Dye Nanoparticles Research Articles

Control of the fluorescence lifetime in dye based nanoparticles.

Fluorescent dye based nanoparticles (NPs) have received increased interest due to their high brightness and stability. In fluorescence microscopy and assays, high signal to background ratios and multiple channels of detection are highly coveted. To this end, time-resolved imaging offers suppression of background and temporal separation of spectrally overlapping signals. Although dye based NPs and time-resolved imaging are widely used individually, the combination of the two is uncommon. This is likely due to that dye based NPs in general display shortened and non-mono-exponential lifetimes. The lower quality of the lifetime signal from dyes in NPs is caused by aggregation caused quenching (ACQ) and energy migration to dark states in NPs. Here, we report a solution to this problem by the use of the small-molecule ionic isolation lattices (SMILES) concept to prevent ACQ. Additionally, incorporation of FRET pairs of dyes locks the exciton on the FRET acceptor providing control of the fluorescence lifetime. We demonstrate how SMILES NPs with a few percent rhodamine and diazaoxatriangulenium FRET acceptors imbedded with a cyanine donor dye give identical emission spectra and high quantum yields but very different fluorescence lifetimes of 3 ns and 26 ns, respectively. The two spectrally identical NPs are easily distinguished at the single particle level in fluorescence lifetime imaging. The doping approach for dye based NPs provides predictable fluorescence lifetimes and allows for these bright imaging reagents to be used in time-resolved imaging detection modalities.

Production of dye nanoparticles via a supercritical gas anti‐solvent process and optimisation of the process conditions

AbstractNanoparticles of dyes and pigments with high quality and efficiency can be successfully used in the supercritical dyeing process of the textile industries, which is introduced as a waterless and greener dyeing method. In this study, nanoparticles of the Quinoline yellow dye, known as colour index (CI) Solvent Yellow 33, were precipitated via the supercritical gas anti‐solvent (GAS) process. This process was performed at various pressures (100, 130, and 150 bar), temperatures (308, 318, and 328 K), and solute concentrations (10, 30, and 50 mg/ml), designed by the Box–Behnken design (BBD) method. It was found that increasing the pressure, reducing the temperature, and reducing the initial concentration of the liquid solution provided favourable conditions for the production of nano‐sized particles with narrow size distribution and uniform morphology. Accordingly, the optimum operating conditions of the GAS process which resulted in precipitation of the dye nanoparticles, with a mean particle size of 125 nm, were determined at a temperature of 318 K, pressure of 150 bar, and the initial concentration of 10 mg/ml. The characteristics of the precipitated particles were analysed with high‐performance liquid chromatography (HPLC), field‐emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), dynamic light scattering (DLS), and Fourier‐transform infrared (FTIR) spectrometry analysis. Based on the DSC and XRD results, GAS processed samples have lower crystallinity and lower particle size. Also, nano‐metric size and narrow size distribution of the precipitated dye particles were confirmed through the FESEM and DLS results.

Development of a dye nanoparticle-loaded test strip for the Zn(II) determination in metal plating wastes.

Zincon/Latex-NR3+ nanocomposite-loaded dye nanoparticle coated test strip (Zincon/Latex-NR3+ DNTS) was fabricated to detect Zn(II) in plating wastewater by a unique color change from red-purple to deep blue and evaluated its detection performance in actual plating samples. The 5 × 5mm square-cut DNTS attached sticks were immersed into 10mL aliquots of aqueous solutions containing Zn(II) ion and 0.01M TAPS buffer at pH 8.4 with stirring at 250rpm for 60min. The calibration curve for Zn(II) was prepared based on the integrated area intensity of reflectance by TLC at 620nm with the 3σ detection limit was 48.61ppb, and the quantitative range was approximately up to 1000ppb. Although Cu(II), Mn(II), Ni(II), and Co(II) showed competitive interference due to complex formation with Zincon, a mixture of masking reagent including thiourea, 2-aminoethanthiol, and o-phenanthroline was effective in removing the contamination. To eliminate Cr(III) interference based on the incorporation of Zn(II) into Cr(III) hydrolyzed polymer, adding KBrO3 and H2SO4 under boiling for several minutes was required. With appropriate pretreatment, all results of actual plating water samples by Zincon/LatexNR3+ DNTS were close to those of ICP-OES.

Insights into the Biocompatibility and Biological Potential of a Chitosan Nanoencapsulated Textile Dye.

