Materials For Bone Tissue Engineering Research Articles

Nonviral Gene Delivery Embedded in Biomimetically Mineralized Matrices for Bone Tissue Engineering

Research in bone tissue engineering aims to design materials that are effective at generating bone without causing significant side effects. The osteogenic potential of combining matrices and protein growth factors has been well documented, however, improvements are necessary to achieve optimal therapeutic benefits upon clinical translation. In this article, rat calvarial defects were treated with gene-activated matrices (GAMs). The GAMs used were collagen sponges mineralized with a simulated body fluid (SBF) containing a nonviral gene delivery system. Both in vitro and in vivo studies were performed to determine the optimal mode of gene delivery. After 6 weeks, the defects were extracted to assess bone formation and tissue quality through histological and microcomputed tomography analyses. The optimal GAM consisted of a collagen sponge with polyethylenimine plasmid DNA (PEI-pDNA) complexes embedded in a calcium phosphate coating produced by SBF, which increased total bone formation by 39% compared with 19% for control samples. A follow-up in vivo study was performed to optimize the ratio of growth factors included in the GAM. The optimal ratio for supporting bone formation after 6 weeks of implantation was five parts of pBMP-2 to three parts pFGF-2. These studies demonstrated that collagen matrices biomimetically mineralized and activated with plasmids encoding fibroblast growth factor-2 (FGF-2) and bone morphogenetic protein-2 (BMP-2) can optimally improve bone regeneration outcomes. Impact statement Bone tissue engineering has explored both nonviral gene delivery and the concept of biomimetic mineralization. In this study, we combined these two concepts to further enhance bone regeneration outcomes. We demonstrated that embedding polyethylenimine (PEI)-based gene delivery within a mineral layer formed from simulated body fluid (SBF) immersion can increase bone formation rates. We also demonstrated that the ratio of growth factors utilized for matrix fabrication can impact the amount of bone formed in the defect site. This research highlights a combined approach using SBF and nonviral gene delivery both in vitro and in vivo and prepares the way for future optimization of synthetic gene activated matrices.

Decellularized Extracellular Matrices in Bone Tissue Engineering: From Cells to Tissues. Mini-Review

Extracellular matrix (ECM) plays a critical role in the maintenance of cellular survival, proliferation, and differentiation potential. Decellularized ECM (dECM) used in tissue engineering applications mimics the native microenvironment to regulate cellular communications, metabolism, and intracellular signaling pathways relevant to differentiation and tissue regeneration. Herein, we reviewed the sources of dECM utilized in bone tissue engineering and their effects on osteogenesis promotion. PubMed, Science Direct, and Scopus databases were explored to provide original articles published mostly from 2015 to 2020. Then, in vitro and in vivo studies considering advancements on the effect of decellularized extracellular matrices on stem cell osteogenic commitment were reviewed. dECM is mainly extracted from cultures of mesenchymal stem cells (MSCs), fibroblasts, osteoblasts, endothelial cells as well as from bone, periosteum, cartilage, and tendon tissues. dECM provides supportive niches to MSC stemness, proliferation, migration, and osteogenic commitment via triggering substantial intracellular pathways. In general, dECM is discussed as a promising naturally-derived material in bone tissue engineering with the potency to synchronize the cell-substrate interactions, and initiating signaling pathways involved in MSC osteogenic differentiation and tissue reconstruction.

Sponge-like processed D-periodic self-assembled atelocollagen supports bone formation in vivo

