Clinical and histological efficacy of a new implant surface in achieving early and stable osseointegration: An in vivo study.

An advantage of treated implant surfaces is their increased degree of hydrophilicity and wettability compared with untreated, machined, smooth surfaces that are hydrophobic. The present preclinical in vivo study aimed to compare the two implant surface types, namely SLActive (Straumann, Basel, Switzerland) and nanohydroxyapatite (Hiossen, Englewood Cliffs, NJ, USA), in achieving early osseointegration. The authors hypothesised that the nanohydroxyapatite surface is comparable to SLActive for early bone-implant contact. Six male mixed foxhounds underwent mandibular premolar and first molar extraction, and the sockets healed for 42 days. The mandibles were randomised to receive implants with either SLActive (control group) or nanohydroxyapatite surfaces (test group). A total of 36 implants were placed in 6 animals, and they were sacrificed at 2 weeks (2 animals), 4 weeks (2 animals) and 6 weeks (2 animals) after implant surgery. When radiographic analysis was performed, the difference in bone level between the two groups was statistically significant at 4 weeks (P = 0.024) and 6 weeks (P = 0.008), indicating that the crestal bone level was better maintained for the test group versus the control group. The bone-implant contact was also higher for the test group at 2 (P = 0.012) and 4 weeks (P = 0.011), indicating early osseointegration. In conclusion, this study underscored the potential of implants with nanohydroxyapatite surfaces to achieve early osseointegration.

Polycaprolactone Hybrid Scaffold Loaded With N,O-Carboxymethyl Chitosan/Aldehyde Hyaluronic Acid/Hydroxyapatite Hydrogel for Bone Regeneration.

Hydrogels have emerged as potential materials for bone grafting, thanks to their biocompatibility, biodegradation, and flexibility in filling irregular bone defects. In this study, we fabricated a novel NAH hydrogel system, composed of N,O-carboxymethyl chitosan (NOCC), aldehyde hyaluronic acid (AHA), and hydroxyapatite (HAp). To improve the mechanical strength of the fabricated hydrogel, a porous polycaprolactone (PCL) matrix was synthesized and used as a three-dimensional (3D) support template for NAH hydrogel loading, forming a novel PCL/NAH hybrid scaffold. A mixture of monosodium glutamate (M) and sucrose (S) at varied weight ratios (5M:5S, 7M:3S, and 9M:1S) was used for the fabrication of 3D PCL matrices. The morphology, interconnectivity, and water resistance of the porous PCL scaffolds were investigated for optimal hydrogel loading efficiency. The results demonstrated that PCL scaffolds with porogen ratios of 7M:3S and 9M:1S possessed better interconnectivity than 5M:5S ratio. The compressive strength of the PCL/NAH hybrid scaffolds with 9M:1S (561.6 ± 6.1 kPa) and 7M:3S (623.8 ± 6.8 kPa) ratios are similar to cancellous bone and all hybrid scaffolds were biocompatible. Rabbit models with tibial defects were implanted with the PCL/NAH scaffolds to assess the wound healing capability. The results suggest that the PCL/NAH hybrid scaffolds, specifically those with porogen ratio of 7M:3S, exhibit promising bone healing effects.

Multilayer Gelatin-Supported BMP-9 Coating Promotes Osteointegration and Neo-Bone Formation at the n-CDHA/PAA Composite Biomaterial-Bone Interface.

