Commercial Dyes Research Articles

Unit-Emitting Carbon Dots for Cell Imaging and Lipid Droplet Quantification

The interactions between carbon dots (C-dots) and cells and the corresponding subcellular organelle localization are both significant for bio-sensing and bio-imaging. In this study, we explore cellular uptake and internalization behaviors of two kinds of lipophilic unit-emitting C-dots for three different kinds of cells. It is found that both C-dots can localize in lipid droplets with high efficiency. Compared with commercial dyes, the imaged lipid droplets by the proposed C-dots possess well-defined outlines. Based on such superior imaging performances, the quantification of lipid droplets for cells pretreated by oleic acid stimulation and starvation is well achieved.

Development of a live cell assay for the zinc transporter ZnT8

Zinc is an essential trace element that is involved in many biological processes and in cellular homeostasis. In pancreatic β-cells, zinc is crucial for the synthesis, processing, and secretion of insulin, which plays a key role in glucose homeostasis and which deficiency is the cause of diabetes. The accumulation of zinc in pancreatic cells is regulated by the solute carrier transporter SLC30A8 (or Zinc Transporter 8, ZnT8), which transports zinc from cytoplasm in intracellular vesicles. Allelic variants of SLC30A8 gene have been linked to diabetes. Given the physiological intracellular localization of SLC30A8 in pancreatic β-cells and the ubiquitous endogenous expression of other Zinc transporters in different cell lines that could be used as cellular model for SLC30A8 recombinant over-expression, it is challenging to develop a functional assay to measure SLC30A8 activity. To achieve this goal, we have firstly generated a HEK293 cell line stably overexpressing SLC30A8, where the over-expression favors the partial localization of SLC30A8 on the plasma membrane. Then, we used the combination of this cell model, commercial FluoZin-3 cell permeant zinc dye and live cell imaging approach to follow zinc flux across SLC30A8 over-expressed on plasma membrane, thus developing a novel functional imaging- based assay specific for SLC30A8. Our novel approach can be further explored and optimized, paving the way for future small molecule medium-throughput screening.

Effective dye detoxification by Cassia fistula flower extract- powered photocatalytic nanocomposite, SnO2:Mo/rGO and phytotoxicity evaluation of treated water using cowpea seeds

As industrial effluents consisting of toxic organic dye molecules cause severe harms to humans and damages to the environment, the detoxification of industrial waste water becomes one of the priority areas to be considered by countries all over the world. In this context, the present study is focused on the synthesis of an eco-friendly nanocomposite SnO2:Mo/rGO to photo-catalytically detoxify dye effluents. The detoxifying efficiency of this photocatalytic nanocomposite prepared using the flower extract of Cassia fistula was examined by decomposing methylene blue (cationic-MB) and rose bengal (anionic-RB) dyes. The nanocomposite is found to be superior compared to its constituents (SnO2:Mo and rGO) for both MB (99 %) and RB (98 %) dyes. After treatment, the water was examined for its non-toxicity by supplying it for seed germination process using Cowpea seeds (Vigna unguiculata). The seed germination results clearly reveal that near complete detoxification of dye solution is achieved, when SnO2:Mo/rGO nanocomposite is used as photocatalyst. Thus, the SnO2:Mo/rGO nanocomposite synthesized using Cassia fistula flower extract can be considered as a potential photocatalyst for commercial dye detoxification processes.

SnS thin films deposited at room temperature – Efficient and reusable dark catalyst for water remediation at ambient conditions

This study describes the dark catalytic degradation of cationic, anionic, and commercial dyes by SnS thin films under dark ambient conditions without the assistance of any external stimuli. The thin films were deposited by a modified SILAR (Successive Ionic Layer Adsorption and Reaction) method at room temperature and characterised using XRD, XPS, FESEM, TGA, and UV–visible spectrophotometers. The dark catalytic degradation of methylene blue (MB) dye was investigated using a spectrophotometer and validated by LCMS analysis and an adsorption desorption test. Within 15 min, 48 % of the MB dye (original concentration: 10 mg/l) had been degraded by the catalyst, and by 90 min, the degeneration was almost complete. The ROS (reactive oxygen species) scavenger test and indicator test confirmed the role of the hydroxyl radical in the degradation process. The influence of initial dye concentration, magnetic stirring, and the composition of the catalyst on the degradation efficiency was also studied. The same catalyst was used five times in succession to test its reusability, and it was then structurally and thermally characterised to test its stability. This study emphasises the possible use of SnS thin film as an effective, reliable, and reusable around-the-clock catalyst for the degradation of dye-contaminated waste water without the assistance of light or any chemical additives.

