Scaffolds For Bone Tissue Engineering Research Articles

Impacts of pre-treatment methods on the morphology, crystal structure, and defects formation of hydroxyapatite extracted from Nile tilapia scales.

The comprehensive control of hydroxyapatite (HAp), involving morphological and structural variations, particle sizes, and defect formations, has garnered considerable attention for its versatile functionalities, rendering it applicable in diverse contexts. This work examined the shape, structure and optical characteristics, and defect formation in hydroxyapatite (HAp) extracted from Nile tilapia (Oreochromis niloticus) scales with various pre-treatments through experiments and density functional theory (DFT) calculations. Utilizing scanning electron microscopy, our findings revealed that dried fish scales (FS-D) exhibited a layered pattern of collagen fibers, while boiled fish scales (FS-B) had smoother surfaces and significantly reduced collagen content. After calcination, the FS-D sample produced nanorods with an average length of 150 ± 44 nm, whereas the FS-B samples yielded agglomerated spherical particles whose size increased with the rising calcining temperature. In-depth analysis through X-ray diffraction and Fourier-transform infrared spectroscopy confirmed the presence of biphasic calcium phosphates in the FS-B samples, while the FS-D sample presented a pure HAp phase. The boiled fish scale calcined at 800 °C (FS-B800) exhibited an optical band gap (Eg) of 5.50 eV, whereas the dried fish scale calcined at 800 °C (FS-D800) showed two Eg values of 2.87 and 3.97 eV, as determined by UV-visible spectroscopy. DFT calculations revealed that the band gap of 3.97 eV correlated with OH- vacancies, while that of 2.87 eV indicated Mn-substituted HAp, explaining the blue powder. The Eg value for the white powder resembled pure HAp, S- and Cl- substituted OH- vacancies, and various cations substituting Ca sites of HAp. Different pre-treatment procedures influence the characteristics of HAp, offering opportunities for applications in bone replacement and scaffolds for bone tissue engineering.

Cross Talk Between Cells and the Current Bioceramics in Bone Regeneration: A Comprehensive Review.

The conventional approach for addressing bone defects and stubborn non-unions typically involves the use of autogenous bone grafts. Nevertheless, obtaining these grafts can be challenging, and the procedure can lead to significant morbidity. Three primary treatment strategies for managing bone defects and non-unions prove resistant to conventional treatments: synthetic bone graft substitutes (BGS), a combination of BGS with bioactive molecules, and the use of BGS in conjunction with stem cells. In the realm of synthetic BGS, a multitude of biomaterials have emerged for creating scaffolds in bone tissue engineering (TE). These materials encompass biometals like titanium, iron, magnesium, and zinc, as well as bioceramics such as hydroxyapatite (HA) and tricalcium phosphate (TCP). Bone TE scaffolds serve as temporary implants, fostering tissue ingrowth and the regeneration of new bone. They are meticulously designed to enhance bone healing by optimizing geometric, mechanical, and biological properties. These scaffolds undergo continual remodeling facilitated by bone cells like osteoblasts and osteoclasts. Through various signaling pathways, stem cells and bone cells work together to regulate bone regeneration when a portion of bone is damaged or deformed. By targeting signaling pathways, bone TE can improve bone defects through effective therapies. This review provided insights into the interplay between cells and the current state of bioceramics in the context of bone regeneration.

Preparation and properties of a 3D printed nHA/PLA bone tissue engineering scaffold loaded with a β-CD-CHX combined dECM hydrogel.

