Two-photon excited fluorescence of silica nanoparticles loaded with a fluorene-based monomer and its cross-conjugated polymer: their application to cell imaging

Aparicio-Ixta, Laura; Ramos‐Ortíz, Gabriel; Pichardo‐Molina, J. L.; Maldonado, José Luis; Rodríguez, Mario; Tellez-Lopez, Víctor M.; Martínez‐Fong, Daniel; Zolotukhin, Mikhail G.; Fomine, Serguei; Menéses-Nava, M. A.; Barbosa-Garcı́a, Oracio

doi:10.1039/c2nr31925j

Cited by 35 publications

(23 citation statements)

References 43 publications

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“…By the use of these fluorescent based techniques, fluorescent emmission of nanoparticles and the subcellular location of nanoparticles have been determined. Two photon exitation techniques and NIR fluorophores can increase the penetration depths of the detection techniques [23][24][25][26] . Using fluorescent based techniques, it is also possible to observe physological processes within a cell.…”

Section: Intracellular Trafficking Of Nanoparticles Ros Production Amentioning

confidence: 99%

Determination of nanoparticle localisation within subcellular organelles in vitro using Raman spectroscopy

et al. 2015

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Ease of sample preparation, narrow spectral bandwidth and minimal influence from water are features of Raman spectroscopy which make it a powerful, label-free way to study a wide range of biological structures and phenomena. In this context, given the concerns over their toxicology arising from their increased production and use, evaluation of nanoparticle uptake and localisation in biological systems and determination of the mechanisms of subcellular interaction and trafficking can provide long-term solutions for nanotoxicology, and potential strategies for nanomedicine. In this study, Raman spectroscopy is explored to monitor the sequential trafficking of nanoparticles through subcellular organelles in-vitro and to establish the spectroscopic signatures of those organelles. A549 human lung carcinoma cells were exposed to 40 nm carboxylate-modified and fluorescently-labelled polystyrene nanoparticles for 4, 12 and 24hrs. Raman spectroscopy was applied to nanoparticle exposed cells to determine the localisation within cellular compartments. Confocal laser scanning fluorescence microscopy (CLSM) with different organelle staining kits confirmed the localisation of the nanoparticles in organelles at the chosen exposure periods and colocalization was quantified using ImageJ with the JACoP colocalisation plugin. To confirm nanoparticle localisation and elucidate the spectroscopic signatures of the different subcellular organelles, a combination of K-means clustering (KMCA) and Principal components analysis (PCA) was applied to the Raman spectroscopic maps. The study showed the applicability of the techniques for elucidation of the localisation of polystyrene nanoparticles within the cell as well as determination of their local environment, differentiating the spectral signatures of intracellular compartments such as endosomes, lysosomes and endoplasmic reticulum, in a completely label free manner.

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Section: Intracellular Trafficking Of Nanoparticles Ros Production Amentioning

confidence: 99%

Determination of nanoparticle localisation within subcellular organelles in vitro using Raman spectroscopy

et al. 2015

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“…Both the steady-state fluorescence (black circles) and electroluminescence (purple stars) curves show emission peaks of PF-1 in the green-yellow region with broad emission bands centered at 544 nm (FWHM of 80 nm) and 551 nm (FWHM of 90 nm), respectively. Fluorescence quantum yield in solution was determined to be close to one [31]. These results indicate that PF-1 is able to recombine excitons efficiently; therefore, it is interesting to study the potential of the material for applications such as PLEDs or lasing.…”

Section: Pledsmentioning

confidence: 91%

“…On the other hand, cross-conjugated compounds are relatively unexplored as active materials in optoelectronic or photonic devices; they can be found as quinones, radialenes, fulvalenes and fused aromatics [27]. Cross-conjugated systems have been implemented as PLEDs [28], nonlinear optical materials, and magnetic materials, and they also favor donoracceptor interactions [29][30][31][32]. When the cross-conjugated polymer chain is connected to a donor material, a strong intramolecular charge transfer is observed, leading to high fluorescence intensities [30].…”

Section: Introductionmentioning

confidence: 99%

“…When the cross-conjugated polymer chain is connected to a donor material, a strong intramolecular charge transfer is observed, leading to high fluorescence intensities [30]. Motivated by this emission property, our group had previously synthesized the fluorene crossconjugated polymer (PF-1), whose chemical structure is shown in Figure 1, and used this material to develop organic nanoparticles which exhibit very intense fluorescence induced by two-photon absorption in the wavelength range between 740 and 820 nm; these advantageous properties of nanoparticles of PF-1 were used to implement their use in multiphoton microscopy [31]. Likewise, we demonstrated coherent frequency conversion within the telecommunication wavelength band (1100-1600 nm) [32].…”

