Fluorescence Characteristics Research Articles

Preparation and Characterization of Novel α-Naphthol Luminophors for Optoelectronic Devices.

Luminophors of α-Naphthol doped with varying concentrations of anthracene and perylene were prepared by conventional solid state reaction method to explore its fluorescence characteristics. The fluorescence spectra of bicomponent and tricomponent luminophors reveals the fluorescence excitation energy transfer (FRET) process. The prepared bi and tri component luminophors were excited at 290nm which corresponds to host excitation wavelength. The weak violet fluorescence of host, α-Naphthol, gets quenched and give anthracene like emission in bicomponent luminophor systems. Further doping with second host, perylene, in anthracene containing α-Naphthol luminophors, red shifted emission was observed at 605nm. The structural parameters, thermal stability and electrical properties of doped luminophors were studied by using X-ray diffraction, TGA-DSC and Cyclic Voltammetry respectively. The particle size of the prepared luminophors was confirmed by scanning electron microscopy (SEM).

Solution plasma synthesis of nitrogen-doped carbon dots from glucosamines: Comparative fluorescence modulation for dopamine detection

The intriguing fluorescence characteristics of carbon dots (CDs) have led to many sensor applications, particularly for dopamine (DA), a molecule linked to various diseases. This study prepares CDs from glucose and glucosamine (nitrogen-free and nitrogen-containing precursors) using a simple solution plasma process (SPP). We explore how nitrogen elements and counterions in glucosamine (hydrochloride and sulfate) affect CD properties and their ability to modulate fluorescence for DA detection. Glucosamine offers three advantages over glucose: (i) single-step CD synthesis via SPP, (ii) enhanced fluorescence of CDs, and (iii) improved fluorescence response to DA. We investigate the DA detection capabilities of N,S-CDs (from glucosamine sulfate) and N,Cl-CDs (from glucosamine hydrochloride). Both can sense DA with distinct photoluminescence responses. N,S-CDs show selectivity and fluorescence brightening upon DA interaction, with a detection limit of 33.05 μM. N,Cl-CDs demonstrate higher sensitivity with a lower detection limit of 0.1212 μM through fluorescence quenching. Silver ions (Ag+) may also contribute to N,Cl-CDs quenching; however, the observed color change to gray due to silver nanoparticle (AgNP) formation helps pinpoint the quenching substance. The varied photoluminescence responses arise from different surface functional groups: N,S-CDs have amino-rich surfaces, while N,Cl-CDs have conjugated carbonyl-rich surfaces. This study illustrates the mechanisms of DA detection and AgNP formation, suggesting the potential of CDs in medical diagnostics as selective tools for disease diagnosis. Additionally, we compare the DA sensing methodology of our CDs with existing literature, highlighting the advantages of our sensor.

Insights into Marine Bioluminescence: Unraveling the Intricacies of Natural Fluorescence Probes

The enigmatic allure of the abyssal depths has long captivated human imagination, veiling enigmas beneath its inscrutable facade. Within our review article, we embark on an expedition into this captivating domain, where nature's own bioluminescent envoys – encompassing Green Fluorescent Protein (GFP), ZsGreen, Red Fluorescent Protein (RFP), mCherry, TagRFP, mKate, Neptune, HcRed, and Phycoerythrin – unveil the remarkable splendor of the subaqueous realm. This odyssey delves into the intricate dynamics of bio-imaging, fluorescence characteristics, and detection methodologies, revealing the mesmerizing tableau of underwater life. Join us as we unravel the captivating narratives surrounding these natural fluorescence probes, illuminating the extraordinary subaquatic spectacle that continues to captivate scientists and ocean enthusiasts alike.

Fabrication and Fluorescence Analysis of Rhodamine Dyes in Polycarbonate Serpentine Microfluidic System.

