The three-dimensional (3D) printing technology combined with bone tissue engineering has become one of the major methods for mandibular reconstruction. However, the key factor retarding mandible reconstruction is the barrier of understanding and achieving the complex 3D gridwork formed by the trabeculae. This study innovatively constructed a low-temperature 3D printing silk fibroin/collagen/hydroxyapatite (SF/COL/HA) composite scaffold with a stable structure and remarkable biocompatibility. We designed three kinds of six-layer scaffolds with mixed fiber cross-angle structures (FCAS) of [0°/90°/0°/90°/0°/90°], [0°/45°/90°/135°/180°/225°] and [0°/30°/60°/90°/120°/150°]. Material properties of these scaffolds such as porosity, water absorption rate, X-ray diffraction, Fourier transform infrared spectroscopy, and compression performance were detected. Then, the MC3T3-E1 cells were seeded on these scaffolds and the adhesion, proliferation, and differentiation were investigated. To be more convincing, the same experiments were performed on another polycaprolactone/hydroxyapatite scaffold. The results suggested that the changes of FCAS affected the mechanical properties of 3D printed scaffolds and performance of seeded cells. Besides, the 90° FCAS significantly enhanced the compressive modulus in two groups and were more conducive to the cell proliferation and osteogenesis, which provided evidence for exploring the influence of FCAS on the properties of scaffolds and the application of two composite scaffolds in tissue regeneration.

Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumours in the oral and maxillofacial regions and is highly malignant and prone to recur despite the development of various effective treatments, including surgery and chemoradiotherapy. Actually, it is difficult to ensure the complete elimination of tumour cells, and maxillofacial bone defects caused by surgery are hard to heal by themselves. In addition, chemoradiotherapy can bring serious side effects. Therefore, it is imperative to develop a postoperative therapy to kill residual squamous cancer cells and repair bone defects without any side effects. Here, we prepared a three-dimensional (3D) scaffold by a 3D printing technique and freeze-drying method, which contained collagen, silk and hydroxyapatite (CSH) and was functionalized with MXene nanosheets (M-CSH). The considerable photothermal effect with long-term stability can significantly kill squamous CAL-27 cancer cells in vitro and inhibit tumour growth in vivo, increasing the probability of the M-CSH scaffold being applied in the photothermal therapy of OSCC. Moreover, the cell proliferation- and osteogenic-related protein expression of mouse embryonic osteogenic precursors (MC3T3-E1) indicated excellent biocompatibility and osteogenic activity of M-CSH scaffolds. The good compression modulus (52.83 ± 2.25 kPa) and in vivo bone formation performance made it possible to be used as reconstructive materials for bone defects. This scaffold is likely promising in future tissue engineering, especially for the multifunctional treatment of maxillofacial tumours.

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