Search

In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. [ABSTRACT FROM AUTHOR]

Background: In the process of bone defective reparation and engineered bone tissue construction, osteoblasts are adhered to the surface of the scaffold materials and impart the external mechanical load to the osteoblasts. So, the dynamic mechanical property of the scaffolds play an important role in the bone tissue repair and it is valuable to research. Material type and the architectural design of scaffolds are also important to facilitate cell and tissue growth. The aim of this study was to prepare a kind of material with good pore connectivity and analyze its dynamic mechanical property.Methods: Fabrication and characterization of micro-hydroxyapatite(m-HA)/chitosan(CS) polymer composite scaffolds with well interconnected spherical pore architectures were reports. Micro-HA was prepared by being calcined and ball milled. Paraffin spheres in the range of 160-330 µm were fabricated with a dispersion method and used as the porogen in the fabrication of the scaffolds. Polymer scaffolds were fabricated by the technique of compression molding and particulate leaching method. The effects of the porogen content on the properties of the scaffolds were studied.Results: With the increase of porogen, the pore of the scaffolds increased and became interconnected. Cyclic loading of three scaffolds were tested with 10 % strain under four levels of loading frequency, 0.1, 0.5, 1 and 1.5 Hz. The porous composite scaffolds exhibited a viscosity-elastic behaviour with a maximum stress of 3-4 kPa. At each frequency, modulus value is decreased with the paraffin microspheres content, but there was no significance difference in the peak stress of the three samples. All the samples tested displayed clear hysteresis loops. There was no significance difference in the peak hysteresis of the three samples, and the hysteresis difference values between the sixth compression cycle and the initial cycle for three samples was similar, with no statistically significant differences.Conclusions: Micro-HA/CS composite scaffolds with interconnected spherical macropores were fabricated using pherical paraffin as porogen. The porous composite scaffolds exhibited a viscosity-elastic behaviour with good repeatability. It is benefit to study the influence of the mechanical load on the cell of the scaffold. [ABSTRACT FROM AUTHOR]

• A high accuracy deformation measurement method for semi-continuous materials is proposed. • The deformation field of 3D printed scaffolds is accurately measured. • The first visualization of cell differentiation on scaffolds was achieved by experimental measurements. • The effects of loading in vitro and water content on cell differentiation were investigated. • This work corroborates that in vitro loading culture and modulation of scaffold pore structure can be exploited to design scaffolds with regions that guide specific tissue development. Three-dimensional (3D) mechanical microenvironments, such as 3D strain fields in tissue engineering scaffolds have a crucial impact on the interactions between scaffold architecture, mechanical stimuli, and tissue differentiation. However, the discontinuity induced by the pores poses a challenge to the measurement of the 3D strains of the scaffolds. Herein, we present a tissue engineering scaffold optical coherence elastography (TES-OCE) method to visualize the full-field 3D strain fields of the tissue engineering scaffolds when cells are cultured on them and to explore the relationship between mechanical stimulation and cell differentiation. A semi-continuous digital volume correlation (SC-DVC) method based on a material component identification algorithm was proposed to automatically extract the scaffold architecture information and obtain the 3D strain fields with high accuracy. The non-uniform deformation field of a 3D printed tissue engineering scaffold with various water contents under loading in vitro was measured by the TES-OCE method, based on the tissue shear strain field obtained above, the area of cell differentiation phenotype on tissue engineering scaffolds was accurately predicted. Experimental results show that the loads and water absorption of the scaffold significantly affects the 3D tissue shear strain field in the tissue engineering scaffold. Thus, the cell differentiation fate can be modulated by loading culture and scaffold pore structure. The TES-OCE provides a new experimental method to delineate the interrelationship between tissue engineering scaffolds, the mechanical microenvironment, and cell proliferation and differentiation. It may be further developed as an effective tool to guide the design and development of superior tissue engineering scaffolds. [ABSTRACT FROM AUTHOR]

A biomaterial that can remove remaining oral squamous cell carcinoma (OSCC) cells and repair oral mucosal damage is urgently needed. This graphical abstract described a composite scaffold that would simultaneously kill OSCC cells and promote the regeneration of the oral mucosa. [Display omitted] • Quercetin acts as an inhibitor when heat shock proteins make tumor cells more resistant to photothermal therapy. • Ti 3 C 2 MXene and quercetin are effectively carried by scaffold made of collagen and silk fibroin. • The composite scaffold successfully limits tumor cells migration and promotes oral mucosal defects regeneration. The most prevalent oral and maxillofacial cancer is oral squamous cell carcinoma (OSCC). Patient survival is compromised by relapse due to post-operative tumor remnants and significant mucosal defects. Photothermal therapy (PTT) is used to ablate local malignancies, but the capacity of tumor cells to resist it is correlated with the overexpression of heat shock protein 70 (HSP70). In this work, PTT and tissue engineering scaffold were rationally integrated to construct a Ti 3 C 2 MXene, collagen, silk fibroin and quercetin composite scaffold (M-CSQ scaffold), a 3D printed biomaterial that simultaneously kill OSCC cells and promote the regeneration of the mucosal defects. The M-CSQ scaffolds were prepared by cryogenic 3D printing and freeze-drying techniques with sufficient pores that allow an abundant cell migration and provide a proliferation space. Ti 3 C 2 MXene has excellent photothermal conversion ability and stability. Quercetin targeted HSP70 to decrease its expression in OSCC cells, consequently weakening their resistance to high temperature and enhancing the effect of PTT. The M-CSQ scaffold effectively killed OSCC cells in vitro and inhibited tumor growth in vivo. In addition, the M-CSQ scaffold provided adhesion sites for Sprague-Dawley rat (SD rat) buccal mucosal fibroblasts and promoted the repair of buccal mucosal wounds. [ABSTRACT FROM AUTHOR]

The property of collagen–chitosan porous scaffold varies according to cross-linking density and scaffold composition. This study was designed to compare the properties of collagen–chitosan porous scaffolds cross-linked with γ-irradiation and carbodiimide (CAR) for the first time. Eleven sets of collagen–chitosan scaffolds containing different concentrations of chitosan at a 5% increasing gradient were fabricated. Fourier transform infrared spectroscopy was performed to confirm the success of cross-linking in the scaffolds. The scaffold morphology was evaluated under scanning electron microscope (SEM). SEM revealed that chitosan was an indispensable material for the fabrication of γ-ray irradiation scaffold. The microstructure of γ-ray irradiation scaffold was less stable than those of alternative scaffolds. Based upon swelling ratio, porosity factor, and collagenase degradation, γ-ray irradiation scaffold was less stable than CAR and 25% proportion of chitosan scaffolds. Mechanical property determines the orientation in γ-irradiation and CAR scaffold.In vitrodegradation test indicated that γ-irradiation and CAR cross-linking can elevate the scaffold biocompatibility. Compared with γ-ray irradiation, CAR cross-linked scaffold containing 25% chitosan can more significantly enhance the bio-stability and biocompatibility of collagen–chitosan scaffolds. CAR cross-linked scaffold may be the best choice for future tissue engineering. [ABSTRACT FROM PUBLISHER]