The synthesis of rhodamine dyes (R6G and R1010) and their fluorescence characterization within polymer-based microfluidics, offers an exciting and novel approach in materials science and chemical analysis. This work investigates the emission of polycarbonate substrates (PC) by UV-visible. The ablation threshold (16mj.sec-1) of PC at 193nm wavelength after that ablation process continued to produce microfluidic serpentine channels on PC by using G-Code. The fluorescence characteristics of Rhodamine 6G and Rhodamine 101 are investigated. Absorption and emission at peak wavelength were analyzed against R6G and R101 concentrations. Furthermore, the refractive indices of both R6G and R101 vis concentrations are examined. As a result at low concentrations, there was the highest overlapping, and at high concentrations, there was the smallest overlapping. R101 showed better photostability and a more consistent diffusion, whereas R6G had a faster diffusion and stronger fluorescence intensity. These differences were caused by the different molecular structures of the dyes and their interactions with the PCmicrochannel. Incorporating R6G and R101 dyes into a polycarbonate PC microfluidic chip would enhances both the resolution and sensitivity of fluorescence detection. The limited microfluidic setup facilitates ultra-high-resolution investigation and minimizing sample volumes, making it suitable for applications requiring precise measurements. The innovation relies on the utilization of the unique fluorescence characteristics of R6G (Rhodamine 6G) and R101 (Rhodamine 101) dyes to enhance the performance of polycarbonate microfluidic devices. R6G has high fluorescence quantum yield and stability, rendering it suitable for sensitive detection, while R101 offers superior brightness and improved resistance to photobleaching. Incorporation of these dyes into polymeric microfluidics improves sensitivity and facilitates real-time, dynamic sample analysis. This method offers a portable, economical solution with high-throughput capabilities, greatly enhancing both analytical and process accuracy across a variety of applications.

A Temperature-Sensitive Fluorescent Supramolecular Polymer Constructed by Discrete Platinum(II) Metallacycle and Pillar[5]arene-Based Host-Guest Interactions.

The application of thermosensitive fluorescent supramolecular polymers in advanced optical materials, chemical sensors, artificial optical devices, and external stimulus responses remains underdeveloped. In this study, we introduced a novel method for constructing a mechanically interlocked fluorescent supramolecular polymer utilizing host-guest interactions, including C-H···π interactions and π-π stacking. This polymer exhibits outstanding temperature-sensitive fluorescence properties and is environmentally friendly due to its recyclability. Leveraging the polymer's fluorescence response at critical temperature ranges, we developed a high-temperature warning device. This device utilizes the temperature-sensitive fluorescence characteristic of the polymer to indicate dangerous temperature levels, thereby demonstrating its potential in practical safety applications.

Preparation of coal-based carbon quantum dots and their fluorescence properties

In the field of life sciences, cellular movements play a significant role in influencing the activities of organisms. Current methodologies have limitations in the monitoring of cell recognition, biological macromolecule localization, cell labeling, migration, and biosensors. Although metal–semiconductor quantum dots are commonly used, they may pose toxicity risks to the lungs and kidneys. On the other hand, carbon quantum dots possess the unique optoelectronic properties of traditional quantum dots while exhibiting low toxicity, good biocompatibility, excellent photostability, and abundant raw material sources. In this research, carbon quantum dots were synthesized using the nitric acid oxidation method. The study investigated the effects of temperature, time, and the type of low-rank coal on the synthesis of carbon quantum dots. The structure and properties of the carbon quantum dots, specifically their fluorescence characteristics, were thoroughly analyzed. The proposed synthesis approach includes the nitration of coal macromolecules and the thickening of aromatic clusters through the Scholl reaction, leading to enhanced fluorescence quantum efficiency. The findings of this study indicate that the carbon quantum dots produced through this method demonstrate a high fluorescence quantum yield, making them ideal fluorescent agents for material preparation and offering potential applications in the field of life sciences.

