Fig. 1

Detection and performance analysis of iron-based metal-organic frameworks (MOF-Fe). A: Scanning electron microscopy (SEM) image of MOF-Fe postsolvothermal synthesis, predominantly revealing polyhedral prism-like particles. B: SEM image of MOF-Fe after 30 days, showing degradation into smaller octahedra. C: Elemental mapping images of MOF-Fe nanoparticles, illustrating the distribution of carbon, oxygen, nitrogen, and iron within the MOF-Fe particles. D: The particle size distribution of the MOF-Fe particles shows an average cross-sectional diameter of 1.80 μm and a height of 11.50 μm. E: pH measurement curves of MOF-Fe suspensions at varying concentrations and in the control groups over different time points (zero days, one day, four days, six days, and eight days). The solvent is simulated body fluid. The pH was maintained within a physiological range of 6.50 to 7.40, demonstrating good stability. F: Absolute zeta potential measurements of MOF-Fe nanoparticles at various concentrations at 25 °C. G: Fourier transform infrared (FT-IR) spectroscopy. H: Pore size distribution of MOF-Fe nanoparticles, with a surface area of 553.48 m²/g, total pore volume of 0.32 cm³/g, micropore volume of 0.069 cm³/g, and average pore diameter of 4.10 nm. I: X-ray photoelectron spectroscopy (XPS) assessment results. J: Inductively coupled plasma optical emission spectroscopy (ICP‒OES) curves of free iron ions in different MOF-Fe suspension supernatants from the start of the experiment to Day 30. K: The elemental composition of the MOF-Fe particles was determined by energy dispersive X-ray spectroscopy (EDS), and the proportions of C, O, and Fe were 66.32%, 25.21%, and 6.51%, respectively. The data are presented as the means ± SDs (n = 3). *p < 0.05, **p < 0.01