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Dendrimeric nanoparticles for two-photon photodynamic therapy and imaging: synthesis, photophysical properties and cytotoxicity under two-photon irradiation in the NIR
摘要： The synthesis and the photophysical properties of a new class of fully organic monodisperse nanoparticles for combined two-photon imaging and photodynamic therapy are described. The design of such nanoparticle is based on the covalent immobilization of a dedicated quadrupolar dye - which combine large two-photon absorbing (2PA) properties, fluorescence and singlet oxygen generation ability - in a phosphorous-based dendrimeric architecture. Firstly, a bifunctional quadrupolar dye bearing two different grafting moieties, a phenol function and an aldehyde function, was synthesized. It was then covalently grafted through its phenol function to a phosphorus-based dendrimer scaffold of generation 1. The remaining aldehyde functions were then used to carry on the dendrimer synthesis up to generation 2 introducing finally at its periphery 24 water-solubilizing triethyleneglycol chains. A dendrimer confining 12 photoactive quadrupolar units in its inner scaffold and showing water solubility was thus obtained. Interestingly, the G1 and G2 dendrimers retain some fluorescence as well as significant singlet oxygen production efficiencies while they were found to show very high 2PA cross-sections in a broad range of the NIR biological spectral window. Hydrophilic dendrimer G2 was tested in vitro on breast cancer cells, first in one- and two-photon microscopy, which allowed for visualization of their cell internalization, then in two-photon photodynamic therapy. While being non-toxic in the dark and, more importantly, under daylight exposition, dendrimer G2 proved to be very efficient cell death inducer only under two-photon irradiation in the NIR.
关键词： photophysics,photodynamic therapy,dendrimers,imaging,fluorescence
更新于2025-09-23 15:23:52
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Silver Nanostructures on Graphene Oxide as the Substrate for Surface-Enhanced Raman Scattering (SERS)
摘要： Nanosized surface-enhanced Raman scattering (SERS) substrates fabricated by the controlled growth of metal nanostructures on water-dispersed two-dimensional nanomaterials can open a new avenue for SERS analysis of liquid samples in biological fields. In this work, regular and uniform Ag nanostructures were grown on the surface of graphene oxide (GO) through a microwave-assisted hydrothermal method. Polyamidoamine (PAMAM) dendrimers were assembled on the surface of GO to form GO/PAMAM templates for growing Ag nanostructures, which are primarily comprised of Ag dimers and trimers. The prepared Ag/GO nanocomposites are highly dispersed and stable in aqueous solution and may be used as substrates for enhanced Raman detection of rhodamine 6 G (R6G) in aqueous solution. This special substrate provides high-performance SERS and suppresses R6G fluorescence in aqueous solution and is promising as a nanosized material for the enhanced Raman detection of liquid samples in biological diagnostics.
关键词： graphene oxide (GO),Surface-enhanced Raman scattering (SERS),polyamidoamine (PAMAM) dendrimers,transmission electron microscopy (TEM),Fourier transform infrared (FTIR) spectroscopy,rhodamine 6G (R6G)
更新于2025-09-23 15:23:52
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A Spirobixanthene‐Based Dendrimeric Hole‐Transporting Material for Perovskite Solar Cells
摘要： A dendrimer based on a spirobixanthene core, termed DH1, is designed and synthesized as a hole-transporting material (HTM) for perovskite solar cells (PSCs). DH1 showing a hyperbranched structure with methoxydiphenylamine carbazole dendrons stretching outward along the para-phenylene spacer acquires a large molecular size of up to 1.9 nm, which favors good thermal stability and amorphous property. The thus obtained DH1-based pinhole-free film as a hole-transport layer results in a power conversion efficiency of 17.13% and reduced hysteresis behavior of MAPbI3-based planar PSCs. This work provides the first example of the use of dendrimer-type HTM for PSC application, demonstrating a promising approach to design HTMs in a quasiglobular dendrimer with a large molecular size.
