Nerve Growth Factor-Preconditioned Mesenchymal Stem Cell-Derived Exosome-Functionalized 3D-Printed Hierarchical Porous Scaffolds with Neuro-Promotive Properties for Enhancing Innervated Bone Regeneration.

The essential role of the neural network in enhancing bone regeneration has often been overlooked in biomaterial design, leading to delayed or compromised bone healing. Engineered mesenchymal stem cells (MSCs)-derived exosomes are becoming increasingly recognized as potent cell-free agents for manipulating cellular behavior and improving therapeutic effectiveness. Herein, MSCs are stimulated with nerve growth factor (NGF) to regulate exosomal cargoes to improve neuro-promotive potential and facilitate innervated bone regeneration. In vitro cell experiments showed that the NGF-stimulated MSCs-derived exosomes (N-Exos) obviously improved the cellular function and neurotrophic effects of the neural cells, and consequently, the osteogenic potential of the osteo-reparative cells. Bioinformatic analysis by miRNA sequencing and pathway enrichment revealed that the beneficial effects of N-Exos may partly be ascribed to the NGF-elicited multicomponent exosomal miRNAs and the subsequent regulation and activation of the MAPK and PI3K-Akt signaling pathways. On this basis, N-Exos were delivered on the micropores of the 3D-printed hierarchical porous scaffold to accomplish the sustained release profile and extended bioavailability. In a rat model with a distal femoral defect, the N-Exos-functionalized hierarchical porous scaffold significantly induced neurovascular structure formation and innervated bone regeneration. This study provided a feasible strategy to modulate the functional cargoes of MSCs-derived exosomes to acquire desirable neuro-promotive and osteogenic potential. Furthermore, the developed N-Exos-functionalized hierarchical porous scaffold may represent a promising neurovascular-promotive bone reparative scaffold for clinical translation.

Electreted Sandwich Membranes with Persistent Electrical Stimulation for Enhanced Bone Regeneration.

Physiologically relevant electrical microenvironments play an indispensable role in manipulating bone metabolism. Although implanted biomaterials that simulate the electrical properties of natural tissues using conductive or piezoelectric materials have been introduced in the field of bone regeneration, the application of electret materials to provide stable and persistent electrical stimulation has rarely been studied in biomaterial design. In this study, a silicon dioxide electret-incorporated poly(dimethylsiloxane) (SiO2/PDMS) composite electroactive membrane was designed and fabricated to explore its bone regeneration efficacy. SiO2 electrets were homogeneously dispersed in the PDMS matrix, and sandwich-like composite membranes were fabricated using a facile layer-by-layer blade-coating method. Following the encapsulation, electret polarization was conducted to obtain the electreted composite membranes. The surface potential of the composite membrane could be adjusted to a bone-promotive biopotential by tuning the electret concentration, and the prepared membranes exhibited favorable electrical stability during an observation period of up to 42 days. In vitro biological experiments indicated that the electreted SiO2/PDMS membrane promoted cellular activity and osteogenic differentiation of mesenchymal stem cells. In vivo, the electreted composite membrane remarkably facilitated bone regeneration through persistent endogenous electrical stimulation. These findings suggest that the electreted sandwich-like membranes, which maintain a stable and physiological electrical microenvironment, are promising candidates for enhancing bone regeneration.

Nicotine exposure of male mice protects offspring against carbon tetrachloride-induced acute liver injury.

Paternal nicotine exposure can cause a phenotypic change in offspring. To study whether paternal nicotine exposure influences acute liver injury and repair of the offspring, we established a paternal nicotine exposure model in mice and treated the offspring mice with carbon tetrachloride (CCl4 ) to induce acute liver injury. After the treatment of CCl4 , the levels of alanine aminotransferase and aspartate aminotransferase in offspring serum of paternal nicotine exposed mice are about 37.44%, and 30.21% lower than the control mice, respectively. Transcription profiling screen and bioinformatics analysis of differently expressed genes in F1 mice liver revealed that the Wnt pathway was altered. The results demonstrate that nicotine exposure in male mice could enhance the activation of the Wnt pathway in F1 mice liver. The Wnt pathway facilitates cell proliferation and tissue repair. In conclusion, our findings showed that nicotine exposure of male mice protects hepatic against CCl4 -induced acute injury in offspring by activating the Wnt pathway in the F1 liver.

