Fluorescent Dye Rhodamine Research Articles

NEUROTOXIC RISK AND ADSORPTION PROPERTIES OF COARSE NON-FUNCTIONALIZED CARBON PARTICLES DERIVED FROM APPLE WASTE

Aim. Carbon particles have been widely used in different technologies and have great potential for new biological application. Synthesis of carbon particles from agricultural waste using “green” principles is in the mainstream of biotechnology area and attract a great attention in biomedical application. Here, coarse carbon particles (CCPs) were synthesized using “green” principles from dry apple and used in the biological experiments without preliminary functionalization. Methods. Neurotoxic features of CCPs were analysed in isolated presynaptic cortex nerve terminals (synaptosomes) monitoring the extracellular levels of excitatory neurotransmitter L-[14C] glutamate and inhibitory one [3H]GABA, as well as the membrane potential. Results. Measuring the membrane potential of the nerve terminals, it was revealed an inadequate decrease in the fluorescence intensity of the potential-dependent dye rhodamine 6G in the presence of CCPs (1 mg/ml). This decrease was not due to membrane hyperpolarisation because CCPs did not change the extracellular synaptosomal levels of L-[14C] glutamate and [3H]GABA. CCP-induced decrease in the fluorescence intensity of the dye in nerve terminals can be due to its interaction with CCPs. Indeed, the ability of CCPs to interact with rhodamine 6G was shown in synaptosome-free incubation media. Conclusions. Therefore, CCPs did not possess neurotoxic signs, and so are biocompatible. In both experiments, i.e. without bio object and in biological system, CCPs were able to interact with fluorescent dye rhodamine 6G. In prospect, this feature of CCPs can be used in biotechnology after further investigation of dye interaction conditions.

Experimental study of solute diffusion in oscillating flow in a rectangular cell

Abstract The mass transfer of a passive substance dissolved in a fluid in a rectangular Hele–Shaw cell is experimentally studied. We consider mass transfer when the fluid is (i) at rest and (ii) oscillates. In the first case, mass transfer is carried out due to molecular diffusion. The results of measuring the molecular diffusion coefficient of the fluorescent dye Rhodamine B in water are in good agreement with the data obtained by other methods. In the presence of oscillations, the mass transfer rate increases. The comparison of the obtained experimental results with theoretical predictions reveals that the mass transfer is enhanced due to the Taylor dispersion.

Custom-made spherical fluorescent tracer particles for laser Velocimetry Laboratory Experiments

This article introduces a method for creating custom-made spherical fluorescent particles tailored for fluid mechanics optical velocimetry laboratory measurements techniques such as Particle Image Velocimetry (PIV) and Particle Tracking Velocimetry (PTV) measurement techniques. The incorporation of the fluorescent dye Rhodamine B into the particle bulk significantly reduces direct light reflections and enhances particle detection when enlightened by a laser and using a band-pass filter on the optical measurement device. Furthermore, the study offers a clear guide for adjusting particle diameter by modifying various parameters such as the stirrer used, its stirring speed, the surfactant concentration, and the type of polymer. This allows for the customization of particles best suited for water multiphase flow characterization and transport studies. The resulting particles exhibit excellent sphericity, making them suitable for a wide range of fluid mechanics investigations, from small to large scale. Experimental validations, including size measurements, density assessments, emission spectra analyses, and applicability in a confined flow affirm the effectiveness of the proposed methodology by exhibiting a signal-to-noise ratio four to five times higher than fluorescent surface-stained and non-fluorescent particles.

