Preparation and characterization of gelatin/α-TCP/SF biocomposite scaffold for bone tissue regeneration

Application of Bioactive Materials for Osteogenic Function in Bone Tissue Engineering

Bone tissue defects present a major challenge in orthopedic surgery. Bone tissue engineering using multiple versatile bioactive materials is a potential strategy for bone-defect repair and regeneration. Due to their unique physicochemical and mechanical properties, biofunctional materials can enhance cellular adhesion, proliferation, and osteogenic differentiation, thereby supporting and stimulating the formation of new bone tissue. 3D bioprinting and physical stimuli-responsive strategies have been employed in various studies on bone regeneration for the fabrication of desired multifunctional biomaterials with integrated bone tissue repair and regeneration properties. In this review, biomaterials applied to bone tissue engineering, emerging 3D bioprinting techniques, and physical stimuli-responsive strategies for the rational manufacturing of novel biomaterials with bone therapeutic and regenerative functions are summarized. Furthermore, the impact of biomaterials on the osteogenic differentiation of stem cells and the potential pathways associated with biomaterial-induced osteogenesis are discussed.

Enhanced mechanic properties of calcium phosphate cements via mussel-inspired adhesive as bone substitute: Highlights of their interactions

BACKGROUND

Inspired by natural bones, many organic components were added to Calcium Phosphate Cements (CPCs) to improve their mechanical strength. However, the strength of these composite CPCs is limited by the low strength of organic components itself and the weak interaction between organic components and CPCs.

OBJECTIVE

Firstly, a composite CPC containing mussel-inspired adhesive, Poly-(Dopamine Methacrylamide-co-2-methoxy Ethylacrylate) (pDM) was developed. Secondly, the interactions between pDM and CPC and their effect on mechanical properties were investigated.

METHODS

The interactions between pDM and CPC were performed by Nuclear Magnetic Resonance, Laser Raman, X-ray Photoelectron Spectroscopy, Fourier Transform-Infrared Spectroscopy and X-ray Diffraction Analysis.

RESULTS

The toughness and compressive strength of pDM-CPC scaffold were both significantly enhanced, because of the enhanced interface binding strength among CPC and pDM due to their interaction and the improved mechanical strength of pDM owing to its self-oxidation cross-linking. The toughness of pDM-CPC scaffolds increased with the increased contents of pDM, while pDM-CPC scaffold containing 35 wt.% pDM had the highest compressive strength of all, which the latter was more than five times compared to that of CPC.

CONCLUSION

The mechanically strong pDM-CPC scaffolds has potential application in bone regeneration as well as in craniofacial and orthopedic repair.

Silk fibroin nanoparticles and β-tricalcium phosphate loaded tissue engineered gelatin bone scaffolds: A Nature-based, low-cost solution

Tissue engineering has recently attracted attention as an alternative to traditional treatment methods for tissue and organ damage. Since bone is one of the most important vital parts of the body, the treatment of bone damage is important. Silk fibroin is a natural polymer with properties such as biocompatibility and biodegradability, which attracts attention with its controlled release, especially in drug delivery systems. In this study, gelatin-based scaffolds loaded with silk fibroin nanoparticles and β -tricalcium phosphate (β -TCP) were developed to be used as a potential drug delivery system in bone tissue engineering. The chosen nanoparticle formulation has a 294 nm average diameter with a 0.380 polidispersity index (PDI). In vitro characterization of scaffolds was performed by mechanical, morphological characterization, swelling capacity, Differential Scanning Calorimetry (DSC), Fourier-Transform Infrared Spectroscopy (FT-IR) measurements, and biocompatibility was evaluated by cell culture studies. Swelling index, tensile strength, elongation at break, and Young modulus of the β -TCP and silk nanoparticles loaded scaffold were found as 456%, 1.476 MPa, 6.75%, and 24 MPa, respectively. In vitro cell culture studies have shown that scaffolds prepared in the present study can accelerate osteoblast differentiation and increase the healing rate of bone tissues. In addition, they have the potential to be used as a drug delivery system in bone tissue engineering that needs to be evaluated with further studies.

