Current state of laser synthesis of metal and alloy nanoparticles as ligand-free reference materials for nano-toxicological assays

• Christoph Rehbock,
• Jurij Jakobi,
• Lisa Gamrad,
• Selina van der Meer,
• Daniela Tiedemann,
• Ulrike Taylor,
• Wilfried Kues,
• Detlef Rath and
• Stephan Barcikowski

Beilstein J. Nanotechnol. 2014, 5, 1523–1541, doi:10.3762/bjnano.5.165

• . However, previous examination in this context revealed decreased motility of spermatozoa incubated with gold nanoparticles in serum-free medium. These results were associated with membrane attachment of aggregated nanoparticles blocking surface thiol groups involved in sperm movement [147], which probably

Purification of ethanol for highly sensitive self-assembly experiments

• Kathrin Barbe,
• Martin Kind,
• Christian Pfeiffer and
• Andreas Terfort

Beilstein J. Nanotechnol. 2014, 5, 1254–1260, doi:10.3762/bjnano.5.139

• test, one gram of the zeolite loaded with different amounts of gold-NPs was stirred into solutions of dodecanethiol in ethanol. After ten minutes, the solution was tested for remaining thiol using Ellman’s reagent. By increasing the concentrations of the solutions in small steps until the test became

• increasing gold content. This is probably due to partial melting and subsequent coalescence of the gold-NPs [39], which results in a smaller surface to bulk ratio, i.e., a lower fraction of thiol binding sites. In contrast to this, the dodecanethiol uptake capacity of zeolite-supported gold-NPs pyrolyzed at

• regeneration at different temperatures are plotted against the number of loading-regeneration cycles. The thiol uptake capacities of the three samples remain essentially constant, though the data show some scattering, which at least partially is due to the fact that the uptake was measured in a stepwise manner

Classical molecular dynamics investigations of biphenyl-based carbon nanomembranes

• Andreas Mrugalla and
• Jürgen Schnack

Beilstein J. Nanotechnol. 2014, 5, 865–871, doi:10.3762/bjnano.5.98

• induce strong correlations of binding sites of neighboring biphenyls [17]. For such an investigation classical potentials for hydrocarbons would have to be used [13][14]. The thiol groups as well as the metallic support are absent in our simulation. Since the initial state is an overall planar

In vitro toxicity and bioimaging studies of gold nanorods formulations coated with biofunctional thiol-PEG molecules and Pluronic block copolymers

• Tianxun Gong,
• Douglas Goh,
• Malini Olivo and
• Ken-Tye Yong

Beilstein J. Nanotechnol. 2014, 5, 546–553, doi:10.3762/bjnano.5.64

• functional thiol-poly(ethylene glycol) (PEG-SH) molecules and Pluronic block copolymers (PEO–PPO–PEO) (see chemical formula of PEG-SH and Pluronic (PEO–PPO–PEO) in Supporting Information File 1, Figure S1) are commonly used to prepare non-ionic polymer encapsulated AuNRs with a stealth property for in vivo

• by means of the chemisorption process between the thiol moiety and the gold particle surface [24][25]. Pluronic is a commercially available triblock copolymer with a hydrophobic segment of poly(propylene oxide) (PPO) polymer sandwiched between two hydrophilic segments of PEO. In our previous study

One-step synthesis of high quality kesterite Cu₂ZnSnS₄ nanocrystals – a hydrothermal approach

• Vincent Tiing Tiong,
• John Bell and
• Hongxia Wang

Beilstein J. Nanotechnol. 2014, 5, 438–446, doi:10.3762/bjnano.5.51

• complexes prior to the hydrothermal reaction [22][23]. However, the formation of Cu7S4 and Cu1.8S compounds in our case suggests that Cu2+ is reduced to Cu+ by interaction with the –SH (thiol) group of TGA (oxidation of TGA to dithiodiglycolate) [27]. The XRD pattern of the precipitate collected from the

Nanoscale patterning of a self-assembled monolayer by modification of the molecule–substrate bond

• Cai Shen and
• Manfred Buck

Beilstein J. Nanotechnol. 2014, 5, 258–267, doi:10.3762/bjnano.5.28

• followed by adsorption of AdSH. The appearance of Au adatom islands upon the thiol exchange suggests that the interfacial structures of BP2 and AdSH SAMs are different. Keywords: copper; electrodeposition; gold adatoms; nanolithography; negative resist; Introduction The applications of organic adsorbates