Fibrous biopolymeric collagen extracted from animal tissues has been widely used for fabricating matrices for bone tissue engineering (BTE). However, animal extracted collagens can trigger immune reactions when implanted in vivo and the presence of native crosslinks leads to batch-to-batch variability. Atelocollagen, a monomeric form of collagen, is free of telopeptides, which are mainly responsible for the immunogenicity of collagen, and can self-assemble in vitro to obtain fibrils with the characteristic D-periodic staining pattern of native collagen. However, atelocollagen-based biomaterials have not extensively been studied and, hence, their suitability for BTE remains relatively unexplored. Besides, to stabilize collagen biomaterials, chemical and physical crosslinking are used, although chemical agents are cytotoxic while the physical methods yield a less effective crosslinking. A combination of physical and chemical crosslinking is a suitable alternative that has rarely been tested in BTE programs. In this work, a sponge-like biomaterial (DCol-S) was processed from D-periodic self-assembled atelocollagen and its stabilization was studied using the combination of a dehydrothermal treatment (DHT) and minimal glutaraldehyde (GTA) exposition crosslinking, to increase the resistance to degradation of the scaffold without a major effect on the biomaterial structure. The microstructural features of the final sponges were characterised and compared to a commercial biomaterial processed from native bovine collagen (Helistat®, Integra Lifesciences, NJ, USA), demonstrating that a D-periodic nanostructure was obtained and maintained after processing of the sponges. MC3T3-E1 preosteoblast adhesion, proliferation and differentiation assays in vitro showed that DCol-S is biocompatible. Furthermore, intramuscular implantation of the biomaterials loaded with rhBMP-2 revealed that the double-crosslinked sponges were able to support ectopic bone formation, while sponges stabilised only with the DHT treatment were not. Altogether, these findings show that atelocollagen-based sponges stabilised with a DHT treatment followed by a mild GTA crosslinking are a suitable alternative to polymeric extracted collagen for BTE applications.

Chitosan-Based Biomimetically Mineralized Composite Materials in Human Hard Tissue Repair.

Chitosan is a natural, biodegradable cationic polysaccharide, which has a similar chemical structure and similar biological behaviors to the components of the extracellular matrix in the biomineralization process of teeth or bone. Its excellent biocompatibility, biodegradability, and polyelectrolyte action make it a suitable organic template, which, combined with biomimetic mineralization technology, can be used to develop organic-inorganic composite materials for hard tissue repair. In recent years, various chitosan-based biomimetic organic-inorganic composite materials have been applied in the field of bone tissue engineering and enamel or dentin biomimetic repair in different forms (hydrogels, fibers, porous scaffolds, microspheres, etc.), and the inorganic components of the composites are usually biogenic minerals, such as hydroxyapatite, other calcium phosphate phases, or silica. These composites have good mechanical properties, biocompatibility, bioactivity, osteogenic potential, and other biological properties and are thus considered as promising novel materials for repairing the defects of hard tissue. This review is mainly focused on the properties and preparations of biomimetically mineralized composite materials using chitosan as an organic template, and the current application of various chitosan-based biomimetically mineralized composite materials in bone tissue engineering and dental hard tissue repair is summarized.

Simple conversion of 3D electrospun nanofibrous cellulose acetate into a mechanically robust nanocomposite cellulose/calcium scaffold

Cellulose and its derivatives are widely used as nanofibrous biomaterials, but obtaining 3D cellulose nanofibers is difficult and relevant research is scarce. In the present study, we propose a simple method for converting electrospun 3D cellulose acetate/lactic acid nanofibers via calcium hydroxide treatment into a 3D cellulose/calcium lactate nanocomposite matrix. The conversion resulted in producing a stronger nanofibrous matrix (1.382 MPa vs. 0.112 MPa) that is more hydrophilic and cell-friendly compared to the untreated cellulose acetate/lactic acid group. The successful conversion was verified via FTIR, XPS, TGA, DTG, and XRD. The ability of the scaffolds to provide a suitable environment for cell growth and infiltration was verified by CCK assay and confocal microscopy. The porous nature, mechanical strength, and presence of calcium make the 3D cellulose/calcium lactate matrix a promising material for bone tissue engineering.

Bacterial Cellulose-Based Metallic Green Nanocomposites for Biomedical and Pharmaceutical Applications.

Bacterial cellulose (BC) is a microbial biosynthesized polymer having exceptional physical and mechanical features as compared to plants derived cellulose. BC has a wide range of applications such as traditional dessert as well as gelling, stabilizing and thickening agent in many foods. The more unconventional applications of BC include but not limited to enzymes immobilization, tissue engineering, artificial blood vessels and heart valve prosthesis, bone and cartilage regeneration, corneal replacement, skin tissues repair and dental root canal treatment. This review presents the applications of BC expanded by preparing its nanocomposites with drugs, fibres, metals and metallic oxides. These nanocomposites have been studied for applications in drug delivery and biosensors. The current review focuses on the potential applications of BC-based green metallic and metal-based inorganic nanocomposites as wound dressing material, a tool for microbial control, cardiovascular stenting, and as bone tissue engineering material. In addition, the potential pharmaceutical applications of BC-based green metallic nanocomposites have also been discussed. The reported BC-based nanocomposites owe advantages in terms of stability, environment friendliness and cost-effectiveness, prolonged therapeutic effects and biocompatibility with body tissues, with faster wound healing and negligible cytotoxicity. The current review provides a deep insight into the assessment of such nanocomposites in terms of useful applications and potential commercialization for pharmaceutical as well biomedical purposes.

