Polycaprolactone

Magnesium alloy rods (diameter = 2 mm, length = 15 mm) were prepared through vacuum melting method in which the proportion of Mg, Zinc, and Ca is 68wt%, 28wt%, 4wt%. For the surface modification of magnesium alloy rods, Polycaprolactone (PCL, molecular weight = 80,000, CAS 24980-41-4, Macklin, Shanghai, CHINA) was firstly added into dichloromethane (CAS 75-09-2, Aladdin, Shanghai, CHINA) with the mass ratio of PCL to dichloromethane is 1:25, then the mixture were heated to 50℃ at a speed of 3℃/min and were stirred till PCL were absolutely dissolved, then the magnesium alloy rods were dipped into the PCL solution and kept for 10 secs before removing from the solution. After holding in air at room temperature for 1 min, the PCL coated magnesium alloy rods were immersed into ethanol for 5 min to extract the remained dichloromethane^{35 (link),36 (link)}. The above surface modification process was performed once. To prepare the composite scaffolds, 1.25 g of Bioglass powder, 2.03 g of calcinated MgO and 1.72 g of KH₂PO₄ powder were mixed with 3 g of deionized water, then the mixture was poured into a prepared molds with the PCL modified magnesium alloy rods in the center (as shown in Supplementary Fig. S1), then the composite scaffold was removed from the mold after 10 min of cement solidification.