Porphyrin-Based Metal–Organic Frameworks for PD-L1 Detection via “Coordination Disaggregation-Induced Enhancement” Strategy

Porphyrins, known for their exceptional photoelectrochemical properties and high luminescence, are promising candidates for electrochemiluminescence (ECL) applications. However, their tendency to aggregate in aqueous solutions due to π-π stacking leads to luminescence quenching and reduced efficiency. To address this, we developed a "coordination disaggregation-induced enhancement" strategy, utilizing metal-organic frameworks (MOFs) as stable platforms for immobilizing porphyrin. These porphyrin-based MOFs not only increase the loading of luminescent groups and suppress the aggregation-caused quenching (ACQ) effect but also enhance electron transfer via uniform dispersion of pyrrole N in the porphyrin ligand, thereby improving ECL intensity. Additionally, they exhibit favorable biocompatibility and low toxicity, making them suitable for biomedical applications. By combining porphyrin-based MOFs as donors with PDA@MnO₂ composites as quenchers, we constructed a quenching-type ECL immunosensor for detecting programmed death ligand 1 (PD-L1). This sensor achieves a detection range of 10 fg/mL to 100 ng/mL, with a limit of detection as low as 2.48 fg/mL, which demonstrates great potential for highly sensitive biomarker detection and promising applications in early cancer diagnosis and other medical diagnostics.