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186 results on '"Gobbo, Pierangelo"'

10. Orthogonal Light-Dependent Membrane Adhesion Induces Social Self-Sorting and Member-Specific DNA Communication in Synthetic Cell Communities

Author

Heidari, Ali, Sentürk, Oya I., Yang, Shuo, Joesaar, Alex, Gobbo, Pierangelo, Mann, Stephen, de Greef, Tom F.A., Wegner, Seraphine V., Heidari, Ali, Sentürk, Oya I., Yang, Shuo, Joesaar, Alex, Gobbo, Pierangelo, Mann, Stephen, de Greef, Tom F.A., and Wegner, Seraphine V.

Abstract

Developing orthogonal chemical communication pathways in diverse synthetic cell communities is a considerable challenge due to the increased crosstalk and interference associated with large numbers of different types of sender-receiver pairs. Herein, the authors control which sender-receiver pairs communicate in a three-membered community of synthetic cells through red and blue light illumination. Semipermeable protein-polymer-based synthetic cells (proteinosomes) with complementary membrane-attached protein adhesion communicate through single-stranded DNA oligomers and synergistically process biochemical information within a community consisting of one sender and two different receiver populations. Different pairs of red and blue light-responsive protein-protein interactions act as membrane adhesion mediators between the sender and receivers such that they self-assemble and socially self-sort into different multicellular structures under red and blue light. Consequently, distinct sender-receiver pairs come into the signaling range depending on the light illumination and are able to communicate specifically without activation of the other receiver population. Overall, this work shows how photoswitchable membrane adhesion gives rise to different self-sorting protocell patterns that mediate member-specific DNA-based communication in ternary populations of synthetic cells and provides a step towards the design of orthogonal chemical communication networks in diverse communities of synthetic cells.

Published
2023

17. High-resolution Raman imaging of bundles of single-walled carbon nanotubes by tip-enhanced Raman spectroscopy

Author

Kazemi-Zanjani, Nastaran, Gobbo, Pierangelo, Zhu, Ziyan, Workentin, Mark S., and Lagugne-Labarthet, Francois

Subjects
Raman spectroscopy -- Methods -- Analysis, Surface plasmon resonance -- Properties -- Analysis, Near field microscopy -- Methods -- Analysis, Electron microscopy -- Methods -- Analysis, X-ray spectroscopy -- Methods -- Analysis, Thermogravimetry -- Methods -- Analysis, Atomic force microscopy -- Methods -- Analysis, Nanotubes -- Properties -- Spectra -- Analysis, Resolution (Optics) -- Analysis -- Research, Chemistry
Abstract

Bundles of single-walled carbon nanotubes (SWCNTs) prepared by plasma torch method and further purified, are deposited over a glass coverslip to estimate the spatial resolution of tip-enhanced Raman spectroscopy measurements. For this purpose, near-field Raman maps and spectra of isolated bundles of carbon nanotubes are collected using optimized experimental conditions such as a tightly focused beam using a 1.4 numerical aperture oil immersion microscope objective and a gold coated atomic force microscope probe illuminated by a radially polarized 632.8 nm wavelength to selectively excite the localized surface plasmon confined at the extremity of the tip. The near-field nature of the collected Raman signals is evaluated through measuring the decay of the Raman signal with respect to the tip-sample separation. Key words: tip-enhanced Raman spectroscopy, localized surface plasmon resonance, near-field spectroscopy, radial polarization, atomic force microscopy, spatial resolution, enhancement factor, single-walled carbon nanotubes. Des fagots de nanofils de carbone simple-paroi, prepares par torche plasma puis purifies sont deposes sur des lamelles de microscope dans la perspective de mesurer la resolution spatiale de mesures Raman locales exaltees par effet de pointe. A cette fin, des cartographies ainsi que des spectres Raman sont collectes dans des conditions experimentales optimisees basees sur l'utilisation d'un objectif de microscope a forte ouverture numerique (O.N. 1.4) et d'une excitation avec une polarisation radiale a 632, 8 nm afin d'exciter selectivement le plasmon de surface localise et de confiner ce dernier a l'extremite de la pointe en or. Le champ proche Raman est evalue en analysant la decroissance du signal collecte en fonction de la distance entre la pointe et l'echantillon. Mots-cles: spectroscopie Raman exaltee par effet de pointe, plasmon de surface localise, microscopie en champ proche, polarisation radiale, microscopie a force atomique, resolution spatiale, facteur d'exaltation, nanofils de carbone a simple paroi., Introduction The discovery of surface-enhanced Raman spectroscopy (SERS) in the early 1970's was a milestone in improving the inherent low efficiency of inelastic Raman scattering. (1, 2) The improved sensitivity [...]

