High Fluorescence Quantum Yield Research Articles

Pentagon-embedded N-doped coumarinacenes: tandem synthesis and tunable photophysical attributes for biomolecular probing.

We have synthesized a novel series of nitrogen-doped pentagon-embedded coumarinacenes, namely carbazole-coumarins, via a tandem 1,4-elimination Diels-Alder aromatization reaction. These planar, N-substituted carbazole-coumarins exhibit excellent functionalizability, enhanced photostability and solvent polarity-tunable absorption and blue-to-red emission with notably high fluorescence quantum yields, attesting to their remarkable photophysical properties. These attributes highlight the carbazole-coumarins' potential as robust and efficient fluorescent materials for diverse applications in various fields, including as probes for studying biomolecular systems and dynamics.

Advancements in organic fluorescent materials: unveiling the potential of peripheral group modification in dithienyl-diketopyrrolopyrrole derivatives for one- and two-photon bioimaging.

The quest for novel organic fluorescent materials capable of two-photon absorption (2PA) has intensified in recent years due to their promising applications in biological imaging. Two-photon fluorescence microscopy (2PFM) offers high spatial-temporal resolution, reduced photodamage, and deeper tissue penetration compared to conventional techniques. However, the development of bright two-photon molecular markers remains a challenge, necessitating compounds with high fluorescence quantum yield and 2PA cross-section (σ2PA). Strategies such as increasing π-conjugation have shown promise but are hindered by synthesis complexities and limited biocompatibility. Alternatively, incorporating electron-donating (ED) or electron-withdrawing (EW) peripheral groups in a main structure has emerged as a viable approach, leading to significant enhancements in σ2PA. This study highlights the advantages and challenges of these strategies, emphasizing the importance of exploring new organic compounds and evaluating the efficacy of peripheral groups for advanced two-photon bioimaging applications.

High fluorescence quantum yield of methionine-doped carbon quantum dots for achieving rapid assay of tetracyclines in foodstuffs

The trace-level detection of tetracyclines (TCs) in food products is essential to ensure food safety and public health. Herein, we prepared the methionine-doped carbon quantum dots (Met-CQDs) using citric acid as the precursor. Met-CQDs exhibited a Gaussian unimodal peak centered at 440 nm in the fluorescent excitation spectrum, along with a remarkable greenish-blue emission and a fluorescent quantum yield of 33.5 %. Furthermore, the presence of TC (the quencher) caused a rapid quenching of the fluorescence of Met-CQDs, accompanying with a color transition from light blue to dark bule as TC concentrations increased. The coloring variation was also detected by the images captured by smartphones and RGB analysis software, facilitating portable detection of TC utilizing Met-CQDs as a fluoroprobe. The findings indicate that the Met-CQDs based fluoroprobe exhibits high selectivity, rapid response (only ∼1 min) according to an “ON-OFF” sensing model. This fluorescence sensing method gave a low detection limit (LOD) of 0.032 μM and excellent linearity for TC in the concentration range of 0.1–500 μM. Also, the smartphone-based fluorescence-visualizing approach displayed good linearity with a LOD of 0.33 μM. The interactions between this fluoroprobe and TC occurred by virtue of both inner filter effect (IFE) and static-quenching principle. The average recovery for TC in the milk, honey, and tap water samples was determined to be 98.46 ± 1.71 % by a fluorometric method. Overall, both fluorometric and RGB approaches demonstrate strong correlation with conventional LC-MS/MS, and thus the as-fabricated Met-CQDs are promising for the preliminary screening of TCs’ residues in food products.

Fluorescent TICT Probe for Precise Monitoring of Cellular Lipid Droplets.

Lipid droplets (LD) are crucial in pathological processes or conditions associated with abnormal lipid metabolism, such as obesity, diabetes, atherosclerosis, fatty liver diseases, and cancers. Cancer cells frequently contain elevated levels of nonpolar lipid droplets (LDs), serving as energy reserves. The proliferation of LDs, accompanied by an increase in viscosity, is a characteristic feature of cancer cells that prompted us to devise a fluorescent sensor for LD detection at physiological pH. However, developing fluorescent LD-specific probes with high polarity sensitivity and deep tissue/cell imaging capability remains challenging. Therefore, we present a TICT probe with strong solvatochromism, superior response to viscosity, microenvironment sensitivity, and a large Stokes shift. Additionally, it offers numerous advantages, including high sensitivity, specificity, high fluorescence quantum yield, and remarkable spatial resolution, which enables precise monitoring of lipid droplets (LD). Thus, this probe can effectively monitor alterations in viscosity and polarity of lipid droplet expression in live cells, thereby offering the potential for visualizing physiological abnormalities or pathological conditions. The probe offers excellent lipid droplet targeting and also sensitively monitors the oleic-acid-mediated lipid droplet accumulation and immunosuppressant/inflammatory drugs in HeLa cells.