BACKGROUND: The development of biomaterials capable of accelerating bone wound repair is a critical focus in bone tissue engineering. This study aims to evaluate the osteointegration and bone regeneration potential of a novel multilayer gelatin-supported Bone Morphogenetic Protein 9 (BMP-9) coated nano-calcium-deficient hydroxyapatite/poly-amino acid (n-CDHA/PAA) composite biomaterials, focusing on the material-bone interface, and putting forward a new direction for the research on the interface between the coating material and bone. METHODS: The BMP-9 recombinant adenovirus (Adenovirus (Ad)-BMP-9/Bone Marrow Mesenchymal Stem Cells (BMSc)) was produced by transfecting BMSc and supported using gelatin (Ad-BMP-9/BMSc/Gelatin (GT). Multilayer Ad-BMP-9/BMSc/GT coated nano-calcium deficient hydroxyapatite/polyamino acid (n-CDHA/PAA) composite biomaterials were then prepared and co-cultured with MG63 cells for 10 days, with biocompatibility assessed through microscopy, Cell Counting Kit-8 (CCK-8), and alkaline phosphatase (ALP) assays. Subsequently, multilayer Ad-BMP-9/BMSc/GT coated n-CDHA/PAA composite biomaterial screws were fabricated, and the adhesion of the coating to the substrate was observed using scanning electron microscopy (SEM). In vivo studies were conducted using a New Zealand White rabbit intercondylar femoral fracture model. The experimental group was fixed with screws featuring multilayer Ad-BMP-9/BMSc/GT coatings, while the control groups used medical metal screws and n-CDHA/PAA composite biomaterial screws. Fracture healing was monitored at 1, 4, 12, and 24 weeks, respectively, using X-ray observation, Micro-CT imaging, and SEM. Integration at the material-bone interface and the condition of neo-tissue were assessed through these imaging techniques. RESULTS: The Ad-BMP-9/GT coating significantly enhanced MG63 cell adhesion, proliferation, and differentiation, while increasing BMP-9 expression in vitro. In vivo studies using a rabbit femoral fracture model confirmed the biocompatibility and osteointegration potential of the multilayer Ad-BMP-9/BMSc/GT coated n-CDHA/PAA composite biomaterial screws. Compared to control groups (medical metal screws and n-CDHA/PAA composite biomaterial screws), this material demonstrated faster fracture healing, stronger osteointegration, and facilitated new bone tissue formation with increased calcium deposition at the material-bone interface. CONCLUSION: The multilayer GT-supported BMP-9 coated n-CDHA/PAA composite biomaterials have demonstrated favorable osteogenic cell interface performance, both in vitro and in vivo. This study provides a foundation for developing innovative bone repair materials, holding promise for significant advancements in clinical applications.

Comparison of various chitosan-based in situ forming gels with sodium fluoride varnish for enamel biomineralization: an in-vitro pH cycling model.

This study aimed to evaluate chitosan (CS)-based formulations loaded with 5% sodium fluoride (NaF) and/or 10% nanohydroxyapatite (nHA) to remineralize the demineralized primary tooth enamel surface. Ninety enamel blocks were demineralized and were divided into six groups (n = 15): (1) CS-based hydrogel, (2) CS-based hydrogel loaded with NaF, (3) CS-based hydrogel loaded with nHA, (4) CS-based hydrogel loaded with NaF and nHA, (5) 5% NaF varnish, and (6) negative control with no intervention. After intervention, the specimens were pH cycled by 2 h immersion in demineralizing solution and 22 h immersion in remineralizing solution for 8 days. The remineralization effects were evaluated by Vickers microhardness measurements and field emission scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (FESEM-EDS). The best mean ± SD percentage microhardness recovery in remineralized enamel (%REMH) was found in group 4 (56.90 ± 5.49). The %REMH of groups 2 (30.74 ± 3.51) and 5 (29.23 ± 5.65) were statistically the same (p = 0.943). FESEM images confirmed partial coverage of the porous demineralized enamel with a newly formed mineralized layer. Based on EDS findings, the Ca/P ratio values of the treated enamel surfaces with CS-based hydrogels ranged between 1.71 and 1.87, and the highest F content was noticed in group 2 (1.02 ± 0.03). Although, all tested CS-based hydrogels demonstrated the potential to repair demineralized enamel, nHA- and NaF-containing CS-based hydrogel showed the highest remineralization effect. We infer that this new hybrid hydrogel is a potentially useful dental material for tooth biomineralization.

Barrier Membrane with Janus Function and Structure for Guided Bone Regeneration.

Guided bone regeneration (GBR) technology has been demonstrated to be an effective method for reconstructing bone defects. A membrane is used to cover the bone defect to stop soft tissue from growing into it. The biosurface design of the barrier membrane is key to the technology. In this work, an asymmetric functional gradient Janus membrane was designed to address the bidirectional environment of the bone and soft tissue during bone reconstruction. The Janus membrane was simply and efficiently prepared by the multilayer self-assembly technique, and it was divided into the polycaprolactone isolation layer (PCL layer, GBR-A) and the nanohydroxyapatite/polycaprolactone/polyethylene glycol osteogenic layer (HAn/PCL/PEG layer, GBR-B). The morphology, composition, roughness, hydrophilicity, biocompatibility, cell attachment, and osteogenic mineralization ability of the double surfaces of the Janus membrane were systematically evaluated. The GBR-A layer was smooth, dense, and hydrophobic, which could inhibit cell adhesion and resist soft tissue invasion. The GBR-B layer was rough, porous, hydrophilic, and bioactive, promoting cell adhesion, proliferation, matrix mineralization, and expression of alkaline phosphatase and RUNX2. In vitro and in vivo results showed that the membrane could bind tightly to bone, maintain long-term space stability, and significantly promote new bone formation. Moreover, the membrane could fix the bone filling material in the defect for a better healing effect. This work presents a straightforward and viable methodology for the fabrication of GBR membranes with Janus-based bioactive surfaces. This work may provide insights for the design of biomaterial surfaces and treatment of bone defects.