Construction of a Near-Infrared Fluorescent Probe for Dynamic Monitoring and Early Diagnosis of Heart Failure.

Cardiac hypertrophy characterized by abnormal cardiomyocyte viscosity is a typical sign of heart failure (HF) with vital importance for early diagnosis. However, current biochemical and imaging diagnostic methods are unable to detect this subclinical manifestation. In this work, we developed a series of NIR-I fluorescence probes for detecting myocardial viscosity based on the pyridazinone scaffold. The probes showed weak fluorescence due to free intramolecular rotation under low-viscosity conditions, while they displayed strong fluorescence with limited intramolecular rotation in response to a high-viscosity environment. Among them, CarVis2 exhibited higher stability and photobleaching resistance than commercial dyes. Its specific response to viscosity was not influenced by the pH and biological species. Furthermore, CarVis2 showed rapid and accurate responses to the viscosity of isoproterenol (ISO)-treated H9C2 cardiomyocytes with good biocompatibility. More importantly, CarVis2 demonstrated excellent sensitivity in monitoring myocardial viscosity variation in HF mice in vivo, potentially enabling earlier noninvasive identification of myocardial abnormalities compared to traditional clinical imaging and biomarkers. These findings revealed that CarVis2 can serve as a powerful tool to monitor myocardial viscosity, providing the potential to advance insights into a pathophysiological mechanism and offering a new reference strategy for early visual diagnosis of HF.

Key features of blend denim fabrics performance with dyed weft silk yarn and different weave structures

This research aimed to weave the warp indigo-dyed cotton yarn with un-dyed or dyed silk yarn and analyze the impact of different weft yarn structures on the properties of denim fabrics. The dyed silk yarn was performed by a selection of different anionic indigo and non-indigo blue dyestuffs. The dyeing shades of the anionic Indigo Carmine dye on silk exhibited high build-up at the acidic pH range 2–2.5 with poor washing fastness and even so, the cationic aftertreatment of the dyed silk samples showed un-matched color with indigo-dyed cotton yarns. The dyeing properties of two commercial non-indigo reactive and acid dyes on silk add other advantages. To ascertain the dyeing shades evaluation of the non-indigo dyes on silk, two sets of blended denim fabrics were investigated. The first set included a weft-wise silk yarn dyed with reactive dye RB 5, and the second set included silk yarns dyed with acid dye AB 193. Weaving of the blended fabrics was carried out in Twill 3/1, 3/2 Z,and Satin 53 patterns and exhibited significant color effects of the dyed silk yarns to those of the un-dyed control samples. The dyeing shades of the non-indigo RB 5 and AB 193 dyed weft-wise silk yarns were found to be matched in color performance with the conventionally indigo- dyed cotton yarns. Ultraviolet resistance of the blend denim fabrics was evaluated, showing significant improvement in UPF of the weft-wise dyed silk. The study claimed that the dyed silk yarns a good candidate for newly developed blend denim fabrics.

Disazo disperse dyes crosslinked with varied characteristic groups: Their synthesis, characterization, and application on polyester fabrics