Traditionally synthetic textile dyes are hazardous and toxic compounds devoid of any biological activity. As nanoencapsulation of yellow everzol textile dye with chitosan has been shown to produce biocompatible nanoparticles which were still capable of dyeing textiles, this work aims to further characterize the biocompatibility of yellow everzol nanoparticles (NPs) and to ascertain if the produced nanoencapsulated dyes possess any biological activity against various skin pathogens in vitro assays and in a cell infection model. The results showed that the NPs had no deleterious effects on the HaCat cells' metabolism and cell wall, contrary to the high toxicity of the dye. The biological activity evaluation showed that NPs had a significant antimicrobial activity, with low MICs (0.5-2 mg/mL) and MBCs (1-3 mg/mL) being registered. Additionally, NPs inhibited biofilm formation of all tested microorganisms (inhibitions between 30 and 87%) and biofilm quorum sensing. Lastly, the dye NPs were effective in managing MRSA infection of HaCat cells as they significantly reduced intracellular and extracellular bacterial counts.

Coemissive luminescent nanoparticles combining aggregation-induced emission and quenching dyes prepared in continuous flow

Achieving an ideal light-harvesting system at a low cost remains a challenge. Herein, we report the synthesis of a hybrid dye system based on tetraphenylene (TPE) encapsulated organic dyes in a continuous flow microreactor. The composite dye nanoparticles (NPs) are synthesized based on supramolecular self-assembly to achieve the co-emission of aggregation-induced emission dyes and aggregation-caused quenching dyes (CEAA). Numerical simulations and molecular spectroscopy were used to investigate the synthesis mechanism of the CEAA dyes. Nanoparticles of CEAA dyes provide a platform for efficient cascade Förster resonance energy transfer (FRET). Composite dye nanoparticles of TPE and Nile red (NiR) are synthesized for an ideal light-harvesting system using coumarin 6 (C-6) as an energy intermediate. The light-harvesting system has a considerable red-shift distance (~126 nm), high energy-transfer efficiency (ΦET) of 99.37%, and an antenna effect of 26.23. Finally, the versatility of the preparation method and the diversity of CEAA dyes are demonstrated.

J-aggregates albumin-based NIR-II fluorescent dye nanoparticles for cancer phototheranostics.

Phototheranostics, relying on energy conversions of fluorophores upon excitation, integrating diagnostic fluorescence imaging and photo-driven therapy, represents a promising strategy for cancer precision medicine. Compared with the first near-infrared biological window (NIR-I), fluorophores imaged in the second window (NIR-II, 1000–1700 ​nm) exhibit a higher temporal and spatial resolution and tissue penetration depth. Polymethine cyanine-based dye IR1061 is a typical NIR-II small-molecule organic fluorophore, but its low water solubility and short circulation time limiting its biological applications. Therefore, human serum albumin (HSA) nanoparticles with great biocompatibility and biosafety were employed to fabricate hydrophobic IR1061, which exhibited red-shifted absorption band as typical for J-aggregates. Moreover, IR1061@HSA nanoparticles can be successfully used for NIR-II imaging to noninvasively visualize the tumor vascular networks, as well as real-time intraoperative image-guided tumor resection. Interestingly, benefiting from the high photothermal conversion efficiency brought by J-aggregates, IR1061@HSA nanoparticles were also explored for photothermal therapy (PTT) and cause efficient thermal ablation of tumors. Overall, IR1061@HSA, as a novel J-aggregates albumin-based NIR II dye nanoparticle with high biocompatibility, provides an integrated versatile platform for cancer phototheranostics with promising clinical translation prospects.

Novel green printing of cotton, wool and polyester fabrics with natural madder dye nanoparticles

In this study, madder dye nanoparticles have been successfully prepared by using a simple ball milling technique. Madder dye nanoparticles are characterized by using UV-vis. absorption, XRD, TEM, FTIR spectroscopy and SEM. The prepared madder dye nanoparticles are used as an active ingredient for printing cotton, wool, and polyester fabrics via dye printing technique and pigment printing technique. Factors of printing process, such as substrates mordanting, thickeners type, urea concentration and p H of printing paste, urea concentration of first paste and binder concentration of second paste, are studied. Results show that fabrics printed with madder dye nanoparticles via mentioned two methods show very good to excellent fastness properties with a full green method. These data indicate that printed samples have high quality for colour strength without any environmental hazards as compared to other conventual and nanotechnological aspects.