Substituent groups effects on AIEgens of fluorenone derivatives: Optical properties, bioimaging, and LED devices

Understanding structure-property relationships is crucial for developing materials with a high fluorescence quantum yield (ΦF) and optimizing their performance. In this study, three fluorenone-carbazole-based molecules (FO-Cz1, FO-Cz2, and FO-Cz3) were synthesized, which have similar structures but varying substituent groups (carbazole, 3,6-di‑tert‑butyl‑9H-carbazole, and 3,6-diphenyl-9H-carbazole). The different substituent groups significantly changed the optical properties of the luminogens. The experimental results confirmed that FO-Cz1, FO-Cz2, and FO-Cz3 were AIEgens, and the introduction of a phenyl group gave FO-Cz3 strong αAIE(I/I0) and greater solid fluorescence quantum yields than FO-Cz1 and FO-Cz2. Analysis of photophysical properties, theoretical calculations, and X-ray crystallography revealed that the emission properties of FO-Cz1, FO-Cz2, and FO-Cz3 were influenced by the use of flexible substituent groups. The substituent groups avoided π-π stacking, reduced non-radiative transitions, and enhanced fluorescence in the aggregated state. Substituent groups on the benzene ring gave FO-Cz3 a tightly-packed structure and strong emission. It was used for cancer cell imaging and LED devices, in which FO-Cz3 exhibited high photostability and biocompatibility, making it a superior photosensitizer for bioimaging and applications in OLED devices. This research sheds light on the AIE behaviors of fluorenone complexes and offers valuable insights for the development of organic luminescent materials.

Diarenofuran[b]-fused BODIPYs: One-Pot SNAr-Suzuki Synthesis and Properties.

We present a streamlined methodology that integrates regioselective tetrahalogen-BODIPY and o-hydroxyphenylboronic acid in a one-pot process, leveraging SNAr nucleophilic substitution in conjunction with Suzuki coupling to afford diarenofuran [b]-fused BODIPYs (DBFB1-9) with commendable yields (85-95%) and short reaction times (0.5-1.0 h). X-ray structure analyses of DBFB5,7-9 elucidate that these diarenofuran[b]-fused BODIPYs adopt a "butterfly" conformation, maintaining a highly rigid planarity. A comprehensive examination of the spectroscopic and electrochemical properties of these diarenofuran[b]-fused BODIPY derivatives, incorporating various substituents, reveals intriguing characteristics, including pronounced absorption and emission in the near-infrared region (NIR), elevated fluorescence quantum yields (ΦF = 75-89% in dichloromethane), and tunable HOMO-LUMO levels. Remarkably, compared to DBFB1-8, DBFB9 possesses a large extended π-conjugated system, resulting in significant red shifts in its absorption and emission maxima, reaching 623 and 635 nm, respectively, and a reduced HOMO-LUMO gap. Despite this substantial structural expansion, DBFB9 maintains a surprisingly high fluorescence quantum yield (ΦF = 80%), underscoring its exceptional photophysical performance and strong potential for applications requiring efficient NIR emission and robust fluorescence retention.