Laser-induced fluorescence spectroscopic investigation of Echium amoenum decoction

Herbs containing medicinal ingredients with nutritional value have recently gained attention as an alternative to synthetic drugs. Aside from their pharmaceutical worthiness, a variety of naturally occurring chromophores with specific optical properties have made them valuable sources of natural pigments for many biophotonic applications. Echium Amoenum (EA) is one of the colorful flowers that has been used in traditional medicine for a long time. To our knowledge, although several studies have been carried out on the characterization of EA ingredients and their chemical activities, information on EA fluorescence is still lacking. Here, laser induced fluorescence (LIF) features of the decoction of EA petals were evaluated and found to be highly dependent on the excitation wavelength, EA concentration, and detection geometry. The abundance of pigments, the boundaries of their absorption/emission spectral regions, and the corresponding energy transfer ascertain the contribution of certain chromophores to the cumulative fluorescence activity. Upon deconvolution of the LIF spectra, it was revealed that the different emission bands of rosmarinic acid (corresponding to its dissociated forms) and the luminescent activity of luteolin and β-carotene mainly determine the quantum distribution of the fluorescence of EA. Angular measurement of LIF in a symmetric cylindrical arrangement revealed the presence of the inner filters mainly due to the reabsorption of LIF photons by anthocyanins (flavone, pelargonidin, delphinidin and cyanidin) and carotenoids. We hope that the obtained results will be useful in various fields of photochemistry and biophotonics.

Copper‐Mediated C–H Cyclization of Heterocycles: Facile Access to Multiple Resonance Thermally Activated Delayed Fluorescence Materials

AbstractReported herein is the first example of a copper‐mediated C─H cyclization of heterocycles to construct structurally diverse carbonyl‐bridged triphenylamine compounds with multiple resonance thermally activated delayed fluorescence (TADF) characteristics. The one‐pot synthesis method exhibits a broad substrate scope and opens a new avenue for rapidly screening high‐performance organic TADF luminescent materials. Novel organic TADF single‐molecule white‐light material 5g with anti‐Kasha dual‐emission character is the first time developed herein and shows a Commission Internationale de l’Eclairage (CIE) coordinate of (0.33, 0.35) in the thin film, and can be used to fabricate robust and low cost organic white light‐emitting diodes (LED). Furthermore, the anti‐Kasha dual‐emission material 5g is fabricated as water‐dispersed nanoparticles (NPs)NPs, which can be efficiently endocytosed into the HeLa cells and dual emission imaging in living cells, and be used in two‐channel emission intensity ratio imaging to observe the intercellular structure.

Exploring Riboflavin Quantification in Honey via Spectrofluorimetry: A Statistical Examination of Influential Extrinsic Variables

Background: The present study is focused on the collection of honey samples from the different geographical and climatic conditions of Khyber Pakhtunkhwa and analyzing them for the determination of riboflavin. Quantification of riboflavin, being natively fluorescent, was accomplished using spectrofluorimetric method. Riboflavin has characteristic fluorescence spectra with maximum excitation at 464 nm followed by an emission peak at 525 nm. Method: The procedure followed in this work comprised the construction of a calibration curve by plotting the fluorescence intensity of a series of riboflavin solutions versus concentration. This curve was used for the quantification of riboflavin in the collected honey samples. The effect of several external factors such as the altitude of the sampling area, type of honey bee, type of flowers from which the nectar was collected, and sampling season on the concentration of riboflavin in the honey samples was statistically evaluated. Results and Discussion: It was concluded that the samples collected from lower altitudes have high concentrations (1.156±0.08 μg g-1) of riboflavin. Similarly, the samples collected in autumn were found to have a maximum average riboflavin concentration of 1.37±0.06 μg g-1, which was higher in comparison to the samples collected in other seasons of the year. Likewise, the effect of flora on the concentration of riboflavin was also investigated and it was found that honey samples collected from areas where the nectar was collected from Ziziphus contains maximum riboflavin concentration averaged at 1.383±0.1 μg g-1. Conclusion: Based on the size of the honey bees, the samples collected from hives of small honey bees were found to have a maximum riboflavin concentration of 1.176±0.07 μg g-1. This study suggests that besides the studied vitamin, the rest of the vitamins and other nutritional components may vary in the honey samples depending upon external factors. conclusion: It was concluded that the samples collected from lower altitudes have high concentration (1.156±0.08 μg g-1) of riboflavin. Similarly, the samples collected in autumn were found to have a with a maximum average riboflavin concentration of 1.37±0.06 μg g-1, which was higher in comparison to the samples collected in other seasons of the year. Likewise, the effect of flora on the concentration of riboflavin was also investigated and it was found that honey samples collected from areas where the nectar was collected from Ziziphus contains maximum riboflavin concentration averaged at 1.383±0.1 μg g-1. Based on the size of the honey bees the samples collected from hives of small honey bees were found to have maximum riboflavin concentration of 1.176±0.07 μg g-1. This study suggests that beside the studied vitamin, the rest of the vitamins and other nutritional components may vary in the honey samples depending upon external factors.

