Unraveling the Pathways to UVA‐Induced DNA Photodamage: (6–4) Photoproduct as a Potential “Trojan Horse”

Wagenknecht, Hans‐Achim

doi:10.1002/cphc.201300598

Cited by 8 publications

(3 citation statements)

References 48 publications

(50 reference statements)

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“…This distinct feature has become a key concept in the design of photo-responsive systems 15 . To date, most wavelength-dependent reactions require activation by UV light, which has low penetration characteristics and can be harmful to species in biological environments 16 . Thus, identifying a catalyst-free system that does not require (harsh) UV light and can afford deeper light penetration is an ongoing quest.…”

Section: Introductionmentioning

confidence: 99%

Green light triggered [2+2] cycloaddition of halochromic styrylquinoxaline—controlling photoreactivity by pH

et al. 2020

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Photochemical reactions are a powerful tool in (bio)materials design due to the spatial and temporal control light can provide. To extend their applications in biological setting, the use of low-energy, long wavelength light with high penetration propertiesis required. Further regulation of the photochemical process by additional stimuli, such as pH, will open the door for construction of highly regulated systems in nanotechnology-and biology-driven applications. Here we report the green light induced [2+2] cycloaddition of a halochromic system based on a styrylquinoxaline moiety, which allows for its photo-reactivity to be switched on and off by adjusting the pH of the system. Critically, the [2+2] photocycloaddition can be activated by green light (λ up to 550 nm), which is the longest wavelength employed to date in catalyst-free photocycloadditions in solution. Importantly, the pH-dependence of the photoreactivity was mapped by constant photon action plots. The action plots further indicate that the choice of solvent strongly impacts the system's photo-reactivity. Indeed, higher conversion and longer activation wavelengths were observed in water compared to acetonitrile under identical reaction conditions. The wider applicability of the system was demonstrated in the crosslinking of an 8-arm PEG to form hydrogels (ca. 1 cm in thickness) with a range of mechanical properties and pH responsiveness, highlighting the potential of the system in materials science.

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Section: Introductionmentioning

confidence: 99%

Green light triggered [2+2] cycloaddition of halochromic styrylquinoxaline—controlling photoreactivity by pH

et al. 2020

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“…In other words, the dynamic formation of covalent bonds possesses limitations when different molecular units are involved. Broadly speaking, in the context of (macro)molecular architecture transformations, dynamic covalent bond (re)formation between structures can be traditionally achieved through [2 + 2] and [4 + 4] photodimerizations. − In these cases, photocycloaddition occurs under one wavelength (λ up to 550 nm), while cycloreversion requires a different one, typically of a higher energy (λ < 250 nm), which can be invasive for the material involved. − All the above-mentioned examples represent notable approaches toward smart polymer systems that can alter their shape, and hence properties, in response to external stimuli on-demand. However, the stimuli used so far (e.g., elevated temperatures or high energy light irradiation), as well as the prolonged reaction times (e.g., up to 48 h) and disruptive multi-step processes with intermediate purification, necessitate the design of intelligent polymer systems that can adapt to the desired transformation in the least invasive manner, whilst maintaining practicality, absolute control, and high uniformity.…”

Section: Introductionmentioning

confidence: 62%

Reversible Transformations of Polymer Topologies through Visible Light and Darkness

2022

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A fundamentally important characteristic of a macromolecule is its shape. Herein, visible light and darkness are used as the only stimuli to reversibly alter the topology of welldefined polymers in a one-pot procedure. For this, linear naphthalene-containing polyacrylates are used as scaffolds for the visible light-induced cycloaddition with various substituted triazolinediones (i.e., butyl, stearyl, perfluoro, and polymeric), resulting in differently shaped graft polymers, including brushes and combs. The thus-formed cycloadduct linkages dissociate in the dark, resulting in the regeneration of the parent linear polymer at ambient temperature, establishing a dual-topology transformation by only switching green light on and off. By applying different temperatures during the cycloreversion process, the dissociation rate of the cycloadducts can be tuned in a facile manner, thus allowing for time control over the regeneration of the parent polymer. By engineering a polymer that consists of differently substituted naphthalenes at the chain ends and on the side chains, the inherently different cycloreversion rates of the formed cycloadducts are leveraged to achieve in situ multi-topology transformations without external stimuli. The shape transformations have been repeated up to 4 times sequentially in one pot without the need of any purification. The topological alterations are microscopically depicted through reversible self-assembly, with the polymers adopting different morphologies upon visible light or darkness. The versatile yet practical nature of this polymer "reshaping" strategy provides facile access to multifaceted polymer systems and, consequently, to a plethora of potential applications thereof.

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“…Spatio-temporal control 8 enables the on-demand, remote and spatially addressable visualization of biological processes and can only be established using light as the trigger. 9 The majority of reported light-induced bioorthogonal reactions, such as photo-induced cycloadditions between tetrazoles and alkenes (“photoclick” reactions) 10 employ UV 11 or violet light ( λ max = 405 nm), 12 which can be harmful to living cells, 13 while featuring low penetration depths in tissue. 14 This reaction type had been employed in the labelling of proteins 15 or nucleic acids, 16 using wavelengths comprise between 305 and 405 nm as the trigger.…”

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confidence: 99%

DNA labelling in live cells via visible light-induced [2+2] photocycloaddition

et al. 2023

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Unraveling the Pathways to UVA‐Induced DNA Photodamage: (6–4) Photoproduct as a Potential “Trojan Horse”

Abstract: Double jeopardy: The Pyo chromophore in the (6-4) photoproduct is able to induce a secondary photoproduct in DNA by excitation with UVA light.

Cited by 8 publications

References 48 publications

Green light triggered [2+2] cycloaddition of halochromic styrylquinoxaline—controlling photoreactivity by pH

Green light triggered [2+2] cycloaddition of halochromic styrylquinoxaline—controlling photoreactivity by pH

Reversible Transformations of Polymer Topologies through Visible Light and Darkness

DNA labelling in live cells via visible light-induced [2+2] photocycloaddition

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