SYNTHESIS AND CHARACTERIZATION OF COMPOSITES BASED ON HYDROXYAPATITE NANOPARTICLES AND CHITOSAN EXTRACTED FROM SHELLS OF THE FRESHWATER CRAB Potamon algeriense

Nanocrystalline hydroxyapatite (n-HAp), which has low crystallinity, has attracted great attention due to its similarity to the inorganic part of human bone. Therefore, many studies have focused on creating new formulations combining n-HAp with some biopolymers, such as chitosan, in order to imitate biological bone tissue. The importance of chitosan and its derivatives in biomedical applications has grown significantly in the last three decades due to its biodegradability and renewable source. Besides, chitosan and its derivatives present excellent biocompatibility and biofunctionality, which make them promising materials in bone tissue engineering. In the present study, the chitosan was, first, extracted from the shell of the freshwater crab species Potamon algeriense following demineralization, deproteinization, decolouration (raw chitin) and deacetylation (chitosan) steps. Then, a novel composite based on n-HAp and extracted chitosan (CTS) with varying chitosan contents, from 5% to 20% (w/w), was synthesized and characterized for potential application in tissue regeneration. The obtained composites were characterized using X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. The precipitated n-HAp/CTS nanocomposites similar to natural bone are promising composites for bone tissue engineering applications.

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.

Lanthanum-doped mesoporous bioglasses/chitosan composite scaffolds enhance synchronous osteogenesis and angiogenesis for augmented osseous regeneration

With the progressive research of fabrication methodologies of biomaterials, hierarchically porous structures and bioactive compositions have been identified to promote bone repair and regeneration. In this study, we firstly fabricated lanthanum-doped bioglasses/chitosan (La-BGs/CS) composite scaffolds for novel bone tissue engineering materials. The La-BG microspheres in the scaffolds possessed hierarchically porous structures combining hollow cores and mesoporous shells. The effects of La-BGs/CS scaffolds on osteogenesis and angiogenesis were evaluated both in vitro and in vivo. The as-doped lanthanum oxide in the scaffolds remarkably promoted osteogenic differentiation of bone marrow-derived mesenchymal stem cells via activating ERK signaling pathway, and stimulated migration and tube formation of human umbilical vein endothelial cells. As compared with the BGs/CS scaffolds, the La dopants in the La-BGs/CS scaffolds contributed to higher expression levels of both osteogenic and angiogenic-related genes. Moreover, the mesopores and macropores within the La-BGs/CS scaffolds enhanced the osteoconductivity and stimulated bone regeneration in cranial defect model of rats. The La-BGs/CS scaffolds could also promote vascularization in vivo as demonstrated by Microfil perfusion, which further augmented osseous regeneration. Therefore, the La-BGs/CS scaffolds provide an admirable application and novel platform for bone tissue engineering.

Strategies for Using Polydopamine to Induce Biomineralization of Hydroxyapatite on Implant Materials for Bone Tissue Engineering.

In the field of tissue engineering, there are several issues to consider when designing biomaterials for implants, including cellular interaction, good biocompatibility, and biochemical activity. Biomimetic mineralization has gained considerable attention as an emerging approach for the synthesis of biocompatible materials with complex shapes, categorized organization, controlled shape, and size in aqueous environments. Understanding biomineralization strategies could enhance opportunities for novel biomimetic mineralization approaches. In this regard, mussel-inspired biomaterials have recently attracted many researchers due to appealing features, such as strong adhesive properties on moist surfaces, improved cell adhesion, and immobilization of bioactive molecules via catechol chemistry. This molecular designed approach has been a key point in combining new functionalities into accessible biomaterials for biomedical applications. Polydopamine (PDA) has emerged as a promising material for biomaterial functionalization, considering its simple molecular structure, independence of target materials, cell interactions for adhesion, and robust reactivity for resulting functionalization. In this review, we highlight the strategies for using PDA to induce the biomineralization of hydroxyapatite (HA) on the surface of various implant materials with good mechanical strength and corrosion resistance. We also discuss the interactions between the PDA-HA coating, and several cell types that are intricate in many biomedical applications, involving bone defect repair, bone regeneration, cell attachment, and antibacterial activity.