Current Status of Tissue Regenerative Engineering for the Treatment of Uterine Infertility

With the recent developments in tissue engineering, scientists have attempted to establish seed cells from different sources, create cell sheets through various technologies, implant them on scaffolds with various spatial structures, or load scaffolds with cytokines. These research results are very optimistic, bringing hope to the treatment of patients with uterine infertility. In this article, we reviewed articles related to the treatment of uterine infertility from the aspects of experimental treatment strategy, seed cells, scaffold application, and repair criteria so as to provide a basis for future research.

Low-temperature deposition manufacturing technology: a novel 3D printing method for bone scaffolds

The application of three-dimensional printing technology in the medical field has great potential for bone defect repair, especially personalized and biological repair. As a green manufacturing process that does not involve liquefication through heating, low-temperature deposition manufacturing (LDM) is a promising type of rapid prototyping manufacturing and has been widely used to fabricate scaffolds in bone tissue engineering. The scaffolds fabricated by LDM have a multi-scale controllable pore structure and interconnected micropores, which are beneficial for the repair of bone defects. At the same time, different types of cells or bioactive factor can be integrated into three-dimensional structural scaffolds through LDM. Herein, we introduced LDM technology and summarize its applications in bone tissue engineering. We divide the scaffolds into four categories according to the skeleton materials and discuss the performance and limitations of the scaffolds. The ideas presented in this review have prospects in the development and application of LDM scaffolds.

The study of self-regulating α-TCP based composite by micro/nano scaled silk fibroin and α-CSH on physicochemical and biological properties of bone cement

A novel self-hardening α-tricalcium phosphate (α-TCP) bone cement complexed with different content of α-calcium sulfate hemihydrate (α-CSH) and micrometer hydroxyapatite mineralized silk fibroin (HA-SF) using micro/SF as curing liquid has been investigated in this work, which was capable of tunable setting time, degradation, mechanical property and ability to anti-washout. After addition 0 ∼ 25% α-CSH to the α-TCP cement with SFFs as curing liquid, it shortened the setting time of the modified composite to 10 ∼ 30 min. Furthermore, the addition of SFFs improved the compressive strength of the composite from 5.41 MPa to 9.44 MPa. The composites with both Na₂HPO₄ and SFFs as curing liquid showed good anti-collapse performance. The weight loss ratio of bone cement was -0.18 ∼ 12.08% in 4 weeks when the content of α-CSH in α-TCP/α-CSH was between 0 ∼ 25 wt%. During the degradation of α-CSH, the amorphous α-TCP were deposited as hydroxyapatite to formed a plate-like products on the surface of composite. Compared to the composite with Na₂HPO₄ solution as the curing liquid, alkaline phosphatase (ALP) activity of the composites using SFFs as curing liquid were maintained at high levels on the 14th day especially when the Ca/P ratio was 1.7. This study provides a theoretical basis for the regeneration of bone defects guided by bone cement materials.

Calcium Phosphate Functionalization and Applications in Dentistry

The oral and maxillofacial hard tissues support the maxillofacial shape and serve as the foundation for functional activities. Defects in these tissues not only impair patients’ ability to perform their normal physiological functions but also have a significant negative impact on their psychological well-being. Moreover, these tissues have a limited capacity for self-healing, necessitating the use of artificial materials to repair defects. Calcium phosphate is a fine-grained inorganic biomineral found in vertebrate teeth and bones that has a comparable composition to human hard tissues. Calcium phosphate materials are biocompatible, bioactive, and osteogenic for hard tissue repair, despite drawbacks such as poor mechanical qualities, limiting their clinical efficacy and application. With the advancement of materials science and technology, numerous techniques have been developed to enhance the characteristics of calcium phosphate, and one of them is functionalization. Calcium phosphate can be functionally modified by changing its size, morphology, or composition through various preparation processes to achieve multifunctionality and improve physical and chemical properties, biocompatibility, and osteogenic potential. The purpose of this review is to provide new ideas for the treatment of oralmaxillofacial hard tissue defects and deficiencies by summarizing the functionalization strategies of calcium phosphate materials and their applications in dentistry.