Effect of Pore Size on Cell Behavior Using Melt Electrowritten Scaffolds.

Tissue engineering technology has made major advances with respect to the repair of injured tissues, for which scaffolds and cells are key factors. However, there are still some issues with respect to the relationship between scaffold and cell growth parameters, especially that between the pore size and cells. In this study, we prepared scaffolds with different pore sizes by melt electrowritten (MEW) and used bone marrow mensenchymal stem cells (BMSCs), chondrocytes (CCs), and tendon stem cells (TCs) to study the effect of the scaffold pore size on cell adhesion, proliferation, and differentiation. It was evident that different cells demonstrated different adhesion and proliferation rates on the scaffold. Furthermore, different cell types showed differential preferences for scaffold pore sizes, as evidenced by variations in cell viability. The pore size also affected the differentiation and gene expression pattern of cells. Among the tested cells, BMSCs exhibited the greatest viability on the 200-µm-pore-size scaffold, CCs on the 200- and 100-µm scaffold, and TCs on the 300-µm scaffold. The scaffolds with 100- and 200-µm pore sizes induced a significantly higher proliferation, chondrogenic gene expression, and cartilage-like matrix deposition after in vitro culture relative to the scaffolds with smaller or large pore sizes (especially 50 and 400 µm). Taken together, these results show that the architecture of 10 layers of MEW scaffolds for different tissues should be different and that the pore size is critical for the development of advanced tissue engineering strategies for tissue repair.

A host-coupling bio-nanogenerator for electrically stimulated osteogenesis.

Implantable self-powered generators (ISPGs) have been extensively explored as energy supplies for driving electronics and electrically stimulated therapeutics in vivo. However, some drawbacks arise, such as complicated architectonics, inescapability of wire connection, energy instability, and consumption. In this study, a host-coupling bio-nanogenerator (HCBG) is developed to configure a self-powered regional electrical environment for powerful bone regeneration. An HCBG consists of a porous electret nanofiber mat coupled with interstitial fluid and stimulated objects of the host after implantation, forming a host coupling effect. This bio-nanogenerator not only overcomes the disadvantages of general ISPGs, but also accomplishes both biomechanical energy scavenging and electrical stimulation therapeutics. The enhancement of osteogenesis differentiation of bone marrow mesenchymal stem cells in vitro and bone regeneration in vivo are remarkably achieved. Moreover, osteogenic ability is systematically evaluated by regulating the electrical performance of HCBGs. Osteogenic differentiation is activated by upregulating more cytosolic calcium ion, following to activate the calcium ion-induced osteogenic signal pathway, while applying electrical stimulation. As an implantable medical technology, the HCBG provides an explorative insight to facilitate the development of ISPG-based electrical medical therapeutics.

A low-temperature-printed hierarchical porous sponge-like scaffold that promotes cell-material interaction and modulates paracrine activity of MSCs for vascularized bone regeneration.

