Hydroxyapatite coated titanium with curcumin and epigallocatechin gallate for orthopedic and dental applications

Immuno-osteoinductive 3D printed hydrogel scaffolds with triple crosslinking and GA/EGCG release for bone healing

Bone defects, caused by trauma, osteomyelitis, or osteoporosis, represent a significant global health challenge in orthopedics. However, current bone repair strategies often neglect the critical role of the immune microenvironment, which can impede effective bone regeneration. To address this gap, we developed a 3D-printed triple crosslinked hydrogel scaffold incorporating slow-release glycopyrrolate (GA) and epigallocatechin gallate (EGCG), that it could promote bone regeneration by modulating the immune response. We evaluated their immunomodulatory and bone-regenerative effects through in vitro cellular experiments and rat cranial defect models. Results demonstrated that these scaffolds effectively modulated the immune microenvironment, reducing inflammation while promoting osteoblast differentiation and proliferation, thereby significantly enhancing new bone formation and density. In conclusion, our novel 3D-printed hydrogel scaffold offers a promising approach to bone defect repair through its unique combination of mechanical strength, immunomodulation, and osteogenesis. This study provides valuable insights into leveraging immunomodulatory agents for enhanced bone regeneration, highlighting potential clinical applications.

Development of multifunctional PAA-alginate-carboxymethyl cellulose hydrogel-loaded fiber-reinforced biomimetic scaffolds for controlled release of curcumin

Critical-sized bone defects in osteosarcoma treatment demand multifunctional scaffolds that must effectively integrate two key functions, promoting osteogenesis and delivering targeted chemoprevention. This study introduces a dual-component system featuring pH-responsive hydrogels and hydroxyapatite-based fiber-reinforced biomimetic scaffolds designed for controlled and localized curcumin delivery, while addressing its solubility and stability issues. The hydrogel system comprises a double network of polyacrylic acid, sodium alginate, carboxymethyl cellulose, and potato starch, specifically modified to encapsulate curcumin. The encapsulated curcumin is integrated into porous hydroxyapatite-based scaffolds, which are reinforced with ceramic, carbon, and glass fibers to enhance structural support. Our results demonstrate that the hydrogel-loaded scaffold system ensures sustained release of curcumin. Release rates at pH 7.4 are 13 % (2.6 μg/ml) for CRF, 11 % (2.2 μg/ml) for CF, and 3 % (0.6 μg/ml) for GLF. At pH 5.0, release rates increase to 53 % (10.6 μg/ml) for CRF, 38 % (7.6 μg/ml) for CF, and 25 % (5.1 μg/ml) for GLF. Additionally, the cumulative curcumin release for GLF increased from 5 % to 44 % over 24 h, reflecting physiological and acidic conditions, respectively. The pH sensitivity suggests potential utility for controlled and targeted curcumin delivery, as the release behavior corresponds to pH conditions associated with osteosarcoma microenvironments.

Curcumin and vitamin D3 release from calcium phosphate enhances bone regeneration

Improving early in vivo osseointegration and removing residual cancer cells after tumor removal requires the development of novel bone implants with osteogenic and anti-cancer properties. Here, curcumin and vitamin D3 (Cur/VitD3) are loaded into calcium phosphate (CaP) matrices to improve in vivo osteogenesis and inhibit the proliferation of human osteosarcoma cells. Patient-specific, 3D-printed tricalcium phosphate (TCP) loaded with Cur/VitD3 increases the viability of in vitro osteoblast cells after 11 days. When delivered in combination, Cur/VitD3 loaded hydroxyapatite (HA)-coated Ti64 implant promotes new bone formation by 2.7-fold compared to the control after 6 weeks. This delivery system also decreases osteosarcoma cell viability relative to the 3D-printed TCP after day 11, indicating its anti-cancer properties. These findings contribute to the understanding of multifunctional CaP bone grafts to improve early osteogenesis after severe bone trauma and suppress the proliferation of osteosarcoma cells after tumor resection surgery.

Research Progress on the Application of Natural Medicines in Biomaterial Coatings

With the continuous progress of biomedical technology, biomaterial coatings play an important role in improving the performance of medical devices and promoting tissue repair and regeneration. The application of natural medicine to biological materials has become a hot topic due to its diverse biological activity, low toxicity, and wide range of sources. This article introduces the definition and classification of natural medicines, lists some common natural medicines, such as curcumin, allicin, chitosan, tea polyphenols, etc., and lists some biological activities of some common natural medicines, such as antibacterial, antioxidant, antitumor, and other properties. According to the different characteristics of natural medicines, physical adsorption, chemical grafting, layer-by-layer self-assembly, sol-gel and other methods are combined with biomaterials, which can be used for orthopedic implants, cardiovascular and cerebrovascular stents, wound dressings, drug delivery systems, etc., to exert their biological activity. For example, improving antibacterial properties, promoting tissue regeneration, and improving biocompatibility promote the development of medical health. Although the development of biomaterials has been greatly expanded, it still faces some major challenges, such as whether the combination between the coating and the substrate is firm, whether the drug load is released sustainably, whether the dynamic balance will be disrupted, and so on; a series of problems affects the application of natural drugs in biomaterial coatings. In view of these problems, this paper summarizes some suggestions by evaluating the literature, such as optimizing the binding method and release system; carrying out more clinical application research; carrying out multidisciplinary cooperation; broadening the application of natural medicine in biomaterial coatings; and developing safer, more effective and multi-functional natural medicine coatings through continuous research and innovation, so as to contribute to the development of the biomedical field.

