon and lithium are widely studied in periodontal regeneration, as they stimulate bone repair via silicic acid release while providing regenerative stimuli through lithium activation of the Wnt/β-catenin pathway. Yet, existing materials for combined lithium and silicon release have limited control over ion release amounts and kinetics. Porous silicon can provide controlled silicic acid release, inducing osteogenesis to support bone regeneration. Prelithiation, a strategy developed for battery technology, can introduce large, controllable amounts of lithium within porous silicon, but yields a highly reactive material, unsuitable for biomedicine. This work debuts a strategy to lithiate porous silicon nanowires (LipSiNs) which generates a biocompatible and bioresorbable material. LipSiNs incorporate lithium to between 1% and 40% of silicon content, releasing lithium and silicic acid in a tailorable fashion from days to weeks. LipSiNs combine osteogenic, cementogenic and Wnt/β-catenin stimuli to regenerate bone, cementum and periodontal ligament fibres in a murine periodontal defect.

Tracking cellular uptake, intracellular trafficking and fate of nanoclay particles in human bone marrow stromal cells

Clay nanoparticles, in particular synthetic smectites, have generated interest in the field of tissue engineering and regenerative medicine due to their utility as cross-linkers for polymers in biomaterial design and as protein release modifiers for growth factor delivery. In addition, recent studies have suggested a direct influence on the osteogenic differentiation of responsive stem and progenitor cell populations. Relatively little is known however about the mechanisms underlying nanoclay bioactivity and in particular the cellular processes involved in nanoclay-stem cell interactions. In this study we employed confocal microscopy, inductively coupled plasma mass spectrometry and transmission electron microscopy to track the interactions between clay nanoparticles and human bone marrow stromal cells (hBMSCs). In particular we studied nanoparticle cellular uptake mechanisms and uptake kinetics, intracellular trafficking pathways and the fate of endocytosed nanoclay. We found that nanoclay particles present on the cell surface as μm-sized aggregates, enter hBMSCs through clathrin-mediated endocytosis, and their uptake kinetics follow a linear increase with time during the first week of nanoclay addition. The endocytosed particles were observed within the endosomal/lysosomal compartments and we found evidence for both intracellular degradation of nanoclay and exocytosis as well as an increase in autophagosomal activity. Inhibitor studies indicated that endocytosis was required for nanoclay upregulation of alkaline phosphatase activity but a similar dependency was not observed for autophagy. This study into the nature of nanoclay-stem cell interactions, in particular the intracellular processing of nanosilicate, may provide insights into the mechanisms underlying nanoclay bioactivity and inform the successful utilisation of clay nanoparticles in biomaterial design.

Slow release of attapulgite based nano-enabled glyphosate improves soil phosphatase activity, organic P-pool and proliferation of dominant bacterial community

Glyphosate (Glp) was encapsulated onto the dopamine-modified attapulgite to develop an attapulgite-based nano-enabled Glp (DGlp) in this study with comparable weed control effects to pure Glp and commercial Glp solutions. Within 24 hours, the active Glp molecule was slowly released from DGlp at a maximum remaining rate of over 90%, and then degraded similarly to Glp solution in soil. The addition of DGlp improved soil available phosphorus (P) contents, phosphatase activity, and enzyme extractable P fraction. However, compared to Glp solution, DGlp addition had no effect on the transformation of soil inorganic P fractions. The 16S rRNA sequencing and co-occurrence network results revealed that DGlp had no significant effect on the soil bacterial diversity but diminished the complexity of soil bacterial network. According to the Mantel test, DGlp addition stimulated soil phosphatase activity and proliferation of dominant bacterial taxa (Proteobacteria and Firmicutes) capable of degrading Glp. Proteobacteria and Firmicutes that had been extensively recruited and enriched for their phosphatase activities may have mobilized reactive enzyme-P, significantly enhancing the transformation of reactive organic P and P-pool in soil. These results contributed to our understanding of the ecotoxicity and environmental impacts of nano-enabled Glp prior to its successful and sustainable application in agriculture.