Mesenchymal stem cells (MSCs) secrete paracrine trophic factors that are beneficial for tissue regeneration. In this study, a sponge-like scaffold with hierarchical and interconnected pores was developed using low-temperature deposition modeling (LDM) printing. Its effects on the cellular behavior, especially on the paracrine secretion patterns of MSCs, were comprehensively investigated. We found that compared with the scaffolds printed via the fused deposition modeling (FDM) technique, the LDM-printed sponges enhanced the adhesion, retention, survival, and ingrowth of MSCs and promoted cell-material interactions. Moreover, the paracrine functions of the cultured MSCs on the LDM-printed sponges were improved, with significant secretion of upregulated immunomodulatory, angiogenic, and osteogenic factors. MSCs on the LDM-printed sponges exert beneficial paracrine effects on multiple regenerative processes, including macrophage polarization, tube formation, and osteogenesis, verifying the enhanced immunomodulatory, angiogenic, and osteogenic potential. Further protein function assays indicated that focal adhesion kinase (FAK), downstream AKT, and yes-associated-protein (YAP) signaling might participate in the required mechanotransductive pathways, through which the hierarchical porous structures stimulated the paracrine effects of MSCs. In a rat distal femoral defect model, the MSC-laden LDM-printed sponges significantly promoted vascularized bone regeneration. The results of the present study demonstrate that the hierarchical porous biomimetic sponges prepared via LDM printing have potential applications in tissue engineering based on their cell-material interaction promotion and MSC paracrine function modulation effects. Furthermore, our findings suggest that the optimization of biomaterial properties to direct the paracrine signaling of MSCs would enhance tissue regeneration.

Paternal nicotine exposure promotes hepatic fibrosis in offspring.

Paternal nicotine exposure can alter phenotypes in future generations. The aim of this study is to explore whether paternal nicotine exposure affects the hepatic repair to chronic injury which leads to hepatic fibrosis in offspring. Our results demonstrate that nicotine down regulates mmu-miR-15b expression via the hyper-methylation on its CpG island shore region in the spermatozoa. This epigenetic modification imprinted in the liver of the offspring. The decreased mmu-miR-15b promotes the expression of Wnt4 and activates the Wnt pathway in the offspring mice liver. The activation of the Wnt pathway improves the activation and proliferation of hepatic stellate cells (HSCs) leading to liver fibrosis. Moreover, the Wnt pathway promotes the activation of the TGF-ß pathway and the two pathways cooperate to promote the transcription of extracellular matrix (ECM) genes. In conclusion, this study found that nicotine promotes hepatic fibrosis in the offspring via the activation of Wnt pathway by imprinting the hyper-methylation of mmu-miR-15b.

High-precision, gelatin-based, hybrid, bilayer scaffolds using melt electro-writing to repair cartilage injury.

Articular cartilage injury is a common disease in the field of orthopedics. Because cartilage has poor self-repairing ability, medical intervention is needed. Using melt electro-writing (MEW) technology, tissue engineering scaffolds with high porosity and high precision can be prepared. However, ordinary materials, especially natural polymer materials, are difficult to print. In this study, gelatin was mixed with poly (lactic-co-glycolic acid) to prepare high-concentration and high-viscosity printer ink, which had good printability and formability. A composite scaffold with full-layer TGF-ß1 loading mixed with hydroxyapatite was prepared, and the scaffold was implanted at the cartilage injury site; microfracture surgery was conducted to induce the mesenchyme in the bone marrow. Quality stem cells thereby promoted the repair of damaged cartilage. In summary, this study developed a novel printing method, explored the molding conditions based on MEW printing ink, and constructed a bioactive cartilage repair scaffold. The scaffold can use autologous bone marrow mesenchymal stem cells and induce their differentiation to promote cartilage repair.

Bioinspired stratified electrowritten fiber-reinforced hydrogel constructs with layer-specific induction capacity for functional osteochondral regeneration.

Despite significant advances in osteochondral tissue engineering, it remains challenging to successfully reconstruct native-like complex tissues organized in three-dimension with spatially varying compositional, structural and functional properties. In this contribution, inspired by the gradients in extracellular matrix (ECM) composition and collagen fiber architecture in native osteochondral tissue, we designed and fabricated a tri-layered (superficial cartilage (S), deep cartilage (D) and subchondral bone (B) layer) stratified scaffold in which a mesenchymal stem cell (MSC)-laden gelatin methacrylamide (GelMA) hydrogel with zone-specific growth factor delivery was combined with melt electrowritten triblock polymer of poly(ε-caprolactone) and poly(ethylene glycol) (PCEC) networks with depth-dependent fiber organization. Introducing PCEC fibers into the weak GelMA hydrogel contributed to a significant increase in mechanical strength. In vitro biological experiments indicated that the stratified fiber-reinforced and growth factor-loaded hydrogel construct induced the MSCs to differentiate down both the chondrogenic and osteogenic lineages and that the engineered complex exhibited cellular phenotype and matrix accumulation profiles resembling those of the native tissue. Simultaneous cartilage and subchondral bone regeneration were achieved in vivo by using the tri-layered integrated scaffold. More importantly, the inclusion of the S layer could impart the regenerated cartilage with a more lubricating and wear-resistant surface. These findings suggest that the bioinspired construct mimicking the spatial variations of native osteochondral tissue might serve as a promising candidate to enhance osteochondral regeneration.