Tuning Circularly Polarized Afterglow Color via Modulation of Energy and Chirality Transfer in Co‐Doped Films

AbstractCircularly polarized luminescence (CPL) materials offer exciting potential due to their unique light properties. However, controlling the color of afterglow emission, a key feature for many applications remains a challenge. Here, a co‐doping strategy is presented for precise control of multicolor CPL afterglow in films. This approach utilizes chiral naphthylphosphoric acid derivatives as energy and chirality transfer donors, commonly used fluorescent dye rhodamine B (RB) and PVA are selected as the acceptor and the polymeric matrix, respectively. Remarkably, the co‐doped films exhibit ultra‐long green circular polarization phosphorescence lasting several seconds with high efficiency (14.23%), lifetime (1025.5 ms), and dissymmetry factor (8.44 × 10−3). Crucially, by adjusting the acceptor content, it can precisely tune the phosphorescence‐to‐fluorescence ratio and achieve multicolor afterglow. This control stems from a combination of Förster resonance energy transfer, chirality transfer, and color‐mixing effects. Furthermore, this approach significantly improves the asymmetry factor of the CPL afterglow by an order of magnitude (5.17 × 10−2). It is anticipated that this straightforward approach to precisely regulating the afterglow color of CPL will provide invaluable insights for the future design of highly efficient and innovative CPL materials.

Fabrication of Rhenium Disulfide/Mesoporous Silica Core-Shell Nanoparticles for a pH-Responsive Drug Release and Combined Chemo-Photothermal Therapy.

A stimuli-responsive drug delivery nanocarrier with a core-shell structure combining photothermal therapy and chemotherapy for killing cancer cells was constructed in this study. The multifunctional nanocarrier ReS2@mSiO2-RhB entails an ReS2 hierarchical nanosphere coated with a fluorescent mesoporous silica shell. The three-dimensional hierarchical ReS2 nanostructure is capable of effectively absorbing near-infrared (NIR) light and converting it into heat. These ReS2 nanospheres were generated by a hydrothermal synthesis process leading to the self-assembly of few-layered ReS2 nanosheets. The mesoporous silica shell was further coated on the surface of the ReS2 nanospheres through a surfactant-templating sol-gel approach to provide accessible mesopores for drug uploading. A fluorescent dye (Rhodamine B) was covalently attached to silica precursors and incorporated during synthesis in the mesoporous silica walls toward conferring imaging capability to the nanocarrier. Doxorubicin (DOX), a known cancer drug, was used in a proof-of-concept study to assess the material's ability to function as a drug delivery carrier. While the silica pores are not capped, the drug molecule loading and release take advantage of the pH-governed electrostatic interactions between the drug and silica wall. The ReS2@mSiO2-RhB enabled a drug loading content as high as 19.83 mg/g doxorubicin. The ReS2@mSiO2-RhB-DOX nanocarrier's cumulative drug release rate at pH values that simulate physiological conditions showed significant pH responsiveness, reaching 59.8% at pH 6.8 and 98.5% and pH 5.5. The in vitro testing using HeLa cervical cancer cells proved that ReS2@mSiO2-RhB-DOX has a strong cancer eradication ability upon irradiation with an NIR laser owing to the combined drug delivery and photothermal effect. The results highlight the potential of ReS2@mSiO2-RhB nanoparticles for combined cancer therapy in the future.

Исследование зависимости физико-химических свойств флуоресцентных гибридных полимерных носителей от условий гидротермального синтеза

Currently, the search for new types of carriers for low-molecular weight substances, as well as the development of optimal methods for the effective encapsulation of these substances are important tasks of modern chemistry and pharmacology. However, there are still limitations in this area, among which one of the most significant is the lack of the optimal carrier capable of stably retaining a low-molecular weight substance. The work presents hybrid polymer structures obtained by in situ hydrothermal synthesis as an effective candidate for these purposes. The fluorescent dye rhodamine B has been used as a model low-molecular weight substance for encapsulation into the structures. The resulting hybrid polymer structures demonstrated good stability when stored in an aqueous environment for 336 h with the release of the low-molecular weight dye rhodamine B no more than 2%. In addition, the influence of the conditions for obtaining hybrid carriers (including the composition of the carriers (thickness of the polymer shell and the presence of a calcium carbonate core) and synthesis temperature) on their physical-chemical characteristics has been studied. Thus, the optimal approach for obtaining fluorescent hybrid polymer carriers with a set of desired properties has been revealed. In particular, it has been shown that the optimal production conditions are hydrothermal synthesis temperature of 180 °C and the absence of CaCO 3 core inside the polyelectrolyte shell which allow us to obtain a stable hybrid polymer carrier with bright fluorescence. The results presented in this study can be used to create functional platforms and systems with tunable fluorescent properties and the ability to deliver low-molecular weight substances.