Osteogenic potentials in canine mesenchymal stem cells: unraveling the efficacy of polycaprolactone/hydroxyapatite scaffolds in veterinary bone regeneration.

BACKGROUND: The integration of stem cells, signaling molecules, and biomaterial scaffolds is fundamental for the successful engineering of functional bone tissue. Currently, the development of composite scaffolds has emerged as an attractive approach to meet the criteria of ideal scaffolds utilized in bone tissue engineering (BTE) for facilitating bone regeneration in bone defects. Recently, the incorporation of polycaprolactone (PCL) with hydroxyapatite (HA) has been developed as one of the suitable substitutes for BTE applications owing to their promising osteogenic properties. In this study, a three-dimensional (3D) scaffold composed of PCL integrated with HA (PCL/HA) was prepared and assessed for its ability to support osteogenesis in vitro. Furthermore, this scaffold was evaluated explicitly for its efficacy in promoting the proliferation and osteogenic differentiation of canine bone marrow-derived mesenchymal stem cells (cBM-MSCs) to fill the knowledge gap regarding the use of composite scaffolds for BTE in the veterinary orthopedics field. RESULTS: Our findings indicate that the PCL/HA scaffolds substantially supported the proliferation of cBM-MSCs. Notably, the group subjected to osteogenic induction exhibited a markedly upregulated expression of the osteogenic gene osterix (OSX) compared to the control group. Additionally, the construction of 3D scaffold constructs with differentiated cells and an extracellular matrix (ECM) was successfully imaged using scanning electron microscopy. Elemental analysis using a scanning electron microscope coupled with energy-dispersive X-ray spectroscopy confirmed that these constructs possessed the mineral content of bone-like compositions, particularly the presence of calcium and phosphorus. CONCLUSIONS: This research highlights the synergistic potential of PCL/HA scaffolds in concert with cBM-MSCs, presenting a multidisciplinary approach to scaffold fabrication that effectively regulates cell proliferation and osteogenic differentiation. Future in vivo studies focusing on the repair and regeneration of bone defects are warranted to further explore the regenerative capacity of these constructs, with the ultimate goal of assessing their potential in veterinary clinical applications.

Small intestine submucosa decorated 3D printed scaffold accelerated diabetic bone regeneration by ameliorating the microenvironment.

The 3D printed scaffolds constructed from polymers have shown significant potential in the field of bone defect regeneration. However, the efficacy of these scaffolds can be markedly reduced in certain pathological conditions like diabetes, where an altered inflammatory microenvironment and diminished small blood vessels complicate the integration of these polymers with the host tissue. In this study, the bioactivity of a 3D-printed poly(lactide-co-glycolide) (PLGA) scaffold is enhanced through the integration of hydroxyapatite (HA), icariin (ICA), and small intestine submucosa (SIS), a form of decellularized extracellular matrix (dECM). The decoration of SIS on the 3D-printed PLGA/HA/ICA scaffold not only improves the mechanical and degradative performance, but also extends the release of ICA from the scaffold. Both in vitro and in vivo studies demonstrate that this functionalized scaffold mitigates the persistent inflammatory conditions characteristic of diabetic bone defects through inducing macrophages towards the M2 phenotype. Additionally, the scaffold promotes angiogenesis by enhancing the migration and tube formation of vascular cells. Furthermore, the synergistic effects of ICA and SIS with the HA scaffolds contribute to the superior osteogenic induction capabilities. This functionalization approach holds significant promise in advancing the treatment of bone defects within the diabetic population, paving a step forward in the application of polymer-based 3D printing technologies in regenerative medicine.

3D chitosan/hydroxyapatite scaffolds containing mesoporous SiO2-HA particles: A new step to healing bone defects.

