Effects of surface functionalization on the adsorption of human serum albumin onto nanoparticles – a fluorescence correlation spectroscopy study

• Pauline Maffre,
• Stefan Brandholt,
• Karin Nienhaus,
• Li Shang,
• Wolfgang J. Parak and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2036–2047, doi:10.3762/bjnano.5.212

• Fe–Pt nanoparticles (NPs, 6 nm radius), CdSe/ZnS quantum dots (QDs, 5 nm radius) and Au and Ag nanoclusters (1–4 nm radius), which are enshrouded by various water-solubilizing surface layers exposing different chemical functional groups (carboxyl, amino and both), thereby endowing the NPs with

• measure the binding of various proteins. In the present study, we focus on a single protein, again HSA, and explore the change in protein binding onto CdSe/ZnS core–shell QDs with different surface functionalities. These NPs were water-solubilized with small thiolated ligands, leading to thin coatings

• , implying that HSA binding to these QDs results in a greater radius increase. Figure 3 shows the increase of RH for various CdSe/ZnS QD preparations as a function of the HSA concentration, calculated from the FCS autocorrelation data. Regardless of the QD surface functionalization (and in agreement with our

Data-adaptive image-denoising for detecting and quantifying nanoparticle entry in mucosal tissues through intravital 2-photon microscopy

• Torsten Bölke,
• Lisa Krapf,
• Regina Orzekowsky-Schroeder,
• Tobias Vossmeyer,
• Jelena Dimitrijevic,
• Horst Weller,
• Anna Schüth,
• Antje Klinger,
• Gereon Hüttmann and
• Andreas Gebert

Beilstein J. Nanotechnol. 2014, 5, 2016–2025, doi:10.3762/bjnano.5.210

• fully motile with no evidence of decreased viability for experiments lasting up to 8 h. The animal experiments were approved by the local government (Ministerium für Umwelt, Naturschutz und Landwirtschaft Schleswig-Holstein, Germany, V742-72241.122). Preparation and properties of nanoparticles CdSe/CdS

Controlling the optical and structural properties of ZnS–AgInS₂ nanocrystals by using a photo-induced process

• Takashi Yatsui,
• Fumihiro Morigaki and
• Tadashi Kawazoe

Beilstein J. Nanotechnol. 2014, 5, 1767–1773, doi:10.3762/bjnano.5.187

• affords precise control over the size of CdSe QDs with a very low size variation that is as small as a fifth of the atomic interface [11], and it has been used to manufacture commercially available display devices [12]. On the other hand, the reduction of toxic components such as Cd and Se is required

• the size of nanocrystals have been reported for CdSe [14], ZnO [16][17], and Si [18] (Figure 1b). We measured the excitation spectra of the synthesized ZAIS nanocrystals to find the optimum wavelength for controlling the spectra. Based on the synthesis method described in [13], solid-solution

Donor–acceptor graphene-based hybrid materials facilitating photo-induced electron-transfer reactions

• Anastasios Stergiou,
• Georgia Pagona and
• Nikos Tagmatarchis

Beilstein J. Nanotechnol. 2014, 5, 1580–1589, doi:10.3762/bjnano.5.170

• materials composed of graphene and photoactive components, such as porphyrins and phthalocyanines, have been prepared and evaluated regarding photo-induced charge transfer phenomena [16][17][18]. Moreover, semiconducting quantum dots such as CdS [19][20][21][22], CdSe [23][24][25][26], CdTe [27][28], ZnO

In vitro interaction of colloidal nanoparticles with mammalian cells: What have we learned thus far?