关键词： dendrimers,spirobixanthene,perovskite solar cells,hole-transporting materials
更新于2025-09-19 17:13:59
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Solution-Processible Blue Fluorescent Dendrimers with Carbazole/Diphenylamine Hybrid Dendrons for Power-Efficient Organic Light-Emitting Diodes
摘要： Two blue ?uorescent dendrimers named PVAC2 and PVACA have been newly synthesized and investigated, where the carbazole/diphenylamine hybrid dendron is adopted instead of oligocarbazole. Compared with the reference dendrimer PVCt3, the emission maxima of PVAC2 and PVACA are found to be red-shifted accompanied by a slight reduction of the photoluminescence quantum yield in ?lms. Most importantly, the highest occupied molecular orbital level is elevated from ?5.35 eV of PVCt3 to ?5.20 eV of PVAC2 and ?4.95 eV of PVACA. Because of the favored hole injection, the turn-on voltage is accordingly decreased from 3.6 to 3.2 and 2.6 V. The value of PVACA is even lower than the theoretical limit of 2.78 V. In addition, PVAC2 exhibited the best nondoped device performance, showing a nearly doubled power e?ciency of 4.80 lm/W relative to PVCt3 (2.37 lm/W). The results clearly indicate that dendron engineering is also a promising strategy to develop solution-processible blue ?uorescent dendrimers capable of being used for power-e?cient organic light-emitting diodes.
关键词： solution-processible,blue fluorescent dendrimers,power-efficient organic light-emitting diodes,carbazole/diphenylamine hybrid dendron
更新于2025-09-12 10:27:22
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Self‐Assembled Polyamidoamine Dendrimer on Poly (methyl meth‐ acrylate) for Plasmonic Fiber Optic Sensors
摘要： We report a novel one-step polyamidoamine (PAMAM) dendrimer based polymethyl methacrylate (PMMA) surface functionalization strategy for the development of polymeric optical (POF) based plasmonic sensors utilizing gold nanoparticles (AuNP). Simple contact angle measurements over PMMA sheets reveal the ability of the dendrimers to strongly bind to PMMA surface without additional acid/alkali pretreatment, unlike the conventional hexamethylene diamine (HMDA) based surface modification. Subsequently, U-bent POF probes with high evanescent wave absorbance sensitivity were exploited for relative quantification of the surface amine groups using fluorescein isothiocyanate (FITC) binding and efficient chemisorption of gold nanoparticles (AuNP) in order to identify the optimum conditions viz. dendrimer concentration, incubation time and dendrimer generation. While FITC binding showed a proportional increase in amine functional density with PAMAM concentration and time, interestingly the AuNP (40 nm) binding studies revealed the formation of loose PAMAM multilayers and their desorption. PAMAM (G4) concentration as low as 5 mM and incubation time of 24 h provide faster binding rate with densely packed AuNP and the RI sensitivity of ~ 15 (A546 nm/RIU). This simpler and inexpensive strategy could also be exploited for the development of functional PMMA substrates for various applications including nanotechnology, bio-imaging, drug delivery and analytical separations.
关键词： gold nanoparticles (AuNP),dendrimers,plasmonic sensors,polymethyl methacrylate (PMMA),polymeric optical fibers (POF),evanescent wave absorbance
更新于2025-09-11 14:15:04
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Synthesis and Photophysical Properties of a Series of Novel Porphyrin Dendrimers Containing Organoiron Complexes
摘要： This article is focused on the design and photophysical properties of a series of novel porphyrin and metalloporphyrin dendrimers containing cationic η6-chloroarene-η5-cyclopentadienyliron(II) complexes functionalized with naphthalene and capped with ferrocene. The incorporation of cationic η6-chloroarene-η5-cyclopentadienyliron moieties into the dendrimer structures enhances solubility, and facilitates nucleophilic aromatic substitution and addition reactions due to the intense electron-withdrawing ability of the iron center. Divergent approaches were employed to yield highly symmetrical branched materials, with interesting and potentially useful properties. The preparation of these dendrimers was achieved via metal-mediated nucleophilic aromatic substitutions and Steglich esterifications. These dendrimers and their precursors were characterized through nuclear magnetic resonance spectroscopy, infrared spectroscopy, and UV–Visible and fluorescence spectroscopy. Substitution on the porphyrin core with various side chains and terminal functional groups and chromophores had little impact on the porphyrin emission properties, allowing for a wide variety of fluorescent macromolecules to be prepared which retain this characteristic emission. Also, the presence or absence of the organopyrene moieties also had little effect on the emission from these compounds. Complexation of a metal cation, such as Zn2+, by these compounds, did however result in a significant blue shift in the observed fluorescence; this interesting result has the potential for applications in the development of fluorescent-based cation sensors.