Biocompatible scaffolds with high mechanical strengths that contain biodegradable components could boost bone regeneration compared with nondegradable bone repair materials. In this study, porous chitosan (CS)/hydroxyapatite (HA) scaffolds containing mesoporous SiO2-HA particles were fabricated through the freeze-drying process. According to field emission scanning electron microscopy (FESEM) results, combining mesoporous SiO2-HA particles in CS/HA scaffolds led to a uniform porous structure. It decreased pore sizes from 320 ± 1.1 µm to 145 ± 1.4 µm. Moreover, the compressive strength value of this scaffold was 25 ± 1.2 MPa. The in-vitro approaches exhibited good sarcoma osteogenic cell line (SAOS-2) adhesion, spreading, and proliferation, indicating that the scaffolds provided a suitable environment for cell cultivation. Also, in-vivo analyses in implanted defect sites of rats proved that the CS/HA/mesoporous SiO2-HA scaffolds could promote bone regeneration via enhancing osteoconduction and meliorating the expression of osteogenesis gene to 19.31 (about 5-fold higher compared to the control group) by exposing them to the bone-like precursors. Further, this scaffold's new bone formation percentage was equal to 90 % after 21 days post-surgery. Therefore, incorporating mesoporous SiO2-HA particles into CS/HA scaffolds can suggest a new future tissue engineering and regeneration strategy.

Type-I Collagen Polypeptide-Based Composite Nanofiber Membranes for Fast and Efficient Bone Regeneration.

The clinical treatment of bone defects includes allogeneic bone transplantation and autologous bone transplantation. However, they all have their own limitations, and the scope of application is limited. In recent years, bone tissue engineering scaffolds based on a variety of materials have been well developed and achieved good bone regeneration ability. However, most scaffold materials always face problems such as high biotoxicity, leading to inflammation and poor bioactivity, which limits the bone regeneration effect and prolongs the bone regeneration time. In our work, we prepared hydroxyapatite, erythropoietin (EPO), and osteogenic growth peptide (OGP) codoped type-I collagen (Col I) polypeptide nanofiber membranes (NFMs) by electrostatic spinning. In cell experiments, the composite NFMs had low cytotoxicity and promoted osteogenic differentiation of rat bone marrow mesenchymal stem cells. Quantitative real-time polymerase chain reaction and alkaline phosphatase staining confirmed the high expression of osteogenic genes, and alizarin red S staining directly confirmed the appearance of calcium nodules. In animal experiments, the loaded hydroxyapatite formed multiple independent mineralization centers in the defect center. Under the promotion of Col I, EPO, and OGP, the bone continued to grow along the mineralization centers as well as inward the defect edge, and the bone defect completely regenerated in about two months. The hematological and histological analyses proved the safety of the experiments. This kind of design to promote bone regeneration by simulating bone composition, introducing mineralization center and signal molecules, can shorten repair time, improve repair effect, and has good practical prospects in the future.

Fabrication of strontium ions substituted hydroxyapatite from the shells of the golden apple snail (Pomacea canaliculate L) with enhanced osteoconductive and improved biological properties.

The use of biogenic calcium ions for the source of hydroxyapatite (HAp or HA) are very common and have been being explored extensively. However, it usually results high crystalline HA, due to high reaction and decomposition temperatures. In this study, strontium (Sr2+) doped HA from the golden apple snail shells (Pomacea canaliculate L) was successfully synthesized. It was indicated that Sr ions completely replaced calcium (Ca) ions, increased the lattice constant, and consecutively reduced HA crystallinity. Smaller crystal size and ß-type carbonate (CO32-) ions substitution with Ca/P close to 1.67 molar ratio that mimic bone crystals were observed in Sr-doped HA, with significant increased rate of MC3T3-E1 cells viability and higher IC50 values. It was proven that Sr ions substitution resolved challenges on the use of biogenic sources for HA fabrication. Further in vivo study is needed to continue to valorise the results into real biomedical and clinical applications.

In vitro/In vivo Evaluations of Hydroxyapatite Nanoparticles with Different Geometry.