Room temperature, long afterglow, water-soluble materials with multicolor tunability

Developing solution-processable room-temperature long afterglow (RTLA) materials with multi-color tunable emissions based on an inorganic matrix is of considerable practical importance in diverse applications but rarely reported. Herein, a series of water-soluble multicolor afterglow materials (t@LP@Rh123, t@LP@Rh6G, t@LP@RhB, respectively) with afterglow emission colors of green, orange-yellow and red were achieved through triplet-to-singlet Förster-resonance energy transfer (T1-S1 FRET), where the cyan afterglow material t@LP obtained by solventless mechanical grinding method of 4-[2,2':6′,2″-Terpyridin]-4′-ylbenzoic acid and Laponite (LP) was used as an energy donor, and fluorescent dyes Rhodamine 123, Rhodamine 6G and Rhodamine B were used as energy acceptors. Notably, the obtained series of multicolor afterglow materials still exhibit obvious afterglow emission in aqueous solution, which make them potentially useful in the fields of anti-counterfeiting and multilevel information encryption.

Colorful Room‐Temperature Phosphorescence Including White Afterglow from Mechanical Robust Transparent Wood for Time Delay Lighting

The preparation of mechanical robust organic room‐temperature phosphorescence (RTP) materials especially with white afterglow is attractive but rarely reported. Herein, a method to produce mechanical robust colorful RTP transparent wood (PTW) by infiltrating delignified wood with poly (vinyl alcohol) solutions containing arylboronic acids with various π conjugations is reported. The doubly rigid environment provided by the B─O covalent bonds and hydrogen bonds can stabilize the triplet excitons, leading to a ultralong lifetime of up to 2.13 s and excellent RTP emission stability (without obviously quenching over a month) of the target PTW. Besides, as a promising structural material for optical applications, the PTW shows combined advantages of multicolored persistent luminescence (from blue to green and then to red), good optical transmittance (≈90%), and striking mechanical strength (≈154 MPa). More importantly, by introducing appropriate amount of fluorescent dye rhodamine 6 G to the PTW with blue afterglow, white afterglow with a lifetime of 1.85 s is successfully achieve through triplet‐to‐singlet Förster resonance energy transfer. The PTW can function as afterglow window, anticounterfeiting label, and time delay lighting. This success paves the way for the development of mechanical robust, ecofriendly, and practical RTP materials.

Influence of Concentration Gradients on Electroconvection at a Cation-Exchange Membrane Surface.

Membrane-based systems, such as electrodialysis, play an important role in desalination and industrial separation processes. Electrodialysis uses alternating anion- and cation-exchange membranes with a perpendicular electric field to generate concentrated and diluate streams from a feed solution. It is known that under overlimiting current conditions, reduced charge and mass transfer at the membrane interface leads to regions of high ion depletion generating instability and vortices termed electroconvection. While electroconvective mixing is known to directly impact the separation efficiency of electrodialysis, the influence of ion concentration gradients across the membrane experienced in a functional electrodialysis system is not known. Here, we report the influence of ion concentration gradients across a cation exchange membrane (Nafion) that is both aligned with and opposed to the applied electric field. Experiments were conducted by coflowing NaCl solutions of different concentrations (0.1-100 mM) on each side of the membrane, and electroconvection was visualized with a fluorescence dye (Rhodamine 6G). We obtained concentration profiles from fluorescence image data and systematically measured the thickness of the depletion boundary layer dBL under different conditions. We found smaller dBL values at a higher flow rate both with and without concentration gradients. Our results show that electroconvection is enhanced when the electric field is opposite to the direction of the concentration gradient.

An anti-freeze fluorescent organogel with rapid shape-forming properties for constructing artificial light harvesting systems used in extremely cold environments.