We previously synthesized a group of carbamate-linked disazo disperse dyes that showed excellent fastness properties on polyester fabric by using the thermosol dyeing process. However, the color yield of the dyed fabric was not sufficiently high to be accepted by users, especially when using a high-temperature dyeing process. To further optimize the structures of disazo disperse dyes and observe the effect of the linking groups on the dyeing properties, in this work, we used p-phenylene diisocyanate or terephthaloyl chloride as crosslinking agents and aniline derivatives containing hydroxyl or amino groups as reactants to synthesize four disazo disperse dyes containing various characteristic groups, including ester, carbamate, amide, and urea groups. The structures of these new dyes were characterized by nuclear magnetic resonance, mass spectrometry, and Fourier-transform infrared spectroscopy analyses. The spectral properties in an N,N-dimethylformamide solvent were measured, the structural parameters of the dyes were calculated using the density functional theory method, and the dyeing properties were investigated by using high-temperature and thermosol dyeing processes, and also compared with these for the commercial dye, C·I.Disperse Red 153. The results showed that there were slight differences in the molar extinction coefficients and maximum absorbance wavelengths between the new dyes, but the effects of characteristic groups on the structural features and the dyeing properties of the new dyes were significant. The ester-linked dye (D1) had the highest color depth when a high-temperature process was used in the presence of 50 mL/L of methyl salicylate because of its highest ClogP (N-octanol/water partition coefficient) value, corresponding to its more hydrophobic nature, while all the other dyes produced lower color yields. When used in the thermosol dyeing process, the carbamate-linked dye (D2) yielded the highest color depth, followed by the ester-linked dye (D1) and amide-linked dye (D3), and the urea-linked dye (D4) produced the lowest color depth due to its highest hydrophilic properties. Finally, it was demonstrated that the new dyes had excellent color fastnesses except for the urea-linked dye (D4), which exhibited a slightly lower light fastness, While the commercial dye used as the control showed a relatively poor sublimation and light fastness although its color depth and chroma value performed slightly better than the new dyes as used by the thermosol dyeing process.

Structure-Inherent Tumor-Targeted IR-783 for Near-Infrared Fluorescence-Guided Photothermal Therapy.

IR-783, a commercially available near-infrared (NIR) heptamethine cyanine dye, has been used for selective tumor imaging in breast, prostate, cervical, and brain cancers in vitro and in vivo. Although the molecular mechanism behind the structure-inherent tumor targeting of IR-783 has not been well-demonstrated, IR-783 has unique properties such as a good water solubility and low cytotoxicity compared with other commercial heptamethine cyanine dyes. The goal of this study is to evaluate the phototherapeutic efficacy of IR-783 as a tumor-targeted photothermal agent in human colorectal cancer xenografts. The results demonstrate that IR-783 shows both the subcellular localization in HT-29 cancer cells and preferential accumulation in HT-29 xenografted tumors 24 h after its intravenous administration. Furthermore, the IR-783 dye reveals the superior capability to convert NIR light into heat energy under 808 nm NIR laser irradiation in vitro and in vivo, thereby inducing cancer cell death. Taken together, these findings suggest that water-soluble anionic IR-783 can be used as a bifunctional phototherapeutic agent for the targeted imaging and photothermal therapy (PTT) of colorectal cancer. Therefore, this work provides a simple and effective approach to develop biocompatible, hydrophilic, and tumor-targetable PTT agents for targeted cancer phototherapy.

Nano-architected titania/gold@GO nanosheets for sonocatalytic degradation of azo dyes in textile wastewater

Environmental pollution is creating serious risks to both human health and the atmosphere which has been a major threat on a global scale. Therefore, it is necessary to focus on the evolution of the environment and trace contaminants for effective and reliable detection and degradation methods. Photochemical methods such as Surface-Enhanced Raman Scattering (SERS) and sono-catalytic degradation can be used to accelerate the detection and degradation of toxic dyes. In the present work, a Gold/Titania/Graphene oxide nanocomposite (ATG) was investigated as a capable dual substrate for SERS sensing and sono-catalytic degradation of pollutants. The nanosize distribution (6–12 nm) of ATG was synthesized by a solvothermal route. X-ray diffraction pattern illustrates the anatase phase of the titanium dioxide. Sonocatalytic degradation was aided using Raman spectroscopy. The effectiveness of ATG as a sono-catalytic substrate and SERS sensor was first evaluated using commercial dyes, such as malachite green and Bismarck brown. Furthermore, research has been conducted on the harmful elements in textile effluents (TE). The NN and C-N bands found in the SERS spectra of TE indicates the presence of carcinogenic azo-dye impurities. The enhancement factor was observed to be 5.77×1012 with the limit of detection (LOD) as 6.0×10−12M. Additionally, the sono-catalysis of ATG was evaluated for the elimination of these dye pollutants in TE. Following sono-catalysis by ATG, a high degradation rate constant of approximately 8.44 ×10−3/min was noted in TE with 89 % of degradation efficiency. The enhanced SERS detection, sono-catalytic degradation of synthetic dyes and effluent stem from the combined action of’ plasmonic characteristics of Au NPs, anatase TiO2, and the π-π stacking characteristic of GO.