Jaw defects, which can result from a multitude of causes, significantly affect the physical well-being and psychological health of patients. The repair of these infected defects presents a formidable challenge in the clinical and research fields, owing to their intricate and diverse nature. This study aims to develop a personalized bone tissue engineering scaffold that synergistically offers antibacterial and osteogenic properties for treating infected maxillary defects. This study engineered a novel temperature-sensitive, sustained-release hydrogel by amalgamating β-cyclodextrin (β-CD) with chlorhexidine (CHX) and a decellularized extracellular matrix (dECM). This hydrogel was further integrated with a polylactic acid (PLA)-nano hydroxyapatite (nHA) scaffold, fabricated through 3D printing, to form a multifaceted composite scaffold (nHA/PLA/dECM/β-CD-CHX). Drug release assays revealed that this composite scaffold ensures prolonged and sustained release. Bacteriological studies confirmed that the β-CD-CHX loaded scaffold exhibits persistent antibacterial efficacy, thus effectively inhibiting bacterial growth. Moreover, the scaffold demonstrated robust mechanical strength. Cellular assays validated its superior biocompatibility, attributed to dECM and nHA components, significantly enhancing the proliferation, adhesion, and osteogenic differentiation of osteogenic precursor cells (MC3T3-E1). Consequently, the nHA/PLA/dECM/β-CD-CHX composite scaffold, synthesized via 3D printing technology, shows promise in inducing bone regeneration, preventing infection, and facilitating the repair of jaw defects, positioning itself as a potential breakthrough in bone tissue engineering.

Bioactive and biomimetic 3D scaffolds for bone tissue engineering using graphitic carbon nitride as a sustainable visible light photoinitiator

Graphitic carbon nitride (g-C3N4) is explored as a novel sustainable visible light photoinitiator for the preparation of biomimetic 3D hydrogel scaffolds comprising gelatin methacrylamide (GelMA) and dopamine methacrylamide for use in tissue engineering. The initiator efficiency was assessed by comparing the swelling behavior and the stability of photopolymerized hydrogels prepared with GelMA of different degrees of functionalization and different comonomer compositions. Bioactive composite hydrogels with a 50 wt% nanohydroxyapatite (nHAp) content, to closely mimic the actual bone composition, were successfully obtained by the introduction of nHAp in the prepolymer solutions followed by photopolymerization. The composite hydrogels demonstrated enhanced mechanical properties and excellent stability in PBS verifying the preparation of robust 3D scaffolds for use in cancellous or pre-calcified bone tissue engineering applications. The in vitro cell response of the composite scaffolds exhibited high cell viability and enhanced differentiation of pre-osteoblasts to mature osteoblasts, demonstrating their osteogenic potential. This work establishes, for the first time, the excellent properties of g-C3N4 as a sustainable, visible light initiator, fully satisfying the principles of green chemistry, for the preparation of robust and biologically relevant hydrogels, and proposes a new approach to overcome the main challenges of conventional photoinitiators in cell scaffold fabrication, such as photobleaching, high cost and non-scalable synthesis employing toxic organic precursors and solvents.

3D Molybdenum Disulfide Nanospheres Loaded with Metformin to Enhance SCPP Scaffolds for Bone Regeneration.

Conventional strontium-doped calcium polyphosphate (SCPP) ceramics have attracted a lot of attention due to good cytocompatibility and controlled degradation. However, their poor mechanical strength, brittleness, and difficulty in eliminating unavoidable postoperative inflammation and bacterial infections in practical applications limit their further clinical application. In this study, carboxylated molybdenum disulfide nanospheres (MoS2-COOH) were first prepared via a one-step hydrothermal method. The optimal doping concentration of MoS2-COOH was then incorporated into SCPP to overcome its poor mechanical strength. To further enhance the anti-inflammatory properties of scaffolds, metformin (MET) was loaded onto MoS2-COOH through covalent bond cross-linking (MoS2-MET). Then MoS2-MET was doped into SCPP (SCPP/MoS2-MET) according to the previously obtained concentration, resulting in the controlled and sustained release of MET from the SCPP/MoS2-MET scaffolds for 21 days in vitro. The SCPP/MoS2-MET scaffolds were shown to have good biological activity in vitro to promote stem cell proliferation and the potential to promote mineralization in vitro. It also showed good osteoimmunomodulatory activity could reduce the expression of proinflammatory factors and effectively induce the differentiation of BMSCs under inflammatory conditions, upregulating the expression of relevant osteoblastic cytokines. In addition, SCPP/MoS2-MET scaffolds could effectively inhibit Staphylococcus aureus and Escherichia coli. In vivo experiments also demonstrated better osteogenic potential of SCPP/MoS2-MET scaffolds compared with the other scaffold-samples. Thus, the introduction of carboxylated molybdenum disulfide nanospheres is a promising approach to improve the properties of SCPP and may provide a new modification strategy for inert ceramic scaffolds and the construction of multifunctional composite scaffolds for bone tissue engineering.

