High Photostability Research Articles

A hole-selective hybrid TiO2 layer for stable and low-cost photoanodes in solar water oxidation

The use of conductive and corrosion-resistant protective layers represents a key strategy for improving the durability of light absorber materials in photoelectrochemical water splitting. For high performance photoanodes such as Si, GaAs, and GaP, amorphous TiO2 protective overlayers, deposited by atomic layer deposition, are conductive for holes via a defect band in the TiO2. However, when coated on simply prepared, low-cost photoanodes such as metal oxides, no charge transfer is observed through amorphous TiO2. Here, we report a hybrid polyethyleneimine/TiO2 layer that facilitates hole transfer from model oxides BiVO4 and Fe2O3, enabling access to a broader scope of available materials for practical water oxidation. A thin polyethyleneimine layer between the light absorber and the hybrid polyethyleneimine/TiO2 acts as a hole-selective interface, improving the optoelectronic properties of the photoanode devices. These polyethyleneimine/TiO2 modified photoanodes exhibit high photostability for solar water oxidation over 400 h.

1,4-Benzodioxane Substituted Aza-BODIPY: Towards Photostable yet Efficient Triplet Photosensitizer.

We report herein the synthesis of aza-BODIPY substituted with 1,4-benzodioxane-6-yl substituents at 3,5 positions of the chromophore system. Both pyrrole rings of the aza-BODIPY in question were substituted with bromine atoms in order to induce highly desirable photophysical properties, such as highly populated excited triplet state (T1) and long excited triplet-state lifetime (τT) of 21 μs. The photosensitized oxygenation of a model compounds, viz. DPBF, points to a high singlet oxygen and/or other ROS formation quantum yield of 0.42. The photosensitizer studied exhibited an absorption band within the so-called "therapeutic window", with λabs 678 nm. As estimated by CV/DPV measurements the 1,4-benzodioxane-6-yl substituted aza-BODIPYs studied exhibited a multi-electron oxidations at a relatively low potentials (Eox), pointing to the very good electron-donating properties of these molecules. High photostability and thermal stability was observed for all compounds studied. The good singlet oxygen quantum yield measured combined with an exceptional photostability makes this aza-BODIPY a promising candidate for applications such as photocatalysis and photodynamic therapy (PDT).

Enhancing mycotoxins detection through quantum dots-based optical biosensors

Abstract Quantum dot-based optical biosensors represent a significant advancement for detection of mycotoxins that are toxic secondary metabolites produced by fungi and pose serious health risk effects. This review highlights the importance of detection of filamentous fungi such as Aspergillus, Penicillium, Fusarium, Claviceps, and Alternaria in mycotoxin production, leading to contamination of agricultural products and subsequent health issues. Conventional detection methods such as thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), gas chromatography (GC), and enzyme-linked immunosorbent assay (ELISA) are discussed with their respective advantages and limitations. Then the innovative use of quantum dots (QDs) in fabrication of biosensors is discussed in the present review, emphasizing their unique optical properties, such as size-tunable fluorescence and high photostability. These properties enable the development of highly sensitive and specific biosensors for mycotoxin detection. The application of QD-based biosensors, based on their applied bioreceptors including antibodies, molecularly imprinted polymers (MIPs) and aptamer, is explored through various detection strategies and recent advancements. The review concludes by underscoring the potential of QD-based biosensors in providing portable, cost-effective, and efficient solutions for real-time monitoring of mycotoxin for enhancing food safety and protecting public health.

Advancing Two-Photon Photodynamic Therapy Over NIR-II Excitable Conjugated Microporous Polymer with NIR-I Emission.

The availability of second near-infrared (NIR-II) excitable two-photon photosensitizers with NIR-I emission for efficient photodynamic therapy (PDT) is limited by challenges in molecular design. In this study, a NIR-II light-excitable two-photon conjugated microporous polymer (Tph-Dbd) with emission in the NIR-I region is developed. The large conjugated system and delocalized electronic structures endow Tph-Dbd with a large two-photon absorption cross-section under NIR-II light excitation. Moreover, the efficient electron acceptor and donor units within the π-conjugated backbones result in NIR-I emission for high signal-to-background ratio imaging, as well as separated highest occupied molecular orbitaland lowest unoccupied molecular orbital distributions for excellent singlet oxygen generation ability. The excellent NIR-II excitable two-photon absorption activity, NIR-I emission, good biocompatibility, and high photostability allow Tph-Dbd to be used for efficient in vitro fluorescence imaging guided PDT. Moreover, the impressive photothermal effect of Tph-Dbd can overcome the limitations of PDT in the treatment of hypoxic tumors. This study highlights a strategy for designing NIR-II excitable two-photon photosensitizers for advanced PDT.

