## 1 Introduction  
Bone defects can be caused by accidents, tumor resection, genetic factors, or other pathological conditions. Although bone reconstruction is one of the most perfect healing procedures in the human body, in the case of large bone defects the intrinsic reconstruction by the organism is insufficient [1]. The treatment of bone defects using bone grafts is of particular importance in orthopedic, plastic, and maxillofacial surgery. The gold standard for treating large bone defects is autologous bone grafting in which bone is harvested from one site of the patient and transplanted to another site. However, this kind of implant has two main disadvantages: the limited amount of available bone and the surgical procedure required for bone harvesting, usually from the ilium or the calvarium. Allografts are grafts transplanted between genetically different individuals of the same species. Xenografts are bone transplants that are implanted to a person from a donor who belongs to a genetically different species. Allographs have the risks of immunoreactions and rejection while xenografts have the risk of disease transmission to the host [2,3]. The development of alloplastic materials that will exhibit osteoinductive properties and will be absorbed simultaneously with the formation of new bone led to the preparation of bone implants based on calcium phosphate (CP), such as CP cements or ceramics [4, 5, 6]. Furthermore, the range of other synthetic bone grafts includes metals, plastics, bioactive glasses, etc. [7]. In recent years there has been a strong interest in the manufacturing of smart implants for bone tissue engineering applications. The term \"smart implants\" refers to materials or constructs that indicate a reversible response to an external or internal stimulus such as pH, temperature, electric or magnetic field, mechanical forces, light, etc. This response enhances cell activity and induces tissue regeneration [8; 9]. In the comprehensive review by [PERSON] et al., new strategies of using magnetic materials for bone tissue engineering are described. For example, magnetic scaffolds containing superparamagnetic iron oxide nanoparticles (SPIONS) increase osteogenic differentiation, cell growth, and bone regeneration [10]. The effectiveness of magnetic field on bone tissue engineering applications depends on several factors, including the nature of magnetic nanoparticles, and the type of magnetic field (static or time-varying magnetic field) [11]. Another stimuli-responsive and non-invasive strategy used in bone tissue regeneration is based on light irradiation. The recent progress of light-responsive nanomaterials with applications in tissue engineering is reviewed by [PERSON] et al. The light irradiation source is NIR light (700-1300 nm), which shows higher tissue penetration. NIR phototherapy for bone cancer treatment, is based on hyperthermia and can be used independently or in combination with NIR light-responsive nanoparticles. The most commonly used light-responsive nanomaterials include gold nanostructures, carbon-based nanomaterials (graphene, nanotubes), metal oxides, and sulfides such as magnetic nanoparticles, MOS\({}_{2}\) nanosheets, etc. Incorporation of NIR light-responsive nanoparticles into 3D printed scaffolds combines the phototherapy of bone cancers with bone remodeling during therapy [12]. In addition to magnetic materials, soft materials in the form of temperature or pH responsive hydrogels are considered very important materials for bone repair. The main advantages of hydrogels are focused on their similarity with the extracellular matrix and their high biocompatibility since they are obtained from biogenic sources. Representative natural hydrogels include chitosan, alginate, gelatin, hyaluronic acid, etc. The drawback of these materials is their low mechanical properties and their low stability in aqueous solutions. However, chemically crosslinked hydrogels showed better mechanical properties and enhanced stability in aqueous media [13].