Purpose: Hydroxyapatite-based nanoparticles have found diverse applications in drug delivery, gene carriers, diagnostics, bioimaging and tissue engineering, owing to their ability to easily enter the bloodstream and target specific sites. However, there is limited understanding of the potential adverse effects and molecular mechanisms of these nanoparticles with varying geometries upon their entry into the bloodstream. Here, we used two commercially available hydroxyapatite nanoparticles (HANPs) with different geometries (less than 100 nm in size each) to investigate this issue. Methods: First, the particle size, Zeta potential, and surface morphology of nano-hydroxyapatite were characterized. Subsequently, the effects of 2~2000 µM nano-hydroxyapatite on the proliferation, migration, cell cycle distribution, and apoptosis levels of umbilical vein endothelial cells were evaluated. Additionally, the impact of nanoparticles of various shapes on the differential expression of genes was investigated using transcriptome sequencing. Additionally, we investigated the in vivo biocompatibility of HANPs through gavage administration of nanohydroxyapatite in mice. Results: Our results demonstrate that while rod-shaped HANPs promote proliferation in Human Umbilical Vein Endothelial Cell (HUVEC) monolayers at 200 µM, sphere-shaped HANPs exhibit significant toxicity to these monolayers at the same concentration, inducing apoptosis/necrosis and S-phase cell cycle arrest through inflammation. Additionally, sphere-shaped HANPs enhance SULT1A3 levels relative to rod-shaped HANPs, facilitating chemical carcinogenesis-DNA adduct signaling pathways in HUVEC monolayers. In vivo experiments have shown that while HANPs can influence the number of blood cells and comprehensive metabolic indicators in blood, they do not exhibit significant toxicity. Conclusion: In conclusion, this study has demonstrated that the geometry and surface area of HANPs significantly affect VEC survival status and proliferation. These findings hold significant implications for the optimization of biomaterials in cell engineering applications.

Integrating molecular-caged nano-hydroxyapatite into post-crosslinked PVA nanofibers for artificial periosteum.

Artificial periosteum is deemed a novel strategy for inducing endogenous bone regeneration, but ideal periosteum substitutes achieved by orchestrating a biomimetic microenvironment for bone regeneration remain a significant challenge. Here, we design and fabricate a hybridized nanofiber-based artificial periosteum with boosted osteoinduction properties. Via a "molecular cage" biomineralization strategy, nano-hydroxyapatite (nano-HAp) with a controllable size (∼22 nm) and excellent dispersion serves as unique nano-additives for water-soluble polyvinyl-alcohol (PVA)-based artificial periosteum. The PVA/HAp composite is electrospun into nanofibers to replicate the extracellular-matrix-inspired nanostructure for inducing cell adhesion, proliferation, and fate manipulation. A simple post-crosslinking treatment is subsequently applied to further booster its mechanical strength (6.6 MPa) and swelling stability. The optimized sample of C-PVA/HAp (10 wt% nano-HAp) artificial periosteum features excellent biocompatibility and remarkable in vitro mineralization. Cell experiments demonstrate that its effectively boasted cell modulation for enhanced osteogenesis without the aid of growth factors, showing a possible activation of the ERK/MAPK signaling pathway. This work provides an effective strategy for designing novel HAp nano-additives and expands the possibility of biomimetic fabrication for more advanced nanofiber-based artificial periosteum.

Synergetic association of hydroxyapatite-mediated biofilm and suspended sludge enhances resilience of partial nitrification/anammox (PN/A) system treating high-strength anaerobic membrane bioreactor (AnMBR) permeate.

A single-stage partial nitrification/anammox (PN/A) system with biocarriers was used to treat the permeate from an anaerobic membrane reactor (AnMBR) processing organic fraction of municipal solid wastes. The suitable Ca/P ratio and high pH in the AnMBR permeate facilitated hydroxyapatite (HAP) formation, enhancing the biofilm attachment and the settleability of suspended sludge. This maintained sufficient biomass and a stable microbial structure after flushing to mitigate the free nitrous acid inhibition. Robust anammox bacteria in the biofilm and ammonia-oxidizing bacteria in the suspended sludge ensured that the PN/A system achieved an 87.3 % nitrogen removal efficiency at an influent NH4+-N concentration of 1802 mg/L. This study demonstrates that AnMBR permeate with high Ca, P and NH4+-N content is suitable for single-stage PN/A system with biocarriers due to the high resilience enhanced by HAP, offering a reference for the treatment of high-strength AnMBR permeate.

Hydroxyapatite nanoparticle improves ovine oocyte developmental capacity by alleviating oxidative stress in response to vitrification stimuli.