• Moritz Nazarenus,
• Qian Zhang,
• Mahmoud G. Soliman,
• Pablo del Pino,
• Beatriz Pelaz,
• Susana Carregal-Romero,
• Joanna Rejman,
• Barbara Rothen-Rutishauser,
• Martin J. D. Clift,
• Reinhard Zellner,
• G. Ulrich Nienhaus,
• James B. Delehanty,
• Igor L. Medintz and
• Wolfgang J. Parak

Beilstein J. Nanotechnol. 2014, 5, 1477–1490, doi:10.3762/bjnano.5.161

• such as Ag, ZnO, or CdSe is in particular triggered by the highly acidic pH in endo-/lysosomal compartments [156]. In both cases adverse biological effects are typically correlated with the production of reactive oxygen species (ROS) [157][158]. Also membrane damage plays a decisive role. In case of

The cell-type specific uptake of polymer-coated or micelle-embedded QDs and SPIOs does not provoke an acute pro-inflammatory response in the liver

• Markus Heine,
• Alexander Bartelt,
• Oliver T. Bruns,
• Denise Bargheer,
• Artur Giemsa,
• Barbara Freund,
• Ludger Scheja,
• Christian Waurisch,
• Alexander Eychmüller,
• Rudolph Reimer,
• Horst Weller,
• Peter Nielsen and
• Joerg Heeren

Beilstein J. Nanotechnol. 2014, 5, 1432–1440, doi:10.3762/bjnano.5.155

• of cadmium-containing nanocrystals, pathological alterations in response to the injection of CdSe–ZnS core–shell QDs were observed only in some of these studies [9][11], while others found ultrastructural changes in the kidneys [10] or the spleen [12]. These results are surprising taking into account

• is known about the contribution of different cell types involved in nanocrystals uptake as well as biological responses to nanocrystals with regard to hepatic cell types. Here we demonstrate that polymer coat-embedded CdSe/CdS/ZnS-based QDs and SPIOs are internalized primarily by liver sinusoidal

An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

• Parul Chawla,
• Son Singh and
• Shailesh Narain Sharma

Beilstein J. Nanotechnol. 2014, 5, 1235–1244, doi:10.3762/bjnano.5.137

• photovoltaics [5][6]. To this day, numerous inorganic semiconductors such as ZnO, TiO2, CdSe, CdS, PbSe and PbS have been studied. Particular focus has been put on the investigation of selenides or sulfides in conjunction with organic polymers (MEH-PPV, P3HT) for hybrid solar cell applications [6][7]. However

Surface processes during purification of InP quantum dots

• Natalia Mordvinova,
• Pavel Emelin,
• Alexander Vinokurov,
• Sergey Dorofeev,
• Artem Abakumov and
• Tatiana Kuznetsova

Beilstein J. Nanotechnol. 2014, 5, 1220–1225, doi:10.3762/bjnano.5.135

• interest as a replacement for toxic CdSe quantum dots (QDs). Among them, InP QDs attracted the most attention because they are not toxic and have a broad photoluminescence color range in the visible spectrum. There are several methods to synthesize InP NCs. The most popular synthetic route is the reaction

Functionalized nanostructures for enhanced photocatalytic performance under solar light

• Liejin Guo,
• Dengwei Jing,
• Maochang Liu,
• Yubin Chen,
• Shaohua Shen,
• Jinwen Shi and
• Kai Zhang

Beilstein J. Nanotechnol. 2014, 5, 994–1004, doi:10.3762/bjnano.5.113

• Pt/TiO2 nanocrystal photocatalysts exhibited enhanced photocatalytic hydrogen production under visible light irradiation [18]. Lee et al. also reported that CdS and CdSe nanocrystals dispersed on the internal surface of mesoporous TiO2 films could lead to the promoted photocatalytic hydrogen

Optimizing the synthesis of CdS/ZnS core/shell semiconductor nanocrystals for bioimaging applications

• Li-wei Liu,
• Si-yi Hu,
• Ying Pan,
• Jia-qi Zhang,
• Yue-shu Feng and
• Xi-he Zhang

Beilstein J. Nanotechnol. 2014, 5, 919–926, doi:10.3762/bjnano.5.105

• bandgap (Eg) of 2.42 eV. By tailoring its composition and size, or surface functionality, it is possible to enhance luminescence emission and quantum yield of these QDs. The use of a coating agent can make CdS more stable. ZnS QDs are less cytotoxic than CdTe and CdSe QDs of the same size and surface

