Organic Dye Nanoparticles Research Articles

A Review of Organic Dye Based Nanoparticles: Preparation, Properties, and Engineering/Technical Applications

Abstract: Organic dye-based nanoparticles (ODNPs) are fabricated with desired morphologies using laser ablation, reprecipitation, ion association, and self-assembly methods. Primitively, this review introduces the theory of the molecular origins of dye aggregation, manifestations of the formations of monomer to J-dimer, H-dimer, and oblique dimer (mixed J and H dimer) in ODNPs. Although, organic dye nanoparticles have better basic properties than their monomer counterparts. These nanoparticles are suitable candidates for many engineering and technical applications. Furthermore, we have discussed OLEDs, optoelectronics, sensing, environmental, light-harvesting antennas, cryptography, and biomedical imaging applications. The conclusion made from the critical review analysis opens up a new horizon for the future development of ODNPs applications.

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.

Fabrication of ultrathin TiO2 film with nanogrooves to trap organic dye nanoparticles

Ultrathin TiO2 films were formed on the surface of commercially available DVD-R disks by a two-step sol–gel process, with nanogrooves on the lower surface transcribed from the DVD-R disk surface. Water suspension of organic dye nanoparticles (NPs) fabricated by laser processing of dye solution was spread over the TiO2 film, attaining a successful trap of luminescent dye NPs inside the transcribed nanogrooves, which will open up a new way of luminescent NP deposition with a predesigned pattern, in view of printing mass production of static image “digital signage devices.” For this application, all the NPs need to be placed between and in contact with two line electrodes. As a test pattern, we have tried to deposit silver nanowires (AgNWs) in parallel arrangement in the nanogrooves of TiO2 film by the doctor blade method.

Real-time imaging and tracking of ultrastable organic dye nanoparticles in living cells

Semiconductor quantum dots and upconversion nanoparticles have been broadly used for live cell imaging due to their color tunability and photostability etc. However, these inorganic materials often contain heavy metals and potentially have metabolism problems. To overcome these issues, herein, we report a type of organic dye nanoparticles (NPs) with coating of a thin silica layer and folic acid targeting molecules on the surface for live cell imaging. These organic NPs possess superior characteristics of high fluorescence intensity, large Stokes shift, good photostability, emission in the NIR range, and targeted delivery, enabling them to be a powerful fluorescent probe for living cell imaging. In our study, we successfully demonstrate their applications in investigating cell division, exploring the cellular uptake kinetics and pathway of NPs, observing the distribution of NPs, and live-time tracking the trajectory of specific NPs. Considering the excellent properties and unique clathrin- and caveollae-independent intracellular uptake pathway, we expect that this type of organic dye NPs will play an important role in live cell imaging.

A protein-dye hybrid system as a narrow range tunable intracellular pH sensor.

Accurate monitoring of pH variations inside cells is important for the early diagnosis of diseases such as cancer. Even though a variety of different pH sensors are available, construction of a custom-made sensor array for measuring minute variations in a narrow biological pH window, using easily available constituents, is a challenge. Here we report two-component hybrid sensors derived from a protein and organic dye nanoparticles whose sensitivity range can be tuned by choosing different ratios of the components, to monitor the minute pH variations in a given system. The dye interacts noncovalently with the protein at lower pH and covalently at higher pH, triggering two distinguishable fluorescent signals at 700 and 480 nm, respectively. The pH sensitivity region of the probe can be tuned for every unit of the pH window resulting in custom-made pH sensors. These narrow range tunable pH sensors have been used to monitor pH variations in HeLa cells using the fluorescence imaging technique.

Near-infrared fluorescence imaging using organic dye nanoparticles

Near-infrared (NIR) fluorescence imaging in the 700–1000 nm wavelength range has been very attractive for early detection of cancers. Conventional NIR dyes often suffer from limitation of low brightness due to self-quenching, insufficient photo- and bioenvironmental stability, and small Stokes shift. Herein, we present a strategy of using small-molecule organic dye nanoparticles (ONPs) to encapsulate NIR dyes to enable efficient fluorescence resonance energy transfer to obtain NIR probes with remarkably enhanced performance for in vitro and in vivo imaging. In our design, host ONPs are used as not only carriers to trap and stabilize NIR dyes, but also light-harvesting agent to transfer energy to NIR dyes to enhance their brightness. In comparison with pure NIR dyes, our organic dye nanoparticles possess almost 50-fold increased brightness, large Stokes shifts (∼250 nm) and dramatically enhanced photostability. With surface modification, these NIR-emissive organic nanoparticles have water-dispersity and size- and fluorescence- stability over pH values from 2 to 10 for almost 60 days. With these superior advantages, these NIR-emissive organic nanoparticles can be used for highly efficient folic-acid aided specific targeting in vivo and ex vivo cellular imaging. Finally, during in vivo imaging, the nanoparticles show negligible toxicity. Overall, the results clearly display a potential application of using the NIR-emissive organic nanoparticles for in vitro and in vivo imaging.