Section: Introductionmentioning

confidence: 99%

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Light Emission Properties of a Cross-Conjugated Fluorene Polymer: Demonstration of Its Use in Electro-Luminescence and Lasing Devices

et al. 2016

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Light emission properties of a fluorene cross-conjugated polymer (PF-1) based on the monomer 4,7-bis[2-(9,9-dimethyl)fluorenyl] benzo[1,2,5]thiadiazole are reported. This polymer exhibits solubility at high concentrations, good processability into thin solid films of good quality and a broad emission band with a fluorescence quantum yield of approximately 1. Based on these features, in this paper we implemented the use of PF-1 as an active layer in polymer light-emitting diodes (PLEDs) and as a laser gain medium in solution. To get insight on the conducting properties of PF-1, two different electron injectors, poly [(9,9-bis(3 1 -(N,N-dimethylamino) propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) and lithium fluoride (LiF), were used in a simple PLED architecture. PLEDs with the PFN film were found to exhibit better performance with a maximum luminous efficiency of 40 cd/A, a turn-on voltage (V on ) of approximately 4.5 V and a luminance maximum of 878 cd/m 2 at 5.5 V, with a current density of 20 A/m 2 . For the lasing properties of PF-1, we found a lasing threshold of around 75 µJ and a tunability of 20 nm. These values are comparable with those of rhodamine 6G, a well-known laser dye.

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“…Coupling to specifi c biomolecules Not reported Possible [53] Relatively easy bio-conjugation [34,54,55] Cell penetration Easy a) [21] Easy [56] More diffi cult without biomolecule [54] Toxicity Dependent on amount of surfactant and material a) [21] Dependent on amount of surfactant and fl uorophore [57] Very low [58,59] Nonlinear optical properties Not reported σ TPA ≈ 100-2000 GM [53,60] σ TPA ≈ 217-1200 GM [61] …”

Section: Structurementioning

confidence: 95%

Two‐Photon Imaging of a Cellular Line Using Organic Fluorescent Nanoparticles Synthesized by Laser Ablation

Aparicio-Ixta

Alba-Rosales

Ramos‐Ortíz

et al. 2016

Part & Part Syst Charact

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A comparative study of the optical properties of organic fl uorescent nanoparticles fabricated by laser ablation (NPs-LA), reprecipitation (NPs-RP), and microemulsion (NPs-ME) methods is presented. These nanoparticles contain a fl uorene-based p-conjugated molecule (BT2). Distinctive electronic transitions are observed in samples due to the specifi c way in which the molecule BT2 is assembled in each type of nanoparticles; for instance, transitions involved in absorption and emission spectra of NPs-LA result in blueshifting with respect to the molecular solution of BT2, whereas redshifting is observed in NPs-RP and NPs-ME. Further, the results show that under infrared excitation, the aqueous suspensions of NPs-LA exhibit the highest fl uorescence induced by two-photon absorption (≈790 GM at 740 nm), as well as the best photostability, compared with aqueous suspensions of NPs-RP and NPs-ME. The nanoparticles synthetized by the three aforementioned methods are employed as exogenous agents for the visualization of human cervical cancer cell line (HeLa) using confocal and two-photon microscopy. Under similar experimental conditions, it is found that microscopy images of the best quality are obtained with NPs-LA. These results show that laser ablation is a suitable technique for the fabrication of organic fl uorescent nanoparticles used as contrast agents for in vitro fl uorescence microscopy.O-NPs have been successfully exploited as contrast agents (fl uorescent markers) for in vitro and in vivo studies in cellular lines and organisms, [ 5 ] medical imaging, [ 6 ] diagnostic purposes, [ 7 ] and positive confi rmation of the site-specifi c delivery of a drug with the goal of obtaining effective treatment of diseases. [ 8,9 ] Some advantages obtained by using organic nanostructures are: i) stability of fl uorescent organic materials in aqueous suspensions, ii) reduced toxicity, iii) decreased degradation, and iv) selectivity toward specifi c targets.Simple and versatile strategies of fabrication have been used to obtain O-NPs with different morphologies and optical properties in aqueous media. Reprecipitation (RP), [ 10 ] self-assembly, [ 11 ] ion-association, [ 12 ] condensation, [ 13 ] microemulsion (ME), [ 14 ] and laser ablation (LA) [ 15 ] are some methods used to fabricate O-NPs. For the preparation of O-NPs comprising luminescent properties, the most commonly employed methods are RP and ME. [ 16,17 ] LA has also been used to obtain fl uorescent O-NPs, [18][19][20] and some basic characterization of their optical properties has been performed, but to the best of our knowledge, demonstration of their use in the context of biophotonic applications, i.e., imaging of biological samples, has

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Two-photon excited fluorescence of silica nanoparticles loaded with a fluorene-based monomer and its cross-conjugated polymer: their application to cell imaging

Cited by 35 publications

References 43 publications

Determination of nanoparticle localisation within subcellular organelles in vitro using Raman spectroscopy

Determination of nanoparticle localisation within subcellular organelles in vitro using Raman spectroscopy

Light Emission Properties of a Cross-Conjugated Fluorene Polymer: Demonstration of Its Use in Electro-Luminescence and Lasing Devices

Two‐Photon Imaging of a Cellular Line Using Organic Fluorescent Nanoparticles Synthesized by Laser Ablation

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