Advances in 3D Printing of Highly Bioadaptive Bone Tissue Engineering Scaffolds.

The number of patients with bone defects caused by trauma, bone tumors, and osteoporosis has increased considerably. The repair of irregular, recurring, and large bone defects poses a great challenge to clinicians. Bone tissue engineering is emerging as an appropriate strategy to replace autologous bone grafting in the repair of critically sized bone defects. However, the suitability of bone tissue engineering scaffolds in terms of structure, mechanics, degradation, and the microenvironment is inadequate. Three-dimensional (3D) printing is an advanced additive-manufacturing technology widely used for bone repair. 3D printing constructs personalized structurally adapted scaffolds based on 3D models reconstructed from CT images. The contradiction between the mechanics and degradation is resolved by altering the stacking structure. The local microenvironment of the implant is improved by designing an internal pore structure and a spatiotemporal factor release system. Therefore, there has been a boom in the 3D printing of personalized bone repair scaffolds. In this review, successful research on the preparation of highly bioadaptive bone tissue engineering scaffolds using 3D printing is presented. The mechanisms of structural, mechanical, degradation, and microenvironmental adaptations of bone prostheses and their interactions were elucidated to provide a feasible strategy for constructing highly bioadaptive bone tissue engineering scaffolds.

Nanomechanical Mapping of Three Dimensionally Printed Poly-ε-Caprolactone Single Microfibers at the Cell Scale for Bone Tissue Engineering Applications.

Poly-ε-caprolactone (PCL) has been widely used in additive manufacturing for the construction of scaffolds for bone tissue engineering. However, its use is limited by its lack of bioactivity and inability to induce cell adhesion, hence limiting bone tissue regeneration. Biomimicry is strongly influenced by the dynamics of cell-substrate interaction. Thus, characterizing scaffolds at the cell scale could help to better understand the relationship between surface mechanics and biological response. We conducted atomic force microscopy-based nanoindentation on 3D-printed PCL fibers of ~300 µm thickness and mapped the near-surface Young's modulus at loading forces below 50 nN. In this non-disruptive regime, force mapping did not show clear patterns in the spatial distribution of moduli or a relationship with the topographic asperities within a given region. Remarkably, we found that the average modulus increased linearly with the logarithm of the strain rate. Finally, a dependence of the moduli on the history of nanoindentation was demonstrated on locations of repeated nanoindentations, likely due to creep phenomena capable of hindering viscoelasticity. Our findings can contribute to the rational design of scaffolds for bone regeneration that are capable of inducing cell adhesion and proliferation. The methodologies described are potentially applicable to various tissue-engineered biopolymers.

Characterization and in vitro bioactivity evaluation of polyvinyl alcohol incorporated electro spun chitosan/ fluor apatite nanofibrous scaffold for bone tissue engineering

In this study, polyvinyl alcohol/chitosan/fluor apatite scaffolds with different concentrations of polyvinyl alcohol of 0.075 g ml−1 and 0.1 g ml−1, respectively named A and B fabricated by electrospinning method to use in tissue engineering. By examining the scaffolds by FE-SEM, an appetite layer formation which was on the scaffold surface was clearly observable. Increasing the concentration of polyvinyl alcohol from 0.075 g ml−1 to 0.1 g ml−1 in the nanofibrous scaffolds improved degradation characteristic with an optimized value of 26 ± 2 and 42 ± 1 % after 28 days, respectively. The mean diameter of fibers both scaffolds was 405 nm and 212 nm, respectively. Furthermore, the percentage of porosity in both scaffolds was calculated as 84% and 91%, separately. The level of hydrophilicity of the scaffolds was measured by the dynamic contact angle method. Moreover, the increase in the percentage of polyvinyl alcohol led to the decrease in the average contact angle in scaffold A and scaffold B from 90° to 70°, respectively. The results of bone marrow culture test with MG-63 (NCBI C555) cell on the surface of scaffolds demonstrated not cytotoxicity in the resulting scaffolds as well as a suitable substrate for the adhesion and growth of the cells. According to our findings, the electrospun fluorapatite-incorporated-chitosan/polyvinyl alcohol scaffold could provide a new nanocomposite for biomedical applications.

