Graphene\nOxide/Black Phosphorus Functionalized Collagen\nScaffolds with Enhanced Near-Infrared Controlled In Situ Biomineralization\nfor Promoting Infectious Bone Defect Repair through PI3K/Akt Pathway

Infectious\nbone defects resulting from surgery, infection, or trauma\nare a prevalent clinical issue. Current treatments commonly used include\nsystemic antibiotics and autografts or allografts. Nevertheless, therapies\ncome with various disadvantages, including multidrug-resistant bacteria,\ncomplications arising from the donor site, and immune rejection, which\nmakes artificial implants desirable. However, artificial implants\ncan fail due to bacterial infections and inadequate bone fusion after\nimplantation. Thus, the development of multifunctional bone substitutes\nthat are biocompatible, antibacterial, osteoconductive, and osteoinductive\nwould be of great clinical importance. This study designs and prepares\n2D graphene oxide (GO) and black phosphorus (BP) reinforced porous\ncollagen (Col) scaffolds as a viable strategy for treating infectious\nbone defects. The fabricated Col-GO@BP scaffold exhibited an efficient\nphotothermal antibacterial effect under near-infrared (NIR) irradiation.\nA further benefit of the NIR-controlled degradation of BP was to promote\nbiomineralization by phosphorus-driven and calcium-extracted phosphorus\nin situ. The abundant functional groups in GO could synergistically\ncapture the ions and enhance the in situ biomineralization. The Col-GO@BP\nscaffold facilitated osteogenic differentiation of bone marrow-derived\nmesenchymal stem cells (BMSC) by leveraging its mild photothermal\neffect and biomineralization process, which upregulated heat shock\nproteins (HSPs) and activated PI3K/Akt pathways. Additionally, systematic\nin vivo experiments demonstrated that the Col-GO@BP scaffold obviously\npromotes infectious bone repair through admirable photothermal antibacterial\nperformance and enhanced vascularization. As a result of this study,\nwe provide new insights into the photothermal activity of GO@BP nanosheets,\ntheir degradation, and a new biological application for them.