Hydroxyapatite-Bovine Serum Albumin-Paclitaxel Nanoparticles for Locoregional Treatment of Osteosarcoma.

Osteosarcoma is the most primary type of bone tumor occurring in the pediatric and adolescent age groups. In order to obtain the most appropriate prognosis, both tumor recurrence inhibition and bone repair promotion are required. In this study, a ternary nanoscale biomaterial/antitumor drug complex including hydroxyapatite (HA), bovine serum albumin (BSA) and paclitaxel (PTX) is prepared for post-surgical cancer treatment of osteosarcoma in situ. The HA-BSA-PTX nanoparticles, about 55 nm in diameter with drug loading efficiency (32.17 wt%), have sustained release properties of PTX and calcium ions (Ca2+ ) and low cytotoxicity to human fetal osteoblastic (hFOB 1.19) cells in vitro. However, for osteosarcoma (143B) cells, the proliferation, migration, and invasion ability are significantly inhibited. The in situ osteosarcoma model studies demonstrate that HA-BSA-PTX nanoparticles have significant anticancer effects and can effectively inhibit tumor metastasis. Meanwhile, the detection of alkaline phosphatase activity, calcium deposition, and reverse transcription-polymerase chain reaction proves that the HA-BSA-PTX nanoparticles can promote the osteogenic differentiation. Therefore, the HA-BSA-PTX nanodrug delivery system combined with sustained drug release, antitumor, and osteogenesis effects is a promising agent for osteosarcoma adjuvant therapy.

A 3D-Bioprinted dual growth factor-releasing intervertebral disc scaffold induces nucleus pulposus and annulus fibrosus reconstruction.

Regeneration of Intervertebral disc (IVD) is a scientific challenge because of the complex structure and composition of tissue, as well as the difficulty in achieving bionic function. Here, an anatomically correct IVD scaffold composed of biomaterials, cells, and growth factors were fabricated via three-dimensional (3D) bioprinting technology. Connective tissue growth factor (CTGF) and transforming growth factor-ß3 (TGF-ß3) were loaded onto polydopamine nanoparticles, which were mixed with bone marrow mesenchymal stem cells (BMSCs) for regenerating and simulating the structure and function of the nucleus pulposus and annular fibrosus. In vitro experiments confirmed that CTGF and TGF-ß3 could be released from the IVD scaffold in a spatially controlled manner, and induced the corresponding BMSCs to differentiate into nucleus pulposus like cells and annulus fibrosus like cells. Next, the fabricated IVD scaffold was implanted into the dorsum subcutaneous of nude mice. The reconstructed IVD exhibited a zone-specific matrix that displayed the corresponding histological and immunological phenotypes: primarily type II collagen and glycosaminoglycan in the core zone, and type I collagen in the surrounding zone. The testing results demonstrated that it exhibited good biomechanical function of the reconstructed IVD. The results presented herein reveal the clinical application potential of the dual growth factors-releasing IVD scaffold fabricated via 3D bioprinting. However, the evaluation in large mammal animal models needs to be further studied.

Preparation of high precision multilayer scaffolds based on Melt Electro-Writing to repair cartilage injury.