关键词： Dendrimers,Porphyrins,Organoiron
更新于2025-09-10 09:29:36
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Click synthesis of glycosylated porphyrin-cored PAMAM dendrimers with specific recognition and thermosensitivity
摘要： Glycoporphyrin dendrimers have received increasing attentions due to their distinct physical and chemistry properties, such as fluorescence and water solubility. They also acted as a promising photodynamic therapy (PDT) sensitizer and used in the study of carbohydrate-protein interaction. In this study, different generations of porphyrin-cored dendrimers consisting of glycosylated siloxane-poly (amido amine) typed dendron (PP-Si-PAMAM-Dm-Lac, m = 1, 2, and 3), multifunctional specific-targeting sensitizers, had been synthesized via click reaction. The structure of PP-Si-PAMAM-Dm-Lac was characterized by 1H NMR, GPC, FT-IR, UV-vis and fluorescence analyses. This glycoporphyrin dendrimers, not only obtained high fluorescence quantum yield and singlet oxygen production efficiency, but also showed specific recognition of lectin and remarkable temperature-responsive property (20–80 °C). These properties proved a facile click synthetic strategy of glycosylated siloxane-poly (amido amine) typed dendrimers with multiple functions as a promising tumor-selective photsensitizer (PS) for PDT and also allow applications in highly sensitive fluorescent probes over a larger temperature window.
关键词： Thermosensitivity,Glycosylated porphyrin,Dendrimers,PDT,Specific recognition
更新于2025-09-09 09:28:46
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Photodegradable coumarin-derived amphiphilic dendrons for DNA binding: Self-assembly and phototriggered disassembly in water and air-water interface
摘要： In this article, we demonstrate the self-assembly and photoresponive behavior of a novel coumarin-based amphiphilic dendron in both aqueous solution and air-water interface. The dendritic structure, namely C-IG1, was composed of a lipophilic cholesterol and hydrophilic poly(amido amine) (PAMAM) dendron, and the amphiphilic counterpart is interconnected by a photolabile coumarin carbonate ester, enabling the photoinduced degradation of the amphiphiles in protic solvents via SN1-like mechanism. A Nile red solubilization fluorescence assay suggests a low critical aggregation concentration for the micelle formation of C-IG1 in aqueous solutions (3.9 × 10?5 M); the Langmuir analysis further indicates that C-IG1 possesses significant compressibility in air-water interface, eventually forming homogeneous monolayers with a final molecular area (A0) of 36 ?2. Notably, the micelles and Langmuir monolayer are quite stable until photo-triggered dissociation based on the photodeavage of C-IG1 amphiphile activated by 365-nm incident light. Moreover, the transition in interfacial morphology of the Langmuir monolayer during the assembly and photodegradation processes also can be visually analyzed by incorporating Nile red probes with in situ monitoring through fluorescence microscopy. The thin film deposited on a glass substrate by the Langmuir-Blodgett technique also shows a photoresponsive behavior based on the change in the contact angles of a water droplet on the surface upon light stimulation. The binding affinity of C-IG1 and cyclic DNA determined by the fluorescence quenching analysis of the coumarin reporter suggests a ground-state macromolecular complexation process occurring through polyvalent interactions between the pseudodendrimers and biomacromolecules. The ethidium bromide displacement assay further indicates thus dendriplex formation at low nitrogen-to-phosphorous value (N/P < 1) and confirms that the decomplexation accompanied by DNA release can be achieved through an active phototriggered route under spatiotemporal control.
关键词： Dendrimers,Langmuir analysis,Photocleavage,Gene delivery,Amphiphilic dendrons
更新于2025-09-04 15:30:14
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Blue Luminescent ZnO Nanoclusters Stabilized by Esterifiable Polyamidoamine Dendrimers and their UV-Shielding Applications
摘要： Zinc oxide quantum dots (QDs) were added to the water solutions of esterifiable polyamidoamine (PAMAMs) and the ZnO nanoclusters were prepared. The ZnO nanoclusters are stable in water and show bright blue fluorescence under UV lamp. TEM images showed that the ZnO nanoclusters consisted of numerous ZnO QDs. FTIR spectra of ZnO nanoclusters demonstrated the successful modification of ZnO QDs by the esterifiable polyamidoamine dendrimers. The UV-visible absorption spectra indicated that the ZnO nanoclusters exhibited wider and red-shifted comparing with ZnO QDs. The fluorescent spectra showed that the emission peaks at 404 nm of the ZnO QDs became weaker and a new emission peaks appeared at 330 nm after modifying the ZnO QDs with polyamidoamine dendrimers. The UV-visible transmittance spectra showed that the poly(vinyl alcohol)/ZnO nanoclusters film absorbed nearly 99 % of UV light at wavelengths between 200 and 240 nm while 75 % between 240 and 300 nm.
关键词： Poly(vinyl alcohol),Nanoclusters,ZnO quantum dots,UV-shielding,Polyamidoamine dendrimers
更新于2025-09-04 15:30:14