Enhanced osteogenic and antibacterial properties of polyetheretherketone by ultraviolet-initiated grafting polymerization of a gelatin methacryloyl/epsilon-poly-L-lysine/laponite hydrogel coating

Polyetheretherketone (PEEK) is a promising material for use in orthopedic implants, but its bio-inert character and lack of antibacterial activity limit its applications in bone repair. In the present study, considering the advantages of PEEK in self-initiated graft polymerization and of hydrogels in bone tissue engineering, we constructed a hydrogel coating (GPL) consisting of Gelatin methacryloyl (GelMA), methacrylamide-modified ε-poly-l-lysine (ε-PLMA) and Laponite on PEEK through UV-initiated crosslinking. The coating improved the hydrophilicity of PEEK, and the coating degraded slowly so that approximately 80% was retained after incubation in PBS for 8 weeks. In vitro studies revealed that as compared to culturing on PEEK, culturing on PEEK-GPL led to enhanced viability and adhesion of cultured human umbilical cord Wharton's jelly-derived mesenchymal stem cells (hWJ-MSCs). Due to the synergistic effect of the micron-scale three-dimensional surface and Laponite, PEEK-GPL exhibited a significantly improved induction of osteogenic differentiation of hWJ-MSCs compared to PEEK, as demonstrated by increased alkaline phosphatase activity, matrix mineralization, and expression of osteogenesis-related genes. Furthermore, PEEK-GPL showed antibacterial activity upon contact with Staphylococcus aureus and Escherichia coli, and this activity would be maintained before complete degradation of the hydrogel because the ε-PLMA was cross-linked covalently into the coating. Thus, PEEK-GPL achieved both osteogenesis and infection prevention in a single simple step, providing a feasible approach for the extensive use of PEEK in bone implants.

Multifunctional Lithium-Doped Mesoporous Nanoparticles for Effective Dentin Regeneration in vivo

Introduction

Effective infection control without irritating the pulp tissue is the key to successful vital pulp therapy. Developing a novel antibacterial biomaterial that promotes dentin regeneration for pulp capping is thus a promising strategy for enhancing vital pulp therapy.

Methods

Lithium-doped mesoporous nanoparticles (Li-MNPs) were synthesized using an alkali-catalyzed sol-gel method. The particle size, elemental distribution, surface morphology, pore structure, and ion release from Li-MNPs were measured. Human dental pulp stem cells (hDPSCs) and Streptococcus mutans (S. mutans) were used to evaluate the biological effects of Li-MNPs. In addition, a dental pulp exposure mouse model was used to evaluate the regenerative effects of Li-MNPs.

Results

Li-MNPs had a larger surface area (221.18 m2/g), a larger pore volume (0.25 cm3/g), and a smaller particle size (520.92 ± 35.21 nm) than MNPs. The in vitro investigation demonstrated that Li-MNPs greatly enhanced the biomineralization and odontogenic differentiation of hDPSCs through the Wnt/β-catenin signaling pathway. Li-MNPs showed a strong antibacterial effect on S. mutans. As expected, Li-MNPs significantly promoted dentin regeneration in situ and in vivo.

Conclusion

Li-MNPs promoted dentin regeneration and inhibited S. mutans growth, implying a possible application as a pulp capping agent in vital pulp therapy.