Rationale: Articular cartilage injury is quite common. However, post-injury cartilage repair is challenging and often requires medical intervention, which can be aided by 3D printed tissue engineering scaffolds. Specifically, the high accuracy of Melt Electro-Writing (MEW) technology facilitates the printing of scaffolds that imitate the structure and composition of natural cartilage to promote repair. Methods: MEW and Inkjet printing technology was employed to manufacture a composite scaffold that was then implanted into a cartilage injury site through microfracture surgery. While printing polycaprolactone (PCL) or PCL/hydroxyapatite (HA) scaffolds, cytokine-containing microspheres were sprayed alternately to form multiple layers containing transforming growth factor-ß1 and bone morphogenetic protein-7 (surface layer), insulin-like growth factor-1 (middle layer), and HA (deep layer). Results: The composite biological scaffold was conducive to adhesion, proliferation, and differentiation of mesenchymal stem cells recruited from the bone marrow and blood. Meanwhile, the environmental differences between the scaffold's layers contributed to the regional heterogeneity of chondrocytes and secreted proteins to promote functional cartilage regeneration. The biological effect of the composite scaffold was validated both in vitro and in vivo. Conclusion: A cartilage repair scaffold was established with high precision as well as promising mechanical and biological properties. This scaffold can promote the repair of cartilage injury by using, and inducing the differentiation and expression of, autologous bone marrow mesenchymal stem cells.

A multifunctional electrowritten bi-layered scaffold for guided bone regeneration.

The guided bone regeneration (GBR) concept has been extensively utilized to treat maxillofacial bone defects in clinical practice. However, the repair efficacy of currently available GBR membranes is often compromised by their limited bone regeneration potential and deficient antibacterial activity. In this study, inspired by the bi-layered structure design of the commonly used Bio-GideⓇmembrane, we designed and fabricated a new kind of multifunctional bi-layered "GBR scaffold" combining solution electrospinning writing (SEW) and solution electrospinning (SES) techniques using a single SEW printer. Copper-loaded mesoporous silica nanoparticles (Cu@MSNs) were incorporated into the poly(lactic-co-glycolic acid)/gelatin (PLGA/Gel, denoted as PG) fiber matrix to construct a composite PG-Cu@MSNs fibrous scaffold. The obtained GBR scaffold consisted of a loose and porous SEW layer to support and facilitate bone ingrowth, and a dense and compact SES layer to resist non-osteoblast interference. The resulting enhanced mechanical properties, coordinated degradation profile, and facile preparation procedure imparted the composite scaffold with good clinical feasibility. In vitro biological experiments indicate that the PG-Cu@MSNs composite scaffold exhibited favorable osteogenic and antibacterial properties. Furthermore, an in vivo rat periodontal defect model further confirmed the promising bone regeneration efficacy of the PG-Cu@MSNs scaffold. In conclusion, the developed electrowritten Cu@MSNs-incorporated bi-layered scaffold with hierarchical architecture and concurrent osteogenic and antibacterial functions may hold great potential for application in GBR.

4D-Printed Dynamic Materials in Biomedical Applications: Chemistry, Challenges, and Their Future Perspectives in the Clinical Sector.

Most of the biomedical materials printed using 3D bioprinting are static and are unable to alter/transform with dynamic changes in the internal environment of the body. The emergence of four-dimensional (4D) printing addresses this problem. By preprogramming dynamic polymer materials and their nanocomposites, 4D printing is able to produce the desired shapes or transform functions under specific conditions or stimuli to better adapt to the surrounding environment. In this review, the current and potential applications of 4D-printed materials are introduced in different aspects of the biomedical field, e.g., tissue engineering, drug delivery, and sensors. In addition, the existing limitations and possible solutions are discussed. Finally, the current limitations of 4D-printed materials along with their future perspective are presented to provide a basis for future research.

Proteoglycan 4 predicts tribological properties of repaired cartilage tissue.