Dual-Activated Photoacoustic Probe for Reliably Detecting Hydroxyl Radical in Ischemic Cardiovascular Disease in Mouse and Human Samples.

Cardiovascular disease (CVD) is a chronic disease characterized by the accumulation of lipids and fibrous tissue within the arterial walls, potentially leading to vascular obstruction and an increased risk of heart disease and stroke. Hydroxyl radicals play a significant role in the formation and progression of CVD as they can instigate lipid peroxidation, resulting in cellular damage and inflammatory responses. However, precisely detecting hydroxyl radicals in CVD lesions presents significant challenges due to their high reactivity and short lifespan. Herein, we present the development and application of a novel activatable optical probe, Cy-OH-LP, designed to detect hydroxyl radicals in lipid-rich environments specifically. Built on the Cy7 molecular skeleton, Cy-OH-LP exhibits near-infrared absorption and fluorescence characteristics, and its specific response to hydroxyl radicals enables a turn-on signal in both photoacoustic and fluorescence spectra. The probe demonstrated excellent selectivity and stability in various tests. Furthermore, Cy-OH-LP was successfully applied in an in vivo model to detect hydroxyl radicals in mouse models, providing a potential tool for diagnosing and monitoring AS. The biosafety of Cy-OH-LP was also verified, showing low cytotoxicity and no significant organ damage in mice. The findings suggest that Cy-OH-LP is a promising tool for the specific detection of hydroxyl radicals in lipid-rich environments, providing new possibilities for research and clinical applications in the field of oxidative stress-related diseases.

Utilizing Arthrospira platensis for the fabrication of zinc oxide nanoparticles: Analysis and assessment for enhancing drought tolerance in Sub1A QTL bearing rice seedlings

In the present study, the underlying pathways for zinc oxide nanoparticles (ZnO-NPs) mediated modulation of oxidative stress under drought were evaluated in rice seedlings. Principally, rice cultivar (cv. Swarna Sub1) was used to assess the potential of the Sub1A QTL for its drought sensitivity in response to bio-fabricated ZnO-NPs. ZnO-NPs were synthesized from algal (Arthrospira platensis) extract and characterized for their opto-physical properties, confirming size (54 nm), hydrodynamicity (-18.54), amorphous-cubic shape and others features. Fifteen-day-old rice seedlings were primed with 25 ppm ZnO-NPs and exposed to 12 % polyethylene glycol (PEG) mediated drought stress (DS) for 7-days under laboratory conditions. Primarily, Sub1A QTL responded to drought-induced anoxic stress with a significant increase in the activities of alcohol dehydrogenase (447.41 %) and pyruvate decarboxylase (96.51 %) through ZnO-NPs sensitization. Plants recorded a significant reduction in root growth, which regained 89.25 % with ZnO-NPs treatments. ZnO-NPs also recovered relative water content (49 %), proline (99.2 %), and improved chlorophyll fluorescence (90.9 %) under stress. Furthermore, drought-induced membrane leakage was stabilized by reducing ionic conductivity through the distribution of wall-bound polyamines. A characteristic feature of fluorescence also reinforced the sustenance of photosynthetic activities by ZnO-NPs under drought. Alternatively, rice seedlings showed regulation of oxidative stress, where lipid peroxidation and protein carbonylation were reduced by 270 % and 178.2 %, respectively. This was observed with the minimization of superoxide and hydrogen peroxide concentrations by regulating apoplastic oxidase activity (117.64 %) with distinct polymorphisms in proteins. These observations suggest that ZnO-NPs can ameliorate drought-induced oxidative stress in rice, providing insights for improved nano-fertigation.