Design, Synthesis and Characterization of BODIPY based 1H‐Tetrazole Ligands

Four novel fluorescence active ligands (1‐4) consisting of a 1H‐tetrazol‐1‐yl moiety as coordinating unit and a 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) derivative as fluorophore, bridged via alkyl (‐(CH2)n‐, n = 1‑3) or benzyl (‐CH2‐C6H4‐) spacers were designed. Successful synthesis is demonstrated by multinuclear NMR spectroscopy, as well as powder and single crystal XRD analysis. The methylene bridged ligand 2 (4,4‐difluoro‐1,3,5,7‐tetramethyl‐8‐[(1H‐tetrazol‐1‐yl)methyl]‐4‐bora‐3a,4a‐diaza‐s‐indacene) crystallizes in different polymorphs and solvatomorphs, in contrast to the other three ligands, which show no polymorphism under identical conditions. Photophysical studies revealed high fluorescence quantum yields (69 – 95%) in solution for the ‐(CH2)2‐ bridged ligand 3 (4,4‐difluoro‐1,3,5,7‐tetramethyl‐8‐[(1H‐tetrazol‐1‐yl)ethyl]‐4‐bora‐3a,4a‐diaza‐s‐indacene) and the ‐(CH2)3‐ bridged ligand 4 (4,4‐difluoro‐1,3,5,7‐tetramethyl‐8‐[(1H‐tetrazol‐1‐yl)propyl]‐4‐bora‐3a,4a‐diaza‐s‐indacene). Non‐radiative decay due to rotational motion of the 1H‐tetrazol‐1‐yl‐ and/or ‐CH2‐C6H4‐ moiety for 2 and 1 (4,4‐difluoro‐1,3,5,7‐tetramethyl‐8‐[4‐((1H‐tetrazol‐1‐yl)methyl)phenyl]‐4‐bora‐3a,4a‐diaza‐s‐indacene) respectively leads to reduced quantum yields of ≥ 35%. Complete fluorescence quenching upon aggregation is prevented by installation of the sterically demanding 1H‐tetrazol‐1‐yl moiety and a spacer in meso‐position of the BODIPY core to elongate the intermolecular distances between two adjacent BODIPY cores. Detailed photophysical and crystallographic investigations are supported by theoretical calculations.

Carbazolyl-Decorated Metal-Organic Framework with a High Fluorescent Quantum Yield for Detection and Photocatalytic Degradation of Organic Contaminants.

A carbazolyl-based fluorescent metal-organic framework with deep-blue light emission and a high quantum yield (88%) has been screened out by changing the ratio of mixed ligands, named Cz-MOF-2, which was constructed by ZrO4(OH)4 clusters, 3-(9-ethyl-9H-carbazol-3-yl)-4-methylthieno[2,3-b]thiophene-2,5-dicarboxylate (H2ECMTDC) and 3,4-dimethyl-dihydrothieno[2,3-b]thiophene-2,5-dicarboxylate (H2DMTDC). Cz-MOF-2 has excellent sensitivity in fluorescent sensing of 2,6-dichloro-4-nitroaniline (DCN), nitrofurazone (NZF), and nitrofurantoin (NFT) with detection limits of 3.37 × 10-7, 1.64 × 10-5, and 1.76 × 10-5 M, respectively. The quenching mechanisms involving electron transfer and competitive absorption were comprehensively elucidated through DFT calculations and UV absorption experiments. Cz-MOF-2 has been fabricated into a rapidly regenerated composite membrane with PVDF as a visualized fluorescent sensor for DCN. Furthermore, the carbazolyl groups covalently modified in the framework endowed Cz-MOF-2 with a suitable band gap (2.58 eV) for photocatalytic degradation of organic contaminants. It demonstrated superior photocatalytic efficiency compared to UiO-66 and NH2-UiO-66 in the degradation of tetracycline (TC), and the removal efficiency was up to 85% (20 mg of catalyst, 50 mL, 20 mg/L TC solution and 180 min) under simulated sunlight irradiation using a 300 W Xe lamp. Photoelectrochemical tests demonstrate that Cz-MOF-2 exhibits high photocurrent density and low charge transfer resistance, which provide evidence for the efficient charge separation capability. Radical trapping experiments and ESR detection have substantiated that ·O2- and h+ are the primary active species involved in this photocatalytic reaction. This work highlights the potential of MOFs in the targeted design and development of fluorescent sensors and photocatalysts for environmental detection and remediation.

Carborane-based BODIPY dyes: synthesis, structural analysis, photophysics and applications.

Icosahedral boron clusters-based BODIPY dyes represent a cutting-edge class of compounds that merge the unique properties of boron clusters with the exceptional fluorescence characteristics of BODIPY dyes. These kinds of molecules have garnered substantial interest due to their potential applications across various fields, mainly including optoelectronics, bioimaging, and potential use as boron carriers for Boron Neutron Capture Therapy (BNCT). Carborane clusters are known for their exceptional stability, rigid geometry, and 3D-aromaticity, while BODIPY dyes are renowned for their strong absorption, high fluorescence quantum yields, and photostability. The integration of carborane into BODIPY structures leverages the stability and versatility of carboranes while enhancing the photophysical properties of BODIPY-based fluorophores. This review explores the synthesis and structural diversity of boron clusters-based BODIPY dyes, highlighting how carborane incorporation can lead to significant changes in the electronic and optical properties of the dyes. We discuss the enhanced photophysical characteristics, such as red-shifted absorption and emission poperties, charge and electronic transfer effects, and improved cellular uptake, resulting from carborane substitution. The review also delves into the diverse applications of these compounds. In bioimaging, carborane-BODIPY dyes offer superior fluorescence properties and cellular internalization, making them ideal for cell tracking. In photodynamic therapy, (PDT) these dyes can act as potent photosensitizers capable of generating reactive oxygen species (ROS) for targeted cancer treatment making them excellent candidates for PDT. Additionally, their unique electronic properties make them suitable candidates for optoelectronic applications, including organic light-emitting diodes (OLEDs) and sensors. Overall, carborane-BODIPY dyes represent a versatile and promising class of materials with significant potential for innovation in scientific and technological applications. This review aims to provide a comprehensive overview of the current state of research on carborane-BODIPY dyes, highlighting their synthesis, properties, and broad application spectrum.

