Singlet oxygen-based electrosensing by molecular photosensitizers

Abstract

Enzyme-based electrochemical biosensors are an inspiration for the development of (bio)analytical techniques. However, the instability and reproducibility of the reactivity of enzymes, combined with the need for chemical reagents for sensing remain challenges for the construction of useful devices. Here we present a sensing strategy inspired by the advantages of enzymes and photoelectrochemical sensing, namely the integration of aerobic photocatalysis and electrochemical analysis. The photosensitizer, a bioinspired perfluorinated Zn phthalocyanine, generates singlet-oxygen from air under visible light illumination and oxidizes analytes, yielding electrochemically-detectable products while resisting the oxidizing species it produces. Compared with enzymatic detection methods, the proposed strategy uses air instead of internally added reactive reagents, features intrinsic baseline correction via on/off light switching and shows C-F bonds-type enhanced stability. It also affords selectivity imparted by the catalytic process and nano-level detection, such as 20 nM amoxicillin in μl sample volumes.

An Isolated Molecule of Iron(II) Phthalocyanin Exhibits Quintet Ground‐State: A Nexus between Theory and Experiment

“…Metal phthalocyanines are extensively studied planar molecules possessing ag reat application potentiala sp hotosensitizers, [1] electrocatalysts for CO 2 reduction, [2] promising systems for spintronic devices, [3][4][5] and energy harvestingf rom singlet fission. [6] Amongm etal phthalocyanines, iron(II) phthalocyanine (FePc)h olds as pecific position mainly due to itss uperior applicability in variousf ields including single-molecule quantum dots, [7] electrocatalysts for oxygen reduction reaction, [8][9][10] bifunctional catalysts for lithium-oxygen batteries, [11] model systems for heme-like coordinationc hemistry [12] and molecular frameworks to engineer novel low-dimensional magnetically ordered materials.…”

Photoelectrochemistry for Measuring the Photocatalytic Activity of Soluble Photosensitizers

“…The suggested method is not limited by methanol and can be used in other media where electrochemical regeneration of HQ (or another analogous redox reporter) can be observed. This includes water if the tested dye is soluble in water or immobilized on a supporting material, while the photoelectrochemical cell may operate in drop by making use of a screen‐printed electrode. The suggested method is rapid, reproducible and does not require complex or expensive equipment.…”

The good, the bad, and the ugly–controlling singlet oxygen through design of photosensitizers and delivery systems for photodynamic therapy

“…In a recent example of a novel sensing strategy Trashin et al used a perfluorinated Zn phthalocyanine to generate singlet oxygen that subsequently oxidized analytes, the products of which can be detected electrochemically. 135 Combination therapy has also come to the foreground of the PDT stage but with it questions arising from coadministration need to be further addressed and understood.…”