fig4

Figure 4. (A) Conductive annular graphene substrate^[46]. Reprinted with permission. Copyright 2021, John Wiley & Sons, Inc; (B) Highly conductive flexible multi-walled carbon nanotube membrane^[8]. Reprinted with permission. Copyright 2022, Elsevier; (C) Fe₃O₄@BaTiO₃ nanoparticles-loaded hyaluronic acid/collagen hydrogel^[48]. Reprinted with permission. Copyright 2021, John Wiley & Sons, Inc; (D) CFO and BT core-shell structured nanoparticles^[49]. Reprinted with permission. Copyright 2022, Elsevier. BT: BaTiO₃; CFO: CoFe₂O₄; MWCNT: multi-walled carbon nanotube; NSCs: neural stem cells; rBMSCs: rat bone marrow mesenchymal stem cells.