Expanded porphyrins: functional photoacoustic imaging agents that operate in the NIR-II region

Chen, Jingqin; Sedgwick, Adam; Sen, Sajal; Ren, Yongmao; Sun, Qinchao; Chau, Calvin; Arambula, Jonathan F.; Sarma, Tridib; Liu, Song; Sessler, Jonathan L.; Liu, Chengbo

doi:10.1039/d1sc01591e

Cited by 38 publications

(40 citation statements)

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“…333 Due to its central role in cancer development, the tumor pH is an important biomarker in cancer that has been exploited for targeted drug delivery and imaging, 339–341 as well as the development of many activatable PA probes. 342–371 Here we highlight some recent examples.…”

Section: Activatable Pa Probesmentioning

confidence: 98%

Targeted contrast agents and activatable probes for photoacoustic imaging of cancer

2022

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Section: Activatable Pa Probesmentioning

confidence: 98%

Targeted contrast agents and activatable probes for photoacoustic imaging of cancer

2022

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“…Another approach capable of achieving enhanced tissue penetration depth is photoacoustic (PA) imaging, where optical excitation is coupled with acoustic detection (light in, sound out), thereby enabling high resolution and deep tissue imaging at centimetre depths (Knox and Chan, 2018;Cheng et al, 2020;Ren et al, 2020;Chen et al, 2021;Lucero et al, 2021). PA probes that can be activated by specific biological species are of particular interest as they have the potential to complement other clinically used diagnostic systems (i.e., Ultrasound) for disease diagnosis.…”

Section: Current State Of the Artmentioning

confidence: 99%

Fluorescent Chemosensors for Ion and Molecule Recognition: The Next Chapter

et al. 2021

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Over the past 30 years fluorescent chemosensors have evolved to incorporate many optical-based modalities and strategies. In this perspective we seek to highlight the current state of the art as well as provide our viewpoint on the most significant future challenges remaining in the area. To underscore current trends in the field and to facilitate understanding of the area, we provide the reader with appropriate contemporary examples. We then conclude with our thoughts on the most probable directions that chemosensor development will take in the not-too-distant future.

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“…The studies indicated that fluorenophyrin was a nonaromatic distorted macrocycle and the fluorene moiety was in completely out-of-plane arrangement with the rest of the macrocycle. In continuation of our studies on fluorene-embedded porphyrinoids, herein we report the synthesis of bis-(fluorene)-embedded hexaphyrins 2a/2b , which are expanded porphyrins − containing two fluorene moieties and four pyrrole rings connected via six meso carbons in a macrocyclic framework. These hexaphyrins 2a/2b were investigated by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR), absorption, electrochemical, and density functional theory (DFT)/time-dependent (TD)-DFT studies, and we present our findings herein.…”

Section: Introductionmentioning

confidence: 99%

Bis-(Fluorene)-Embedded Hexaphyrins

Yadav

Ravikanth

2022

J. Org. Chem.

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The polyaromatic hydrocarbon containing expanded porphyrins, bis-(fluorene)-embedded hexaphyrins, were synthesized by condensing fluorene-based tripyrrane with pentafluorobenzaldehyde in CH2Cl2 in the presence of 1 equiv of BF3·OEt2 under an inert atmosphere followed by oxidation with DDQ in open air at room temperature. The reaction worked only when 1 equiv of BF3·OEt2 was added to the reaction mixture under concentrated reaction conditions. The bis-(fluorene)-embedded macrocycles were characterized and studied by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR), absorption, electrochemical, and density functional theory (DFT)/time-dependent (TD)-DFT techniques. In 1H NMR, the hexaphyrins showed a few broad unresolved resonances at room temperature, but the NMR spectra were well-resolved at lower temperatures, indicating that the hexaphyrins were very flexible. The DFT-optimized structures indicated that the two fluorene units at the crossing point of the figure-eight loop makes an angle of ∼79.73° with each other, the fluorene moieties maintained their own planarity, and one of the fluorene moieties was not involved in conjugation with the rest of the macrocycle. The absorption spectra of hexaphyrins showed one intense sharp band in the higher energy region and a broad band in the lower energy region. The electrochemical studies indicated that expanded hexaphyrins are relatively electron-rich and showed three easier oxidations and one reduction. The DFT/TD-DFT studies are in agreement with the experimental observations.

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Expanded porphyrins: functional photoacoustic imaging agents that operate in the NIR-II region

Abstract: Photoacoustic imaging (PAI) relies on the use of contrast agents with strong molar absorptivity in the NIR-I/NIR-II region. Expanded porphyrins, synthetic analogues of natural tetrapyrrolic pigments (e.g. heme and chlorophyll),...

Cited by 38 publications

References 39 publications

Targeted contrast agents and activatable probes for photoacoustic imaging of cancer

Targeted contrast agents and activatable probes for photoacoustic imaging of cancer

Fluorescent Chemosensors for Ion and Molecule Recognition: The Next Chapter

Bis-(Fluorene)-Embedded Hexaphyrins

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