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• the photosensitizer Quantum dots are fluorescent nanoparticles with sizes of several nm, which contain a core of hundreds to thousands of atoms of group II and VI elements (e.g., CdS, CdSe and CdTe) or group III and V elements (e.g., InAs and InP). Due to the quantum confinement effect of the charge

• up to nearly 80% and open circuit voltages up to the 1 V range [24]. Ho et al. revealed that the CdSe–TiO2 coupled system had a much higher photocatalytic activity than that of pure TiO2 and CdSe in the degradation of 4-chlorophenol under visible light irradiation [34]. Wang et al. reported facet ZnO

• greatly prolonged lifetime of photoexcited carriers [36]. We also investigated the photoelectrochemical behavior of CdS sensitized TiO2 film with {001} facet enriched anatase nanocrystals [37]. Zhang et al. developed a double-sided CdS and CdSe quantum dot co-sensitized ZnO nanowire arrayed photoanode for

Photoactivation of luminescence in CdS nanocrystals

• Valentyn Smyntyna,
• Bogdan Semenenko,
• Valentyna Skobeeva and
• Nikolay Malushin

Beilstein J. Nanotechnol. 2014, 5, 355–359, doi:10.3762/bjnano.5.40

• dots synthesis, nature of the coating agent, surrounding atmosphere, density of the quantum dots, and the radiation intensity. Note that so far the unusual behaviour of the irradiation-induced QD luminescence has been observed either in QDs of CdSe or in nanocrystals of CdSe/ZnS/TOPO and has been

• influence of humid argon and oxygen on the photoinduced amplification of the photoluminescence intensity of CdSe/ZnS quantum dots of is presented. It is suggested that this effect is the result of solvation of the charged states of the surface traps. Two competing processes may occur during the irradiation

• , when the samples are placed in a humid atmosphere. The dominance of either of them depends on the humidity level. It has been found experimentally that under low humidity, the main process is a reaction with oxygen, and at high humidity the photoinduced interaction of CdSe/ZnS QDs with water molecules

Energy transfer in complexes of water-soluble quantum dots and chlorin e6 molecules in different environments

• Irina V. Martynenko,
• Anna O. Orlova,
• Vladimir G. Maslov,
• Alexander V. Baranov,
• Anatoly V. Fedorov and
• Mikhail Artemyev

Beilstein J. Nanotechnol. 2013, 4, 895–902, doi:10.3762/bjnano.4.101

• University, Minsk, Belarus 10.3762/bjnano.4.101 Abstract The photoexcitation energy transfer is found and investigated in complexes of CdSe/ZnS cationic quantum dots and chlorin e6 molecules formed by covalent bonding and electrostatic interaction in aqueous solution and in porous track membranes. The

• CdSe/ZnS with different core sizes (2.5 nm, 3.5 nm, and 5 nm) were synthesized using similar methods as previously described [9]. All QD samples have a QY of about 20% in hydrophobic solvents and 5–8% in aqueous solutions. Complex formation in aqueous solutions To form water-soluble complexes of

• quantum dots and Ce6 molecules two methods of QD solubilization were used. In the case of covalent binding the hydrophobic CdSe/ZnS/TOPO QDs with a core diameter of 3.5 nm were initially solubilized by L-cysteine. In the second step, the L-cysteine molecules were replaced with molecules of hydroxy

Photoelectrochemical and Raman characterization of In₂O₃ mesoporous films sensitized by CdS nanoparticles

• Mikalai V. Malashchonak,
• Sergey K. Poznyak,
• Eugene A. Streltsov,
• Anatoly I. Kulak,
• Olga V. Korolik and
• Alexander V. Mazanik

Beilstein J. Nanotechnol. 2013, 4, 255–261, doi:10.3762/bjnano.4.27

• . Keywords: cadmium sulfide (CdS); indium oxide (In2O3); nanoparticles; successive ionic layer adsorption and reaction (SILAR); Introduction In third-generation solar cells molecular dyes (in the Grätzel cells [1]) as well as nanoparticles of semiconducting metal chalcogenides (CdS, CdSe, CdTe, PbS, PbSe