BREWERY WASTE FOR INDIGO BLUE ADSORPTION

Brewery waste (BW) is among the natural adsorbents that have been evaluated for different chemical pollutants removal present in the aqueous medium. In this work, we investigated the BW capacity to remove the commercial indigo blue dye (IB) from laboratory aqueous solutions and river water samples. Results utilizing laboratory distilled water showed a satisfactory maximum capacity (166.94 mg/g) of BW for IB. The ∆G value (-16.53 Kj/mol) and other parameters reveal a favorable adsorptive process. Furthermore, tests in glass columns using river water samples enriched with IB (1,000 mg/L) revealed high BW efficiency for IB removal (96.0 %). These results are important to demonstrate that BW can be more a new alternative for IB removal from water. In addition, this study provides an alternative for the reuse of BW.

Trident anchoring-lipid droplets strategy for fluorescence/super-resolution/lifetime imaging and diagnosis of fatty liver in vivo

Lipid droplets (LDs) are crucial dynamic organelles within cells that play an indispensable role in cellular energy supply, membrane formation, and signal transduction. Therefore, detecting and tracking LDs with high selectivity and resolution is particularly important. In this study, we describe a “trident” anchoring strategy (based on polarity, lipophilicity, and viscosity sensitivity) to achieve highly specific and dynamic imaging of LDs. A series of carbazole-substituted fluorescent protein (Car-FP) mimics conjugated with different electron-nature substituents (A–H) were synthesized and characterized. Spectroscopic properties indicate that the electron-donating triphenylamine (TPA)-conjugated H exhibits high sensitivity to polarity, viscosity response, and lipophilicity. Co-localization experiments in cells also demonstrate that H selectively localizes at LDs in living cells, displaying a bright yellow fluorescence signal (λex = 488 nm; λem = 577 nm) with a larger Stokes shift (89 nm) than the commercial LD dye bodipy 493/503 (10 nm). Super-resolution fluorescence imaging (SIM) and lifetime imaging (FLIM) are employed to visualize the distribution and aggregation in cell models of nonalcoholic fatty liver disease as well as zebrafish and mice models, demonstrating the potential applications of H in LD biology research and diagnosis of related diseases.

Removal of Commercial Textile Dye DRMD from Wastewater Using Two-Dimensional Mesoporous Graphene Oxide Adsorbent

Environmental toxins from textile effluents, including organic contaminants, heavy metals, and dyes, pose significant health risks such as renal illness, allergies, dermatitis, and cancer when released into the aquatic environment. While various dye removal methods exist, adsorption is highlighted as a potentially effective solution due to its low cost, simplicity, and ease of use. An adsorbent of two-dimensional mesoporous Graphene Oxide (GO) was produced using Hummer’s method from cost-effective graphite powder. This was then utilized to eliminate the Doracryl Red MD (DRMD) textile dye from the aqueous system. To characterize the synthesized material, XRD, FTIR, and SEM analyses were performed. Zeta Potential and AFM analysis were used to determine surface charge and roughness, respectively. BET analysis was performed to obtain information regarding the surface area and porosity of the mesoporous GO. The highest adsorption capacity for the adsorption of the dye DRMD was found at 917.62 mg/gm. A variety of factors, including the influence of solution pH, adsorbent dosage, adsorption temperature, concentration of dye solution, and contact time, were thoroughly investigated. Adsorption data best fit the Langmuir model and demonstrated pseudo-second-order reaction kinetics. After repeatedly washing used adsorbents with 2% HCl solution, 88.62% of its initial adsorption capacity was retained after the 4th cycle. Hence, the enhanced adsorption capacity and recyclability of Graphene Oxide (GO) render it a promising candidate for the treatment of wastewater polluted with organic dyes.