Using polyvinyl alcohol (PVA) and perylene-3,9-dicarboxylic acid (PDA) as raw materials, a new anti-freeze (-50 °C) fluorescent organogel with rapid shape-forming (2 h) properties was synthesised based on a certain proportion of the binary solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Then, an artificial light-harvesting system (ALHS) used in extremely cold environments was successfully constructed by mixing fluorescent dyes sulphorhodamine101 (SR101) and rhodamine 6G (R6G) into them as acceptors.

Rhodamine B‐based lipase activity assay with natural substrates—development and application

SummaryFor the various application fields of lipases in food, an accurate and reliable prediction of their performance is needed. This is not provided by the current artificial substrate‐based assays, because natural substrates should be applied. The fluorescent dye Rhodamine B (RB) enables the tracking of released fatty acids in real time and therefore offers the possibility to assess lipase activity towards any substrate. A high‐throughput assay including RB was established, validated and applied to a range of five fats/oils and two isolated lipids for a range of seven lipases. The results show that lipase reactions under different conditions are not comparable. Besides the substrate and the lipase, the milieu of the reaction has a decisive impact. For the prediction of lipase reactions in foods, further aspects such as the accessibility of substrates need to be taken into consideration.

Concentration polarization around polyelectrolyte-coated electrodes. Model and observations

An investigation on the phenomenon of concentration polarization (CP) in conducting porous particles is presented in this work, considering both bare and polyelectrolyte-coated particles. The conducting nature of the porous structure brings about the induction of a surface (and hence volume) charge distribution by the applied external field. The polymer charge (with its counterions from solution) is superimposed on this field-induced component. From the solution of Poisson’s equation, the concentration and potential profiles are evaluated, and from them, the concentration polarization can be calculated. The results are presented as concentration perturbation as a function of time after application of the field, both for bare and coated particles. Experiments are also performed aimed at measuring the CP using a solution of fluorescent dye (rhodamine B). From the increase or decrease of fluorescence, the concentration perturbations are observed around the particle. Importantly, depletion of concentration is observed on both sides of the particle when this is bare. In contrast, if the particles are coated, the classical pattern of a pole of increased concentration and an opposite one of decreased concentration is found. Dielectric dispersion experiments in suspensions of bare and brush-coated particles confirm this fact.

Achieving color-tunable persistent afterglow from ultralong polyacrylamide-based room-temperature phosphorescence materials through phosphorescence Förster resonance energy transfer

Polymer-based pure organic room-temperature phosphorescence (RTP) materials have received widespread attention due to their great application prospects in many fields. However, the reports about polymer-based multicolor RTP materials were still rare. Herein, a series of monochromatic PAM-based RTP materials are constructed by facilely doping boric acid derivatives into polyacrylamide (PAM) matrices. Due to the strong intermolecular hydrogen-bonding interaction, 4-carboxyphenylboronic acid (CPBA) doped system PAM/CPBA achieves an ultralong RTP lifetime of 753 ms with a naked-eye visible blue afterglow up to 12 s. Significantly, PAM/CPBA as energy donor and the commercial fluorescent dye fluorescein (FL) or rhodamine B (RhB) as energy acceptor are used to fabricated ternary doping systems to achieve multicolor afterglow emission through phosphorescence Förster resonance energy transfer (FRET). The afterglow colors of PAM/CPBA/FL and PAM/CPBA/RhB can be easily adjusted from blue to yellow or purple by changing the doping content of FL or RhB. Inspiringly, a nearly white afterglow emission from the quaternary doping system PAM/CPBA/RhB/FL is achieved by varying the amount of FL content. Furthermore, the prepared PAM-based binary and ternary doping RTP materials can be applied in the field of information encryption.

Leveraging the MMV Pathogen Box to Engineer an Antifungal Compound with Improved Efficacy and Selectivity against Candida auris.