• reductive desorption of the less tightly bound thiol molecules in the UPD-free Au areas to yield either nanoporous SAMs or binary SAMs in the case of backfilling with a second type of thiol [11]. So far, however, this approach has been lacking control as UPD is mediated by random defects [24][26][27] which

• perfection [24][28][29][30], as a consequence of the specific molecular architecture characterised by an aromatic moiety linked to the thiol head group by a short aliphatic chain (see Figure 1a). Designing the molecules such that different factors that determine the enthalpy of the system compete to some

Fabrication of carbon nanomembranes by helium ion beam lithography

• Xianghui Zhang,
• Henning Vieker,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2014, 5, 188–194, doi:10.3762/bjnano.5.20

• approaches have been used to exploit the capabilities of HIM, such as ion milling [21], scanning helium ion beam lithography (SHIBL) [22], and helium ion beam induced deposition (HIBID) [20]. Here we used 4'-nitro-1,1'-biphenyl-4-thiol (NBPT) as a molecular precursor to form SAMs on a Au substrate and

• , this is due to the energy distribution of helium ion excited secondary electrons being shifted to lower energies. Experimental Preparation of self-assembled monolayers For the preparation of 4'-nitro-1,1'-biphenyl-4-thiol (NBPT) SAMs we used a 300 nm polycrystalline Au layer with (111) crystal planes

Surface assembly and nanofabrication of 1,1,1-tris(mercaptomethyl)heptadecane on Au(111) studied with time-lapse atomic force microscopy

• Tian Tian,
• Burapol Singhana,
• Lauren E. Englade-Franklin,
• Xianglin Zhai,
• T. Randall Lee and
• Jayne C. Garno

Beilstein J. Nanotechnol. 2014, 5, 26–35, doi:10.3762/bjnano.5.3

• thiols were found to assemble slowly, requiring more than six hours to generate films. A clean gold substrate was first imaged in ethanolic media using liquid AFM. Next, a 0.01 mM solution of multidentate thiol was injected into the liquid cell. As time progressed, molecular-level details of the surface

• –Au bonds to the substrate. Keywords: liquid AFM; multidentate; nanografting; nanolithography; self-assembly; Introduction Multidentate thiol-based adsorbates attach to gold surfaces through multiple bonds that provide enhanced stability to self-assembled monolayers (SAMs) [1][2]. Although detailed

• investigations of monodentate thiol-based SAMs have been widely reported, relatively few studies of SAMs derived from bidentate or tridentate thiol adsorbates are available. One might predict that the bulkier headgroups of multidentate adsorbates would strongly influence the kinetics, stability, and surface

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

• -terminated polyethylene glycol (PEG-OH)thiol and amino-terminated polyethylene glycol (PEG-NH2)thiol with a ratio of 3 to 1. This enables to obtain stable colloidal solutions of quantum dots. Then the covalent binding of the QD surface amino groups with the Ce6 carboxyl functional groups using EDAC as a

Site-selective growth of surface-anchored metal-organic frameworks on self-assembled monolayer patterns prepared by AFM nanografting

• Tatjana Ladnorg,
• Alexander Welle,
• Stefan Heißler,
• Christof Wöll and
• Hartmut Gliemann

Beilstein J. Nanotechnol. 2013, 4, 638–648, doi:10.3762/bjnano.4.71

• the orientation of the SURMOF. Here, we demonstrate for the first time the site-selective growth of the SURMOF HKUST-1 on thiol-based self-assembled monolayers patterned by the nanografting technique, with an atomic force microscope as a structuring tool. Two different approaches were applied: The

• in-situ synthesis, which was introduced by Bein et al. [15]. In this synthesis the MOF crystals are grown by dipping a gold coated substrate, which is terminated with a thiol-based self-assembled monolayer (SAM), into a solution containing a mixture of the metal nodes and the organic linkers. As a

• gold coated substrate is modified by the deposition of a thiol-based SAM, that carries either an –OH, a –COOH or a pyridine unit. The SAM, and in particular its surface termination, plays a crucial role in this context and also determines the growth direction of the SURMOF [14][15]. On a CH3-terminated