Synthesis, structure and photochemical properties of asymmetric NMe2-bearing aza-BODIPYs as novel photothermal agents

Using 1-(4-(dimethylamino)phenyl)ethanone, a series of asymmetric aza-BODIPYs carrying the dimethylamino (–NMe2) group were successfully prepared (Scheme 1). The solid-state structure of trifluoromethyl substituted aza-BODIPY (CF3-BDP) was confirmed by X-ray crystallographic analysis, and the boron atom in the center showed a slightly distorted sp3 hybridization. The maxima absorption of aza-BODIPYs with the –NMe2 group were found to locate in the range of 740–780 nm. Their molar extinction coefficients are high, but the fluorescence quantum yields are very low, mainly due to the intramolecular charge transfer (ICT) effect from the −NMe2 group to aza-BODIPY scaffold. The singlet oxygen yields of CF3-BDP was calculated to be 0.053 and slightly higher than that (ΦΔ = 0.02) of tetraphenyl aza-BODIPY. In order to improve water-solubility and biocompatibility, we prepared dye nanoparticles by self-assembly. Based on the photothermal properties of CF3-BDP nanoparticles (NPs), methoxy substituted aza-BODIPY (OMe-BDP) NPs and ring-fused substituted aza-BODIPY (OMeR-BDP) NPs, the photothermal conversion efficiencies of CF3-BDP NPs, OMe-BDP NPs and OMeR-BDP NPs were calculated to be 49%, 49% and 50%, which are comparable to those (35–50.5%) of the reported aza-BODIPY-based photothermal agents (PTAs). CF3-BDP NPs could efficiently kill cancer cells through the photothermal effect by near-infrared laser irradiation, and CF3-BDP NPs are highly desirable for the photothermal therapy.

Theranostic Squalene-NIR Dye Nanoparticles with Photodynamic/Photothermal and Mitochondria Targeting Properties

Theranostic Squalene-NIR Dye Nanoparticles with Photodynamic/Photothermal and Mitochondria Targeting Properties

Multifunctional performance of printed protein fabrics using natural madder dye and silver nanoparticles

Multifunctional performance of printed protein fabrics using natural madder dye and silver nanoparticles

Effects of two different solvents on Schottky barrier of organic device

In this paper, the effects of two different solvents on the Schottky barrier of ITO/ blend of methyl red dye—fullerene nanoparticles/Al - M electrode have been studied. We have taken chlorobenzene solvent and toluene solvent. Three different devices have been made by taking three different weight ratios of the dye—nanoparticles blend which is 1:1, 1:2, and 2:1. The estimation of the interfacial Schottky barrier at the junction of metal-organic dye is estimated using the device’s dark I—V plot. Interfacial Schottky barrier at the metal-organic junction is least for 2:1 weight ratio of dye - nanoparticle blend in chlorobenzene solvent but for toluene solvent, the Schottky barrier is least for 1:2 weight ratio of dye—nanoparticle blend. The lowering of barrier height at 2:1 and 1:2 ratios in Schottky barrier contacts prepared with chlorobenzene and toluene solvents can be attributed to the filling up of traps at the metal-organic layer interface. The Norde method is also used to check the consistency of the obtained value of the Schottky barrier measured from I—V plots. Reduction in Schottky barrier results in improved current injection process at the metal-organic interface.

Graphene/fluorescein dye-based sensor for detecting As(III) in drinking water

A complex of reduced graphene oxide (rGO) and fluorescein (FL) dye nanoparticles of size between 50 and 100 nm has been prepared and its sensing performance for detection of As(III) in drinking water has been reported. When As(III) binds to the rGO–FL nanoparticles the relative quenching of fluorescence was increased with increase in As(III) concentration thus provide two linear calibration ranges (0–4.0 mmol L−1 and 4.0–10 mmol L−1). The fluorescence quenching mechanism was investigated by using time-resolved fluorescence spectroscopy and molecular modeling. The detection limit of this sensor has been determined as equal to 0.96 µg L−1 which is about 10 times lower than the WHO stipulated standard for As(III) in drinking water (10 µg L−1). The analytical performance and potential application of the nanosensor was compared to commercial field kits used in arsenic monitoring. The sensor proposed in this study is fast, sensitive and accurate for detection of As(III) in drinking water and environmental samples.