Molecular Engineering of membrane structure targeted photosensitizers for antitumor photodynamic therapy

Photodynamic therapy (PDT) has been used to cure special diseases or the diseases that localized at special sites in comparison with conventional therapy, due to its high spatiotemporal selectivity, non-invasion, low drug resistance. However, vast majority of photosensitizers (PSs) still suffer from several limitations including poor aqueous solubility and poor photostability. Here, we used two strategies, promoting the intramolecular charge transfer and terminal modification, to overcome these limitations and enhance therapeutic effects. Three membrane-structure targeted molecules, 3CN-Np, 3CN–OH, and 3CN-QA, were designed and synthesized, which exhibited high extinction coefficient, excellent photostability and reactive oxygen species (ROS) productive capacity. In cell imaging, the designing molecules would stain endoplasmic reticulum for 3CN-Np and 3CN–OH, and cell membrane for 3CN-QA, respectively. Afterwards, we used white light (25 mW/cm2) to irradiate the probe cultured cells for 20 min, the ratio of the dead and live cells was 3.0 for 3CN-Np, 3.5 for 3CN–OH, and 3.7 for 3CN-QA. Based on the high cell apoptosis in vitro under a white-light, 3CN–OH was selected to inhibited tumor growth in vivo, and the tumor volume was reduced to 45 % with non-toxicity to vitals. The study provided new sights in developing PSs with high water-solubility, photostability, and ROS generating ability in white-light mediating PDT system.

Fluorescence Entrenched Probe for Onsite Detection of Amoxicillin Residue in Bovine Milk.

A novel fluorescent probe (E)-3-(4-hydroxyphenyl)-2-((pyrene-1-ylmethylene) amino)propanoic acid (PyT) was developed for the 'turn-on' detection of amoxicillin(AM), residues. The PyT molecule was developed by a simple condensation reaction between a biologically important tyrosine amino acid and pyrene carboxaldehyde. The small fluorophore molecule has spectacular photoluminescence properties such as large stock shift, high photostability, selectivity and sensitivity toward the analytes. The PyT upon dispersion in the liquid phase becomes highly luminescent possessing the restricted intramolecular rotation (RIR) and excited stated intramolecular proton transfer (ESIPT) properties which are the major criteria for aggregation induced emission enhancement (AIEE) mechanism prevailing the aggregation caused quenching (ACQ). PyT molecule shows a binding constant of 3.285 × 104 L mol-1for amoxicillin (AM). The limit of detection(LOD) values are found to be 1.67µM. Consuming bovine milk with antibiotic residues exceeding the maximum residue limit (MRL) can lead to food toxicity and life threatening diseases in humans. The milk sample with AM antibiotic residue in presence of PyT probe shows a distinct blue colour which infers the selectivity and sensitivity of the probe towards the analyte. The fluorescence probe adheres with merits like on site and visual examination by naked eye without aid of any instruments.

Diradicaloid-Loaded Polypeptide Nanoparticles for Two-Photon NIR Phototheranostics.

Stable organic radicals, with unique electronic transitions from the ground state (D0) to the doublet excited state (D1), show promise as high-fluorescence quantum yield dyes. While organic small-molecule photosensitizers (PSs) have advanced for tumor photodynamic therapy (PDT), opportunities exist to enhance their performance and functionality. Herein, we synthesized Thiele's fluorocarbon derivative diradicaloid TFC-I with nearly 100% PLQY and integrated it into amphiphilic polypeptide nanoparticles, P-TI, using a precursor-doping approach. P-TI demonstrated notable features including high photostability, aggregation-induced emission, bright near-infrared fluorescence, substantial quantum yield (37% PLQY), robust near-infrared two-photon absorption (∼400 GM cross section), and superior ROS generation compared to commercial PSs. In vitro and in vivo experiments confirmed that P-TI performed well in mitochondria-targeted PDT, two-photon fluorescence imaging, and biosafety. This work highlights the use of organic stable radicals with precursor-doping for efficient PDT and deep tumor tissue imaging.

