A new highly selective and sensitive assay for fluorescence imaging of *OH in living cells: effectively avoiding the interference of peroxynitrite.
TL;DR: A new nonredox fluorescent probe to realize the imaging of hydroxyl radicals (*OH) in living cells was designed and synthesized and it possessed superior photostability and pH insensitivity.
Abstract: A new nonredox fluorescent probe to realize the imaging of hydroxyl radicals ('OH) in living cells was designed and synthesized. The structure comprised the fluorescent dye boron dipyrromethene (BDP) and a 2,2,6,6-tetramethyl-1-piperidinoxyl (TEMPO) unit. This probe could rapidly respond to 'OH with a detection limit of 18pM, and it possessed superior photostability and pH insensitivity. Other reactive oxygen species (ROS) and relevant intracellular components did not interfere. In particular, the important problem of ONOO - interference was efficiently avoided. An MTT assay proved that the probe was not very cytotoxic. The probe could penetrate into intact cell membranes to selectively detect intracellular . OH without causing cellular damage in living mice macrophages, normal human liver cells. and human hepatoma cells. These advantageous characteristics make the fluorescent probe potentially useful as a new candidate to detect 'OH in broad biosystems.
Citations
More filters
TL;DR: Key Laboratory for Organic Electronics and Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, Nanjing 210046, P. R. China.
Abstract: Yuming Yang,†,§ Qiang Zhao,‡,§ Wei Feng,† and Fuyou Li*,† †Department of Chemistry and State Key Laboratory of Molecular Engineering of Polymers and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, P. R. China ‡Key Laboratory for Organic Electronics and Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, Nanjing 210046, P. R. China.
1,999 citations
1,497 citations
TL;DR: A critical review highlights recent advances that have been made in the development of fluorescent and luminescent probes employed to monitor various ROS/RNS.
Abstract: Oxidative and nitrosative stress induced by ROS/RNS play crucial roles in a wide range of physiological processes and are also implicated in various diseases, including cancer and neurodegenerative disorders. Sensitive and selective methods for the detection of ROS/RNS based on fluorescent and luminescent probes are of great use in monitoring the in vivo production of these species and elucidating their biological functions. This critical review highlights recent advances that have been made in the development of fluorescent and luminescent probes employed to monitor various ROS/RNS (132 references).
853 citations
TL;DR: This review will provide general guidance for the future design of innovative photosensitizers and spur preclinical and clinical studies for PDT-mediated cancer treatments and the challenges that need to be addressed to develop optimal heavy-atom-free photosensiter structures for oncologic photodynamic therapy.
Abstract: Photodynamic therapy (PDT) is a clinically approved therapeutic modality that has shown great potential for the treatment of cancers owing to its excellent spatiotemporal selectivity and inherently noninvasive nature. However, PDT has not reached its full potential, partly due to the lack of ideal photosensitizers. A common molecular design strategy for effective photosensitizers is to incorporate heavy atoms into photosensitizer structures, causing concerns about elevated dark toxicity, short triplet-state lifetimes, poor photostability, and the potentially high cost of heavy metals. To address these drawbacks, a significant advance has been devoted to developing advanced smart photosensitizers without the use of heavy atoms to better fit the clinical requirements of PDT. Over the past few years, heavy-atom-free nonporphyrinoid photosensitizers have emerged as an innovative alternative class of PSs due to their superior photophysical and photochemical properties and lower expense. Heavy-atom-free nonporphyrinoid photosensitizers have been widely explored for PDT purposes and have shown great potential for clinical oncologic applications. Although many review articles about heavy-atom-free photosensitizers based on porphyrinoid structure have been published, no specific review articles have yet focused on the heavy-atom-free nonporphyrinoid photosensitizers.In this account, the specific concept related to heavy-atom-free photosensitizers and the advantageous properties of heavy-atom-free photosensitizers for cancer theranostics will be briefly introduced. In addition, recent progress in the development of heavy-atom-free photosensitizers, ranging from molecular design approaches to recent innovative types of heavy-atom-free nonporphyrinoid photosensitizers, emphasizing our own research, will be presented. The main molecular design approaches to efficient heavy-atom-free PSs can be divided into six groups: (1) the approach based on traditional tetrapyrrole structures, (2) spin-orbit charge-transfer intersystem crossing (SOCT-ISC), (3) reducing the singlet-triplet energy gap (ΔEST), (4) the thionation of carbonyl groups of conventional fluorophores, (5) twisted π-conjugation system-induced intersystem crossing, and (6) radical-enhanced intersystem crossing. The innovative types of heavy-atom-free nonporphyrinoid photosensitizers and their applications in cancer diagnostics and therapeutics will be discussed in detail in the third section. Finally, the challenges that need to be addressed to develop optimal heavy-atom-free photosensitizers for oncologic photodynamic therapy and a perspective in this research field will be provided. We believe that this review will provide general guidance for the future design of innovative photosensitizers and spur preclinical and clinical studies for PDT-mediated cancer treatments.
232 citations
TL;DR: A ratiometric fluorescence biosensor for (•)OH was developed, in which gold nanocluster protected by bovine serum albumin was employed as a reference fluorophore and the organic molecule 2-[6-(4'-hydroxy)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid (HPF) acted as both the response signal and specific recognition element for ( •)OH.