Chlorophyll fluorescence characteristics and lipid metabolism in endangered Cycas panzhihuaensis exposed to drought, high temperature and their combination

Chlorophyll fluorescence characteristics and lipid metabolism in endangered Cycas panzhihuaensis exposed to drought, high temperature and their combination

Recognition of carboxylic acids and phosphonic acids using a 1,8-diphenylanthracene-based diguanidine in solution and solid states

A 1,8-diphenylanthracene-based diguanidine 1 has been designed and synthesized for the recognition of carboxylic acids and phosphonic acid derivatives. The diguanidine 1a forms 1:1 complexes with the dicarboxylic acids and the diphosphonic acid derivatives in a DMSO solution, and the formation of these complexes was confirmed by a DOSY NMR analysis. The binding mode towards the guanidyl group (Type I, Type II, two existing types of binding modes toward three nitrogen atoms) with a diphosphonic acid derivative was successfully demonstrated by the 2D NOESY analysis. The diguanidine 1a does not show any fluorescence in a DMSO solution, but after the addition of carboxylic acids, the formation of a stable complex or the formation of the protonated guanidinium (1a+2H+) were distinguishable by the observation of a light-blue fluorescence around 430 nm. These fluorescence observations can be determined the stability of the complexes of the diguanidine 1a with carboxylic acids. On the other hand, the DMSO solution of diguanidine 1a showed a light-blue fluorescence after the addition of phosphonic acids. Interestingly, diguanidine 1a recognized methylphosphonic acid 9a in the solid state by grinding and showed a green fluorescence, while the other phosphonic acids 9 and dicarboxylic acids (4d: pimelic acid, 4f: azelaic acid) showed a light-blue fluorescence in the solid state, and a selectivity was observed. These fluorescence characteristics of the diguanidine 1 are applicable for the detection of carboxylic acids and phosphonic acids, especially for methylphosphonic acid 9a in the solid state.

Response of Leaf Traits and Photosynthetic Fluorescence Characteristics of Fraxinus malacophylla Seedlings to Rainfall Patterns During Dry and Rainy Seasons in Southwestern China.

Global climate change has led to a shift in rainfall patterns. And as water is an essential ingredient for plant photosynthesis, shifts in rainfall patterns will inevitably affect plant growth. This study was conducted in Kunming, southwest China. In this study, the response of leaf traits and photosynthetic fluorescence properties of Fraxinus malacophylla seedlings to rainfall patterns during the dry and rainy seasons was investigated using a natural rainfall interval of 5 days (T) and an extended rainfall interval of 10 days (T+) as rainfall interval treatments and a monthly average rainfall as a control (W), with the corresponding rainfall treatments of a 40% increase in rainfall (W+) and a 40% decrease in rainfall (W-). The results showed that Pn, Gs, and Tr basically all tended to increase and then decrease with increasing rainfall in the dry season and generally reached the highest under the W treatment; Pn, Gs, Ci, and Tr mostly remained high at 5 days relative to 10 days; PI was overall higher under the W treatment throughout the dry season. Extending the rainfall interval at the beginning of the rainy season significantly reduced Fm; throughout the rainy season, Gs, Ci, and Tr basically showed a decreasing trend with increasing rainfall, reaching the highest under the W-treatment and mostly higher at 5 days than at 10 days. These results suggest that natural rainfall intervals and natural rainfall amounts are more favorable to the growth of Fraxinus malacophylla seedlings in the dry season; reduced rainfall and multiple rainfalls in the rainy season tend to promote photosynthesis in Fraxinus malacophylla. This study reflects the different survival strategies of Fraxinus malacophylla under different rainfall patterns, as well as provides a theoretical basis for understanding how Fraxinus malacophylla can grow better under rainfall variability and for future management.

Laboratory Investigation of Dodecylbenzene Detection in Seawater Via Fluorometric Index of Excitation-emission Matrix Spectra.