Green synthesis of highly fluorescent carbon quantum dots from almond resin for advanced theranostics in biomedical applications

Fluorescent Carbon Quantum Dots (CQDs) are being used in medical applications, particularly in theranostics. These Carbon Quantum Dots have been gaining more attention lately due to their potential as an effective replacement for hazardous synthetic organic dyes in a variety of biomedical applications, including live cell imaging and diagnostics. In this study, highly fluorescent Carbon Quantum Dots by one pot microwave based green route with a size of less than 10 nm, was prepared from commercially available almond resin, Prunus dulcis and conjugated with honey as additional reagent for surface functionalization. They exhibit a deep blue emission on excitation at 350 nm with an elevated quantum yield at 61%. They possess atomic nature and basic features such as high photo-stability, varying fluorescence, greater biocompatibility, and better water solubility. These fluorescent labels exhibit faster cellular invagination without disturbing the cell stability. The CQDs present cell imaging capacity with multi-coloration for visualizing the fine architecture of the nucleus naming, the nuclear membrane and nucleolus, which is linked with their varied, surface structures such as amphiphilic property and higher positive charges. These characteristics with minimal invasion have made carbon quantum dots to become the spotlight in theranostics. They can be used as alternatives to synthetic dyes for fluorescence- related cell-imaging. The intriguing fact about this approach is that it opens the possibility of combining therapy and diagnostics into one unit, which can alter how some diseases are handled and, in turn, transform the field of healthcare.

Infiltration of glass nanofiber-reinforced polylactic acid into delignified hardwood toward photoluminescent and mechanically reliable smart windows

Ultraviolet-protective, mechanically reliable, and photoresponsive wood that can switch color under ultraviolet light was developed. A combination of alkaline earth-doped strontium aluminate (ASA) as a photoluminescent pigment and glass nanofiber-supported polylactic acid as a hosting agent was infused into a delignified wood, producing transparent wood with photochromic activity. The ASA phosphor has proven high thermal stability and photostability. A typical process for producing colorless photoluminescent wood includes the well-dispersion of ASA in glass nanofiber-supported polylactic acid without agglomeration. As proven by the coloration measurements, the current photoluminescent wood becomes green under ultraviolet light and remains transparent under daylight. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) were employed to determine the morphology of the phosphor particles and glass fibers, demonstrating sizes of 12–21 nm and 50–125 nm, respectively. The luminescent wooden samples were studied by numerous microscopic and spectroscopic techniques, including SEM, X-ray fluorescence (XRF), and energy-dispersive X-ray (EDX). Upon excitation at 365 nm, the luminescence wood demonstrated an emission peak at 518 nm. When increasing the ASA concentration, the photoluminescent hardwoods displayed improved ultraviolet protection and better water resistance. The responsiveness of the luminescent wood to UV irradiation was fast and reversible.

Selective Recognition of the Dimeric NG16 Parallel G-Quadruplex Structure Using Synthetic Turn-On Red Fluorescent Protein Chromophore.

Red fluorescent protein (RFP)-based fluorescent probes that can selectively interact with specific nucleic acids are of great importance for therapeutic and bioimaging applications. Herein, we have reported the synthesis of RFP chromophores for selective recognition of G-quadruplex nucleic acids in vitro and ex vivo. We identified DFHBI-DM as a fluorescent turn-on probe that binds to the dimeric NG16 parallel quadruplex with superior selectivity and sensitivity over various parallel, antiparallel, and hybrid topologies. The binding of DFHBI-DM to NG16 exhibited excellent photophysical properties, including high binding affinity, large Stokes shift, high photostability, and quantum yield. The MD simulation study supports the 1:1 binding stoichiometry. It confirms the planar conformation of DFHBI-DM, which makes strong binding interactions with a flat quartet of NG16 compared to other antiparallel and hybrid topologies. The cell imaging and MTT assays revealed that DFHBI-DM is a biocompatible and efficient fluorescent probe for intracellular imaging of NG16. Overall, these results demonstrated that DFHBI-DM could be an effective fluorescent G4-stabilizing agent for the dimeric NG16 parallel quadruplex, and it could be a promising candidate for further exploration of bioimaging and therapeutic applications.

Spacer Twisting Strategy to Realize Ultrabright Near-Infrared II Polymer Nanoparticles for Fluorescence Imaging-Guided Tumor Phototheranostics.