Purpose: One of the essential requirements in maintaining the normal joint motor function is the perfect tribological property of the articular cartilage. Many cartilage regeneration strategies have been developed for treatment in early stages of osteoarthritis, but there is little information on how repaired articular cartilage regains durability. The identification of biomarkers that can predict wear resistant property is critical to advancing the success of cartilage regeneration therapies. Proteoglycan 4 (PRG4) is a macromolecule distributing on the chondrocyte surface that contributes to lubrication. In this study, we investigate if PRG4 expression is associated with tribological properties of regenerated cartilage, and is able to predict its wear resistant status. Methods: Two different strategies including bone marrow enrichment plus microfracture (B/BME-MFX) and microfracture alone (B-MFX) of cartilage repair in sheep were used. PRG4 expression and a series of tribological parameters on regenerated cartilage were rigorously examined and compared. Results: Highly and continuously expression of PRG4 in regenerated cartilage surface was negatively correlated with each tribological parameter (P<0.0001, respectively). Multivariate analysis showed that PRG4 expression was the key predictor that contributed to the promotion of cartilage wear resistance. Conclusion: Higher PRG4 expression in regenerated cartilage is significantly associated with wear resistance improvement. PRG4 may be useful for predicting the wear resistant status of regenerated cartilage and determining the optimal cartilage repair strategy.

Human adipose-derived mesenchymal progenitor cells plus microfracture and hyaluronic acid for cartilage repair: a Phase IIa trial.

Aim: This study aimed to preliminarily evaluate the safety and efficacy of human adipose-derived mesenchymal progenitor cells (haMPCs) in combination with microfracture and hyaluronic acid (HA) for treating cartilage defects. Materials & methods: A total of 30 patients with medial femoro-tibial condylar cartilage defects were randomized into three groups: arthroscopic microfracture group and normal saline injection, arthroscopic microfracture and intra-articular injection of HA, or arthroscopic microfracture in combination with intra-articular injection of HA and haMPCs. Results & conclusions: The data demonstrated that intra-articular injection of haMPCs plus microfracture and HA is a safe procedure to improve joint function in patients with knee cartilage defects. These findings provide an impetus for future research on this treatment. ClinicalTrials.gov Identifier: NCT02855073.

Acteoside inhibits inflammatory response via JAK/STAT signaling pathway in osteoarthritic rats.

BACKGROUND: Osteoarthritis (OA) is a common degenerative disease of synovial joints caused by inflammation. Acteoside (ACT), a major component and lipase inhibitor from the Chinese tea Ligustrum purpurascens kudingcha, has been reported to regulate the inflammation and immune response. The study aims to investigate the effects of ACT on inflammatory responses and joint protection in OA rats. METHODS: Cell proliferation was examined by MTT and colony formation assay. Apoptosis was analyzed using flow cytometry with Annexin V/PI staining. ELISA was employed to examine the concentration of inflammatory cytokines. OA rat model was established by surgery stimulation. RESULTS: ACT treatment significantly inhibited the upregulation of inflammatory cytokines induced by IL-1ß in primary chondrocytes, including IL-6, IL-12, TNF-α and IFN-γ. ACT stimulation also enhanced the cell proliferation, while inhibited cell apoptosis in IL-1ß-treated chondrocytes. Consistently, ACT treatment led to downregulation of cleaved-caspase-3 and apoptosis regulator Bax, and upregulation of Bcl-2. Furthermore, ACT treatment inhibited IL-1ß-induced activation of JAK/STAT pathway. The results were confirmed in surgery-induced OA rat model. Moreover, ACT treatment significantly inhibited synovial inflammation and articular chondrocyte apoptosis in OA rats. CONCLUSION: Our findings indicate that ACT has the potential therapeutic effect on OA through inhibiting the inflammatory responses via inactivating JAK/STAT signaling pathway.

RNA profile of control and nicotine treated Murine Leydig single cell represented in TPM data.