The wide application of ovine oocyte vitrification is limited by its relatively low efficiency. Nanoparticle is potentially to be used in cryopreservation technology for its unique characteristics with high biocompatibility, potent antioxidant property as well as superiority in membrane permeation and heat transduction. However, the effect of nanoparticle on ovine oocyte cryopreservation as well as the underlying mechanism has not been systematically evaluated. The objective of this study was to investigate the impact of nanoparticles on ovine oocytes cryopreservation and further identify the underlying mechanism. Firstly, the effects of Hydroxyapatite (HA) and Fe3O4 nanoparticles on the developmental potential of vitrified ovine oocytes were determined, and the results showed that neither HA (VC = 85.95 ± 6.23 % vs. VH = 92.47 ± 8.11 %, P > 0.05) nor Fe3O4 (VC = 85.95 ± 6.23 % vs. VF = 89.39 ± 6.32 %, P > 0.05) had adverse effect on the survival rate of vitrified-thawed oocytes. Notably, both HA (VC = 77.78 ± 0.09 % vs. VH = 44.00 ± 0.09 %, P＜0.01) and Fe3O4 (VC = 77.78 ± 0.09 % vs. VF = 51.67 ± 0.15 %, P＜0.01) nanoparticles effectively reduced the level of oocyte apoptosis after freezing and thawing. What's more, HA could significantly improve the cleavage rate of frozen oocytes (VC = 33.79 ± 2.83 % vs. VH = 59.54 ± 4.13 %, P＜0.05). Moreover, reduced reactive oxygen species (ROS) level (VC = 13.66 ± 0.47 vs. VH = 12.61 ± 0.53, P < 0.05), increased glutathione (GSH) content (VC = 60.69 ± 7.89 vs. VH = 87.92 ± 1.05, P < 0.05) and elevated mitochondrial membrane potential (MMP) level (VC = 1.43 ± 0.04 vs. VH = 1.63 ± 0.01，P＜0.01) were observed in oocytes treated with HA nanoparticles when compared with that of the control group. Furthermore, Smart-RNA sequence technology was utilized to identify differentially expressed mRNAs (DEMs) induced by nanoparticles during cryopreservation. When compared with the control counterparts, a total of 721 DEMs (309 up-regulated and 412 down-regulated mRNAs) were identified in oocytes treated with HA, while 702 DEMs (480 up-regulated and 222 down-regulated mRNAs) were identified in oocytes treated with Fe3O4. A comparison of DEMs showed that total 692 mRNAs were expressed in oocytes treated with HA and Fe3O4. Notably, we discovered that 15 mRNAs were specially highly expressed in oocytes treated with HA, and Focal adhesion signaling pathway mainly contributed to the improved ovine oocyte quality after vitrification by alleviating oxidative stress.

Biomimetic HA-GO implant coating for enhanced osseointegration via macrophage M2 polarization-induced osteo-immunomodulation.

The pro-inflammatory/anti-inflammatory polarized phenotypes of macrophages (M1/M2) can be used to predict the success of implant integration. Hence, activating and inducing the transformation of immunocytes that promote tissue repair appears to be a highly promising strategy for facilitating osteo-anagenesis. In a previous study, titanium implants were coated with a graphene oxide-hydroxyapatite (GO-HA) nanocomposite via electrophoretic deposition, and the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) was found to be significantly enhanced when the GO content was 2wt%. However, the effectiveness of the GO-HA nanocomposite coating in modifying the in vivo immune microenvironment still remains unclear. In this study, the effects of GO-HA coatings on osteogenesis were investigated based on the GO-HA-mediated immune regulation of macrophages. The HA-2wt%GO nanocomposite coatings exhibited good biocompatibility and favored M2 macrophage polarization. Meanwhile, they could also significantly upregulate IL-10 (anti-inflammatory factor) expression and downregulate TNF-α (pro-inflammatory factor) expression. Additionally, the microenvironment, which was established by M2 macrophages, favored the osteogenesis of BMSCs both in vivo and in vitro. These findings show that the GO-HA nanocomposite coating is a promising surface-modification material. Hence, this study provides a reference for the development of next-generation osteoimmunomodulatory biomaterials.

Synthesis and characterization of cellulose fibers modified zinc phosphate/hydroxyapatite core-shell as enhanced carrier of cisplatin: Loading, release, and cytotoxicity.