Conjugated polymers are becoming popular near-infrared II (NIR-II) phototheranostic agents (PTAs) due to their numerous advantages, such as high photostability, large molar extinction coefficients, and excellent photothermal properties. However, the strong π-π interactions between the chains of the conjugated polymers resulted in their generally low NIR-II emission quantum yields (QY). Therefore, the synthesis of conjugated polymers with high QY is an interesting but challenging task. Herein, we proposed a spacer twisting strategy to realize ultrabright NIR-II polymer nanoparticles for fluorescence imaging-guided tumor phototheranostics. Theoretical calculations indicated that the polymer PY-IT has the largest dihedral angle between the largely π-conjugated skeleton and the spacer, which can effectively inhibit intermolecular π-π stacking, resulting in an improved QY as high as 16.5% in nanoparticles. In addition, PY-IT NPs can effectively perform NIR-II imaging and photothermal treatment of tumors. The work presents some valuable guides for achieving ultrabright NIR-II polymeric PTAs with high QY.

A novel merocyanine photoacid for visible light-controlled pH modulation

Merocyanine-based photoacids generate high proton concentrations under visible light irradiation. In the past decade, it has been established that these photoacids offer significant advantages over photoacid generators (PAGs) and hydroxyaryl photoacids, enabling better spatiotemporal control of proton transfer reactions in bulk media. In this study, we modified the core structure of the first generation of meroyanine photoacids. We developed a novel photoacid with color tuning capabilities and high solubility in polar organic solvents. Specifically, by incorporating a cationic benzoindolium moiety as an acceptor, we have altered the photoacid’s light absorption properties. Unlike the first generation of indolium-based merocyanine photoacids, this photoacid can now be activated with green light (λmax = 525 nm) as well as blue (λmax = 450 nm) and ultraviolet (λmax = 365 nm) lights. Furthermore, the novel photoacid exhibits high photo stability, photo-acidity (Π = 3.28 ± 0.08) and moderate reverse reaction rate (k = 1.08 × 10−3 ± 0.00017 s−1) in solution. We envision that with improved color tuning capabilities, this class of photoacids will be a more versatile tool for controlling proton-induced reactions in different systems, including biological reactions.

Molecular design of −substituted boron difluoride curcuminoids: Tuning luminescence and nonlinear optical properties

Boron β-diketonates are prospective fluorescent dyes for functional organic materials to new technologies in the fields of chemistry, NLO-optics, photonics and bio-imaging. The novel NIR-to-NIR luminophors – curcuminoids of boron difluoride with different substituents at the central carbon atom (at the γ-position) of the chelate ring 1,7-bis(4′-N,N′-dimethylaminophenyl)-4-organyl-gept-1,6-dien-3,5-dionate of boron difluoride (1–5) were synthesized. Luminescence in solutions, crystals and polymer matrices, photobiological properties and NLO properties in polystyrene (PS) and polymethylmethacrylate (PMMA) were studied. The crystal structure has been determined for 1. For 1–5, in PS film, upon excitation by laser (365 nm), two luminescence bands are observed in the blue (430 nm) and red (650–700 nm) regions of the spectrum. For 1–5, two-photon luminescence is recorded in PS and PMMA films. PS 1 films demonstrate high photostability. The synthesized dyes turned out to be almost non-toxic for HCT116 tumor cells both in a long-term dark experiment (72 h) and after photoexcitation in accordance with absorption maxima in the submicromolar concentration range. The compounds were rapidly accumulated by cells within 3 h, demonstrating cytoplasmic distribution and the potential for use as cellular photoimaging agents. The accumulation of dyes with hydrocarbon γ-substitutes (methyl, iso-propyl, phenyl) after 3 and 24 h is more effective compared to dye 2 (commercial product Cranad-2).

Ultrathin B:NiCoOx-modified BiVO4 photoanode with abundant oxygen vacancies for photoelectrochemical glycerol conversion coupled with hydrogen production