Data provided in this article is RNA profile represented in RPKM and RPKM based TPM value for the research article titled Nicotine inhibits Murine Leydig cell differentiation and maturation via regulating Hedgehog signal pathway Jiajie et al., 2019. Nicotine treatment changes the RNA profile of Murine Leydig cells. RNA of 12 control group Leydig cells and 12 nicotine treated Leydig cells are sequenced and the data of 29943 genes are achieved. The information of the gene symbol, gene description, gene type, position and transcript length are provided.

Estrogen reverses nicotine-induced inflammation in chondrocytes via reducing the degradation of ECM.

PROBLEM: Osteoarthritis (OA) is a chronic disease with a very high incidence and the pathology of which is quite complex. Epidemiological investigation showed that OA may be related to smoking and estrogen levels, but there are few studies focused on the cross-effect of these two factors. This research aims to investigate the molecular mechanism of nicotine and estrogen effects on chondrocytes to study the effect of smoking on the incidence of osteoarthritis in women. METHOD OF THE STUDY: Nicotine was added to obtain inflammatory supernatants of macrophages, which were used to induce chondrocyte inflammation. Toluidine staining and immunohistochemistry were used to detect the extracellular matrix (ECM) of chondrocytes, while the important proteins in the metabolism of chondrocytes were detected by Western blot. RESULTS: Nicotine-induced inflammatory supernatant promoted the degradation of ECM, such as type II collagen, aggrecan and proteoglycan 4. While in the presence of physiological concentrations of estrogen, this destructive effect is reversed. On the molecular level, estrogen (17ß-estradiol, 1 nmol/L) can inhibit the matrix degrading enzymes and promote the transforming growth factor (TGF)-ß1 pathway which is involved in matrix synthesis. However, in the presence of inflammatory induction, although estrogen could still inhibit the expression of matrix degrading enzymes, it inhibited the TGF-ß1 pathway. Moreover, the different inflammatory factors in the inflammatory supernatant, mainly tumor necrosis factor-α, interleukin-1ß, had different effects on the metabolic processes of chondrocytes. CONCLUSION: Estrogen reverses nicotine-induced inflammation mainly via reducing the degradation of ECM. The cross-effect of estrogen and inflammatory factor inhibitors can be a potential clinical reference for OA patients.

Bi-layered electrospun nanofibrous membrane with osteogenic and antibacterial properties for guided bone regeneration.

Guided bone regeneration (GBR) membranes have the potential to prevent the invasion of epithelial and connective tissues as well as to maintain a stable space for facilitating the ingrowth of regenerative bone tissue. However, the bioactivity and regeneration potential of currently available membranes still need to be improved. In this study, a novel bi-layered membrane with both osteogenic and antibacterial functions was developed for GBR applications. The loose layer (LL) of the membrane was composed of conjugated electrospun poly (lactic-co-glycolic acid) (PLGA)/gelatin nanofibers incorporating dexamethasone-loaded mesoporous silica nanoparticles (DEX@MSNs), while the dense layer (DL) of the membrane consisted of traditionally electrospun PLGA nanofibers loaded with the broad-spectrum antibiotic doxycycline hyclate (DCH). Morphological results showed that the LL (DEX@MSNs/PLGA/Gel) membrane exhibited a porous and loosely packed structure, which was beneficial for cell adhesion and infiltration, while the DL (DCH/PLGA) membrane remained dense enough to act as a barrier. In vitro drug release tests indicated that both DEX and DCH followed a favorable sustained release profile. The cell viability evaluation suggested that the electrospun membranes possessed good cytocompatibility. Furthermore, in vitro osteogenesis analyses demonstrated that the DEX@MSNs/PLGA/Gel composite membrane possessed an enhanced osteoinductive capacity for rat bone marrow stem cells (BMSCs), which was verified by the increased alkaline phosphatase (ALP) activity, the enhanced calcium deposition, and the upregulated osteocalcin (OCN) expression. In vitro antimicrobial experiments revealed the effective antibacterial potency of the DCH/PLGA membrane. In conclusion, the prepared nanocarrier-incorporated bi-layered composite membrane with combined osteogenic and antibacterial properties may be a promising candidate for GBR application.