Printing Wool Fabrics with Natural Dyes Curcuma and Alkanet (A Critique)

Green printing of wool textiles utilizing green print Paste with natural alkanet dye nanoparticles. The ball-milling technique provides an effective way of generating alkanet-nano particles dye at room temperature and pressure in one step. In this research, we study the effect of alkanet alone and Curcuma dye alone on wool fabric in natural size and nano size and comparing among them. studying K/s of the samples and the properties of fastness. we study the ball milling method to get nanoparticles of alkanet dye. we study the effect of mordants that are attached to fibers before or post-printing of wool fabrics. Regardless of the textile used, nano samples have a K/S value greater than the basic samples. Nano-Curcuma can be replaced for alum mordant with normal Curcuma. K/S values of pre-mordant gained values that were above the simultaneous mordant, regardless of the fabric or size of dye or the quantities of Curcuma in the usage of tannic acid mordant.

Development of a Layered Dye Nanoparticle-coated Test Strip for On-site Analysis of Manganese Aerosol

We propose an advanced test strip for the on-site analysis of manganese aerosol fine particles in a working environment based on two important functions of particle dissolution and Mn2+ detection. Initially, a thin layer of several hundred nanometers composed of 2-(3,5-diBromo-2-pyridylazo)-5-diethylaminophenol (3,5-diBr-PADAP) dye nanoparticles for the color detection of Mn2+ was prepared on the top surface of a fine membrane filter by the filtration of 3,5-diBr-PADAP nanoparticle dispersion. Next, 3 wt% gelatin gel containing 0.05 mol L−1 borax was impregnated over the entire membrane to keep the pH of 3,5-diBr-PADAP thin layer ca. 9.5. Finally, an acidic and a reductive gel layer of ca. 40 μm in thickness containing 5 wt% gelatin and 0.1 mol L−1 L-ascorbic acid was applied for coating over the 3,5-diBr-PADAP layer in order to dissolve manganese oxide particles and to produce Mn2+. The resulting layered test strip was applied for detecting fine manganese particles. Since manganese aerosol is not replicable, a mixture of ca. 1 μm of Mn3O4 particles and ca. 2.3 μm of AlOOH was applied for evaluating the test strip by being contacted with each other. The color of the test strip changed from orange to purple with an increase of the Mn3O4 percentage. A calibration curve by using the b* of the L*a*b* color space exponentially decreased, and it was expressed as b* = 2.28 + 47.8exp(–4.60[Mn]) (r2 = 0.977) with the 3σ detection limit of 0.02 μg cm−2 (n = 5) and the quantification range of 0.08∼1.2 μg cm−2. The successful determination of manganese particle was concluded that the ion transport flow of Mn2+ works well in the reductive gel layer, in the dye layer, and between them during the color detection.

Novel green printing of cotton, wool and polyester fabrics with natural safflower dye nanoparticles

Hiren safflower dye nanoparticles were successfully prepared by using simple ball milling technique at room temperature. UV-vis. absorption, XRD, TEM, FT-IR spectroscopy and SEM were used to characterize safflower dye nanoparticles. The prepared safflower dye nanoparticles were used as active ingredient for printing cotton, wool and polyester fabrics via dye printing technique and pigment printing technique. Factors of printing process were studied such as Mordanting of Substrates, thickeners type, urea concentration and Printing Paste pH for first paste and urea concentration, Printing Paste pH and binder concentration for second paste. Results shows fabrics printed with safflower dye nanoparticles via mentioned two methods shows very good to excellent fastness properties with full green method. These data indicated that printed samples have high quality for colour strength without any environmental hazards compared with other conventual and nanotechnological aspects.

Investigation of nonlinear optical properties of Eosin-B nanoparticles painted ‎

In this study the nonlinear optical properties of Eosin-B dye nanoparticles were studied using the ‎scanning-fluorescence spectrophotometer and fluorometer method. The nano water droplet in the ‎oil medium is prepared by a combination of hexane and surfactant water, which is painted inside ‎the drop by Eosin-B. The droplet size was studied on a nonlinear refractive index using a 532 nm ‎laser with a scanning power of 80 mW. The results show that the surface effects on the nano-‎droplets cause the droplets to have a larger nonlinear refractive index. This change was due to a ‎decrease in the accumulation of dyes inside the droplet as well as a decrease in the polarity of the ‎drop solvent relative to the water solvent.