Trypan blue dye decolorization by Aeromonas caviae isolated from water sewage in Jakarta, Indonesia

Abstract. Pinontoan R, Susanto TSR, Lucy J, Angelina C, Soentoro SE, Purnomo JS, Cornelia M. 2024. Trypan blue dye decolorization by Aeromonas caviae isolated from water sewage in Jakarta, Indonesia. Biodiversitas 25: 1631-1637. The textile industry generates a substantial amount of hazardous chemical waste, which requires proper treatment to mitigate negative environmental and health consequences if left untreated. Studies on the removal of Trypan Blue (TB), a widely used commercial diazo textile dye, by indigenous bacteria are limited. Therefore, this study aimed to isolate, identify, and characterize microorganisms capable of decolorizing TB in textile dye-contaminated wastewater from Jakarta. Microorganisms were initially screened for decolorization activity in solid media containing TB. Among the isolated strains, TB2 isolate exhibited the highest decolorizing potential and was selected for further analysis. The morphological, biochemical, molecular, and phylogenetic characteristics of the TB2 isolate revealed that it belonged to the species Aeromonas caviae. To examine the ability of the isolate to remove TB, various culture conditions, such as pH, temperature, and agitation, were tested. The results demonstrated that the A. caviae TB2 strain could reduce up to 77.10% of TB (0.0025% (w/v)) under static conditions, pH 7.0, and 27°C over six days. To our knowledge, this is the first study to report the ability of the Aeromonas genus to decolorize TB. These results imply the potential use of A. caviae for decolorizing dye-bearing industrial wastewater.

Angle-Resolved Fluorescence of a Dye Coupled to a Plasmonic Nanohole Array

Gold nanohole arrays are periodic metasurfaces that are gathering huge interest in biosensing applications. The bi-dimensional grating-like structure defines their plasmonic response, together with the corresponding mode of angular dispersion. These properties can be used to investigate the interaction processes with the fluorescence features of a properly chosen emitting molecule. By employing a custom gold nanohole array alongside a commercial organic dye, we conducted an accurate angle-resolved optical characterization resorting to fluorescence, reflectance, and transmittance spectra. The coupling between the plasmonic modes and the fluorescence features was then identified as a modification of the dye fluorescence signal in terms of both spectral redistribution and enhancement. By carefully analyzing the results, different measurement efficiencies can be identified, depending on the set-up configuration, to be properly engineered for sensitivity maximization in plasmon-enhanced fluorescence-based applications.

Application of coagulation-microfiltration for membrane fouling mitigation in highly saline dyeing wastewater: Anti-fouling modification of membrane and novel insight of salt into regulation of cake layer formation

Cake layer formation is the dominant microfiltration (MF) membrane fouling mechanism after long-term operation. The regulation of cake layer characteristics is less clarified in the coagulation-microfiltration (CMF) technique due to an incomplete understanding of flocculation mechanism; however, gaining such insight will contribute to improving MF efficiency for water purification. Herein, an antifouling MF membrane for high saline textile wastewater was constructed using polydopamine (pDA) co-deposition with sodium p-styrenesulfonate (SS), and methoxypolyethylene glycols (mPEG). Thereafter, the cake layer formation in the CMF technique could be precisely regulated by adjusting salt concentration (NaCl or Na2SO4). Results indicated that the inorganic salt-induced transformation of flocculation mechanism endows a desired regulation of cake layer characteristics, consequently leading an increase in membrane flux. Various properties and formation of flocs were caused via different flocculation mechanisms (from predominant charge neutralization to integrated interaction) in response to a salt variation, giving rise to a directed transition behavior of cake layer formation from compact to porous structure. Particularly, the coagulation mechanism was validated by the experimental analysis and molecular dynamics simulations. Furthermore, the high salt permeation (>90%) and acceptable dye rejection (>98%) of two commercial reactive dyes could be obtained by the proposed CMF technique, exhibiting a satisfactory fractionation behavior of dyes/inorganic salt. A beneficial contribution is the direct reuse dyeing of NaCl from the spent dyeing bath in new dyeing operations. These results could provide a further understanding of the underlying mechanisms of coagulation-enhancing MF behavior and inspire the precise regulation of cake layer characteristics to achieve efficient MF.