Drug delivery strategies through 3D-printed calcium phosphate

3D printing has revolutionized bone tissue engineering (BTE) by enabling the fabrication of patient- or defect-specific scaffolds to enhance bone regeneration. The superior biocompatibility, customizable bioactivity, and biodegradability have enabled calcium phosphate (CaP) to gain significance as a bone graft material. 3D-printed (3DP) CaP scaffolds allow precise drug delivery due to their porous structure, adaptable structure-property relationship, dynamic chemistry, and controlled dissolution. The effectiveness of conventional scaffold-based drug delivery is hampered by initial burst release and drug loss. This review summarizes different multifunctional drug delivery approaches explored in controlling drug release, including polymer coatings, formulation integration, microporous scaffold design, chemical crosslinking, and direct extrusion printing for BTE applications. The review also outlines perspectives and future challenges in drug delivery research, paving the way for next-generation bone repair methodologies.

The recent progress of bone regeneration materials containing EGCG

Epigallocatechin-3-gallate (EGCG) is the most effective active ingredient in tea polyphenols and belongs to the category of catechins. EGCG has excellent antioxidant activity, anti-inflammatory, osteogenesis-promoting, and antibacterial properties, and has been widely studied in orthopedic diseases such as osteoporosis. To reach the lesion site, achieve sustained release, promote osteogenesis, regulate macrophage polarization, and improve the physical properties of materials, EGCG needs to be cross-linked or incorporated in bone regeneration materials. This article reviews the application of bone regeneration materials combined with EGCG, including natural polymer bone regeneration materials, synthetic polymer bone regeneration materials, bioceramic bone regeneration materials, metal bone regeneration materials, hydrogel bone regeneration materials and metal-EGCG networks. In addition, the fabrication methods for the regenerated scaffolds are also elaborated in the text. To sum up, it reveals the excellent development potential of materials containing EGCG and the shortcomings of current research, which will provide important reference for the future exploration of bone regeneration materials containing EGCG.

Improving Biological Performance of 3D-Printed Scaffolds with Garlic-Extract Nanoemulsions

Complex bone diseases such as osteomyelitis, osteosarcoma, and osteoporosis often cause critical-size bone defects that the body cannot self-repair and require an advanced bone graft material to repair. We have fabricated 3D-printed tricalcium phosphate bone scaffolds functionalized with garlic extract (GE). GE was encapsulated in a nanoemulsion (GE-NE) to enhance bioavailability and stability. GE-NE showed ∼73% drug encapsulation efficiency, with an average particle size of 158 nm and a zeta potential of -14.2 mV. Release of GE-NEs from the scaffold displayed a controlled and biphasic release profile at both acidic and physiological mediums. Results from the osteosarcoma study show that GE-NE demonstrated ∼88% reduction in cancer cell growth while exhibiting no cytotoxicity toward bone-forming cells. Interaction for the functionalized scaffold with Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa showed a substantial reduction in bacteria growth by more than 90% compared to the unfunctionalized scaffold. These findings demonstrate the potential of GE-NEs-treated porous scaffolds to treat bone-related diseases, particularly for non-load bearing applications.

Extrusion 3D-printed tricalcium phosphate-polycaprolactone biocomposites for quercetin-KCl delivery in bone tissue engineering

Critical-sized bone defects pose a significant challenge in advanced healthcare due to limited bone tissue regenerative capacity. The complex interplay of numerous overlapping variables hinders the development of multifunctional biocomposites. Phytochemicals show promise in promoting bone growth, but their dose-dependent nature and physicochemical properties halt clinical use. To develop a comprehensive solution, a 3D-printed (3DP) extrusion-based tricalcium phosphate-polycaprolactone (TCP-PCL) scaffold is augmented with quercetin and potassium chloride (KCl). This composite material demonstrates a compressive strength of 30 MPa showing promising stability for low load-bearing applications. Quercetin release from the scaffold follows a biphasic pattern that persists for up to 28 days, driven via diffusion-mediated kinetics. The incorporation of KCl allows for tunable degradation rates of scaffolds and prevents the initial rapid release. Functionalization of scaffolds facilitates the attachment and proliferation of human fetal osteoblasts (hfOB), resulting in a 2.1-fold increase in cell viability. Treated scaffolds exhibit a 3-fold reduction in osteosarcoma (MG-63) cell viability as compared to untreated substrates. Ruptured cell morphology and decreased mitochondrial membrane potential indicate the antitumorigenic potential. Scaffolds loaded with quercetin and quercetin-KCl (Q-KCl) demonstrate 76% and 89% reduction in bacterial colonies of Staphylococcus aureus, respectively. This study provides valuable insights as a promising strategy for bone tissue engineering (BTE) in orthopedic repair.

