Biotinylation of optically responsive gold/polyelectrolyte nanostructures

Pereira, S.; Trindade, Tito; Barros‐Timmons, Ana

doi:10.1007/s13404-014-0153-x

Cited by 9 publications

(6 citation statements)

References 41 publications

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“…The signal from the gold core was only observed in one of a total of 1000 particles, again due to the low absorption of gold in the IR (Manca et al, 2007;Pereira et al, 2015). The spectra of gold-PAH particles from the 266 nm fs LAAPTOF (not shown) also did not exhibit signal from the gold core, and only low signal intensity from the PAH shell.…”

Section: Sio 2 Particlesmentioning

confidence: 94%

Exploring femtosecond laser ablation in single-particle aerosol mass spectrometry

et al. 2018

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Abstract. Size, composition, and mixing state of individual aerosol particles can be analysed in real time using singleparticle mass spectrometry (SPMS). In SPMS, laser ablation is the most widely used method for desorption and ionization of particle components, often realizing both in one single step. Excimer lasers are well suited for this task due to their relatively high power density (10 7 -10 10 W cm −2 ) in nanosecond (ns) pulses at ultraviolet (UV) wavelengths and short triggering times. However, varying particle optical properties and matrix effects make a quantitative interpretation of this analytical approach challenging. In atmospheric SPMS applications, this influences both the mass fraction of an individual particle that is ablated, as well as the resulting mass spectral fragmentation pattern of the ablated material. The present study explores the use of shorter (femtosecond, fs) laser pulses for atmospheric SPMS. Its objective is to assess whether the higher laser power density of the fs laser leads to a more complete ionization of the entire particle and higher ion signal and thus improvement in the quantitative abilities of SPMS. We systematically investigate the influence of power density and pulse duration on airborne particle (polystyrene latex, SiO 2 , NH 4 NO 3 , NaCl, and custom-made core-shell particles) ablation and reproducibility of mass spectral signatures. We used a laser ablation aerosol time-of-flight single-particle mass spectrometer (LAAPTOF, AeroMegt GmbH), originally equipped with an excimer laser (wavelength 193 nm, pulse width 8 ns, pulse energy 4 mJ), and coupled it to an fs laser (Spectra Physics Solstice-100F ultrafast laser) with similar pulse energy but longer wavelengths (266 nm with 100 fs and 0.2 mJ, 800 nm with 100 fs and 3.2 mJ). We successfully coupled the freefiring fs laser with the single-particle mass spectrometer employing the fs laser light scattered by the particle to trigger mass spectra acquisition. Generally, mass spectra exhibit an increase in ion intensities (factor 1 to 5) with increasing laser power density (∼ 10 9 to ∼ 10 13 W cm −2 ) from ns to fs laser. At the same time, fs-laser ablation produces spectra with larger ion fragments and ion clusters as well as clusters with oxygen, which does not render spectra interpretation more simple compared to ns-laser ablation. The idea that the higher power density of the fs laser leads to a more complete particle ablation and ionization could not be substantiated in this study. Quantification of ablated material remains difficult due to incomplete ionization of the particle. Furthermore, the fslaser application still suffers from limitations in triggering it in a useful time frame. Further studies are needed to test potential advantages of fs-over ns-laser ablation in SPMS.

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Section: Sio 2 Particlesmentioning

confidence: 94%

Exploring femtosecond laser ablation in single-particle aerosol mass spectrometry

et al. 2018

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“…These copolymer@Au nanostructures have also shown potential to be explored for drug carrier/delivery systems, since PEG is also known to have thermal responsiveness [ 41 ]. Moreover, the synthetic strategy outlined in this work also allows the incorporation of monomers containing fluorophores in well-defined positions along the polymer shell, which can be tuned to maximize photoluminescence quenching and thus afford more sensitive biosensors [ 42 ].…”

Section: Resultsmentioning

confidence: 99%

Biofunctional Polymer Coated Au Nanoparticles Prepared via RAFT-Assisted Encapsulating Emulsion Polymerization and Click Chemistry

2020

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The use of reversible addition-fragmentation chain transfer (RAFT)-assisted encapsulating emulsion polymerization (REEP) has been explored to prepare diverse types of colloidal stable core–shell nanostructures. A major field of application of such nanoparticles is in emergent nanomedicines, which require effective biofunctionalization strategies, in which their response to bioanalytes needs to be firstly assessed. Herein, functional core–shell nanostructures were prepared via REEP and click chemistry. Thus, following the REEP strategy, colloidal gold nanoparticles (Au NPs, d = 15 nm) were coated with a poly(ethylene glycol) methyl ether acrylate (PEGA) macroRAFT agent containing an azide (N3) group to afford N3–macroRAFT@Au NPs. Then, chain extension was carried out from the NPs surface via REEP, at 44 °C under monomer-starved conditions, to yield N3–copolymer@Au NPs–core–shell type structures. Biotin was anchored to N3–copolymer@Au NPs via click chemistry using an alkynated biotin to yield biofunctionalized Au nanostructures. The response of the ensuing biotin–copolymer@Au NPs to avidin was followed by visible spectroscopy, and the copolymer–biotin–avidin interaction was further studied using the Langmuir–Blodgett technique. This research demonstrates that REEP is a promising strategy to prepare robust functional core–shell plasmonic nanostructures for bioapplications. Although the presence of azide moieties requires the use of low polymerization temperature, the overall strategy allows the preparation of tailor-made plasmonic nanostructures for applications of biosensors based on responsive polymer shells, such as pH, temperature, and photoluminescence quenching. Moreover, the interaction of biotin with avidin proved to be time dependent.

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“…The comparison between ns-and fs-LAAPTOF spectra of gold-PAH core-shell particles reveals more signal from carbon clusters, which are similar to the peaks from PSL particles, in the fs spectra. The signal from the gold core was only observed in one of a total of 1000 particles, again due to the low absorption of gold in the IR (Manca et al, 2007;Pereira et al, 2015). The spectra of gold-PAH particles from the 266 nm fs LAAPTOF (not shown) also did not exhibit signal from the gold core, and only low signal intensity from the PAH shell.…”

Section: Gold-poly(allylamine Hydrochloride) Core-shell Particlesmentioning

confidence: 94%