Potential of White Rot Fungi from Berbak-Sembilang National Park, Indonesia for Decolorization and Detoxification Commercial Direct Dyes

Commercial direct dyes are frequently employed in the dyeing of Jumputan, a traditional craft originating from South Sumatra, Indonesia. The introduction of synthetic dyes into the environment can have a detrimental impact on ecosystem stability, necessitating the implementation of remedial measures. There has been a growing interest in the utilization of White Rot Fungi (WRF) as a viable biological agent for the purpose of decolorizing and detoxifying synthetic colors. However, it is imperative to investigate the isolated WRF from Berbak-Sembilang National Park (TNBS) due to the varying capacities of decolorization and detoxification exhibited by each WRF. The study involved 5 WRF from TNBS screened in solid media, and grown in a liquid medium containing commercial direct dyes (direct turquoise, direct orange and direct yellow). WRF grown on liquid medium contains a single dye, mixture dyes and temperature characterization. It measured decolorization, biomass and enzyme activities. Toxicity is measured by the BSLT method. The findings indicated that 3 specific fungi, namely Phellinus noxius (BRB 11), Lentinus sajor-caju (BRB 12) and Leotrametes menziesii (BRB 73), exhibited a significant capacity to remove the color from both individual and mixture of direct dyes through the production of laccase and MnP enzymes. The optimal temperature for decolorization of the mixture of direct dyes was 35 °C for BRB 11 (61.4 %) and BRB 73 (60.7 %), whereas BRB 12 (47.4 %) exhibited optimal temperature at 30 °C. The toxicity assay conducted using A. salina showed a progressive rise in the LC50 value, from 15.37 mgL−1 in the control group to a range of 21.63 - 35.84 mgL−1 in the treated group, indicating a detoxification process. However, the most toxic isolate was BRB 12. This study proposes the potential of 2 isolates, Phellinus noxius (BRB 11) and Leotrametes menziesii BRB 73, from TNBS for degradation of single and mixture dye wastewater in the environment. HIGHLIGHTS The discovery of 3 White Rot Fungi from TNBS (Indonesia) has the ability to remove color and reduce the level of toxicity of commercial direct dyes, both individual and mixture of commercial direct dyes. Uncovering one of White Rot Fungi has not been widely published for decolorization and detoxification commercial direct dyes, namely Leotrametes menziesii (BRB 73). The optimal temperature was 35 °C for decolorization of commercial direct dyes by Phellinus noxius (BRB 11) and Leotrametes menziesii (BRB 73) GRAPHICAL ABSTRACT

A Feasibility Study for a Novel Trans-infraorbital Canal Approach to the Maxillary Nerve in Pigs (Sus domesticus).

Experimental maxillofacial surgery is commonly performed in pigs; however, locoregional anesthesia of this area has not been described. This study evaluated the feasibility of a novel maxillary nerve block approach. In part I, cadavers were used to determine anatomic landmarks and assess maxillary nerve dye staining by using 0.03 mL kg-1 of a 1:10 mixture of commercial food dye and 0.5% bupivacaine. In part II, 10 additional pig cadavers underwent bilateral ultrasound-guided maxillary nerve blocks by using trans-infraorbital canal needle placement. The maxillary nerve was harvested and scored based on degree of staining (0 and 1, absent or incomplete staining; 2, staining; >1 cm circumferentially). Intracranial and intraconal spread of dye was evaluated. A Kruskal-Wallis test was used to compare infraorbital canal length estimated either externally via landmarks, internally via ultrasound, or actually measured after dissection. In 18 of 20 (90%) injections, successful staining (score = 2) of maxillary nerves was obtained for a nerve length of 2.4 ± 0.3 cm. Two of 20 cases (10%) had inadequate staining (score <2). At dissection of these 2 cases, the needle tip was observed to have collided with an unerupted tooth (third molar). No intracranial or intraconal spread of dye was observed. We detected no statistical differences between the estimated external, estimated internal, or actual dissection methods for measurement of infraorbital canal length (P = 0.3). Ultrasound-guided trans-infraorbital maxillary nerve block in pigs is a feasible technique, warranting further work to evaluate its in vivo efficacy and safety.