Apertureless scanning near-field optical microscopy of sparsely labeled tobacco mosaic viruses and the intermediate filament desmin

• Alexander Harder,
• Mareike Dieding,
• Volker Walhorn,
• Sven Degenhard,
• Andreas Brodehl,
• Christina Wege,
• Hendrik Milting and
• Dario Anselmetti

Beilstein J. Nanotechnol. 2013, 4, 510–516, doi:10.3762/bjnano.4.60

• single thiol-group on every capsid protein subunit of the virus surface (TMVCys, 2130 coupling sites per viral nanotube), is used [31]. The labeling procedure is performed with a substoichiometric molar ratio of 0.02:1 of Atto740 maleimide (Sigma-Aldrich, München, Germany) to viral capsid protein, in

Photocatalytic antibacterial performance of TiO₂ and Ag-doped TiO₂ against S. aureus. P. aeruginosa and E. coli

• Kiran Gupta,
• R. P. Singh,
• Ashutosh Pandey and
• Anjana Pandey

Beilstein J. Nanotechnol. 2013, 4, 345–351, doi:10.3762/bjnano.4.40

• ]. The simplest photocatalytic mechanism of silver ions is that it may take part in catalytic oxidation reactions between oxygen molecules in the cell and hydrogen atoms of thiol groups, i.e., two thiol groups become covalently bonded to one another through disulfide bonds (R–S–S–R), which leads to

Guided immobilisation of single gold nanoparticles by chemical electron beam lithography

• Patrick A. Schaal and
• Ulrich Simon

Beilstein J. Nanotechnol. 2013, 4, 336–344, doi:10.3762/bjnano.4.39

• interest. In this paper we present a straight-forward three-step procedure based on chemical electron beam lithography, which is capable of producing such arrays with gold nanoparticles (AuNPs). Preformed 6 nm AuNPs are immobilised on thiol patterns with a pitch of 100 nm by guided self-assembly

• in any type of periodic or aperiodic pattern. In order to make new steps in this direction, in this work, we present the local reduction of sulfonic acid terminated SAMs into thiol-terminated SAMs by CEBL on electron-transparent SiO2 membranes, which enabled us to analyse the site-selective

• immobilisation of AuNPs by scanning electron microscopy in transmission (SEM-T) and by atomic force microscopy (AFM). Based on these analyses, we were able to optimise the process yielding periodic patterns of single 6 nm AuNPs. Results and Discussion Generation of thiol groups on thin Si/SiO2 membranes

Selective surface modification of lithographic silicon oxide nanostructures by organofunctional silanes

• Thomas Baumgärtel,
• Christian von Borczyskowski and
• Harald Graaf

Beilstein J. Nanotechnol. 2013, 4, 218–226, doi:10.3762/bjnano.4.22

• silicon oxide surfaces are silane compounds such as trichlorosilanes or ethoxysilanes [20][21]. In order to provide the possibility for further chemical modification, functional silanes are of major interest. These molecules possess a functional head-group (e.g., carboxyl, amino or thiol group) in

• functional group. This group is reactive towards nucleophiles such as amine or thiol groups. A successful large-scale binding of FITC to amino-terminated silicon surfaces [27] has been demonstrated previously by fluorescence measurements [28]. The attachment of FITC on the oxide nanostructures is realized in

Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

Current–voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution

• Bernd M. Briechle,
• Youngsang Kim,
• Philipp Ehrenreich,
• Artur Erbe,
• Dmytro Sysoiev,
• Thomas Huhn,
• Ulrich Groth and
• Elke Scheer

Beilstein J. Nanotechnol. 2012, 3, 798–808, doi:10.3762/bjnano.3.89

• (physisorption). In the case of physisorption, one can expect that the current is mediated by tunneling. For thiol end-groups on gold, it has been shown that both chemisorption and physisorption is possible [42][43][44] depending on the surface morphology and the deposition method. For the amine end-group the

• experimental situation is not so clear. However, since in most studies in which molecules with the same molecular core but different end-groups are compared, a higher conductance is found for thiol-terminated molecules than for amine-terminated [39][45], we expect that in the asymmetric junctions the coupling