The uncontrolled administration of the cisplatin drug (CPTN) resulted in numerous drawbacks. Therefore, effective, affordable, and biocompatible delivery systems were suggested to regulate the loading, release, and therapeutic effect of CPTN. Zinc phosphate/hydroxyapatite hybrid form (ZP/HP) and core-shell nano-rod morphology, as well as its functionalized derivative with cellulose (CF@ZP/HP), were synthesized by the facile dissolution precipitation method followed by mixing with cellulose fibers, respectively. The developed CF@ZP/HP displayed remarkable enhanced CPTN loading properties (418.2 mg/g) as compared to ZP/HP (259.8 mg/g). The CPTN loading behaviors into CF@ZP/HP follow the Langmuir isotherm properties (R2 > 0.98) in addition to the kinetic activities of the pseudo-first-order model (R2 > 0.96). The steric assessment validates the notable increase in the existing loading receptors after the functionalization of ZP/HP with CF from 57.7 mg/g (ZP/HP) to 90.5 mg/g. The functionalization also impacted the capacity of each existing receptor to be able to ensure 5 CPTN molecules. This, in addition to the loading energies (<40 kJ/mol), donates the loading of CPTN by physical multi-molecular processes and in vertical orientation. The CPTN releasing patterns of CF@ZP/HP exhibit slow and controlled properties (95.7 % after 200 h at pH 7.4 and 100 % after 120 h at pH 5.5), but faster than the properties of ZP/HP. The kinetic modeling of the release activities together with the diffusion exponent (>0.45) reflected the release of CPTN according to both erosion and diffusion mechanisms. The loading of CPTN into both ZP/HP and CF@ZP/HP also resulted in a marked enhancement in the anticancer activity of CPTN against human cervical epithelial malignancies (HeLa) (cell viability = 5.6 % (CPTN), 3.2 % (CPTN loaded ZP/HP), and 1.12 % (CPTN loaded CF@ZP/HP)).

Biological Effects of Double-Layered Hydroxyapatite and Zirconium Oxide Depositions on Titanium Surfaces.

Purpose: This study aimed to confirm the synergy effect of these two materials by evaluating osteoblast and antibacterial activity by applying a double-layered hydroxyapatite(HA) zirconium oxide(ZrO2) coating to titanium. Methods: The specimens used in this study were divided into four groups: a control group (polished titanium; group T) and three experimental groups: Group TH (RF magnetron sputtered HA deposited titanium), Group Z (ZrO2 ALD deposited titanium), and Group ZH (RF magnetron sputtered HA and ZrO2 ALD deposited titanium). The adhesion of Streptococcus mutans (S.mutans) to the surface was assessed using a crystal violet assay. The adhesion, proliferation, and differentiation of MC3T3-E1 cells, a mouse osteoblastic cell line, were assessed through a WST-8 assay and ALP assay. Results: Group Z showed a decrease in the adhesion of S. mutans (p < 0.05) and an improvement in osteoblastic viability (p < 0.0083). Group TH and ZH showed a decrease in adhesion of S. mutans (p < 0.05) and an increase in osteoblastic cell proliferation and cell differentiation (p < 0.0083). Group ZH exhibited the highest antibacterial and osteoblastic differentiation. Conclusion: In conclusion double-layered HA and ZrO2 deposited on titanium were shown to be more effective in inhibiting the adhesion of S. mutans, which induced biofilm formation, and increasing osteoblastic differentiation involved in osseointegration by the synergistic effect of the two materials.

Insulin promotes the bone formation capability of human dental pulp stem cells through attenuating the IIS/PI3K/AKT/mTOR pathway axis.

BACKGROUND: Insulin has been known to regulate bone metabolism, yet its specific molecular mechanisms during the proliferation and osteogenic differentiation of dental pulp stem cells (DPSCs) remain poorly understood. This study aimed to explore the effects of insulin on the bone formation capability of human DPSCs and to elucidate the underlying mechanisms. METHODS: Cell proliferation was assessed using a CCK-8 assay. Cell phenotype was analyzed by flow cytometry. Colony-forming unit-fibroblast ability and multilineage differentiation potential were evaluated using Toluidine blue, Oil red O, Alizarin red, and Alcian blue staining. Gene and protein expressions were quantified by real-time quantitative polymerase chain reaction and Western blotting, respectively. Bone metabolism and biochemical markers were analyzed using electrochemical luminescence and chemical colorimetry. Cell adhesion and growth on nano-hydroxyapatite/collagen (nHAC) were observed with a scanning electron microscope. Bone regeneration was assessed using micro-CT, fluorescent labeling, immunohistochemical and hematoxylin and eosin staining. RESULTS: Insulin enhanced the proliferation of human DPSCs as well as promoted mineralized matrix formation in a concentration-dependent manner. 10- 6 M insulin significantly up-regulated osteogenic differentiation-related genes and proteins markedly increased the secretion of bone metabolism and biochemical markers, and obviously stimulated mineralized matrix formation. However, it also significantly inhibited the expression of genes and proteins of receptors and receptor substrates associated with insulin/insulin-like growth factor-1 signaling (IIS) pathway, obviously reduced the expression of the phosphorylated PI3K and the ratios of the phosphorylated PI3K/total PI3K, and notably increased the expression of the total PI3K, phosphorylated AKT, total AKT and mTOR. The inhibitor LY294002 attenuated the responsiveness of 10- 6 M insulin to IIS/PI3K/AKT/mTOR pathway axis, suppressing the promoting effect of insulin on cell proliferation, osteogenic differentiation and bone formation. Implantation of 10- 6 M insulin treated DPSCs into the backs of severe combined immunodeficient mice and the rabbit jawbone defects resulted in enhanced bone formation. CONCLUSIONS: Insulin induces insulin resistance in human DPSCs and effectively promotes their proliferation, osteogenic differentiation and bone formation capability through gradually inducing the down-regulation of IIS/PI3K/AKT/mTOR pathway axis under insulin resistant states.