A Hemicyanine‐Based Highly Sensitive and Selective Near‐Infrared Fluorescent Probe for Fe3+ in Aqueous Media

ABSTRACTFerric ion is widely distributed in human cells and an important component of hemoglobin, which can promote the transportation of blood in the human body. Its ability to bind with oxygen is essential for participating in oxidation reactions and enzymatic reactions. Deficiency of iron (III) and excessive accumulation of iron in the blood can cause many health problems in the body, such as anemia, loss of appetite, fibrosis, reduced work routines, and decreased immunity. As a fluorescent dye, cyanine has the advantages of high fluorescence quantum yield, good optical and chemical stability, excitation and emission wavelengths in the near‐infrared region, high molar extinction coefficient, and small influence on pH variation. It is a fluorescent dye that modern scholars choose more. A new near‐IR hemicyanine derivative bearing 1,3‐dithiane moiety was developed as an efficient fluorescence probe 1 for the detection of Fe3+ in aqueous medium (THF/H2O, 1:1, v:v). This near‐IR fluorescence probe 1 exhibits high sensitivity and selectivity toward Fe3+ sensing with detection limit of 0.5 μM under lager scope of pH value (pH = 2–12).

A promising platform for the rapid and sensitive sensing of mercury ion and its applications in biological and environmental system

Mercury ion (Hg2+) is one of harmful heavy metal ions that can accumulate inside the human organism and cause some health problems. Herein, a novel NBD derivative, 1-(2-((7-nitrobenzo[c] [1,2,5] oxadiazol-4-yl) amino) ethyl)-3-phenylthiourea (NBD-SCN), has been reasonably designed, which was simply synthesized by introducing NBD moiety as the fluorophore, phenyl-isothionitrate as the reaction site and ethylenediamine as a linker group, resulting in intense fluorescence emission with high fluorescence quantum yields. Intriguingly, probe NBD-SCN provides a dual-mode colorimetric and fluorescence response pattern for the sensing of mercury ion with great limit of detections (3.6 nM) and rapid response time (4 s). The strong combination of mercury ions and sulfur atoms leads to intramolecular cyclization, causing the color of probe solution changed from orange to pale yellow as well as a complete vanishing of fluorescence intensity. The proposed reaction mechanism was verified by fluorescence and UV titration, 1H NMR, FTIR, HRMS analyses and DFT studies. Motivated by an impressive chromatic variation, test strip sensing platform are facilely constructed for real-time and on-site measurement of Hg2+ levels. Furthermore, confocal imaging experiments verify that this probe can be used for monitoring mercury ion in living mung bean sprouts and in biological systems in real time.

Narrow‐Band Emission of Asymmetric 1,3‐Substituted Pyrene‐Based Deep‐Blue Emitters and Application in OLEDs

AbstractHigh‐efficiency organic blue light‐emitting materials with narrow‐band emission are fundamental components for constructing high color purity and high resolution in high‐performance organic light‐emitting diode (OLED) devices. Herein, new pyrene‐based blue emitters (8–10) with narrow‐band emission are synthesized by asymmetrically introducing biphenyl and triphenylamine units at the 1‐ and 3‐positions of pyrene, respectively. Due to the steric effect and through‐space conjugation, the synergistic effects of both groups not only boost these emitters 8–10 (CIEy < 0.11) with aggregation‐induced emission (AIE) characteristics and high fluorescence quantum yield (>0.68), but also endow narrow full width at half maxima (FWHM) emission (≤36 nm) in the crystallized state (FWHM ≤ 55 nm in the film state). The EL spectra of pyrene‐based 8–10 in nondoped OLEDs exhibit blue emission with a maximum emission (λmax em) in the range of 448–453 nm (CIEy ≤ 0.12). The compounds 8–10 in doped‐OLEDs show a blue emission with a λmax em in the range of 443–445 nm and CIEy ≤ 0.08, with FWHM emission of 57–61 nm. The compound 10‐based doped OLED displays an impressive EL performance with a maximum brightness of 9756 cd m−2 and a maximum external quantum efficiency of 2.58%.

