Macrophages regulate host responses to implants through their dynamic adhesion， release， and activation. Herein， we employ bisphosphonate (BP)-coated gold nanoparticle template (BNP) to direct the swift and convertible formation of Mg-functional Mg-BP nanoparticle (NP) on the BP-AuNP surface via reversible Mg-BP coordination， thus producing (Mg-BP)-Au dimer (MgBNP). Ethylenediaminetetraacetic acid-based Mg chelation facilitates the dissolution of Mg-BP NP， thus enabling the reversion of the MgBNP to the BNP. This convertible nanoassembly incorporating cell-adhesive Mg moieties directs reversible attachment and detachment of macrophages by BP and EDTA， without physical scraping or trypsin that could damage cells. The swift formation of RGD ligand- and Mg-bifunctional RGD-Mg-BP NP that yields (RGD-Mg-BP)-Au dimer (RGDBNP) further stimulates the adhesion and pro-regenerative M2-type polarization of macrophages， both in vitro and in vivo， including rho-associated protein kinase. This swift and non-toxic dimer formation can include diverse bio-functional moieties to regulate host responses to implants.