Rational design for MgO-modified porous carbon towards enhancing zoledronic acid adsorption

Nitrogen-containing bisphosphonates (N-BPs), namely zoledronic acid (ZA), are typically used as antiresorptive drugs by inhibiting osteoclast formation and functions. However, the long-term use of ZA may increase the risk of osteonecrosis of the jaw (ONJ) after tooth extraction. Hence, this study aims to develop a new sustainable adsorption material for capturing the exposed ZA. The porous activated carbon (AC) incorporated with MgO at various ratios was successfully developed and extensively characterized by several techniques. The adsorption behaviors correlated to their physicochemical properties for ZA removal were also carried out. Furthermore, density functional theory (DFT) was applied to investigate the adsorption mechanism of ZA adsorbed on a carbon surface functionalized with crystalline MgO. The results found that the well-dispersed MgO/AC provided a good adsorption capacity for ZA. The MgO with 15 % wt loading shows the highest performance (73 mg/g) on adsorbing ZA under a neutral condition compared to a bare AC (14 mg/g). The MgO/AC adsorbents were cytocompatible with human monocytic cells in vitro. The DFT result demonstrated that the MgO cluster is an active site for ZA adsorption. This evidence could imply that MgO/AC is a potential adsorbent for ZA removal in preventing ZA-related bone complications.