3D Bioprinted Scaffolds for Bone Tissue Engineering: State-Of-The-Art and Emerging Technologies

Treating large bone defects, known as critical-sized defects (CSDs), is challenging because they are not spontaneously healed by the patient’s body. Due to the limitations associated with conventional bone grafts, bone tissue engineering (BTE), based on three-dimensional (3D) bioprinted scaffolds, has emerged as a promising approach for bone reconstitution and treatment. Bioprinting technology allows for incorporation of living cells and/or growth factors into scaffolds aiming to mimic the structure and properties of the native bone. To date, a wide range of biomaterials (either natural or synthetic polymers), as well as various cells and growth factors, have been explored for use in scaffold bioprinting. However, a key challenge that remains is the fabrication of scaffolds that meet structure, mechanical, and osteoconductive requirements of native bone and support vascularization. In this review, we briefly present the latest developments and discoveries of CSD treatment by means of bioprinted scaffolds, with a focus on the biomaterials, cells, and growth factors for formulating bioinks and their bioprinting techniques. Promising state-of-the-art pathways or strategies recently developed for bioprinting bone scaffolds are highlighted, including the incorporation of bioactive ceramics to create composite scaffolds, the use of advanced bioprinting technologies (e.g., core/shell bioprinting) to form hybrid scaffolds or systems, as well as the rigorous design of scaffolds by taking into account of the influence of such parameters as scaffold pore geometry and porosity. We also review in-vitro assays and in-vivo models to track bone regeneration, followed by a discussion of current limitations associated with 3D bioprinting technologies for BTE. We conclude this review with emerging approaches in this field, including the development of gradient scaffolds, four-dimensional (4D) printing technology via smart materials, organoids, and cell aggregates/spheroids along with future avenues for related BTE.

Bone Scaffolds: An Incorporation of Biomaterials, Cells, and Biofactors

Large injuries to bones are still one of the most challenging musculoskeletal problems. Tissue engineering can combine stem cells, scaffold biomaterials, and biofactors to aid in resolving this complication. Therefore, this review aims to provide information on the recent advances made to utilize the potential of biomaterials for making bone scaffolds and the assisted stem cell therapy and use of biofactors for bone tissue engineering. The requirements and different types of biomaterials used for making scaffolds are reviewed. Furthermore, the importance of stem cells and biofactors (growth factors and extracellular vesicles) in bone regeneration and their use in bone scaffolds and the key findings are discussed. Lastly, some of the main obstacles in bone tissue engineering and future trends are highlighted.

3D Printed Composite Scaffolds in Bone Tissue Engineering: A systematic review

OBJECTIVE

This study aimed to analyze the effect of fabrication factors on both biological and physico-chemical features of 3-dimensional (3D) printed composite scaffolds.

METHOD

Electronic search was done according to the PRISMA guideline in PubMed and Scopus databases limited to English articles published until May 2021.Studies in which composite scaffolds were fabricated through computer-aided design and computer-aided manufacturing (CAD-CAM)-based methods were included.Articles regarding the features of the scaffolds fabricated through indirect techniques were excluded.

RESULTS

Full text of 121 studies were reviewed, and 69 met the inclusion criteria. According to analyzed studies, PCL and HA were the most commonly used polymer and ceramic,respectively. Besides,the Solvent-based technique was the most commonly used composition technique, which enabled preparing blends with high concentrations of ceramic materials. The most common fabrication method used in the included studies was Fused deposition modeling (FDM).The addition of bio-ceramics enhanced the mechanical features and the biological behaviors of the printed scaffolds in a ratio-dependent manner. However,studies that analyzed the effect of ceramic weight ratio showed that scaffolds with the highest ceramic content did not necessarily possess the optimal biological and non-biological features.

CONCLUSION

The biological and physico-chemical behaviors of the scaffold can be affected by pre-printing factors, including utilized materials, composition techniques, and fabrication methods. Fabricating scaffolds with high mineral content as of the natural bone may not provide the optimal condition for bone formation. Therefore, it is recommended that future studies compare the efficiency of different kinds of biomaterials rather than different weight ratios of one type.