​Oil-filled submarine cables have come to dominate the reliable delivery of electrical power today, but oil leakages still remain a challenge. This work focuses on exploring the detection of dodecylbenzene (DDB) after leakage. DDB can be dispersed as small droplets in seawater, which the diameter of DDB droplets increased from 60nm to 200nm with the increase of the concentration from 10 ppm to 1000 ppm. Moreover, excitation-emission matrix (EEM) spectra were employed to investigated the detection of DDB. DDB has characteristic fluorescence peaks located at λEx/λEm = 225/350 and 255/350. The FIo/w value of 50 ppm DDB was 28.869, which was significantly different from simulated seawater low as 1.3926. Contaminants such as metal ions (Cu2+, Cd2+, Zn2+) and organic matter (tetracycline) do not significantly affect the qualitative identification of DDB by EEMs. This study suggests a research basis for exploring the way for detection of DDB.

Structural analysis, fluorescence characteristics, and thermal radiation phenomena of Y2O3:Al3+/Er3+ materials doped with varying concentrations of Al3+ ions

In this study, Y2O3: Al3+/Er3+ crystals materials (AYE) were synthesized through laser annealing. The structure and spectral characteristics of Al3+ ions doping in Y2O3: Er3+ crystals are discussed in detail. With the incorporation of Al3+ ions, the AYE structure experiences a phase transformation characterized by a sequence of monophasic and biphasic states: monophasis-biphase-biphase-monophasis-biphase. When the concentration of Al3+ ions is 0–50 %, AYE has fluorescence characteristics under 980 nm excitation, and its I563 nm/I799 nm shows non-thermal coupling phenomenon at low temperature and thermal coupling phenomenon at high temperature, with a maximum relative sensitivity of 1.643 %K−1. When the concentration of Al3+ ion is 60 %-98 %, AYE shows a strong thermal radiation phenomenon under the excitation of a 980 nm laser. Its initial laser power density is as low as 0.71 W/mm2. This is about three times lower than the initial power density of thermal radiation generated by the same level of material. In summary, Y2O3: Al3+/Er3+ crystals materials have a broad application prospect in the field of temperature sensing and thermal radiation materials.

Transformation of dissolved organic matter leached from biodegradable and conventional microplastics under UV/chlorine treatment and the subsequent effect on contaminant removal

The ultraviolet (UV)/chlorine process has been widely applied for water treatment. However, the transformation of microplastic-leached dissolved organic matter (MP-DOM) in advanced treatment of real wastewater remains unclear. Here, we investigated alterations in the photoproperties of MP-DOM leached from biodegradable and conventional microplastics (MPs) and their subsequent effects on the degradation of sulfamethazine (SMT) by the UV/chlorine process. Spectroscopy was used to assess photophysical properties, focusing on changes in light absorption capacity, functional groups, and fluorescence components, while photochemical properties were determined by calculating the apparent quantum yields of reactive intermediates (ΦRIs). For photophysical properties, our findings revealed that the degree of molecular structure modification, functional group changes, and fluorescence characteristics during UV/chlorine treatment are closely linked to the type of MPs. For photochemical properties, the ΦRIs increased with higher chlorine dosages due to the formation of new functionalities. Both singlet oxygen (1O2) and hydroxyl radicals (•OH) formation were strongly correlated with excited triplet state of DOM (3DOM*) in the UV/chlorine treatment. Additionally, we found that the four types of MP-DOM inhibit the degradation of SMT and elucidated the mechanisms behind this inhibition. We also proposed degradation pathways for SMT and assessed the ecotoxicity of the resulting intermediates. This study provides important insights into how the characteristics and transformation of MP-DOM affect contaminant degradation, which is critical for evaluating the practical application of UV-based advanced oxidation processes (UV-AOPs).