• on one side is realized through the thiol end-group and on the other side-arm through the amine end-group. We now discuss our findings and data analysis of the species 4Py, which we probed in the closed state only. Examples of I–V’s and their fittings for the symmetric and the asymmetric case are

Controlled positioning of nanoparticles on a micrometer scale

• Fabian Enderle,
• Oliver Dubbers,
• Alfred Plettl and
• Paul Ziemann

Beilstein J. Nanotechnol. 2012, 3, 773–777, doi:10.3762/bjnano.3.86

• through a thiol-group. To suppress interactions between nanoparticles or the molecules bound to them, usually interparticle distances of 50 nm are sufficient (for a recent study on near-field effects around a single dot see [27]). To guarantee single particle/molecule spectroscopy significantly larger

Paper modified with ZnO nanorods – antimicrobial studies

• Mayuree Jaisai,
• Sunandan Baruah and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2012, 3, 684–691, doi:10.3762/bjnano.3.78

• . As a result, the ZnO nanoparticles that are used for nucleating the nanorods get attached to the surface without the need for any further surface treatments, such as, for example, the surface treatment of polyethylene fibers with dodecane thiol for attachment of ZnO seed nanoparticles prior to

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

• . 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

• -octanedithiol (C8DT), and 1,10-decanedithiol (C10DT). Control experiments were performed with molecules of the same lengths but with only one thiol group. These molecules will be denoted as monothiols (MT, e.g., C6MT for 1-hexanethiol). To form the second layer of NPs, the samples were immersed in a solution of

• quenching was independent of the linker length. This effect is well known for CdSe NPs; it results from the formation of surface traps owing to the thiol binding [28][29][30][31]. The PL quenching, which is independent of the MT length, indicates that the number of traps is the same for all linkers, and

Mapping mechanical properties of organic thin films by force-modulation microscopy in aqueous media

• Jianming Zhang,
• Zehra Parlak,
• Carleen M. Bowers,
• Terrence Oas and
• Stefan Zauscher

Beilstein J. Nanotechnol. 2012, 3, 464–474, doi:10.3762/bjnano.3.53

• and contact forces, and (ii) in the unambiguous interpretation of the contrast in the amplitude images [38][39][40]. We demonstrate the capability of FMM to image mechanical properties in aqueous media on surface-tethered proteins and self-assembled EG3-thiol (triethylene glycol mono-11

• in aqueous solution. Future work to quantify these properties requires additional analytical models that capture the interaction of the cantilever beam with the liquid environment. FMM on patterned EG3-thiol monolayers The properties and applications of alkanethiol self-assembled monolayers (SAMs) on

• gold surfaces have been the subject of interface science research for many years. The self-assembly of alkane thiol molecules on gold surfaces is a two-step process. The initial physisorption step on gold substrates is typically slow and concentration-dependent [55]. Once in contact, the molecules

Colloidal lithography for fabricating patterned polymer-brush microstructures

• Tao Chen,
• Debby P. Chang,
• Rainer Jordan and
• Stefan Zauscher

Beilstein J. Nanotechnol. 2012, 3, 397–403, doi:10.3762/bjnano.3.46

• obtained by sputter deposition of the metal [2][4]. When gold is chosen as the metal, the ensuing pattern can be easily functionalized chemically with a self-assembled monolayer (SAM) of a thiol initiator, which can be subsequently amplified into polymer brushes. Figure 1 shows this strategy for the

• between the microspheres (Figure 1A). After the microsphere mask was removed by sonication, an array of hexagonally arranged triangular gold islands remained (Figure 1B) on which we formed a SAM of thiol initiator (BrC(CH3)2COO(CH2)11SH) [27]. We then synthesized poly(N-isopropylacrylamide) (PNIPAAM

• –surface contact area. This so-called edge-spreading lithography (ESL) employing colloid microspheres as templates has been previously used to fabricate ring-shaped metal patterns [9]. Here we replaced the octadecanethiol (ODT) molecules with thiol initiator (BrC(CH3)2COO(CH2)11SH), and amplified the

Functionalised zinc oxide nanowire gas sensors: Enhanced NO₂ gas sensor response by chemical modification of nanowire surfaces