• nanoparticles were grown in situ (directly on the indium oxide substrate) it is also necessary to take into account their interaction with the host material. A similar approach was applied in the works [23] and [24] to explain Raman spectra of CdSxSe1−x and CdSe embedded in different glass matrixes. The lattice

Horizontal versus vertical charge and energy transfer in hybrid assemblies of semiconductor nanoparticles

• Gilad Gotesman,
• Rahamim Guliamov and
• Ron Naaman

Beilstein J. Nanotechnol. 2012, 3, 629–636, doi:10.3762/bjnano.3.72

• type of transfer process. Wu et al. studied charge separation in type-II heterojunction assemblies of CdSe–CdTe NPs as a function of linker length [23]. They found that for longer linkers, the charge transfer efficiency is smaller. In another study, photogenerated exciton dissociation in PbS NP thin

• . Experimental The NP assemblies were prepared as described previously [4]. Briefly, a monolayer of (3-mercaptopropyl)trimethoxysilane was self-assembled on quartz (Qz, fused silica) substrates. Next, a monolayer of core-only CdSe NPs (~6.3 nm diameter, emission peak at 641 nm) was attached to the thiol tail

• smaller CdSe NPs (≈3.5 nm diameter, emission peak at 580 nm). Since charge and energy transfer processes are expected to occur from the small NPs (larger band gap) to the large ones (smaller band gap), we denoted the small and large NPs as donors and acceptors, respectively. Very dense monolayers of

Combining nanoscale manipulation with macroscale relocation of single quantum dots

• Francesca Paola Quacquarelli,
• Richard A. J. Woolley,
• Martin Humphry,
• Jasbiner Chauhan,
• Philip J. Moriarty and
• Ashley Cadby

Beilstein J. Nanotechnol. 2012, 3, 324–328, doi:10.3762/bjnano.3.36

• , University of Nottingham, Nottingham, NG7 2RD UK Phase Focus Limited, The Kroto Innovation Centre, The University of Sheffield, North Campus, Broad Lane, Sheffield, S3 7HQ, UK 10.3762/bjnano.3.36 Abstract We have controllably positioned, with nanometre precision, single CdSe quantum dots referenced to a

• [13]. The gold nanoparticle was shown to dramatically quench the optical lifetime of the QD and to completely suppress its blinking. Experimental In this work, we position a single fluorophore, a CdSe QD, with nanometre precision on a macroscopic registration template, using automated atomic force

• -molecule microscopy, and atomic force microscopy. Importantly, the samples discussed here were transferred between two laboratories separated by ≈50 km, but it was possible to study the same nanoparticle in both labs. The quantum dots used in this work were CdSe/ZnS core/shell hydrophobic nanocrystals

Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

• Yaron Paz

Beilstein J. Nanotechnol. 2011, 2, 845–861, doi:10.3762/bjnano.2.94

Distance dependence of near-field fluorescence enhancement and quenching of single quantum dots

• Volker Walhorn,
• Jan Paskarbeit,
• Heinrich Gotthard Frey,
• Alexander Harder and
• Dario Anselmetti

Beilstein J. Nanotechnol. 2011, 2, 645–652, doi:10.3762/bjnano.2.68

• sulphuric acid 96% and hydrogen peroxide 30%) for one minute, rinsed thoroughly with MilliQ filtered water and dried with nitrogen. After cleaning, hydrophobic fluorescent CdSe/ZnS nanoparticles [29] with a spectral emission maximum at 585 nm were diluted in n-heptane (Sigma Aldrich), microdispensed to the

Room temperature excitation spectroscopy of single quantum dots

• Christian Blum,
• Frank Schleifenbaum,
• Martijn Stopel,
• Sébastien Peter,
• Marcus Sackrow,
• Vinod Subramaniam and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2011, 2, 516–524, doi:10.3762/bjnano.2.56

• Abstract We report a single molecule detection scheme to investigate excitation spectra of single emitters at room temperature. We demonstrate the potential of single emitter photoluminescence excitation spectroscopy by recording excitation spectra of single CdSe nanocrystals over a wide spectral range of

