TABLE 3.

Smart materials and their applications in BTE.

Materials	Properties	Technique	Applications	References
1. Poly(lactide-co-glycolide) microspheres coupled with P-15	Highly porous structure, reduced degradation rate, enhanced cell growth, migration and proliferation rate due to coupling with P-15	Gas foaming	Bone Tissue engineering	Mittal et al. (2010)
2. Osteoimmunomodulatory biomaterial Heparin-modified gelatin nanofibers, and interleukin 4	Controlled release to modulate polarization of macrophages, reduced inflammation, and enhanced osteoblastic differentiation and bone regeneration	Self- assembled monolayer	DM-associated bone regeneration	Hu et al. (2018)
3. Shape memory smart scaffolds Poly(ε-caprolactone) and HAp nanoparticles loaded with BMP2	Predesigned, deformed for easier implantation into the defect site via minimally invasive surgery followed by expansion to adjust into an deformed bone defect	Sugar leaching	Bone regeneration	Liu et al. (2014)
4. (Photothermally controlled) smart scaffold Nano-hydroxyapatite/graphene oxide/chitosan scaffold	Killing human osteosarcoma cells under irradiation and enhanced osteogenesis in coordination with nHAp, good hemostatic effect and soft tissue restoration and repairing under irradiation	Lyophilization	Osteosarcoma treatment	Ma et al. (2020)
5. Piezoelectric Poly(vinylidene fluoride-trifluoroethylene)	Dynamic compression at 1 Hz frequency, improved MSC chondrogenesis	Electrospinning	Bone tissue engineering	Qasim et al. (2019b)
6. Piezoelectric HA/barium titanate	Periodic loading, enhanced osteoblast proliferation and growth due to electrical stimulation, very similar to the piezoelectric effects on human bone growth, modelling and reconstruction in-vivo		Bone tissue engineering	Tang et al. (2017)
7. N-isopropylacrylamide, pentaerythritol diacrylate monostearate, 2-hydroxyethyl acrylate, and vinyl phosphonic acid	Stimuli responsive, dually responsive macromers, Examine the effect of increasing vinyl phosphonic acid content	Free radical polymerization & thermo-gelation	Cellular delivery	Kretlow et al. (2010)
8. Dual-functionalized Mesoporous silica nanospheres	Drug release rate can be controlled continuously and remotely using single or dual stimuli, thin macromolecular coating acted as a rate modulator for regulating the diffusion kinetics of the drugs	Copolymerization	Thermo and electro-responsive drug delivery	Li et al. (2014)
9. PCL + BMP-2	Higher immobilization efficiency due to conjugation, controlled BMP-2 release, BMSCs upregulated growth and proliferation	Crosslinking and conjugation	Bone tissue regeneration	Zhang et al. (2010)