Published
2015
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32. Click And Bioorthogonal Chemistry For The Chemical Modification Of Nanomaterials

Author

Gobbo, Pierangelo

Subjects
Functional Nanomaterial, Carbon Nanotube, Materials Chemistry, Click Chemistry, Bioorthogonal Chemistry, Gold Nanoparticle
Abstract

The goal of this Ph.D. thesis work is the development of novel reactive nanomaterial templates that can be chemically modified in a facile and robust (i.e., formation of covalent bonds) way for the further modification of the nanomaterial’s physical-chemical properties by the reaction partner molecular system. This type of technology was employed to further expand the application of nanomaterials in nanomedicine, chemical biology and materials science. In order to reach this goal, as a proof of concept, small (d = 3nm) gold nanoparticles (AuNPs) and carbon nanotubes (CNT) were used as the nanomaterial substrates. Innovative synthetic strategies for the introduction of click and bioorthogonal functional groups onto the surface of these nanomaterials were developed. These functional groups include a maleimide that can undergo three click reactions with different functional groups (i.e., Michael addition with nucleophiles, Diels-Alder cycloaddition with dienes, dipolar cycloadditions with dipolar molecules), strained alkynes for bioorthogonal strain-promoted cycloaddition reactions with azides and nitrones, and methyl-2-(diphenylphosphino)benzoate moieties for the bioorthogonal Staudinger-Bertozzi ligation with azides. In order to study and characterize these clickable and bioorthogonal nanomaterial templates, methodologies for the determination of the amount of reactive functionalities introduced onto the nanomaterial’s surface and the evaluation of their proper reactivity were also developed. 1H NMR spectroscopy, transmission electron microscopy, and thermogravimetric analysis, were methodically used for the quantification of the interfacial reactive functionalities. 1H NMR spectroscopy was also employed to follow the correct interfacial reactivity of the nanomaterial template. Finally, in collaboration with Surface Science Western, the use of X-ray photoelectron spectroscopy (XPS) was developed as a method to independently confirm all the previously obtained results and, more specifically, quantitate the amount of interfacial reactive molecules that were introduced, track the interfacial organic chemistry of the nanomaterial template, and determine interfacial reaction yields. In all cases the clickable and bioorthogonal nanomaterial templates were found to react quickly, efficiently and chemoselectively with their chemical reporter through a simple pour-and-mix type of chemistry. The utility of these clickable and bioorthogonal nanomaterial templates was finally showcased in bioconjugation, for the synthesis of fluorogenic biosensors, nanomaterial hybrids and nanomaterial-based MRI contrast agents.

Published
2016

49. 'Shine & Click' Photo-Induced Interfacial Unmasking of Strained Alkynes on Small Water-Soluble Gold Nanoparticles.

Author

Luo, Wilson, Gobbo, Pierangelo, McNitt, Christopher D., Sutton, Dewey A., Popik, Vladimir V., and Workentin, Mark S.

Subjects
*GOLD nanoparticles, *LIGANDS (Chemistry), *CYCLOPROPENONES, *THIOLS, *THERMOGRAVIMETRY
Abstract

In this study, we report the design, synthesis, and characterization of small 3 nm water soluble gold nanoparticles (AuNPs) that feature cyclopropenone-masked strained alkyne moieties capable of undergoing interfacial strain-promoted cycloaddition (i-SPAAC) with azides after exposure to UV-A light. A strained alkyne precursor was incorporated onto AuNPs by direct ligand exchange of a thiol-modified cyclopropenone-masked dibenzocyclooctyne (photoDIBO) ligand. These photoDIBO-AuNPs were characterized by 1H NMR, IR, and UV/Vis spectroscopy, as well as transmission electron microscopy (TEM) and thermogravimetric analysis (TGA), and the extent of modification was quantified. Upon irradiation with UV-A light, photoDIBO-AuNPs underwent efficient and quantitative regeneration of the parent strained alkyne by photochemical decarbonylation to afford DIBO-derivatized AuNPs. DIBO-AuNPs were found to react cleanly and rapidly ( k=5.3×10−2 m−1 s−1) by an interfacial strain-promoted alkyne-azide cycloadditon (i-SPAAC) with benzyl azide, which served as a simple model system. Furthermore, DIBO-AuNPs were reacted with various azides and a nitrone (interfacial strain-promoted alkyne-nitrone cycloaddition, i -SPANC) to showcase the generality of this approach for the facile modification of AuNP surfaces and their properties. The cyclopropenone-based photo-triggered click chemistry at the interface of water-soluble AuNPs offers exciting opportunities for the atom-by-atom control and assembly of functional materials for applications in materials and biomaterials science as well as in chemical biology. [ABSTRACT FROM AUTHOR]

Published
2017
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