• recorded excitation spectra of 48 individual CdSe/ZnS core–shell quantum dots at room temperature. Since the occurrence of emission intermittencies (blinking) is a clear indication for the observation of a single emitter, and because blinking of quantum dots is still not fully understood, we did not apply

• performed [52]. This result implies that the photoluminescence quantum yield in CdSe quantum dot ensembles is independent of the excitation wavelength, and that analyzing the excitation spectra also allows one to draw conclusions about the absorbance spectra of single quantum dots. Following from this, the

Extended X-ray absorption fine structure of bimetallic nanoparticles

• Carolin Antoniak

Beilstein J. Nanotechnol. 2011, 2, 237–251, doi:10.3762/bjnano.2.28

• several examples can be found for EXAFS analysis on nanoparticle systems, e.g., Co [8], CdS [9], CdSe [10], SnO2 [11] and Au [12] nanoparticles, as well as Ag nanoparticles embedded in glass [13][14]. To discuss the advantages and possible drawbacks of EXAFS analysis in nanoparticulate systems, this paper

Precursor concentration and temperature controlled formation of polyvinyl alcohol-capped CdSe-quantum dots

• Chetan P. Shah,
• Madhabchandra Rath,
• Manmohan Kumar and
• Parma N. Bajaj

Beilstein J. Nanotechnol. 2010, 1, 119–127, doi:10.3762/bjnano.1.14

• Chetan P. Shah Madhabchandra Rath Manmohan Kumar Parma N. Bajaj Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085, India 10.3762/bjnano.1.14 Abstract Polyvinyl alcohol-capped CdSe quantum dots, with a size within their quantum confinement limit, were

• prepared in aqueous solution at room temperature, by a simple and environmentally friendly chemical method. The size of the CdSe quantum dots was found to be dependent on the concentrations of the precursors of cadmium and selenium ions, as well as on the aging time and the reaction temperature; all of

• semiconductor materials, such as CdSe, with the aim of producing nanoparticles of desired size distribution. Several methods have been employed for the preparation of such nanomaterials [9][10][11][12][13][14][15][16][17][18]. One of the most important aspects, in all these methods, is the capping agent, which

Fabrication and spectroscopic studies on highly luminescent CdSe/CdS nanorod polymer composites

• Jana Bomm,
• Andreas Büchtemann,
• Angela Fiore,
• Liberato Manna,
• James H. Nelson,
• Diana Hill and
• Wilfried G. J. H. M. van Sark

Beilstein J. Nanotechnol. 2010, 1, 94–100, doi:10.3762/bjnano.1.11

• Society, Copernicus Institute of Sustainable Development and Innovation, Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, the Netherlands 10.3762/bjnano.1.11 Abstract Highly luminescent nanocomposites were prepared by incorporating CdSe/CdS core/shell nanorods into different polymer matrices. The

• . Keywords: CdSe; luminescence lifetime; nanocomposites; nanorods; quantum yield; Introduction Semiconductor nanoparticles have attracted great interest in recent years because of their fascinating optical properties. Their emission wavelength can be tuned directly by changing their size and shape as a

• , aggregation of nanoparticles, loss of transparency and luminescence quenching due to exciton energy transfer [2][7]. Several methods have been described to overcome these problems for quantum dot polymer composites. For example, Bawendi and coworkers incorporated trioctylphosphine oxide covered CdSe/ZnS QDs

Review and outlook: from single nanoparticles to self-assembled monolayers and granular GMR sensors

• Alexander Weddemann,
• Inga Ennen,
• Anna Regtmeier,
• Camelia Albon,
• Annalena Wolff,
• Katrin Eckstädt,
• Nadine Mill,
• Michael K.-H. Peter,
• Jochen Mattay,
• Carolin Plattner,
• Norbert Sewald and
• Andreas Hütten

Beilstein J. Nanotechnol. 2010, 1, 75–93, doi:10.3762/bjnano.1.10

• ]. Bimetallic particles can be classified into 5 groups [30]: Stoichiometrical compounds with well defined crystal structures. Examples are CdSe semiconductor particles or magnetic FePt particles [31]. Undefined mixtures. Two compounds are completely miscible. This situation occurs if the bulk metals have