Water‐Dispersible, pH‐Stable and Highly‐Luminescent Organic Dye Nanoparticles with Amplified Emissions for In Vitro and In Vivo Bioimaging

A new strategy is presented for using doped small-molecule organic nanoparticles (NPs) to achieve high-performance fluorescent probes with strong brightness, large Stokes shifts and tunable emissions for in vitro and in vivo imaging. The host organic NPs are used not only as carriers to encapsulate different doped dyes, but also as fluorescence resonance energy transfer donors to couple with the doped dyes (as acceptors) to achieve multicolor luminescence with amplified emissions (AE). The resulting optimum green emitting NPs show high brightness with quantum yield (QY) of up to 45% and AE of 12 times; and the red emitting NPs show QY of 14% and AE of 10 times. These highly-luminescent doped NPs can be further surface modified with poly(maleic anhydride-alt-1-octadecene)-polyethylene glycol (C18PMH-PEG), endowing them with excellent water dispersibility and robust stability in various bio-environments covering wide pH values from 2 to 10. In this study, cytotoxicity studies and folic acid targeted cellular imaging of these multicolor probes are carried out to demonstrate their potential for in vitro imaging. On this basis, applications of the NP probes in in vivo and ex vivo imaging are also investigated. Intense fluorescent signals of the doped NPs are distinctly, selectively and spatially resolved in tumor sites with high sensitivity, due to the preferential accumulation of the NPs in tumor sites through the passive enhanced permeability and retention effect. The results clearly indicate that these doped NPs are promising fluorescent probes for biomedical applications.

Carrier-free, water dispersible and highly luminescent dye nanoparticles for targeted cell imaging

We develop a new strategy of using surface functionalized small molecule organic dye nanoparticles (NPs) for targeted cell imaging. Organic dye (2-tert-butyl-9,10-di(naphthalen-2-yl)anthracene, TBADN) was fabricated into NPs and this was followed by surface modification with an amphipathic surfactant poly(maleic anhydride-alt-1-octadecene)-polyethylene glycol (C18PMH-PEG) through hydrophobic interactions to achieve good water dispersibility and bio-environmental stability. It should be noted that no additional inert materials were added as carriers, thus the dye-loading capacity of the resulting TBADN NPs is obviously higher than those of previously reported carrier-based structures. This would lead to much larger absorption and then much higher brightness. The resulting TBADN NPs possess comparable, if not higher, brightness than CdSe/ZnS quantum dots under the same conditions, with favorable biocompatibility. Significantly, TBADN NPs are readily conjugated with folic acid, and successfully applied in targeted cell imaging. These results show that water dispersible and highly stable organic NPs would be a promising new class of fluorescent probe for bioapplications in cellular imaging and labeling. This strategy may be straightforwardly extended to other organic dyes to achieve water dispersible NPs for cell imaging and drug delivery.

脉冲能量密度和照射时间对激光消融制备有机染料纳米颗粒的影响

脉冲能量密度和照射时间对激光消融制备有机染料纳米颗粒的影响

Absorption, Luminescence, and Sizing of Organic Dye Nanoparticles and of Patterns Formed Upon Dewetting

Organic nanoparticles made of a push-pull triarylamine dye with an average diameter of 60 nm, were prepared by reprecipitation. We study their photophysical properties by a combination of photothermal and fluorescence microscopy. Photothermal contrast provides a quantitative measure of the number of absorbers. The size of nanoparticles estimated from the absorption measurements was compared with sizes measured by AFM. Fluorescence and absorption microscopy provide quantum yield on the single-particle level as a function of excitation intensity. The quantum yield strongly decreases at high intensities because of singlet-singlet or singlet-triplet annihilation. We also report the formation of molecular thin layers and of labyrinth-shaped structures on glass substrates, presumably induced by dewetting.

Organic Nanoparticles of Cyanine Dye in Aqueous Solution

Abstract Ion-based organic dye nanoparticles ranging from tens to hundreds of nanometers have been prepared in aqueous solution. The synthetic approach is based on “ion-association” (hydrophobic ion-pair formation) in water between the dye cation pseudoisocyanine (PIC) and the anion tetraphenylborate (TPB) or tetrakis(4-fluorophenyl)borate (TFPB) ion. Size tuning of spherical and amorphous PIC nanoparticles was accomplished by varying the molar ratio (ρ) of the loaded anion to the dye cation. Electrophoretic characterization revealed that the increase in surface adsorption of anions onto PIC particles brings about an increase in the negative surface charge density, causing a reduction in the surface tension and the mean size of nanoparticles. We found that the optical absorption properties of the PIC nanoparticles exhibited (i) matrix dependence, that is, the 0–0 band position of the PIC chromophore within similar-sized nanoparticles was dependent on the type of counter anions used, and (ii) size dependence, i.e., the 0–0 band position of the PIC chromophore was dependent on the mean nanoparticle diameter when the particles were prepared using the same counter anion.

Single Molecule Spectroscopy of Organic Dye Nanoparticles

Organic dye nanoparticles 1-13 nm in height and 10-45 nm in width were prepared by the reprecipitation method. With single-molecule/nanoparticle spectroscopy, two distinct types of nanoparticles were found: particles with blue emission and particles with red emission. The difference in spectral characteristics is attributed to the presence of two morphological types of particles in the samples. The presence of two types of nanoparticles in the samples was further corroborated by our ability to separate blue nanoparticles from red nanoparticles by centrifugation.

Preparation of Organic Dye Nanoparticles by Nanosecond Laser Ablation in a Poor Solvent

Microcrystalline powder of several dye compounds suspended in a poor solvent was converted into their nanoparticle dispersion by irradiating with the third harmonics of nanosecond Nd3+: YAG laser (355 nm, 7 ns, 10 Hz). The colored colloidal solutions were stable during more than 1 week without any surfactants. Dye nanoparticles with the mean size of about 50 nm were confirmed by SEM observation, and the mean size was almost the same for all compounds. The nanoparticle formation was analyzed by visible absorption measurement. The laser fluence dependence demonstrates that laser ablation of microcrystals is considered to be responsible to nanoaparticle formation. The mechanism is discussed in terms of the urtrafast photo-thermal conversion process and the subsequent fragmentation of microcrystal.