Mechanical properties, and in vitro biocompatibility assessment of biomimetic dual layered keratin/ hydroxyapatite scaffolds.

A novel biomimetic dual layered keratin/hydroxyapatite (keratin/HA) scaffold was designed using iterative freeze-drying technique. The prepared scaffolds were studied using several analytical techniques to better understand the biological, structural, and mechanical properties. The developed multilayered, interconnected, porous keratin scaffold with different hydroxyapatite (HA) content in the outer and inner layer, mimics the inherent gradient structure of alveolar bone. SEM studies showed an interconnected porous architecture of the prepared scaffolds with seamless integration between the upper and lower layers. The incorporation of HA improved the mechanical properties keratin/HA scaffolds. The keratin/HA scaffolds exhibited superior mechanical properties in terms of Young's modulus and compressive strength in comparison to pure keratin scaffolds. The biocompatibility studies suggested that both keratin and keratin/HA scaffolds were cyto-compatible, in terms of cell proliferation. Furthermore, it showed that both the tested materials can served as an ideal substrate for the differentiation of Saos-2 cells, leading to mineralization of the extracellular matrix. In summary, ionic liquid based green technique was employed for keratin extraction to fabricate keratin/HA scaffolds and our detailed in vitro investigations suggest the great potential for these composite scaffolds for bone tissue engineering in future.

A remote atmospheric pressure plasma-assisted textile functionalization process on polymeric scaffolds for bone tissue engineering

When adopting polylactic acid (PLA) nonwoven for bone tissue engineering scaffolds, the inert and hydrophobic nature of PLA leads to poor biocompatibility and osteoconductivity, and limits the efficiency of applying bioceramic coatings, such as hydroxyapatite (HAp), for surface functionalization. To tackle these issues, a remote atmospheric pressure plasma (APP) system using a bespoke Pyrex chamber and acrylic acid monomer was designed and employed to functionalize the PLA via depositing carboxylic acid functional groups onto its surface. The remote APP showed being polymeric textile-suitable with an improved efficiency on not only immobilizing carboxylic acid functional groups on the PLA nonwoven than conventional systems but also the alternate soaking process for HAp deposition. Being compared with the neat PLA, the plasma-functionalized PLA exhibited a more hydrophilic surface (from 130.49 ± 1.28° to 117.40 ± 2.53°) with a 30-day stability (from 117.40 ± 2.53° to 119.40 ± 0.75°) and showed better biocompatibility (136 % to the neat PLA) with MC3T3-E1 mouse embryonic osteoblast cells after HAp deposition. The presence of carboxylic acid functional groups and HAp (Ca/P ratio of 1.7) was also identified using X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy and a scanning electron microscope with energy dispersive X-ray analysis.

Freeze casting to engineer gradient porosity in hydroxyapatite-boron nitride nanotube composite scaffold for improved compressive strength and osteogenic potential

Graded porosity plays a crucial role in scaffolds for bone tissue engineering as it facilitates vital processes such as nutrient diffusion, cellular infiltration, and tissue integration. This paper explores the utilization of freeze casting (FC) as a technique to generate composite scaffolds comprising hydroxyapatite (HA) reinforced with 1D-boron nitride nanotubes (BNNTs) featuring graded porosity and improved compressive strength. Comparative studies were conducted using FC at room and sub-zero temperatures to assess the influence of temperature gradient and heat transfer rate on the production of gradient and aligned porosity in HA-BNNT composites. The FC process with a prolonged thermal gradient facilitated the creation of aligned pores in the HA-BNNT, exhibiting a wide distribution of 60% porosity ranging from 1 to 30 μm. Adding high strength 1 vol% BNNT reinforcement resulted in a remarkable 50% enhancement in compressive strength compared to the control sample. Osteoblasts seeded on the HA-BNNT substrate exhibited significantly higher alkaline phosphate activity, indicating accelerated mineralization compared to the control sample. Gradient porosity and wide pore distribution in the HA-BNNT scaffolds promoted osteogenic activities. Overall, the demonstrated FC processing technique and BNNT addition hold great potential for developing functional and biomimetic scaffolds that can effectively promote tissue regeneration, leading to improved clinical outcomes in bone tissue engineering applications.