Study on the properties of PLA/PBAT composite modified by nanohydroxyapatite

Poly(lactic acid) (PLA) and poly(butylene adipate-Co-terephthalate) (PBAT) show high and excellent biocompatibility, which are promising materials used in bone tissue engineering field. In this research, n-HA/PLA/PBAT/MCC composites were prepared by solution blending method. Nano hydroxyapatite (n-HA) was used as nucleation, and microcrystalline cellulose (MCC) was added to improve the degradation performance of the materials. Compared with the composite without n-HA, the crystallinity of the composites with 6% n-HA was increased by 62%. The scanning electron microscopy (SEM) and the transmission electron microscopy (TEM) showed that the n-HA was evenly dispersed in the composites when the addition ration of n-HA was lower than 6%, while obvious agglomeration of n-HA appeared at the addition ratio of 10%. The tensile test demonstrated that the tensile strength of the composites with different addition ratio transcended the needs of bone tissue engineering materials. The introduction of n-HA in obtained composites simulated the composition and structure of native bone, which suggested a potential utility and application prospect in bone tissue engineering.

Preparation and Application of Magnetic Responsive Materials in Bone Tissue Engineering.

At present, many kinds of materials are used for bone tissue engineering, such as polymer materials, metals, etc., which in general have good biocompatibility and mechanical properties. However, these materials cannot be controlled artificially after implantation, which may result in poor repair performance. The appearance of the magnetic response material enables the scaffolds to have the corresponding ability to the external magnetic field. Within the magnetic field, the magnetic response material can achieve the targeted release of the drug, improve the performance of the scaffold, and further have a positive impact on bone formation. This paper first reviewed the preparation methods of magnetic responsive materials such as magnetic nanoparticles, magnetic polymers, magnetic bioceramic materials and magnetic alloys in recent years, and then introduced its main applications in the field of bone tissue engineering, including promoting osteogenic differentiation, targets release, bioimaging, cell patterning, etc. Finally, the mechanism of magnetic response materials to promote bone regeneration was introduced. The combination of magnetic field treatment methods will bring significant progress to regenerative medicine and help to improve the treatment of bone defects and promote bone tissue repair.

Application of green tea extracts epigallocatechin-3-gallate in dental materials: Recent progress and perspectives.

Because of excellent biocompatibility, antioxidant activity, and anti-caries ability, epigallocatechin-3-gallate (EGCG) has been widely studied in the treatment of oral diseases, such as periodontal disease, oral cancer, and dental caries. To reach the site of the lesion or achieve sustained release, play the role of anti-caries, anti-inflammatory, or to maintain or improve the physical properties of the modified material，EGCG need to be cross-linked or embedded with dental adhesives, barrier membranes, bone replacement materials, tissue regeneration materials, and antimicrobial anti-caries materials to better prevent or treat oral diseases. This article reviews the applications of EGCG in oral materials, involving various areas of the oral cavity, reveals their excellent potential, and sees shortcomings in these research to promote the better development of EGCG applications in oral materials such as oral repair materials, bone tissue engineering materials and antibacterial and anti-caries materials.

Synthesis and Properties of Manganese-Containing Calcium Phosphate Materials

We have studied manganese-containing calcium phosphates differing in manganese content and phase composition. At a manganese content of 0.15 wt %, the whitlockite content is ~90 wt % and the calcium pyrophosphate content is ~10 wt %. Increasing the manganese content to 1.49 wt % reduces the whitlockite content to ~70 wt % and increases the calcium pyrophosphate content to ~30 wt %. IR spectroscopy results show that the samples calcined at 400°C have the apatite structure, whereas raising the calcination temperature to 900°C leads to the formation of the whitlockite structure and calcium pyrophosphate. Active sintering begins in the range 920–1050°C. Raising the firing temperature to 1200°C leads to the formation of a densely sintered structure, with melted regions and an average grain size from 15 to 25 μm. With increasing manganese content, the grain size of the ceramics decreases. Our results on cytotoxic properties demonstrate that the samples are not cytotoxic and maintain cell proliferation and spreading. The cytotoxicity of the samples is insensitive to the calcium pyrophosphate and manganese concentrations. The powders and ceramics prepared in this study can be used as key components of novel materials for bone tissue engineering.

Antibacterial graphene-based hydroxyapatite/chitosan coating with gentamicin for potential applications in bone tissue engineering.

