Supra 40 gemini

The morphologies of the as-prepared IONP-CM were observed under an AFM (Signal Hill, CA, United States of America) and a field-emission SEM (Zeiss Supra 40 Gemini, Germany). The mechanical characteristics of the prepared IONP-CM were assessed using a universal material testing machine (Shimadzu Co., Japan). The rheological features of the IONP-CM were determined using a modular advanced rheometer system (HAAKE MARS, Thermo Fisher Scientific, United States of America). This involved conducting strain–sweep measurements over a range of 0.01%–10% strain amplitude at a frequency of 6.28 rad/s, as well as frequency–sweep measurements at frequencies ranging from 1 to 30 rad/s with a fixed 1% strain amplitude. For the IONP release test, the IONP-loaded CM scaffolds were precisely shaped into uniform squares (10 mm × 10 mm). After that, they were co-incubated with 1.5 mL of PBS at 37°C. The concentration of Fe ions released from the scaffolds was determined at predetermined time intervals spanning a 7-day period using inductively coupled plasma atomic emission spectrometry (ICP-OES, Agilent 5800, United States).

The mercaptopyrimidine-modified AuNCs were prepared as described previously (Zheng et al., 2018 (link)). Briefly, 254 mg of mercaptopyrimidine was solubilized in 2 mL of 50% ethanol solution. It was mixed with 1 mL of 10 mM chloroauric acid trihydrate solution in 7 mL ultrapure water and heated to 70°C, followed by continuous stirring at 300 rpm for 12 h before cooling to room temperature. The synthesized AuNCs were purified by centrifuging at 10000 rpm for 10 min to remove bulk gold and dialyzed in membrane tubing (MWCO = 5000) against ultrapure water to remove the excess mercaptopyrimidine molecules. Finally, the as-prepared AuNCs were stored at 4°C until further use. The morphology of AuNCs was characterized by transmission electron microscopy (TEM, JEM-2100, Japan) and field-emission scanning electron microscope (FE-SEM, Zeiss Supra 40 Gemini, Germany). The hydrodynamic size of AuNCs was measured by dynamic light scattering (Malvern Zetasizer Nano ZS90, United Kingdom).