Bioinert ceramics scaffolds for bone tissue engineering by laser-based powder bed fusion: a preliminary review

The implementation of laser powder bed fusion (PBF-LB) on ceramics is far more demanding than their metallic and polymeric counterparts for bone tissue engineering (BTE). The review will shed light on bioinert ceramics-based biomaterials manufacturing through PBF-LB incorporating alumina and yttria-stabilized zirconia as oxide-based ceramics and nitride-based ceramics as non-oxide-based ceramics with particular prominence on their properties and requirements for biomedical devices and BTE. The review paper will also classify bioinert scaffolds processed through PBF-LB as a medium to manufacture drug delivery systems (DDS) and to ameliorate critical-sized bone defects based on the fracture site length of the bone with the various modes of functionalization through the incorporation of drugs, stem cells, and growth factors for personalized medicine.

Fabrication and characterizations of simvastatin-containing mesoporous bioactive glass and molybdenum disulfide scaffold for bone tissue engineering.

Due to the limitations of the current treatment approaches of allograft and autograft techniques, treating bone disorders is a significant challenge. To address these shortcomings, a novel biomaterial composite is required. This study presents the preparation and fabrication of a novel biomaterial composite scaffold that combines poly (D, L-lactide-co-glycolide) (PLGA), mesoporous bioactive glass (MBG), molybdenum disulfide (MoS2), and simvastatin (Sim) to address the limitations of current bone grafting techniques of autograft and allograft. The fabricated scaffold of PLGA-MBG-MoS2-Sim composites was developed using a low-cost hydraulic press and salt leaching method, and scanning electron microscopy (SEM) analysis confirmed the scaffolds have a pore size between 143 and 240 μm. The protein adsorption for fabricated scaffolds was increased at 24 h. The water adsorption and retention studies showed significant results on the PLGA-MBG-MoS2-Sim composite scaffold. The biodegradation studies of the PLGA-MBG-MoS2-Sim composite scaffold have shown 54% after 28 days. In vitro, bioactivity evaluation utilizing simulated body fluid studies confirmed the development of bone mineral hydroxyapatite on the scaffolds, which was characterized using x-ray diffraction, Fourier transform infrared, and SEM analysis. Furthermore, the PLGA-MBG-MoS2-Sim composite scaffold is biocompatible with C3H10T1/2 cells and expresses more alkaline phosphatase and mineralization activity. Additionally, in vivo research showed that PLGA-MBG-MoS2-Sim stimulates a higher rate of bone regeneration. These findings highlight the fabricated PLGA-MBG-MoS2-Sim composite scaffold presents a promising solution for the limitations of current bone grafting techniques.

Macroporous Nanostructured Calcium Phosphate/Chitosan-Gelatin Composite Bone Tissue Engineering Scaffold

Background: Tissue engineering is an emerging technology developed for the therapeutic reconstruction of damaged tissue. Objective: In this study, a ceramic/polymer nanocomposite bone tissue engineering scaffold was prepared by coating a tetracalcium phosphate/dicalcium phosphate mixture slurry on a porous 3D chitosan-gelatin construction. Methods: The phase composition, structural groups, and morphological aspects of the samples were characterized. Furthermore, the 3D composite scaffold was immersed in simulated body fluid (SBF) solution at 37ºC for various periods to track its compositional and structural changes. Results: Based on the results, the coated layer is composed of needle-like carbonated apatite nanosized crystals with some tetracalcium phosphate/dicalcium phosphate initial materials. The nanocomposite was porous with an average macropore size of about 410 μm. The in vitro tests revealed that the composition of the coated layer tends to be apatite crystals, which are similar to natural bone in terms of chemistry and morphology. Conclusion: The results suggest that a simple coating of chitosan-gelatin scaffolds using reactive calcium phosphate particles may introduce a novel nanocomposite scaffold with improved mechanical strength, bioactivity, and osteoconductivity.