BODIPY photosensitizers functionalized with mannose for fluorescence cell-imaging and photodynamic therapy

The synthesis of four water-soluble mannose-tethering BODIPY-based photosensitizers (PSs) with varying substituents (H, OMe, NO2 and I) in the para-phenyl moiety attached to the meso-position of the BODIPY core, offering tumor-targeting and photodynamic therapeutic (PDT) potentials, is reported. The PDT capability of the synthesized PSs was investigated using the cervical cancer cell line HeLa. Owing to the heavy atom effect, BODIPY I, enhanced the intersystem crossing (ISC) to produce singlet oxygen (1O2) and maintained a high fluorescence quantum yield (ΦF) of 0.71. In contrast, the electron-donating methoxy substituent (BODIPY OMe) caused a notable perturbation in the occupied frontier molecular orbitals, subsequently achieving a higher 1O2 generation capability with a high ΦF of 0.85. Conversely, substitution with the electron-withdrawing nitro group (BODIPY NO2) resulted in a perturbation of unoccupied frontier molecular orbitals and generated a forbidden dark S1 state, negatively affecting both fluorescence and 1O2 generation efficiencies. The cytotoxicity of the synthesized water-soluble BODIPY PSs in the dark and under LED irradiation against the HeLa cell line was also assessed, with BODIPY I, OMe and H showing favorable PDT activity. Collectively, the performance of the mannose-conjugated BODIPY PSs in this study contributed promising results for the development of photodynamic therapeutic agents for cancer treatment.

Coumarin-Based ACQ-AIE Conversion Photosensitizer for Mitochondrial Imaging and Synergistic Cancer Therapy.

Most of the traditional fluorescent molecules have the advantages of high fluorescence quantum yield, good stability, and excellent structural adjustability, but they exhibit the characteristics of fluorescence quenching caused by aggregation, which restricts their application in aqueous solutions or solids. The excellent luminescence properties and photosensitive potential of aggregation-induced emission (AIE) materials in a condensed state have made them widely concerned in the scientific research field, so it is very challenging to regulate the transformation of traditional aggregation-caused quenching (ACQ) fluorophores into AIE fluorophores. In this study, the traditional coumarin fluorophore was used as a matrix. After conjugating the triphenylamine AIE group, the triphenylphosphine cation was linked through the alkyl chain to obtain a molecular probe NCTPP with excellent AIE characteristic, water solubility, mitochondrial green light imaging, chemotherapy and photodynamic therapy capabilities. As far as we know, it was the first time that the photosensitivity of coumarin fluorescent molecules was imparted by the ACQ-AIE conversion method.

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.

Solvent mediated synthesis of multicolor narrow bandwidth emissive carbon quantum dots and their potential in white light emitting diodes

The development of efficient and environmentally sustainable materials for white light-emitting diodes (WLEDs) is of paramount importance in the field of lighting technology. In this study, we present a solvent-modulated synthesis approach for the fabrication of multicolor narrow-bandwidth emissive carbon quantum dots (CQDs) as a promising solution for constructing WLEDs. The synthesis method involves the controlled reaction of organic precursors in different solvent environments, leading to the formation of CQDs with distinct emission wavelengths with a relatively small full width at half maximum, ranging from 28 to 42 nm. Moreover, these synthesized multicolor CQDs demonstrate a remarkably high fluorescence quantum yield of up to 65%, indicating their potential for constructing efficient WLED when incorporated in polymer matrix and coated on the surface of blue light-emitting diode (LED).

Dual Sulfone-Bridged Triphenylamine Heteroaromatics for High-Performance Blue Organic Electroluminescence.