Dynamic photo-enhanced polyacrylic acid-based room temperature phosphorescence materials with persistent long-wavelength and even near-infrared luminescence via Förster resonance energy transfer

Stimulus-responsive organic room temperature phosphorescence (RTP) materials have attracted widespread attention in chemical sensors, bioimaging and information security. In this work, a dynamic photo-enhanced RTP material is prepared by doping 1,8-naphthalic anhydride (NA) into the polyacrylic acid (PAA) matrix. After 10 min irradiation of 302 nm UV light, the RTP properties of the doping systems PAA-NA are significantly enhanced and the photo-enhanced performances show excellent reversibility. More interestingly, PAA-NA as energy donor and the commercial dye rhodamine B (RhB) as energy acceptor are used to construct the ternary doping systems PAA-NA-RhB, which exhibit color-tunable long afterglow from orange to red through the triplet-to-singlet Förster resonance energy transfer (TS-FRET) process. Significantly, RhB as the intermediate and near infrared (NIR) dye Nile blue (NiB) as energy acceptor are codoped into energy donor PAA-NA matrices to facilely prepare the quaternary doping systems PAA-NA-RhB-NiB, and persistent NIR luminescence is realized successfully via the stepwise FRET process after 10 min irradiation of 302 nm UV light. The great application potential of the prepared photo-enhanced PAA-based RTP materials in high-level information encryption has been confirmed due to their excellent RTP performance. This study broadens the range of photo-enhanced polymer-based RTP materials and extends the persistent luminescence of PAA-based RTP materials to the long-wavelength and NIR regions.

Rare earth-modified yellow carbon dots for long-term imaging in cells and zebrafish

Carbon dot (CDs) materials are typically hindered by aggregation-caused quenching (ACQ) effect. However, there are limitations in terms of their development and application. The introduction of aggregation-induced emission (AIE) characteristics into CDs has emerged as a viable solution to this challenge. In this work, we synthesized a novel yellow fluorescence (FL) rare earth-doped AIE CDs (named Y-CDs), which integrate the benefits of AIE materials, rare earth materials, and CDs. Y-CDs exhibit bright yellow FL, good temperature sensitivity and pH response properties. In cell imaging, Y-CDs showed excellent targeting capability towards the nuclear in HeLa cells. Y-CDs also showed excellent biocompatibility and safety in imaging of zebrafish embryos and zebrafish. Even on the 10th day following culture of zebrafish embryos, the digestive system and lens of zebrafish can be accurately located and imaged. The work presented here suggests the great potential of replacing commercial dyes with Y-CDs for highly specific nuclear labeling and bioimaging.

PH response mechanism of bifunctional fluorescent carbon quantum dots and application in cancer detection and bioself-targeting imaging

The development of fluorescent probes suitable for lysosome visualisation as well as real-time tracking is crucial because lysosomes play a crucial role in numerous metabolic activities and diseases. In this paper, nitrogen-doped carbon quantum dots (NCQDs) enriched with a large number of hydroxyl, amino, and carboxyl groups were prepared by a simple solvothermal method using tartaric acid and 4-aminosalicylic acid as raw materials. The fluorescence intensity of NCQDs decreased with increasing pH (1–13) due to protonation and deprotonation as well as hydrolysis of surface groups in alkaline environment and detachment of chromophores. This enabled the NCQDs to achieve label-free and rapid visualisation of pH in cells. The disparity in pH levels between cancer cells and normal cells resulted in varying fluorescence brightness of NCQDs observed in these two cells, which enabled the differentiation of cancer cells from normal cells. Most importantly, when NCQDs entered the cell, lysosomes could provide protons for NCQDs, and the protonation of NCQDs' surface groups led to stronger fluorescence after endocytosis of NCQDs in lysosomes. Thus, lysosomal targeted imaging could be achieved without the need to introduce lysosomal-targeted ligands, and NCQDs had a higher biocompatibility and stability compared to commonly used commercial dyes, which made it the ideal choice of lysosomal-targeted fluorescent probes.