Controlled drug release from policaprolactone-piperine electrospun scaffold for bone tissue engineering

Polymeric drug scaffolds have been intensively studied in orthopedic surgery due to their capacity for the regimented and site-specific liberation of the therapeutic agent at the intended locus. In this context, electrospinning is a promising technique for producing scaffolds using biodegradable and biocompatible polymers. In the present study, scaffolds of Polycaprolactone (PCL) with Piperine (PIP) incorporated at different concentrations (1, 3, and 5 %) were obtained by electrospinning. The electrospun PCL, PCL/PIP 1 %, PCL/PIP 3 %, and PCL/PIP 5 % groups were analyzed by FTIR spectroscopy to identify the incorporated drug and through UV-VIS spectroscopy to evaluate its controlled release. In addition, the bone repair was verified by Raman spectroscopy using ᶹ1PO43- vibration data obtained by in vivo analysis. The morphology and diameter of the nanofibers were obtained by scanning electron microscopy (SEM). The PCL, PCL/PIP 1 %, PCL/PIP 3 %, PCL/PIP 5 % scaffolds had diameters of 0.0015 ± 0.002 μm, 1.08 ± 0.007 μm, 1.09 ± 0.02 μm, 0.59 ± 0.016 μm, respectively. Piperine release was pronounced after 15 days. Therefore, at 30 days, the PCL/PIP 1 % scaffold released 64 % ± 0.00062, while the PCL/PIP 3 % and PCL/PIP 5 % scaffolds released only 16.06 ± 0.00012 and 9.08 % ± 0.00031, respectively. This study provided evidence that PCL/Piperine can be used to significantly increase bone regeneration. Results from Raman spectroscopy and histological analysis demonstrated that the PCL/PIP 1 %, 3 %, and 5 % groups had better bone regeneration than the negative control group after 15 days and 30 days of treatment. The prolonged release of piperine promoted by PCL, a hydrophobic drug carrier, caused the neoformation of the bones to be restricted to the inner part of the bone defect, creating an immature bone with evident cellular differentiation.

Advances in the Application of Photothermal Composite Scaffolds for Osteosarcoma Ablation and Bone Regeneration.

Photothermal therapy is a promising approach to cancer treatment. The energy generated by the photothermal effect can effectively inhibit the growth of cancer cells without harming normal tissues, while the right amount of heat can also promote cell proliferation and accelerate tissue regeneration. Various nanomaterials have recently been used as photothermal agents (PTAs). The photothermal composite scaffolds can be obtained by introducing PTAs into bone tissue engineering (BTE) scaffolds, which produces a photothermal effect that can be used to ablate bone cancer with subsequent further use of the scaffold as a support to repair the bone defects created by ablation of osteosarcoma. Osteosarcoma is the most common among primary bone malignancies. However, a review of the efficacy of different types of photothermal composite scaffolds in osteosarcoma is lacking. This article first introduces the common PTAs, BTE materials, and preparation methods and then systematically summarizes the development of photothermal composite scaffolds. It would provide a useful reference for the combination of tumor therapy and tissue engineering in bone tumor-related diseases and complex diseases. It will also be valuable for advancing the clinical applications of photothermal composite scaffolds.

Integrating Fluorescence and Magnetic Resonance Imaging in Biocompatible Scaffold for Real-Time Bone Repair Monitoring and Assessment.

In situ monitoring of bone tissue regeneration progression is critical for the development of bone tissue engineering scaffold. However, engineered scaffolds that can stimulate osteogenic progress and allow for non-invasive monitoring of in vivo bone regeneration simultaneously are rarely reported. Based on a hard-and-soft integration strategy, a multifunctional scaffold composed of 3D printed microfilaments and a hydrogel network containing simvastatin (SV), indocyanine green-loaded superamphiphiles, and aminated ultrasmall superparamagnetic iron oxide nanoparticles (USPIO-NH2 ) is fabricated. Both in vitro and in vivo results demonstrate that the as-prepared scaffold significantly promotes osteogenesis through controlled SV release. The biocomposite scaffold exhibits alkaline phosphatase-responsive near-infrared II fluorescence imaging. Meanwhile, USPIO-NH2 within the co-crosslinked nanocomposite network enables the visualization of scaffold degradation by magnetic resonance imaging. Therefore, the biocomposite scaffold enables or facilitates non-invasive in situ monitoring of neo-bone formation and scaffold degradation processes following osteogenic stimulation, offering a promising strategy to develop theranostic scaffolds for tissue engineering.