Electrophoretic deposition process (EPD) was successfully used for obtaining graphene (Gr)-reinforced composite coating based on hydroxyapatite (HAP), chitosan (CS), and antibiotic gentamicin (Gent), from aqueous suspension. The deposition process was performed as a single step process at a constant voltage (5 V, deposition time 12 min) on pure titanium foils. The influence of graphene was examined through detailed physicochemical and biological characterization. Fourier transform infrared spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, Raman, and X-ray photoelectron analyses confirmed the formation of composite HAP/CS/Gr and HAP/CS/Gr/Gent coatings on Ti. Obtained coatings had porous, uniform, fracture-free surfaces, suggesting strong interfacial interaction between HAP, CS, and Gr. Large specific area of graphene enabled strong bonding with chitosan, acting as nanofiller throughout the polymer matrix. Gentamicin addition strongly improved the antibacterial activity of HAP/CS/Gr/Gent coating that was confirmed by antibacterial activity kinetics in suspension and agar diffusion testing, while results indicated more pronounced antibacterial effect against Staphylococcus aureus (bactericidal, viable cells number reduction >3 logarithmic units) compared to Escherichia coli (bacteriostatic, <3 logarithmic units). MTT assay indicated low cytotoxicity (75% cell viability) against MRC-5 and L929 (70% cell viability) tested cell lines, indicating good biocompatibility of HAP/CS/Gr/Gent coating. Therefore, electrodeposited HAP/CS/Gr/Gent coating on Ti can be considered as a prospective material for bone tissue engineering as a hard tissue implant.

Potential Application of Protamine for Antimicrobial Biomaterials in Bone Tissue Engineering.

Bacterial infection of biomaterials is a serious problem in the field of medical devices. It is urgently necessary to develop new biomaterials with bactericidal activity. Antimicrobial peptides and proteins (AMPs), alternative antibacterial agents, are expected to overcome the bacterial resistance. The aim of this study was to develop a new intelligent material in bone tissue engineering based on protamine-loaded hydroxyapatite (protamine/HAp) that uses AMPs rather than antibiotics. It was found that the adsorption of protamine to HAp followed the Langmuir adsorption model and was due to electrostatic and/or hydrophobic interactions. In vitro bacterial adhesion and growth on protamine/HAp was inhibited in a protamine dose-dependent manner. Adherent bacteria exhibited an aberrant morphology for high dosages of protamine/HAp, resulting in the formation of large aggregates and disintegration of the membrane. The released protamine from protamine/HAp also prevented the growth of planktonic bacteria in vitro. However, a high dosage of protamine from powders at loading concentrations over 1000 μg·mL−1 induced a cytotoxic effect in vitro, although those exhibited no apparent cytotoxicity in vivo. These data revealed that protamine/HAp (less than 1000 μg·mL−1) had both antimicrobial activity and biocompatibility and can be applied for bone substitutes in orthopedic fields.

Hydroxyapatite/bioactive glass functionally graded materials (FGM) for bone tissue engineering

In this work, HA/bioactive glass Functionally Graded Materials (FGMs) are obtained for the first time by means of Spark Plasma Sintering (SPS). Two series of highly dense 5 layered products, namely FGMS1 and FGMS2, are prepared under optimized SPS conditions, i.e. 1000 °C/2 min/16 MPa and 800 °C/2 min/50 MPa, respectively, using a die with varying cross section.Results arising from XRD, SEM, mechanical and biological characterization in SBF, evidence that lower temperature and higher-pressure levels used for FGMS2 samples provide better materials in terms of microstructure, compactness, hardness, elastic modulus and in vitro bioactivity. Indeed, a fully sintered and crack-free microstructure with no crystallisation at the top layer (100% bioactive glass) is correspondingly produced.The obtainment of such FGMs is quite promising, since it permits to vary the relative volume fractions of the two constituents and, consequently, tailor the biological response for specific clinical applications.