Polycyclic heteroaromatics (PHAs) are a highly versatile class of functional materials, especially applicable as efficient luminophores in organic light-emitting diodes (OLEDs). Those constructed by tethered phenyl surrounding the main group center attract extensive attention due to their excellent OLED device performance. However, the development of such a class of emitters is often limited to boron, nitrogen-doped π-conjugated heterocycles. Herein, we proposed a novel kind of blue emitter by constructing a donor-acceptor molecular configuration, utilizing a dual sulfone-bridged triphenylamine (BTPO) core and mono/di-diphenylamine (DPA) substituents. The twisted D-A molecular structures and appropriate donor strength facilitate the effective separation of natural transition orbitals, endowing the emitters with charge-transfer dominant hybridized local and charge-transfer characteristics for the excited states. Both BTPO-DPA and BTPO-2DPA own small S1-T1 splitting energy, thus demonstrating blue thermally activated delayed fluorescence. The more symmetrical structure and enhanced CT features brought by additional DPA moiety confer BTPO-2DPA with a shorter delayed fluorescence lifetime, a higher fluorescence quantum yield and narrower emission. Therefore, BTPO-2DPA based OLED devices exhibit superior blue electroluminescence performance, with external quantum efficiencies reaching 12.31 %.

Toward 95.5% Efficient Red Emissive Carbon Dots: Oxidation State Enhancing Radiative Electron-Transition of Indole Fluorophore.

Red fluorescence carbon dots (CDs) are promising for diverse applications and have attracted tremendous research interest. However, it is still challenging to achieve red fluorescence CDs with high fluorescence quantum yields (QYs > 50%). Herein, three kinds of red fluorescence CDs with QYs of 53.48, 85.21, and 59.18% are prepared. Benefiting from the oxidation induced by atmospheric-pressure O2 plasma processing, 95.5% efficient red fluorescence emission is achieved. It is revealed that the indole based fluorophores act as the red-emitting photoluminescence center. The synergistic effect between the C-O-C structure and indole based fluorophores plays a key role in promoting the efficiency of radiative electron transition and controlling the red fluorescence QYs. Additionally, the CDs show promising prospects for in vivo bioimaging and low in vivo toxicity. This work shows a new way for achieving high-efficiency red fluorescence CDs, and it may guide the development of high-performance CDs for diverse applications.

Elucidating the Supramolecular Interaction of Positively Supercharged Fluorescent Protein with Anionic Phthalocyanines.

Developing bioinspired materials to convert sunlight into electricity efficiently is paramount for sustainable energy production. Fluorescent proteins are promising candidates as photoactive materials due to their high fluorescence quantum yield and absorption extinction coefficients in aqueous media. However, developing artificial bioinspired photosynthetic systems requires a detailed understanding of molecular interactions and energy transfer mechanisms in the required operating conditions. Here, the supramolecular self-assembly and photophysical properties of fluorescent proteins complexed with organic dyes are investigated in aqueous media. Supercharged mGreenLantern protein, mutated to have a charge of +22, is complexed together with anionic zinc phthalocyanines having 4 or 16 carboxylate groups. The structural characterization reveals a strong electrostatic interaction between the moieties, accompanied by partial conformational distortion of the protein structure, yet without compromising the mGreenLantern chromophore integrity as suggested by the lack of emission features related to the neutral form of the chromophore. The self-assembled biohybrid shows a total quenching of protein fluorescence, in favor of an energy transfer process from the protein to the phthalocyanine, as demonstrated by fluorescence lifetime and ultrafast transient absorption measurements. These results provide insight into the rich photophysics of fluorescent protein-dye complexes, anticipating their applicability as water-based photoactive materials.

Polydimethylsiloxanes - Based Fluorescent Probe for H2S Detection in Living Cells.

The development of fluorescent probes for H2S detection especially in living cells is of great significance due to its fundamental role as signal molecule. A promising scaffold for the development of such probes is polydimethylsiloxanes (PDMS), which is cost-effectiveness, non-toxicity, flexibility, and biocompatibility and easy to post-functionalize. Surprisingly, fluorescent probes for H2S detection based on PDMS have not been investigated. Moreover, 4-nitro - 2,1,3-benzoxadiazole (NBD) derivates provides high fluorescence quantum yield, a large molar absorption coefficient, and sensitivity to environmental changes. Through reasonable design and adjustment of substituents on the NBD group, precise control of its fluorescence properties can be achieved. Herein, a novel H2S fluorescent probe, P-NBD, was designed and synthesized by a one-step aromatic ring nucleophilic substitution of Cl-NBD with a PDMS derivative. Due to the occurrence of the cleavage reaction strategy and the intramolecular charge transfer process, P-NBD can detect H2S via a colorimetric method. The limit of detection is down to 93 nM. P-NBD demonstrated considerable detection capability comparable to other reported types of H2S probes. Moreover, the probe can also be utilized for H2S imaging in HeLa cells. This work provides new insights into the design and synthesis of novel H2S probes while also offering experimental evidence for the application of PDMS in cellular imaging.