Photoelectrochemical (PEC) conversion of glycerol (GLY) into high value-added chemicals coupled with clean hydrogen production can be achieved over a BiVO4-based PEC cell, but the low photocurrent density and poor photostability of the most BiVO4 photoanodes limit the PEC performance and sustainable application of solar resources. Herein, we construct a high-efficiency stable photoanode by decorating an amorphous ultrathin B-activation NiCoOx (B:NiCoOx) nanolayer with abundant oxygen vacancies (Ov) on the BiVO4 photoanode via a simple immersing process. We demonstrate the optimized B:NiCoOx/BiVO4 photoanode in the PEC GLY oxidation yields a high photocurrent density of 6.05 mA cm−2 at 1.23 VRHE, a formic acid (FA) production rate of 360.3 mmol m−2 h−1, a dihydroxyacetone (DHA) production rate of 228.4 mmol m−2 h−1, with simultaneously hydrogen production at the cathode. An intermittent 60-h PEC GLY oxidation assay results indicates the superb durability of the B:NiCoOx/BiVO4 photoanode. The outstanding PEC performance is predominantly ascribed to the amorphous ultrathin structure of the B:NiCoOx nanolayer (∼ 2 nm) and the abundant Ov, which effectually accelerates the photogenerated holes transport/extraction and offers more catalytic active sites for the PEC GLY oxidation. Moreover, the free state and adsorbed state •OH radicals originated from active oxygen are deduced to be responsible for the oxidation of GLY to FA and GLY to DHA. This study develops a sustainable BiVO4-based catalyst with high activity and photostability for the PEC GLY oxidation and hydrogen production.

Bimolecular photodissociation of interstellar 1-Cyanonaphthalene via Intermolecular Coulombic decay

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in space and govern the interstellar chemistry. The two isomers of cyanonaphthalene (1-CNN and 2-CNN) were the first PAHs to be recently identified in the Taurus Molecular Cloud (TMC-1). Their large abundance is attributed to high photostability with nearly no photofragmentation at photon energies above the ionization potential. Here, we show that at ambient light and at densities akin to dense molecular clouds and the upper atmosphere of planets and moons, 1-CNN could undergo extensive fragmentation through a new mechanism leading to daughter cations. On UV photoexcitation, at a photon energy way below the ionization threshold, 1-CNN monomers form photoexcited dimer units. Intermolecular Coulombic decay between the two photoexcited units of the dimer leads to ionization, and the subsequent molecular rearrangements form new daughter cations. These daughter cations could react further, contributing to rich bottom-up astrochemistry, and could play a pivotal role in developmental astrobiology. Photofragmentation in atmospheric and astrophysical environments is hitherto known to be unimolecular, while the present results point a pathway involving bimolecular photofragmentation.

Red‐Emitting Pyrazole Azo Hydrazone and Its Metal Complexes for Photophysical Probing, Latent Fingerprints, Anti‐counterfeiting, and Biological Studies

ABSTRACTThe present paper discusses the synthesis of unprecedented red‐emitting mono‐azo compound pyrazole azo fluorescent tag (PAFT) by a diazotization method, followed by an electrophilic substitution reaction. Further, the metal complex of PAFT is also prepared by refluxing the ethanolic solution of the ligand with the corresponding metal (RuCl3 and C4H6CuO4.H2O) salts under suitable experimental conditions. The synthesized fluorophore PAFT displays intense fluorescence in the aggregate state and has excellent qualities, including high purity, low cost, eco‐friendliness, and good photostability. These unique characteristics of PAFT led to the development of new fluorescence‐based technology for the in situ viewing of latent fingerprints. Various spectroscopic and analytical techniques are used to confirm the structural characteristics of the synthesized compounds, including UV–Vis, FT‐IR, (1H) NMR, HRMS, TGA, VSM, ESR, and powder XRD methods. The potency of the antibacterial activity of the compounds was evaluated. The results revealed that compound PAFT and [Ru(PAFT)Cl3] H2O showed excellent sensitivity at 0.8 μL/mL against the Gram‐positive bacteria Staphylococcus aureus.

Multifunctional Bi2S3-Au nanoclusters for fluorescence/infrared thermal imaging guided photothermal therapy

Nanotechnology has attracted extensive attention in the diagnosis and treatment of cancer. Therefore, the research aimed at developing new nanomaterials and exploring their applications in biomedicine has attracted more attention. In this study, Bi2S3-Au nanoclusters (Bi2S3-AuNCs) as fluorescence/infrared thermal imaging-guided photothermal therapy (PTT) was prepared for the first time. It was achieved in a facile and mild way by optimizing the amount of Bi3+ and Au3+ using bovine serum albumin (BSA) as reducer and stabilizer. The as-prepared Bi2S3-AuNCs with special morphology showed high stability, excellent biocompatibility and good photostability. Apart from these, it also can accumulate at tumor sites and exhibit considerable fluorescence/infrared thermal imaging-guided PTT. Bi2S3-AuNCs nanoparticles integrate imaging and therapeutic functions into an advanced application platform, which provides the possibility to build a novel nano-cancer diagnosis and treatment platform.

