Injectable Affinity and Remote Magnetothermal Effects of Bi‐Based Alloy for Long‐Term Bone Defect Repair and Analgesia

Abstract As alternatives, metallic/nonmetallic bone graft materials play significant roles in bone defect surgery to treat external trauma or bone disease. However, to date, there are rather limited long‐term implantable materials owning to in situ molding incapability of metallics and poor mechanical property of nonmetallics. Here, Bi‐based low melting point alloy, with unique properties of injectability, solid‐liquid phase transition, mechanical capability, and biocompatibility, present obvious long‐lasting bone affinity as the excellent artificial bone‐substitute. It is particularly necessary to point out that the targeted injected Bi alloy remains in its original position for up to 210 days without moving, as well as, displays good osseointegration ability to resolve repeated revision trauma caused by losing bone repair material. Additionally, with outstanding electrical and thermal conductivity, an unconventional way using Bi alloy to realize very beneficial hyperthermia analgesia via non‐invasive wireless energy delivery is first proposed, which avoids adverse effects on bone remodeling inflicted by traditional drugs. The significantly decreased expression of pain sensitizing factor, such as, interleukin‐6, neuropeptide substance, and transient receptor potential vanilloid 1 reveals the potential mechanism of hyperthermia analgesia. The present findings suggest the combination therapy of Bi alloy in bone repair and analgesia, which owns far‐reaching clinical application value.