Skeletal microenvironment system utilising bovine bone scaffold co-cultured with human osteoblasts and osteoclast-like cells

A three-dimensional ex vivo bone cell culture system mimicking the skeletal system is useful for bone tissue engineering and as drug discovery platforms. The present study aimed to establish a three-dimensional skeletal culture system using native bovine bone scaffolds and human bone cells. Bovine bone scaffolds were cultured with human foetal osteoblasts 1.19 and human peripheral blood mononuclear cells for 21 days under standard culture conditions. The following groups were established: Decalcified unseeded bone scaffold (DUBS) as baseline control, decalcified seeded bone scaffold (DSBS) to mimic osteoporosis condition and undecalcified seeded bone scaffold to mimic normal condition. The scaffold's porosity and cell attachment on the scaffolds were determined using scanning electron microscopy. Histological evaluation was used to examine changes in trabecular bone structure. Dual-energy X-ray absorptiometry analysis was performed to determine the bone mineral density (BMD) and bone mineral content (BMC) of the scaffolds. A compression test was performed to examine the total biomechanical strength of the scaffolds. The trabecular thickness and number increased, while the trabecular separationwas reduced slightly in DSBS than in DUBS (P>0.05). The BMD and BMC increased significantly (P<0.05), while the compressive strength only increased slightly in DSBS than in DUBS (P>0.05). In conclusion, the ex vivo skeletal microenvironment comprising native bovine bone scaffolds seeded with bone cells is structurally, functionally and mechanically comparable with natural bone. This system may be used as a platform to understand bone physiology and screen for potential drug candidates.

Effect of Morphological Characteristics and Biomineralization of 3D-Printed Gelatin/Hyaluronic Acid/Hydroxyapatite Composite Scaffolds on Bone Tissue Regeneration

The use of porous three-dimensional (3D) composite scaffolds has attracted great attention in bone tissue engineering applications because they closely simulate the major features of the natural extracellular matrix (ECM) of bone. This study aimed to prepare biomimetic composite scaffolds via a simple 3D printing of gelatin/hyaluronic acid (HA)/hydroxyapatite (HAp) and subsequent biomineralization for improved bone tissue regeneration. The resulting scaffolds exhibited uniform structure and homogeneous pore distribution. In addition, the microstructures of the composite scaffolds showed an ECM-mimetic structure with a wrinkled internal surface and a porous hierarchical architecture. The results of bioactivity assays proved that the morphological characteristics and biomineralization of the composite scaffolds influenced cell proliferation and osteogenic differentiation. In particular, the biomineralized gelatin/HA/HAp composite scaffolds with double-layer staggered orthogonal (GEHA20-ZZS) and double-layer alternative structure (GEHA20-45S) showed higher bioactivity than other scaffolds. According to these results, biomineralization has a great influence on the biological activity of cells. Hence, the biomineralized composite scaffolds can be used as new bone scaffolds in bone regeneration.

Use of Silver Nanoparticle–Gelatin/Alginate Scaffold to Repair Skull Defects

The major objectives of this study were to investigate the effects of silver nanoparticles– gelatin (AgNPs) on the physical and chemical properties of gelatin/alginate (Gel/Alg) scaffolds and the bone-promoting effect of AgNP–Gel/Alg scaffolds. Gel/Alg scaffolds consisting of 0 μM, 200 μM, 400 μM, and 600 μM AgNPs were prepared. SEM was used to evaluate the physical properties of the scaffolds. A CCK-8 assay was performed to determine the cell proliferation activity, and Micro-CT and histological analysis were used to assess the osteogenic effect. The pore size, porosity, and the water absorption and degradation rates of AgNP–Gel/Alg scaffolds were found to be increased compared with those of Gel/Alg scaffolds (control group). CCK-8 showed that cell proliferation activity in the 200 μM group was significantly higher than that in the control group. Micro-CT analysis showed that there was more new bone around AgNP–Gel/Alg than the control group, and the amount of bone formation in the 200 μM group was significantly higher than that in the other groups. Masson staining showed that numerous collagen fibers had proliferated around the AgNP–Gel/Alg scaffold and tended to thicken over time. AgNP–Gel/Alg scaffolds promoted the repair of skull defects in New Zealand rabbits and exerted a marked osteogenic effect in vivo. The 200 μM AgNP–Gel/Alg scaffold was shown to be more suitable for bone tissue engineering materials.