Abstract: Determination of hydroxyl radical (•OH) with high sensitivity and accuracy in live cells is a challenge for evaluating the role that •OH plays in the physiological and pathological processes. In this work, a ratiometric fluorescence biosensor for •OH was developed, in which gold nanocluster (AuNC) protected by bovine serum albumin was employed as a reference fluorophore and the organic molecule 2-[6-(4′-hydroxy)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid (HPF) acted as both the response signal and specific recognition element for •OH. In the absence of •OH, only one emission peak at 637 nm ascribed to AuNCs was observed, because HPF was almost nonfluorescent. However, fluorescence emission at 515 nm attributed to the HPF product after reaction with •OH—dianionic fluorescein—gradually increased with the continuous addition of •OH, while the emission at 637 nm stays constant, resulting in a ratiometric determination of •OH. The developed fluorescent sensor exhibited high selectivity for •OH over other reactiv...
194 citations
References
More filters
TL;DR: The pathways that regulate ROS homeostasis are crucial for mitigating the toxicity of ROS and provide strong evidence about specificity in ROS signalling.
Abstract: Reactive oxygen species (ROS) have been shown to be toxic but also function as signalling molecules. This biological paradox underlies mechanisms that are important for the integrity and fitness of living organisms and their ageing. The pathways that regulate ROS homeostasis are crucial for mitigating the toxicity of ROS and provide strong evidence about specificity in ROS signalling. By taking advantage of the chemistry of ROS, highly specific mechanisms have evolved that form the basis of oxidant scavenging and ROS signalling systems.
2,941 citations
TL;DR: Data suggest that H2O2-Fe(2+)-derived oxidant is mainly responsible for the nonenzymatic oxidation of DCFH, which remains an attractive probe as an overall index of oxidative stress in toxicological phenomena.
Abstract: The use of dichlorofluorescin (DCFH) as a measure of reactive oxygen species was studied in aqueous media. Hydrogen peroxide oxidized DCFH to fluorescent dichlorofluorescein (DCF), and the oxidation was amplified by the addition of ferrous iron. Hydrogen peroxide-induced DCF formation in the presence of ferrous iron was completely inhibited by deferoxamine and partially inhibited by ethylenediaminetetraacetic acid, but was augmented by diethylenetriaminepentaacetic acid. Iron-peroxide-induced oxidation of DCFH was partially inhibited by catalase but not by horseradish peroxidase. Nonchelated iron-peroxide oxidation of DCFH was partially inhibited by several hydroxyl radical scavengers, but was independent of the scavenger concentration, and this suggests that free hydroxyl radical is not involved in the oxidation of DCFH in this system. Superoxide anion did not directly oxidize DCFH. Data suggest that H2O2-Fe(2+)-derived oxidant is mainly responsible for the nonenzymatic oxidation of DCFH. In addition, peroxidase alone and oxidants formed during the reduction of H2O2 by peroxidase oxidize DCFH. Since DCFH oxidation may be derived from several reactive intermediates, interpretation of specific reactive oxygen species involved in biological systems should be approached with caution. However, DCFH remains an attractive probe as an overall index of oxidative stress in toxicological phenomena.
2,465 citations
TL;DR: ROS and RNS could contribute to the initiation of cancer, in addition to being important in the promotion and progression phases, as evidence is growing that antioxidants may prevent or delay the onset of some types of cancer.
Abstract: It is increasingly proposed that reactive oxygen species (ROS) and reactive nitrogen species (RNS) play a key role in human cancer development [1–6], especially as evidence is growing that antioxidants may prevent or delay the onset of some types of cancer (reviewed in [7,8]). ROS is a collective term often used by biologists to include oxygen radicals [superoxide (O # J−), hydroxyl (OHJ), peroxyl (RO # J) and alkoxyl (ROJ)] and certain nonradicals that are either oxidizing agents and}or are easily converted into radicals, such as HOCl, ozone (O $ ), peroxynitrite (ONOO−), singlet oxygen ("O # ) and H # O # . RNS is a similar collective term that includes nitric oxide radical (NOJ), ONOO−, nitrogen dioxide radical (NO # J), other oxides of nitrogen and products arising when NOJ reacts with O # J−, ROJ and RO # J. ‘Reactive ’ is not always an appropriate term; H # O # , NOJ and O # J− react quickly with very few molecules, whereas OHJ reacts quickly with almost anything. RO # J, ROJ, HOCl, NO # J, ONOO− and O $ have intermediate reactivities. ROS and RNS have been shown to possess many characteristics of carcinogens [4] (Figure 1). Mutagenesis by ROS}RNS could contribute to the initiation of cancer, in addition to being important in the promotion and progression phases. For example, ROS}RNS can have the following effects. (1) Cause structural alterations in DNA, e.g. base pair mutations, rearrangements, deletions, insertions and sequence amplification. OHJ is especially damaging, but "O # , RO # J, ROJ, HNO # , O $ , ONOO− and the decomposition products of ONOO− are also effective [9–13]. ROS can produce gross chromosomal alterations in addition to point mutations and thus could be involved in the inactivation or loss of the second wild-type allele of a mutated proto-oncogene or tumour-suppressor gene that can occur during tumour promotion and progression, allowing expression of the mutated phenotype [4]. (2) Affect cytoplasmic and nuclear signal transduction pathways [14,15]. For example, H # O # (which crosses cell and organelle membranes easily) can lead to displacement of the inhibitory subunit from the cytoplasmic transcription factor nuclear factor κB, allowing the activated factor to migrate to the nucleus [14]. Nitration of tyrosine residues by ONOO− may block phosphorylation. (3) Modulate the activity of the proteins and genes that respond to stress and which act to regulate the genes that are related to cell proliferation, differentiation and apoptosis [4,14–17]. For example, H # O # can stimulate transcription of c-jun
2,321 citations
TL;DR: The main goal of the present paper is to review the fluorescence methodologies that have been used for detecting ROS in biological and non-biological media.
1,536 citations