The Effectiveness of Curcumin Nanoparticle-Coated Titanium Surfaces in Osteogenesis: A Systematic Review

(1) Background: This systematic review critically appraises and synthesizes evidence from in vitro studies investigating the effects of curcumin nanoparticles on titanium surface modification, focusing on cell adhesion, proliferation, osteogenic differentiation, and mineralization. (2) Methods: A comprehensive electronic search was conducted in PubMed, Cochrane Central Register of Controlled Trials, and Google Scholar databases, yielding six in vitro studies that met the inclusion criteria. The search strategy and study selection process followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A qualitative methodological assessment was performed using the SciRAP (Science in Risk Assessment and Policy) method, which evaluated the reporting and methodological quality of the included studies. (3) Results: All six studies consistently demonstrated that curcumin-coated titanium surfaces inhibited osteoclastogenesis and promoted osteogenic activity, evidenced by enhanced cell adhesion, proliferation, osteogenic differentiation, and mineralization. The mean reporting quality score was 91.8 (SD = 5.7), and the mean methodological quality score was 85.8 (SD = 10.50), as assessed by the SciRAP method. Half of the studies used hydroxyapatite-coated titanium as a control, while the other half used uncoated titanium, introducing potential variability in baseline comparisons. (4) Conclusions: This systematic review provides compelling in vitro evidence supporting the osteogenic potential of curcumin nanoparticle-coated titanium surfaces. The findings suggest that this surface modification strategy may enhance titanium implants' biocompatibility and osteogenic properties, potentially improving dental and orthopedic implant outcomes. However, the review highlights significant heterogeneity in experimental designs and a concentration of studies from a single research group. Further research, particularly in vivo studies and clinical trials from diverse research teams, is essential to validate these findings and comprehensively understand the translational potential of this promising surface modification approach.

Thermal spray processes influencing surface chemistry and in-vitro hemocompatibility of hydroxyapatite-based orthopedic implants

Orthopedic implants made from titanium are a popular choice in the medical field because of their remarkable strength-to-weight ratio. Nevertheless, they may not interact well with human blood, resulting in thrombosis and hemolysis. In fact, non-hemocompatibility is believed to be responsible for about 31 % of medical device failures in the US alone, requiring painful and expensive revision surgery. To address this issue, bioactive hydroxyapatite coatings are applied to Ti-6Al-4V implants using thermal spray techniques. However, the temperature used during thermal processing impacts the coating's surface properties, affecting the mechanical and biological properties. Furthermore, the effectiveness of HA coatings on titanium for orthopedic applications has not been validated by biocompatibility tests, particularly hemocompatibility. In this study, we aimed to investigate the relative efficacy of three thermal spray processes of different temperature ranges: Atmospheric plasma spray (APS) (high temperature), Flame spray (FS) (moderate temperature), and High-Velocity Oxy-Fuel spray (HVOF) (low temperature), and study their impact on coating's surface properties, affecting blood components and implant's strength. The crystallinity of the HA coating increased by 32 % with a decrease in the operating temperature (APS < FS < HVOF). HVOF coating exhibited a ~ 34 % and ~ 120 % improvement in adhesion strength and ~ 31 % and 59 % increment in hardness compared to APS and FS coating, respectively, attributed to its low porosity, low coating thickness (~55 μm), and high degree of crystallinity. The HVOF coating showcased a significant increase in non-hemolytic behavior, with hemolysis rates ~8 and ~ 11 times lower than APS and FS coatings, respectively, owing to its smooth texture and high degree of crystallinity (p < 0.05). Furthermore, the HVOF coating exhibited minimal blood clotting based on the whole blood clotting assay, again confirmed by PT and aPTT assays showing delayed clotting time, indicating its non-thrombogenic behavior. The number of platelets adhered to the three coatings showed no significant difference compared to Ti-6Al-4V. APS and FS coatings showed low platelet activation, unlike HVOF coating and titanium, which revealed round platelets, similar to the negative control. Neither titanium nor HA coatings exhibited antibacterial properties, which may be due to their high affinity for organic substances, which promotes bacterial adhesion and replication. Among the three thermal processes, HVOF coating displayed good apatite growth, non-hemolytic, and non-thrombogenicity with no platelet activation owing to its low processing temperature, high degree of crystallinity (89.7 %), hydrophilicity, smooth (~4 μm) and dense (~97 %) microstructural properties. The results demonstrated that the HVOF-HA coating presented in this work meets the hemocompatible requirements and shows promise for prospective application as an orthopedic implant. Furthermore, this study has the potential to significantly reduce the use of animals in in-vivo research and improve their welfare while also cutting costs.