Fabrication of hierarchically porous silk fibroin-bioactive glass composite scaffold via indirect 3D printing: Effect of particle size on physico-mechanical properties and in vitro cellular behavior

In order to regenerate bone defects, bioactive hierarchically scaffolds play a key role due to their multilevel porous structure, high surface area, enhanced nutrient transport and diffusion. In this study, novel hierarchically porous silk fibroin (SF) and silk fibroin-bioactive glass (SF-BG) composite were fabricated with controlled architecture and interconnected structure, by combining indirect three-dimensional (3D) inkjet printing and freeze-drying methods. Further, the effect of 45S5 Bioactive glass particles of different sizes (<100 nm and 6 μm) on mechanical strength and cell behavior was investigated. The results demonstrated that the hierarchical structure in this scaffold was composed of two levels of pores in the order of 500-600 μm and 10-50 μm. The prepared SF-BG composite scaffolds utilized by nano and micro particles possessed mechanical properties with a compressive strength of 0.94 and 1.2 MPa, respectively, in dry conditions. In a wet condition, the hierarchically porous scaffolds did not exhibit any fluctuation after compression load cell and were incredibly flexible, with excellent mechanical stability. The SF-BG composite scaffold with nanoparticles presented a significant 50% increase in attachment of human bone marrow stem cells in comparison with SF and SF-BG scaffold with microparticles. Moreover, SF-BG scaffolds promoted alkaline phosphatase activity as compared to SF scaffolds without BG particles on day 14. In brief, the 3D porous silk fibroin-based composites containing BG nanoparticles with excellent mechanical properties are promising scaffolds for bone tissue regeneration in high load-bearing applications.

Biodegradable waterborne polyurethane grafted with gelatin hydrolysate via solvent-free copolymerization for potential porous scaffold material

One potential porous scaffold material based on polyester waterborne polyurethane (PEUR) grafted with modified gelatin hydrolysate (GH) has been investigated in this research. First, the GH was modified with a silane coupling agent (KH550), and then the modified GH was mixed with pre-polymer emulsion of PEUR to obtain the PEUR grafted GH emulsion (PEUR-g-GH). The synthesized PEUR-g-GH emulsions were characterized by stability analysis and viscosity test. Moreover, the film-forming property of PEUR-g-GH has also been studied, and the PEUR-g-GH films were characterized regarding the water resistance, solvent resistance, mechanical properties, FTIR, AFM, SEM, DMA, TGA and contact angle testing. Finally, the bioactivity and biodegradation were investigated by soaking PEUR-g-GH scaffolds in simulated body fluid (SBF). The results indicated that the PEUR-g-GH emulsion has good stability, water resisting (the contact angle was over 90^o), the PEUR-g-GH showed excellent film-forming, high storage modulus, good structural homogeneity and thermal stability (the temperature of maximum weight loss was over 350 °C). The freeze-dried sample showed porous structure, and the mutual crosslinking of layers can contribute to a good bearing capacity for scaffold. The SBF biodegradability revealed that the biodegradation rate and degree of films gradually increased with the content of GH increased. In addition, the cells on the material were markedly enhanced, and most of cells have proliferated and formed vesicles, which shown a good biocompatibility.

Recent advances in functional nanostructured materials for bone-related diseases

Bone-related diseases seriously threaten people's health and research studies have been dedicated towards searching for new and effective treatment methods. Nanotechnologies have opened up a new field in recent decades and nanostructured materials, which exist in a variety of forms, are considered to be promising materials in this field. This article reviews the most recent progress in the development of nanostructured materials for bone-related diseases, including osteoporosis, osteoarthritis, bone metastasis, osteomyelitis, myeloma, and bone defects. We highlight the advantages and functions of nanostructured materials, including sustained release, bone targeting, scaffolding in bone tissue engineering, etc., in bone-related diseases. We also include the remaining challenges of these emerging materials.

Evaluation of silymarin/duck's feet-derived collagen/hydroxyapatite sponges for bone tissue regeneration

Tissue engineered scaffolds, made of natural derived materials, have the potential to be used in bone regeneration fields due to the biocompatible and biodegradable features. In this study, we propose duck's feet-derived collagen (DC) sponges blended with hydroxyapatite (HAp), incorporated with different concentrations of silymarin (Smn), for improved bone regeneration. The morphological and structural properties of DC/HAp and DC/HAp loaded with 25, 50 and 100 μM of Smn sponges were analyzed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). In vitro evaluations were carried out on rabbit bone marrow stem cells (rBMSCs) using MTT assay for cell proliferation, ALP assay for osteogenic differentiation and reverse transcription-polymerase chain reaction (RT-PCR) for expression of mRNAs. For the evaluation of new bone formation in vivo, histological analysis and micro computed tomography (μCT) were used. Preliminary results, on Smn/DC/HAp morphology and mechanical properties, showed an interconnected porosity suitable for cells ingrowth and a higher compressive strength with the presence of Smn. Similarly, the cells proliferation and ALP activity modulation were positively influenced by the Smn content. Especially, the 100 μM Smn/DC/HAp sponge efficiently enhances the rBMSCs adhesion, growth and gene expression of osteogenic markers. The enhanced osteoinductive effects of sponges blended with Smn were confirmed using μ-CT and histological evaluations. In conclusion, results suggest that collagen sponges represent an excellent environment for cells growth and proliferation, while Smn plays an important role to improve materials osteogenic properties.