A chitosan-based near-infrared ratiometric fluorescent nanoprobe created by molecular assembly with applications in hypochlorous acid detection in live mouse

Hypochlorous acid (HClO/ClO−) is a key reactive oxidative species (ROS) in the body. The HClO/ClO− concentrations are imbalanced during cancer formation due to the ROS stress response. This paper introduces a novel chitosan-based self-calibration fluorescent nanoprobe (ChCyNil) constructed by molecular assembly for the ratiometric detection of HClO/ClO−. Two chromophores with different fluorescence characteristics and HClO/ClO− sensitivity were labeled on chitosan, and nanoparticles were prepared by a self-assembly strategy for HClO/ClO− detection. ChCyNil exhibits several advantages, such as dual near-infrared emissions at 670 nm and 845 nm, tunable fluorescence intensity, self-calibration fluorescence, and good biocompatibility, improving its accuracy in HClO/ClO− detection. Our study confirmed that ChCyNil exhibits a well-assembled spheroidal nanostructure and good photophysical properties in solution. The fluorescence imaging properties were further proved by detecting endogenous HClO/ClO− produced by LPS/PMA stimuli in cells and zebrafish. In addition, ChCyNil was used to detect the fluorescence behavior of HClO/ClO− in tumors of live mice. The successful design and fabrication of ChCyNil have presented a new strategy for constructing detection tools with improved fluorescence properties for HClO/ClO− in live animals.

Triphenylamine-Based Solid-State Emissive Fluorene Derivative with Aggregation-Induced Emission Enhancement Characteristics

Aggregation-induced emission (AIE) has garnered considerable attention in recent years. Understanding the mechanisms underlying AIE phenomena is crucial. Here, we present the design and synthesis of a novel fluorene derivative (4) based on triphenylamine, which exhibits typical AIE properties. The structure of it was totally characterized using FT-IR, MALDI-TOF mass analysis, elemental analysis, 1H, and 13C NMR spectroscopy. It displayed strong solid-state emission with diverse fluorescence characteristics. The AIE property of the compound was systematically studied using photoluminescence spectroscopy, revealing a distinct yellow light-emitting phenomenon. The solid-state luminescence showed a red shift of 148 nm compared to its luminescence in dilute dimethylformamide (DMF) solutions. Moreover, photophysical characteristics, including absorption and emission spectra, as well as fluorescence lifetime, were examined using UV–vis absorption and fluorescence emission spectroscopy. Compound (4) exhibited superior photosensitization abilities in both solid and solution states, with a notably enhanced effect observed in the solid state compared to the solution state.

Impacts of an intensive traditional mariculture model on offshore environments as evidenced by dissolved organic matter and bacterial communities

Mariculture is a key protein source and economic driver but traditional methods pollute coastal waters, hindering sustainable development. Current research on the ecological impacts of mariculture mainly focuses on specific pollutants and lacks an assessment of the biogeochemical impacts of mariculture discharge. This study examined Xiangshan Bay, a representative intensive mariculture area in China, to explore the impact of mariculture tailwater discharge on water quality, focusing on dissolved organic matter (DOM) and bacterial communities. Based on the fluorescence excitation-emission matrix combined with parallel factor analysis, a characteristic fluorescence component C4 was identified in mariculture tailwater (intensity of 40 ± 4 %, n = 8), while higher C4 components (47 ± 3 %, n = 15) were found throughout the bay. Humic-like components from riverine input (C1 + C2: 32 ± 3 %, n = 15) and protein-like components from domestic sewage (C5: 2 ± 1 %, n = 15) were significantly lower in the seawater samples, indicating the strong influence of mariculture tailwater on the entire DOM structure of the bay. The bacterial community structure showed a response consistent with DOM, as revealed by nonmetric multidimensional scaling analysis. This showed that bacterial communities in mariculture tailwater and bay water samples clustered together, independent of riverine input. The SourceTracker model indicated that mariculture tailwater (91 ± 5 %) predominantly contributed to the bacterial community, with minimal contributions from riverine input (< 5 %). Co-occurrence network analysis further showed that under long-term high-intensity mariculture discharge, the C4 component became the core DOM and was closely associated with the bacterial community. The results here demonstrate the profound impact of traditional mariculture on coastal water quality and show that riverine input is not the primary pollution source in this region, providing clear directions for coastal environmental restoration efforts.