Fungal infections pose a significant and increasing threat to human health, but the current arsenal of antifungal drugs is inadequate. We screened the Medicines for Malaria Venture (MMV) Pathogen Box for new antifungal agents against three of the most critical Candida species (Candida albicans, Candida auris, and Candida glabrata). Of the 14 identified hit compounds, most were active against C. albicans and C. auris. We selected the pyrazolo-pyrimidine MMV022478 for chemical modifications to build structure-activity relationships and study their antifungal properties. Two analogues, 7a and 8g, with distinct fluorine substitutions, greatly improved the efficacy against C. auris and inhibited fungal replication inside immune cells. Additionally, analogue 7a had improved selectivity toward fungal killing compared to mammalian cytotoxicity. Evolution experiments generating MMV022478-resistant isolates revealed a change in morphology from oblong to round cells. Most notably, the resistant isolates blocked the uptake of the fluorescent dye rhodamine 6G and showed reduced susceptibility toward fluconazole, indicative of structural changes in the yeast cell surface. In summary, our study identified a promising antifungal compound with activity against high-priority fungal pathogens. Additionally, we demonstrated how structure-activity relationship studies of known and publicly available compounds can expand the repertoire of molecules with antifungal efficacy and reduced cytotoxicity to drive the development of novel therapeutics.

Sulfonium-cation-containing aggregation-induced emission block copolymers: self-assembly, multicolor emission, and detection for DNA polyplexes

Amphiphilic aggregation-induced emission (AIE) polymers have emerged as highly attractive materials that exhibit the synergistic effect of functional polymeric self-assemblies with AIE luminogens. In this study, we design and synthesize block copolymers containing sulfonium cations and a hydrophobic tetraphenylethene (TPE) unit. These copolymers exhibit distinct self-assembly behaviors with AIE, polyplex formation with DNA, and tunable color emissions. Amphiphilic block copolymer PMTEAMe+Cl--b-PATPE, consisting of 4-(1,2,2-triphenylvinyl)phenyl acrylate (ATPE) and cationized 2-(methylthio)ethyl acrylate (MTEAMe+Cl-), was synthesized via reversible addition–fragmentation chain transfer polymerization, followed by cationization. Self-assembled structures containing TPE-aggregated cores and cationic PMTEAMe+Cl- shells and their emission behaviors were investigated. By introducing charged fluorescent dyes (Rose Bengal and Rhodamine B) into aqueous solutions of amphiphilic PMTEAMe+Cl--b-PATPE, we observed a shift in the emission color from blue to orange/red, which was attributed to the electrostatic interactions and fluorescence resonance energy transfer between the dyes and the copolymers. The emission color and intensity were also governed by polyplex formation between the negatively charged DNA and the positively charged sulfonium segments in the shell, depending on the charged states of the dyes. This system provides a method for efficient visual detection of DNA polyplex formation using multicolor fluorescent coding.

A Ratiometric Fluorescent Probe Based on RhB Functionalized Tb-MOFs for the Continuous Visual Detection of Fe3+ and AA.

In this study, a red-green dual-emitting fluorescent composite (RhB@MOFs) was constructed by introducing the red-emitting organic fluorescent dye rhodamine B (RhB) into metal-organic frameworks (Tb-MOFs). The sample can be used as a ratiometric fluorescent probe, which not only avoids errors caused by instrument and environmental instability but also has multiple applications in detection. The results indicated that the RhB@MOFs exhibited a turned-off response toward Fe3+ and a turned-on response for the continuous detection of ascorbic acid (AA). This ratiometric fluorescent probe possessed high sensitivity and excellent selectivity in the continuous determination of Fe3+ and AA. It is worth mentioning that remarkable fluorescence change could be clearly observed by the naked eye under a UV lamp, which is more convenient in applications. In addition, the mechanisms of Fe3+- and AA-induced fluorescence quench and recovery are discussed in detail. This ratiometric probe displayed outstanding recognition of heavy metal ions and biomolecules, providing potential applications for water quality monitoring and biomolecule determination.

Plug-and-Play Biointerfaces: Harnessing Host-Guest Interactions for Fabrication of Functional Polymeric Coatings.

