Cu-MOF@TMB Integrated Test Strips for Naked Eye Colorimetric Detection of a Critical Biomarker for Metabolic and Renal Disorders
Preeti Sharma, Musheer Ahmad, Nazrul Haq, Devendra Kumar Dewangan, Raghavender Medishetty, Astakala Anil Kumar, Nohyun Lee, Kafeel Ahmad Siddiqui
Abstract
Uric acid (UA) serves as a vital biomarker for diagnosing metabolic and renal disorders, prompting the need for rapid and selective detection methods. Herein, a new copper-based metal–organic framework (Cu-MOF), formulated as [Cu 2 (TCi) 2 ] [Cu 5 (TCi) 2 (H 2 O) 8 (μ 3 –OH) 2 ], was synthesized using Cu(II) ions and tris(2-carboxyethyl) isocyanurate (H 3 TCi) as a flexible linker. Comprehensive characterization through PXRD, FTIR, SEM, EDAX, TGA, XPS, BET and elemental mapping confirmed the framework’s structural integrity. To enhance sensing performance, the MOF was integrated with 3,3′,5,5′-tetramethylbenzidine (TMB), forming Cu-MOF@TMB composites. Among them, Cu-MOF@TMB-1 exhibited the highest sensitivity, achieving a limit of detection (LOD) of 0.941 ppm in aqueous solution, which further improved to 0.235 ppm in model urine and 0.149 ppm in real urine samples. A portable, enzyme-free, test strip-based colorimetric assay enabled rapid, visible detection of UA through a distinct blue color change. This work demonstrates a cost-effective and selective MOF-based sensing platform with strong potential for clinical diagnostics and point-of-care applications.