In situ mineralization of nano-hydroxyapatite on bifunctional cellulose nanofiber/polyvinyl alcohol/sodium alginate hydrogel using 3D printing

This paper reports the manufacturing by 3D printing of scaffolds for in-situ mineralization of hydroxyapatite using aqueous suspensions of alginate and polyvinyl alcohol (PVA)-grafted cellulose nanofibers (CNF). Bifunctional CNF with carboxyl and aldehyde moieties were prepared from bleached bagasse pulp and crosslinked with PVA. Aqueous hydrogels for 3D printing were prepared by directly mixing PVA-grafted CNF with sodium alginate, with and without the addition of phosphate ions. A calcium chloride solution was sprayed during the printing process in order to partially crosslink alginate and to increase the dimensional stability of the printed gel. At the end of the printing process, the prepared scaffolds were dipped into a CaCl2 solution to: i) complete alginate crosslinking and ii) promote hydroxyapatite nucleation and growth by reaction with phosphate ions. In order to better understand the mechanisms governing manufacturing of scaffolds by 3D printing, the rheological behavior of alginate/PVA-grafted CNF and the mechanical properties of unit filaments obtained by direct hydrogel extrusion were investigated. The final scaffolds were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). This study shows that 3D printed sodium alginate/PVA-grafted CNF hydrogels are promising scaffold materials for bone tissue engineering.

Silk fibroin magnetoactive nanocomposite films and membranes for dynamic bone tissue engineering strategies

Bone-related diseases are one of the most common health conditions that limit the quality of life of elderly. Novel materials for bone tissue engineering that actively assist on the regeneration of bone tissue are thus needed. In this work, magnetoactive scaffolds comprised of silk fibroin (SF) with different content of filler – cobalt ferrite nanoparticles – were produced by solvent-casting and electrospinning technique and further evaluated for bone cells growth under static and dynamic magnetic stimulation. The materials were evaluated for their enhanced electric properties, analyzed through the silk fibroin β-sheet content, an important factor for the envisaged cell stimulation strategy, which are in much higher content in films (~50%) than in electrospun fibers (~25%). Cell culture experiments under varying magnetic field, induced a magneto-mechanical stimulation on the materials, hence on cells, promoting improved cell viability after 4 days of culture. The scaffold morphology was found to play an important role in pre-osteoblast proliferation rate, being larger for cells growing on films, which is related to the topography of the material but also to the increased β-sheet content. It is shown that the use of magnetic cues on magnetoactive biocompatible scaffolds is a promising strategy for remote stimulation of bone for its regeneration. Statement of Significance The use of physical stimuli such as electrical and mechanical cues have been proven a powerful tool for bone tissue engineering applications, but the use of magnetic cues on magnetoactive scaffolds has been scarcely reported. This is considered a promising strategy for remote stimulation of bone for its regeneration. The present study provides data on the evaluation of biocompatible silk fibroin scaffolds for bone cells’ proper adhesion and proliferation upon the application of a magnetic stimuli using a custom-made magnetic bioreactor. The conditions created promote a biomimetic microenvironment through the application of a mechanical and electrical cues to cells. This approach is interesting since while scaffolds mimics the morphology of bone, the magnetic bioreactor provides the physical environment of bone, i.e. piezoelectricity, by generating electrical and mechanical cues with magnetic stimulation.

Three-dimensional silk fibroin scaffolds enhance the bone formation and angiogenic differentiation of human amniotic mesenchymal stem cells: a biocompatibility analysis.

Silk fibroin (SF) is a fibrous protein with unique mechanical properties, adjustable biodegradation, and the potential to drive differentiation of mesenchymal stem cells (MSCs) along the osteogenic lineage, making SF a promising scaffold material for bone tissue engineering. In this study, hAMSCs were isolated by enzyme digestion and identified by multiple-lineage differentiation. SF scaffold was fabricated by freeze-drying, and the adhesion and proliferation abilities of hAMSCs on scaffolds were determined. Osteoblast differentiation and angiogenesis of hAMSCs on scaffolds were further evaluated, and histological staining of calvarial defects was performed to examine the cocultured scaffolds. We found that hAMSCs expressed the basic surface markers of MSCs. Collagen type I (COL-I) expression was observed on scaffolds cocultured with hAMSCs. The scaffolds potentiated the proliferation of hAMSCs and increased the expression of COL-I in hAMSCs. The scaffolds also enhanced the alkaline phosphatase activity and bone mineralization, and upregulated the expressions of osteogenic-related factors in vitro. The scaffolds also enhanced the angiogenic differentiation of hAMSCs. The cocultured scaffolds increased bone formation in treating critical calvarial defects in mice. This study first demonstrated that the application of 3D SF scaffolds co-cultured with hAMSCs greatly enhanced osteogenic differentiation and angiogenesis of hAMSCs in vitro and in vivo. Thus, 3D SF scaffolds cocultured with hAMSCs may be a better alternative for bone tissue engineering.