Nanosilicate-functionalized nanofibrous membrane facilitated periodontal regeneration potential by harnessing periodontal ligament cell-mediated osteogenesis and immunomodulation

Although various new biomaterials have enriched the methods for periodontal regeneration, their efficacy is still controversial, and the regeneration of damaged support tissue in the periodontium remains challenging. Laponite (LAP) nanosilicate is a layered two-dimensional nanoscale, ultrathin nanomaterial with a unique structure and brilliant biocompatibility and bioactivity. This study aimed to investigate the effects of nanosilicate-incorporated PCL (PCL/LAP) nanofibrous membranes on periodontal ligament cells (PDLCs) in vitro and periodontal regeneration in vivo. A PCL/LAP nanofibrous membrane was fabricated by an electrospinning method. The characterization of PCL/LAP nanofibrous membrane were determined by scanning electron microscopy (SEM), energy dispersive spectrum of X-ray (EDS), inductively coupled plasma mass spectrometry (ICP-MS) and tensile test. The proliferation and osteogenic differentiation of PDLCs on the PCL/LAP nanofibrous membrane were evaluated. A PDLCs and macrophage coculture system was used to explore the immunomodulatory effects of the PCL/LAP nanofibrous membrane. PCL/LAP nanofibrous membrane was implanted into rat calvarial and periodontal defects, and the regenerative potential was evaluated by microcomputed topography (micro-CT) and histological analysis. The PCL/LAP nanofibrous membrane showed good biocompatibility and bioactivity. It enhanced the proliferation and osteogenic differentiation of PDLCs. The PCL/LAP nanofibrous membrane also stimulated anti-inflammatory and pro-remodeling N2 neutrophil formation, regulated inflammatory responses and induced M2 macrophage polarization by orchestrating the immunomodulatory effects of PDLCs. The PCL/LAP nanofibrous membrane promoted rat calvarial defect repair and periodontal regeneration in vivo. LAP nanosilicate-incorporated PCL membrane is capable of mediating osteogenesis and immunomodulation of PDLCs in vitro and accelerating periodontal regeneration in vivo. It could be a promising biomaterial for periodontal regeneration therapy.

Preparation and In Vitro Osteogenic Evaluation of Biomimetic Hybrid Nanocomposite Scaffolds Based on Gelatin/Plasma Rich in Growth Factors (PRGF) and Lithium-Doped 45s5 Bioactive Glass Nanoparticles

Bone tissue engineering is an emerging technique for repairing large bone lesions. Biomimetic techniques expand the use of organic-inorganic spongy-like nanocomposite scaffolds and platelet concentrates. In this study, a biomimetic nanocomposite scaffold was prepared using lithium-doped bioactive-glass nanoparticles and gelatin/PRGF. First, sol-gel method was used to prepare bioactive-glass nanoparticles that contain 0, 1, 3, and 5%wt lithium. The lithium content was then optimized based on antibacterial and MTT testing. By freeze-drying, hybrid scaffolds comprising 5, 10, and 20% bioglass were made. On the scaffolds, human endometrial stem cells (hEnSCs) were cultured for adhesion (SEM), survival, and osteogenic differentiation. Alkaline phosphatase activity and osteopontin, osteocalcin, and Runx2 gene expression were measured. The effect of bioactive-glass nanoparticles and PRGF on nanocomposites' mechanical characteristics and glass-transition temperature (T _g) was also studied. An optimal lithium content in bioactive glass structure was found to be 3% wt. Nanoparticle SEM examination indicated grain deformation due to different sizes of lithium and sodium ions. Results showed up to 10% wt bioactive-glass and PRGF increased survival and cell adhesion. Also, Hybrid scaffolds revealed higher ALP-activity and OP, OC, and Runx2 gene expression. Furthermore, bioactive-glass has mainly increased ALP-activity and Runx2 expression, whereas PRGF increases the expression of OP and OC genes. Bioactive-glass increases scaffold modulus and T _g continuously. Hence, the presence of both bioactive-glass and nanocomposite scaffold improves the expression of osteogenic differentiation biomarkers. Subsequently, it seems that hybrid scaffolds based on biopolymers, Li-doped bioactive-glass, and platelet extracts can be a good strategy for bone repair.

