A Diode‐Like Dye‐Cu Anisotropic Junction in a Coordination Polymer as a Logic State Ratchet for Intratumor Redox Photomodulation

Abstract

Redox logic materials offer new avenues to modulate intracellular pathologic redox environment area-specifically, but the unambiguity of redox logic states and their unidirectional and repetitive switchability are challenging to realize. By merging a bistable diisophthalic phenazine dye ligand with Cu II salt, a multistable coordination polymer (CP) was constructed, of which the dye-Cu anisotropic junction achieved the diode-like unidirectional electron transfer and logic state ratchet for the first time. Radical cationic CP maintained OFF status with low toxicity in healthy tissues, but was reduced to the neutral SERVO state by the overexpressed glutathione (GSH) in hypoxic tumors. After photoirradiation, the stabilized charge-separated ON status promoted photo-Fenton reaction for reactive oxygen species (ROS) signal transduction, and simultaneously recovered the initial state for catalytic signal amplification of ROS, furnishing intratumor redox photomodulation for therapy.

Harnessing Radicals in Confined Supramolecular Environments Made Possible by MOFs

“…The ideal light‐driven therapeutic agents should act like a logic gate system, which remains in an ‘OFF’ state for ROS generation in healthy tissue while it can be activated to a ‘SERVO’ state when encountering tumor conditions, then turns to be ‘ON’ state upon further photoirradiation. Based on this notion, we designed a bistable spin‐state MOF for cancer therapy that can switch among ‘SERVO’/‘OFF’/‘ON’ statuses through spin‐state modulation, [57] according to the local input of either pathologic or healthy biosignal and the penetrative outer‐field input of light.…”

“…The rigid framework of MOF twisted the electron‐donating (phenazine) and accepting regions (carboxylate‐Cu(II) complexes) (Figure 9A). [57] Fixing the twisted configuration of spatially isolated HOMO (highest occupied molecular orbital)‐LUMO (lowest unoccupied molecular orbital) sections of dye‐based ligands and connecting the discrete LUMO module to the carboxylate‐transition metal node could offer D−A arrays capable of spatially anisotropic electron transfer route (Figure 9B). As a result, Cu− PDPA was constructed in radical cationic form Cu− PDPA ⋅ + , serving as both a diode‐like unidirectional junction as well as a redox logic state ratchet.…”

“…(C) A conceptual scheme for the sequential logic controlled ROS generation by Cu‐ PDPA in pathogenic tissue. (Reproduced with permission from ref [57]. 2023 Wiley‐VCH GmbH)…”

Unveiling Energy Transfer Mechanisms in Nanographene-Incorporated Metal–Organic Frameworks

“…57 for photocatalysis, 58−61 optoelectronics, 62−64 and photodetector 36,65 applications, investigations into their photophysical properties are extremely rare and limited. 66,67 For the development of new MOF systems with enhanced performance, it is essential to understand the fundamental photophysical processes and the correlation between photophysical properties and the underlying topological network. 56,68 Herein, we report nanographene-incorporated MOFs, UMOF-2 series, composed of a nanographene-incorporated hexaphenylethynylbenzene (HPB) and HBC linker, connected by Cu paddle-wheel nodes.…”

“…This behavior promotes the nonradiative decay of the excited state, thereby hampering the emission process . Although numerous MOFs containing paramagnetic metal ions have been reported for photocatalysis, − optoelectronics, − and photodetector , applications, investigations into their photophysical properties are extremely rare and limited. , For the development of new MOF systems with enhanced performance, it is essential to understand the fundamental photophysical processes and the correlation between photophysical properties and the underlying topological network. , …”