Microcavity-Enhanced Fluorescence Energy Transfer from Quantum Dot Excited Whispering Gallery Modes to Acceptor Dye Nanoparticles.

Whispering gallery mode (WGM) microcavities are emerging as potential candidates in the field of biosensing applications, as their resonance wavelengths shift with changes in the refractive index in the region of their evanescent field. Their high-quality resonance modes and accessible surface functionalities make them promising for molecular assays, but their high sensitivity makes them inherently unstable. Here, we demonstrate that WGM resonances also strongly enhance fluorescence energy transfer between donors placed inside the microcavity and acceptors placed outside. We load colloidal quantum dots (QDs) into polymeric microspheres to provide WGMs that benefit from the QD optical features when used as energy-transfer donors. Spectroscopic analysis of the emission from the microcavities shows that the high quality of WGMs enables a very efficient energy transfer to dye-loaded polymer nanoparticle acceptors placed in their vicinity. Compared to Förster resonance energy transfer, WGM-enabled energy transfer (WGET) occurs over a much more extended volume, thanks to the delocalization of the mode over a typically 105 times larger surface and to the extension of the WGM electromagnetic field to larger distances (>100 nm vs a few nm) from the surface of the microcavity. The resulting sensing scheme combines the sensitivity of WGM spectroscopy with the specificity and simple detection schemes of fluorescence energy transfer, thus providing a potentially powerful class of biosensors.

Aggregation-based fluorescence amplification strategy: "turn-on" sensing of aminoglycosides using near-IR carbocyanine dyes and pre-micellar surfactants.

This study is aimed at developing sensing schemes without obtaining selective receptors. A series of simple carbocyanine dyes was synthesized, whose emission was quenched in water with formation of nanoparticles in the range of 20-100nm. Fluorescence in near-IR region is "turned on" in the presence of a drug cation of middle molecular weight (400-700Da) and sodium dodecyl sulfate (SDS), as well as anionic drugs and a cationic surfactant (cetyltrimethylammonium bromide, CTAB). Aggregates (clusters) up to 100-200nm in size were detected using dynamic light scattering (DLS) and Rayleigh light scattering (RLS) techniques in the systems: cationic analyte-SDS, carbocyanine dye-CTAB, and in all brightly fluorescent ternary systems dye-surfactant-analyte. Small ions (<200Da) incapable of multi-point binding do not form the aggregates or cause the emission enhancement. The "turn-on" signal is only observed at the surfactant submicellar concentrations insufficient to solubilize the dye nanoparticles. Based on these findings, we suggest a rapid and simple method for the detection of ≥4·10-5mol/L of neomycin in urine. The proposed strategy paves the way for developing more selective methods.

Preparation of Aqueous Nanodispersions of Disperse Dye by High‐Gravity Technology and Spray Drying

AbstractDisperse dyes are poorly water‐soluble and difficult to stably disperse in an aqueous medium, which greatly limits their application in dyeing synthetic fibers. Micronization can solve this problem. Herein, a facile way to prepare stable aqueous nanodispersions of disperse dye (C.I. disperse yellow 54) is presented by combining high‐gravity antisolvent precipitation in a rotating packed bed (RPB) with spray drying. The as‐prepared product had an average particle size of 120 nm, which could be readily redispersed in water. Compared with raw dye, the wettability and dispersibility of disperse dye nanoparticles were remarkably improved. Furthermore, the dyeing properties of the nanodispersions were obviously better than those of the commercial dye, which was micronized by ball milling.

Organic Dye Nanoparticles with a Special D-π-A Structure for Photoacoustic Imaging and Photothermal Therapy.

FTC dye with a D-π-A structure showed outstanding stability, high extinction coefficient, and good photothermal performance. Thus, nanoparticles based on FTC dye were first fabricated by a nanoprecipitation method for photothermal therapy (PTT) which was guided by photoacoustic imaging (PAI). The prepared FTC NPs showed a photothermal conversion efficiency of ∼52.71%, good photoacoustic performance, and excellent stability in in vitro experiments. Moreover, FTC NPs showed good performance in tumor ablation under a 635 nm laser irradiation and low cytotoxicity to the mice model without laser treatment. Histopathological analysis further confirmed that FTC NPs did not harm the major organs of mice. Given the abovementioned features, FTC NPs have great potential to be effective phototheranostic materials for PAI and PTT.