On-site monitoring of L-adrenaline neurotransmitter in biological samples by chitosan oligosaccharide derived carbon dots

Carbon quantum dots (CDs) are fascinating fluorescent nanomaterial for spectrofluorimetry sensor applications, owing to the fact of its strong chemical stability, high quantum yield and high photostability. At this instance, we have developed the fluorescent sensing technique to detect the L-adrenaline (L-Adr) by nitrogen-doped carbon quantum dots as a sensing probe. The nitrogen-doped carbon dots was synthesized using chitosan oligosaccharide by hydrothermal method. The synthesized chitosan oligosaccharide derived CDs (COL-CDs) exhibits blue fluorescence under UV light and the size of the carbon quantum dots is 3.39 ± 0.08 nm calculated from HR-TEM image. The hormone called L-Adr found in the human body is crucial for controlling visceral processes. Utilizing the process of photo-induced electron transfer (PET), the previously mentioned COL-CDs have applied to sense the L-Adr. The sensing mechanism have explained clearly using Rehm-Weller equation by calculating ΔG. Tap water, blood serum, urine and adrenaline drug samples employed as real sample for the sensing L-Adr. A reagent free paper-based kit established for the purpose of on-site monitoring L-Adr. The smartphone’s colour picker software used to measure the RGB intensity from the paper-based kit.

Supramolecular light-harvesting systems utilizing tetraphenylethylene chromophores as antennas.

Efficient utilization of light energy is crucial for various technological applications ranging from solar energy conversion to optoelectronic devices. Supramolecular light-harvesting systems (LHS) have emerged as promising platforms for enhancing light absorption and energy transfer process. In this Feature Article, we highlight the utilization of tetraphenylethylene (TPE) chromophores as antennas in supramolecular assemblies for light harvesting applications. TPE, as an archetypal aggregation-induced emission (AIE) chromophore, offers unique advantages such as high photostability and efficient light-harvesting capabilities upon self-assembly. We discuss the design principles and synthetic strategies employed to construct supramolecular assemblies incorporating TPE chromophores, elucidating their roles as efficient light-harvesting antennas. Furthermore, we delve into the mechanisms governing energy transfer processes within these assemblies, such as Förster resonance energy transfer (FRET). The potential applications of these TPE-based supramolecular systems in various fields, including photocatalysis, reactive oxygen species generation, optoelectronic devices and sensing, are explored. Finally, we provide insights into future directions and challenges in the development of next-generation supramolecular LHSs utilizing TPE chromophores.

Highly sensitive near-infrared fluorescent probe for monitoring peroxynitrite in nonalcoholic fatty liver disease: Toward early diagnosis and therapeutic evaluation

Nonalcoholic fatty liver disease (NAFLD) poses a significant global health concern, necessitating precise diagnostic tools and effective treatment strategies. Peroxynitrite (ONOO−), a reactive oxygen species, plays a pivotal role in NAFLD pathogenesis, highlighting its potential as a biomarker for disease diagnosis and therapeutic evaluation. This study reports on the development of a near-infrared (NIR) fluorescent probe, designated DRP-O, for the selective detection of ONOO− with high sensitivity and photostability. DRP-O exhibits rapid response kinetics (within 2 min) and an impressive detection limit of 2.3 nM, enabling real-time monitoring of ONOO− dynamics in living cells. Notably, DRP-O demonstrates excellent photostability under continuous laser irradiation, ensuring reliable long-term monitoring in complex biological systems. We apply DRP-O to visualize endogenous ONOO− in living cells, demonstrating its potential for diagnosing and monitoring NAFLD-related oxidative stress. Furthermore, DRP-O effectively evaluates the efficacy of therapeutic drugs in NAFLD cell models, underscoring its potential utility in drug screening studies. Moreover, we confirm DRP-O to enable selective identification of fatty liver tissues in a mouse model of NAFLD, indicating its potential for the early diagnosis of NAFLD. Collectively, DRP-O represents a valuable tool for studying ONOO− dynamics, evaluating drug efficacy, and diagnosing NAFLD, offering insights into novel therapeutic strategies for this prevalent liver disorder.