Gelatin/PVA scaffolds fabricated using a 3D-printing process employed with a low-temperature plate for hard tissue regeneration: Fabrication and characterizations

Tissue engineering aims to repair or replace damaged tissues or organs using biomedical scaffolds cultured with cells. The scaffolds composed of biomaterials should guide the cells to mature into functional tissues or organs. An ideal scaffold to regenerate hard tissues should have mechanical stability as well as biocompatibilities. It has been well known that gelatin can provide outstanding biological activities, but its low mechanical stability can be one of obstacles to be used in hard tissue regeneration. To overcome the issue, we used PVA, which can reinforce the low mechanical stability of the gelatin. The gelatin/PVA scaffolds have been fabricated using a low temperature 3D-printing process. By manipulating various weight fractions of PVA/gelatin, we can obtain the optimal mixture ratio in aspect of the physical and biological properties of the scaffolds. As a result, a weight fraction of 5:5 showed appropriate mechanical strength and enhanced cell activities, such as cell proliferation and differentiation. The gelatin/PVA scaffold showed potential for future application as biomedical scaffold in soft and hard tissue regeneration.

Biomimetic Scaffolds for Bone Tissue Engineering

The use of biomimetic scaffolds for bone tissue engineering has been studied for a long time. Biomimetic scaffolds can assist and accelerate bone regeneration that is similar to that of authentic tissue, which represents the environment of cells in a living organism. Currently, numerous biomaterials have been reported for use as a biomimetic scaffold. This review focuses on the design of biomimetic scaffolds, kinds of biomaterials and methods used to fabricate biomimetic scaffolds, growth factors used with biomimetic scaffold for bone regeneration, mobilization of biological agents into biomimetic scaffolds, and studies on (pre)clinical bone regeneration from biomimetic scaffolds. Then, future prospects for biomimetic scaffolds are discussed.

Bioactive Molecules Release and Cellular Responses of Alginate-Tricalcium Phosphate Particles Hybrid Gel

In this article, a hybrid gel has been developed using sodium alginate (Alg) and α-tricalcium phosphate (α-TCP) particles through ionic crosslinking process for the application in bone tissue engineering. The effects of pH and composition of the gel on osteoblast cells (MC3T3) response and bioactive molecules release have been evaluated. At first, a slurry of Alg and α-TCP has been prepared using an ultrasonicator for the homogeneous distribution of α-TCP particles in the Alg network and to achieve adequate interfacial interaction between them. After that, CaCl2 solution has been added to the slurry so that ionic crosslinked gel (Alg-α-TCP) is formed. The developed hybrid gel has been physico-chemically characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and a swelling study. The SEM analysis depicted the presence of α-TCP micro-particles on the surface of the hybrid gel, while cross-section images signified that the α-TCP particles are fully embedded in the porous gel network. Different % swelling ratio at pH 4, 7 and 7.4 confirmed the pH responsiveness of the Alg-α-TCP gel. The hybrid gel having lower % α-TCP particles showed higher % swelling at pH 7.4. The hybrid gel demonstrated a faster release rate of bovine serum albumin (BSA), tetracycline (TCN) and dimethyloxalylglycine (DMOG) at pH 7.4 and for the grade having lower % α-TCP particles. The MC3T3 cells are viable inside the hybrid gel, while the rate of cell proliferation is higher at pH 7.4 compared to pH 7. The in vitro cytotoxicity analysis using thiazolyl blue tetrazolium bromide (MTT), bromodeoxyuridine (BrdU) and neutral red assays ascertained that the hybrid gel is non-toxic for MC3T3 cells. The experimental results implied that the non-toxic and biocompatible Alg-α-TCP hybrid gel could be used as scaffold in bone tissue engineering.