Polymeric surface coatings capable of effectively integrating desired functional molecules and ligands are attractive for fabricating bio-interfaces necessary for various applications. Herein, we report the design of a polymeric platform amenable to such modifications in a modular fashion through host-guest chemistry. Copolymers containing adamantane (Ada) moieties, diethylene glycol (DEG) units, and silyloxy groups to provide functionalization handles, anti-biofouling character, and surface attachment, respectively, were synthesized. These copolymers were employed to modify silicon/glass surfaces to enable their functionalization using beta-cyclodextrin (βCD) containing functional molecules and bioactive ligands. Moreover, surface functionalization could be spatially controlled using a well-established technique like microcontact printing. Efficient and robust functionalization of polymer-coated surfaces was demonstrated by immobilizing a βCD-conjugated fluorescent rhodamine dye through the specific noncovalent binding between Ada and βCD units. Furthermore, biotin, mannose, and cell adhesive peptide-modified βCD were immobilized onto the Ada-containing polymer-coated surfaces to direct noncovalent conjugation of streptavidin, concanavalin A (ConA), and fibroblast cells, respectively. It was demonstrated that the mannose-functionalized coating could selectively bind to the target lectin ConA, and the interface could be regenerated and reused several times. Moreover, the polymeric coating was adaptable for cell attachment and proliferation upon noncovalent modification with cell-adhesive peptides. One can envision that the facile synthesis of the Ada-based copolymers, mild conditions for coating surfaces, and their effective transformation to various functional interfaces in a modular fashion offers an attractive approach to engineering functional interfaces for several biomedical applications.

Ionically cross-linked micro-sized hydrogels with encapsulated drug: Structure, cell uptake kinetics and cytotoxicity

Micro-sized hydrogels synthesized by electrostatic cross-linking of anionic alginate with Ca2+ cations were additionally loaded with cationic fluorescent dye Rhodamine 6B or cationic antitumor antibiotic doxorubicin. Forming complexes with Ca2+ alginate hydrogels, doxorubicin retained or even reduced its toxicity to tumor and normal cells. The results can be used to design containers for the encapsulation and delivery of drugs and control their interaction with cells.

Tunable ultralong multicolor and near-infrared emission from polyacrylic acid-based room temperature phosphorescence materials by FRET

Polymer-based room temperature phosphorescence (RTP) materials have received significant attention for their potential application in various fields. However, the development of polymer-based RTP materials with persistent multicolor and near-infrared (NIR) emission still faces great challenges. Herein, 4-carboxyphenylboronic acid (CPBA) is facilely doped into polyacrylic acid (PAA) matrix to construct an ultralong RTP material PAA-CPBA, which is the better candidate of energy donor owing to the wide phosphorescence emission band. Two commercial fluorescent dyes rhodamine B (RhB) and fluorescein (FL) are selected as energy acceptors to prepared ternary systems PAA-CPBA-RhB and PAA-CPBA-FL, and tunable multicolor afterglow from blue to red and yellow is realized through phosphorescence Förster resonance energy transfer (FRET). More interestingly, the quaternary doping system PAA-CPBA-RhB-FL exhibits a nearly white afterglow emission. Significantly, a commercial NIR dye Nile blue (NiB) is used to fabricate the other quaternary doping systems PAA-CPBA-RhB-NiB, and persistent luminescence in NIR region is successfully achieved via stepwise FRET using RhB as an intermediate acceptor. Furthermore, due to the different persistent luminescence performance, the multicolor PAA-based RTP materials are successfully applied in multiple information encryption and multicolor displays.

Internalization of PLGA nanoparticles coated with poloxamer 188 in glioma cells: A confocal laser scanning microscopy study

Internalization of poloxamer 188-coated PLGA nanoparticles (NPs) in GL261 murine glioma cells was studied using confocal laser scanning microscopy. For visualization, both poloxamer 188 (P188) and PLGA were labeled covalently with fluorescent dyes Rhodamine B and Cyanine5, respectively. The results indicated that the PLGA NPs coated with poloxamer 188 enter a cell as an integral core–shell structure, which can be helpful for gaining further insight into the in vivo performance of surfactant-coated polymeric NPs as core–shell delivery systems