Fig. 1.

Summary of experimental procedures used in this study. Swift and convertible nano-formation was simply manipulated by the dynamic and reversible coordination of Mg²⁺ and bisphosphonate (BP), to regulate the attachment, detachment, and phenotypic polarization of macrophages. Mg²⁺ and BP assembled into cell-adhesive Mg²⁺-functional Mg²⁺-BP nanoparticle (NP), yielding (Mg²⁺-BP)-Au dimer (MgBNP, shown by a red arrow), whereas EDTA disassembled the Mg²⁺-BP NP, into non-adhesive “BNP” template (shown by a yellow arrow). RGD-BP and Mg²⁺ assembled into RGD- and Mg²⁺-bifunctional RGD-Mg²⁺-BP NP, resulting in (RGD-Mg²⁺-BP)-Au dimer (RGDBNP, shown by a black arrow), to further promote the attachment and M2-type polarization of macrophages