Bone-like apatite formation in biocompatible phosphate-crosslinked bacterial cellulose-based hydrogels for bone tissue engineering applications

Addressing major bone injuries is a challenge in bone regeneration, necessitating innovative 3D hydrogel-based therapeutic approaches to enhance scaffold properties for better bioactivity. Bacterial cellulose (BC) is an excellent scaffold for bone tissue engineering due to its biocompatibility, high porosity, substantial surface area, and remarkable mechanical strength. However, its practical application is limited due to a lack of inherent osteogenic activity and biomineralization ability. In this study, we synthesized bone-like apatite in biocompatible BC hydrogel by introducing phosphate groups. Hydrogels were prepared using fibrous BC, acrylamide (AM), and bis [2-methacryloyloxy] ethyl phosphate (BMEP) as a crosslinker through free radical polymerization (P-BC-PAM). P-BC-PAM hydrogels exhibited outstanding compressive mechanical properties, highly interconnected porous structures, good swelling, and biodegradable properties. BMEP content significantly influenced the physicochemical and biological properties of the hydrogels. Increasing BMEP content enhanced the fibrous structure, porosity from 85.1 % to 89.5 %, and compressive mechanical strength. The optimized hydrogel (2.0P-BC-PAM) displayed maximum compressive stress, toughness, and elastic modulus at 75 % strain: 221 ± 0.08 kPa, 24,674.2 ± 978 kPa, and 11 ± 0.47 kPa, respectively. P-BC-PAM hydrogels underwent biomineralization in simulated body fluid (SBF) for 14 days, forming bone-like apatite with a Ca/P ratio of 1.75, similar to hydroxyapatite. Confirmed by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM), this suggests their potential as scaffolds for bone tissue engineering. MC3T3-E1 osteoblast cells effectively attached and proliferated on P-BC-PAM. In summary, this study contributes insights into developing phosphate-functionalized BC-based hydrogels with potential applications in bone tissue engineering.

Recent advances of responsive scaffolds in bone tissue engineering.

The investigation of bone defect repair has been a significant focus in clinical research. The gradual progress and utilization of different scaffolds for bone repair have been facilitated by advancements in material science and tissue engineering. In recent times, the attainment of precise regulation and targeted drug release has emerged as a crucial concern in bone tissue engineering. As a result, we present a comprehensive review of recent developments in responsive scaffolds pertaining to the field of bone defect repair. The objective of this review is to provide a comprehensive summary and forecast of prospects, thereby contributing novel insights to the field of bone defect repair.

Elastic 3D-Printed Nanofibers Composite Scaffold for Bone Tissue Engineering.

Loading nanoparticles into hydrogels has been a conventional approach to augment the printability of ink and the physicochemical characteristics of scaffolds in three-dimensional (3D) printing. However, the efficacy of this enhancement has often proven to be limited. We amalgamate electrospun nanofibers with 3D printing techniques to fabricate a composite scaffold reminiscent of a "reinforced concrete" structure, aimed at addressing bone defects. These supple silica nanofibers are synthesized through a dual-step process involving high-speed homogenization and low-temperature ball milling technology. The nanofibers are homogeneously blended with sodium alginate to create the printing ink. The resultant ink was extruded seamlessly, displaying commendable molding properties, thereby yielding scaffolds with favorable macroscopic morphology. In contrast to nanoparticle-reinforced scaffolds, composite scaffolds containing nanofibers exhibit superior mechanical attributes and bioactivity. These nanofiber composite scaffolds demonstrate enhanced osteoinductive properties in both in vitro and in vivo evaluations. To conclude, this research introduces a novel 3D printing approach where the fabricated nanofiber-infused 3D-printed scaffolds hold the potential to revolutionize the realm of 3D printing in the domain of bone tissue engineering.