Nanoclays in medicine: a new frontier of an ancient medical practice

Clays have been used as early as 2500 BC in human civilization for medicinal purposes. The ease of availability, biocompatibility, and versatility of these unique charged 2D structures abundantly available in nature have enabled the extensive applications of clays in human history. Recent advances in the use of clays in nanostructures and as components of polymer clay nanocomposites have exponentially expanded the use of clays in medicine. This review covers the details of structures and biomedical applications of several common clays, including montmorillonite, LAPONITE®, kaolinite, and halloysite. Here we describe the applications of these clays in wound dressings as hemostatic agents in drug delivery of drugs for cancer and other diseases and tissue engineering. Also reviewed are recent experimental and modeling studies that elucidate the impact of clay structures on cellular processes and cell adhesion processes. Various mechanisms of clay-mediated bioactivity, including protein localization, modulation of cell adhesion, biomineralization, and the potential of clay nanoparticles to impact cell differentiation, are presented. We also review the current developments in understanding the impact of clays on cellular responses. This review also elucidates new emerging areas of use of nanoclays in osteogenesis and the development of in vitro models of bone metastasis of cancer.

Vascularized bone regeneration accelerated by 3D-printed nanosilicate-functionalized polycaprolactone scaffold

Critical oral-maxillofacial bone defects, damaged by trauma and tumors, not only affect the physiological functions and mental health of patients but are also highly challenging to reconstruct. Personalized biomaterials customized by 3D printing technology have the potential to match oral-maxillofacial bone repair and regeneration requirements. Laponite (LAP) nanosilicates have been added to biomaterials to achieve biofunctional modification owing to their excellent biocompatibility and bioactivity. Herein, porous nanosilicate-functionalized polycaprolactone (PCL/LAP) was fabricated by 3D printing technology, and its bioactivities in bone regeneration were investigated in vitro and in vivo. In vitro experiments demonstrated that PCL/LAP exhibited good cytocompatibility and enhanced the viability of bone marrow mesenchymal stem cells (BMSCs). PCL/LAP functioned to stimulate osteogenic differentiation of BMSCs at the mRNA and protein levels and elevated angiogenic gene expression and cytokine secretion. Moreover, BMSCs cultured on PCL/LAP promoted the angiogenesis potential of endothelial cells by angiogenic cytokine secretion. Then, PCL/LAP scaffolds were implanted into the calvarial defect model. Toxicological safety of PCL/LAP was confirmed, and significant enhancement of vascularized bone formation was observed. Taken together, 3D-printed PCL/LAP scaffolds with brilliant osteogenesis to enhance bone regeneration could be envisaged as an outstanding bone substitute for a promising change in oral-maxillofacial bone defect reconstruction.

Nanosilicate-Functionalized Polycaprolactone Orchestrates Osteogenesis and Osteoblast-Induced Multicellular Interactions for Potential Endogenous Vascularized Bone Regeneration

Massive oral and maxillofacial bone defect regeneration remains a major clinical challenge due to the absence of functionalized bone grafts with ideal mechanical and proregeneration properties. In the present study, Laponite (LAP), a synthetic nanosilicate, is incorporated into polycaprolactone (PCL) to develop a biomaterial for bone regeneration. It is explored whether LAP-embedded PCL would accelerate bone regeneration by orchestrating osteoblasts to directly and indirectly induce bone regeneration processes. The results confirmed the presence of LAP in PCL, and LAP is distributed in the exfoliated structure without aggregates. Incorporation of LAP in PCL slightly improved the compressive properties. LAP-embedded PCL is biocompatible and exerts pronounced enhancements in cell viability, osteogenic differentiation, and extracellular matrix formation of osteoblasts. Furthermore, osteoblasts cultured on LAP-embedded PCL facilitate angiogenesis of vessel endothelial cells and alleviate osteoclastogenesis of osteoclasts in a paracrine manner. The addition of LAP to the PCL endows favorable bone formation in vivo. Based upon these results, LAP-embedded PCL shows great potential as an ideal bone graft that exerts both space-maintaining and vascularized bone regeneration synergistic effects and can be envisioned for oral and maxillofacial bone defect regeneration.