Bone Morphogenetic Protein 7-Loaded Gelatin Methacrylate/Oxidized Sodium Alginate/Nano-Hydroxyapatite Composite Hydrogel for Bone Tissue Engineering.

Background: Bone tissue engineering (BTE) is a promising alternative to autologous bone grafting for the clinical treatment of bone defects, and inorganic/organic composite hydrogels as BTE scaffolds are a hot spot in current research. The construction of nano-hydroxyapatite/gelatin methacrylate/oxidized sodium alginate (nHAP/GelMA/OSA), abbreviated as HGO, composite hydrogels loaded with bone morphogenetic protein 7 (BMP7) will provide a suitable 3D microenvironment to promote cell aggregation, proliferation, and differentiation, thus facilitating bone repair and regeneration. Methods: Dually-crosslinked hydrogels were fabricated by combining GelMA and OSA, while HGO hydrogels were formulated by incorporating varying amounts of nHAP. The hydrogels were physically and chemically characterized followed by the assessment of their biocompatibility. BMP7-HGO (BHGO) hydrogels were fabricated by incorporating suitable concentrations of BMP7 into HGO hydrogels. The osteogenic potential of BHGO hydrogels was then validated through in vitro experiments and using rat femoral defect models. Results: The addition of nHAP significantly improved the physical properties of the hydrogel, and the composite hydrogel with 10% nHAP demonstrated the best overall performance among all groups. The selected concentration of HGO hydrogel served as a carrier for BMP7 loading and was evaluated for its osteogenic potential both in vivo and in vitro. The BHGO hydrogel demonstrated superior in vitro osteogenic induction and in vivo potential for repairing bone tissue compared to the outcomes observed in the blank control, BMP7, and HGO groups. Conclusion: Using hydrogel containing 10% HGO appears promising for bone tissue engineering scaffolds, especially when loaded with BMP7 to boost its osteogenic potential. However, further investigation is needed to optimize the GelMA, OSA, and nHAP ratios, along with the BMP7 concentration, to maximize the osteogenic potential.

LL-37 and bisphosphonate co-delivery 3D-scaffold with antimicrobial and antiresorptive activities for bone regeneration.

This study introduces a novel 3D scaffold for bone regeneration, composed of silk fibroin, chitosan, nano-hydroxyapatite, LL-37 antimicrobial peptide, and pamidronate. The scaffold addresses a critical need in bone tissue engineering by simultaneously combating bone infections and promoting bone growth. LL-37 was incorporated for its broad-spectrum antimicrobial properties, while pamidronate was included to inhibit bone resorption. The scaffold's porous structure, essential for cell infiltration and nutrient diffusion, was achieved through a freeze-drying process. In vitro assessments using SEM and FTIR confirmed the scaffold's morphology and chemical integrity. Antimicrobial efficacy was tested against pathogens of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). In vivo studies in a murine model of infectious bone defect revealed the scaffold's effectiveness in reducing inflammation and bacterial load, and promoting bone regeneration. RNA sequencing of treated specimens provided insights into the molecular mechanisms underlying these observations, revealing significant gene expression changes related to bone healing and immune response modulation. The results indicate that the scaffold effectively inhibits bacterial growth and supports bone cell functions, making it a promising candidate for treating infectious bone defects. Future studies should focus on optimizing the release of therapeutic agents and evaluating the scaffold's clinical potential.