1：Experimental Design and Method Selection:

The study involved designing a nanosized gadolinium(III)-porphyrin coordination polymer (Gd-TCPP NCP) via a hydrothermal method for dual-mode sensing of Fe3+ ions, leveraging its optical properties for colorimetric and fluorometric detection.

2：Sample Selection and Data Sources:

Fetal bovine serum samples were used to validate the method, diluted with Tris-HCl buffer. Various metal ions and amino acids were tested as potential interferents.

3：List of Experimental Equipment and Materials:

Chemicals included L-glutathione, L-cysteine, propionic acid, pyrrole, p-formylbenzoate, metal nitrate and chloride salts, and amino acids from suppliers like J&K Scientific Ltd. and Tianjin Chemical Co. Ltd. Instruments included UV-visible spectrometer (Agilent cray 100), IR spectrophotometer (Bruker Vector 22), ICP-AES (Thermo IRIS advantage), fluorescence spectrometer (Edinburgh Instruments FS920P), TGA instrument (SDT-TGQ 600), TEM (Tecnai G2 F20), microplate reader (SpectraMax i3), and Zetasizer (Nano ZS).

4：Experimental Procedures and Operational Workflow:

Synthesis of Gd-TCPP NCP involved hydrothermal treatment of TCPP and GdCl3·6H2O. Detection involved adding Fe3+ to Gd-TCPP NCP solutions in Tris-HCl buffer, measuring absorption and fluorescence spectra after incubation. Selectivity tests included other ions and amino acids. Cytotoxicity was assessed using MTT assay on HEK-293 cells.

5：2O. Detection involved adding Fe3+ to Gd-TCPP NCP solutions in Tris-HCl buffer, measuring absorption and fluorescence spectra after incubation. Selectivity tests included other ions and amino acids. Cytotoxicity was assessed using MTT assay on HEK-293 cells. Data Analysis Methods:

5. Data Analysis Methods: Data were analyzed using UV-vis and fluorescence spectroscopy, with calibration curves and Stern-Volmer plots for quantification. Statistical analysis included recovery tests and RSD calculations.