• Eric R. Waclawik,
• Jin Chang,
• Andrea Ponzoni,
• Isabella Concina,
• Dario Zappa,
• Elisabetta Comini,
• Nunzio Motta,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2012, 3, 368–377, doi:10.3762/bjnano.3.43

• the thiol. The long DT hydrocarbon chains were expected to create a strongly hydrophobic surface. Similarly ZnO nanowire sensors were functionalised by tris(hydroxymethyl)aminomethane (THMA), and the response of THMA-functionalised sensors was compared to that of the unfunctionalised ZnO nanowire

• thiol (confirmed by FTIR) raised the conductivity of each individual sensor above the measurement range of our instrument (which corresponds to a minimum conductance value of Gmax = 10 mS). We conclude from this that chemisorption of the thiol significantly increased the density of electrons present in

Variations in the structure and reactivity of thioester functionalized self-assembled monolayers and their use for controlled surface modification

• Inbal Aped,
• Yacov Mazuz and
• Chaim N. Sukenik

Beilstein J. Nanotechnol. 2012, 3, 213–220, doi:10.3762/bjnano.3.24

• ]. The preparation of (S)-undec-10-enyl thioacetate from ω-undecenylbromide followed the previously published procedure [17]. ω-Undecenyl thiol was prepared by acid hydrolysis of the thioacetate, as follows: In a round-bottom flask (250 mL) equipped with a magnetic stirring bar and a reflux condenser

• (50 mL) and brine (50 mL). The hexane was dried over MgSO4 and filtered, and the solvent was removed on a rotovap. The crude ω-undecenyl thiol was purified by flash chromatography (hexane): Yield 6.02 g (82%); 1H NMR δ 1.20–1.47 (m, 13H), 1.61 (m, 2H), 2.04 (m, 2H), 2.52 (q, J = 7.5 Hz, 2H), 4.93 (m

• , 2H), 5.81 (ddt, J = 6.6, 10.2, 17 Hz, 1H); 13C NMR δ 24.80, 28.51, 29.06, 29.20, 29.24, 29.56, 29.59, 33.95, 34.19, 114.27, 139.36. The general procedure for the conversion of ω-undecenyl thiol into the thioester–olefin precursors for compounds 1b–i, 2, 3 and 4 is as follows: In a dry, round-bottom

Parallel- and serial-contact electrochemical metallization of monolayer nanopatterns: A versatile synthetic tool en route to bottom-up assembly of electric nanocircuits

• Jonathan Berson,
• Assaf Zeira,
• Rivka Maoz and
• Jacob Sagiv

Beilstein J. Nanotechnol. 2012, 3, 134–143, doi:10.3762/bjnano.3.14

• different from those usually produced in conventional electrochemical deposition on thiol/gold monolayers [36][37][38][39][40][41][42][43][44][45], which may occur in the monolayer-free regions of a destructively patterned monolayer [36][37][38][39][40][41][42], underneath the monolayer [41][42], or on top

Electron-beam patterned self-assembled monolayers as templates for Cu electrodeposition and lift-off

• Zhe She,
• Andrea DiFalco,
• Georg Hähner and
• Manfred Buck

Beilstein J. Nanotechnol. 2012, 3, 101–113, doi:10.3762/bjnano.3.11

• Zhe She Andrea DiFalco Georg Hahner Manfred Buck EaStCHEM School of Chemistry, University of St. Andrews, KY16 9ST, U.K School of Physics and Astronomy, University of St. Andrews, KY16 9ST, U.K 10.3762/bjnano.3.11 Abstract Self-assembled monolayers (SAMs) of 4'-methylbiphenyl-4-thiol (MBP0

• hexadecane thiol (CH3(CH2)15SH, MC16) as a blocking thiol [15]. The present paper is an investigation of a scheme for creating surface features with smaller dimensions by using e-beam patterning of a single-component SAM of ω-(4'-methylbiphenyl-4-yl)thiol (CH3–C6H4–C6H4–SH, MBP0). While selective deposition

• affecting the nucleation rate is specific to metals that bind more strongly to the thiol head group than the original substrate metal. In this case the metal deposited at defects can easily intercalate and diffuse at the SAM–substrate interface [48]. In the case of templated deposition by means of an e-beam