Development of a New Analytical Tool Coupling Mass Spectrometry and Laser Spectroscopy for Polyscopic Nanometrology – PONAME

Charge detection mass spectrometry measures simultaneously and independently the mass-to-charge ratio and the charge of individual ions. Unlike the conventional mass spectrometry, the mass of each ion is deduced directly allowing the study of high molecular weight samples and/or those having an intrinsic polydispersity such as synthetic nanomaterials or macromolecules. Thanks to a high count rate, mass distribution histograms can be built ion-by-ion by this “single-particle” analytical technique. Analytical data characteristic of the distribution such as mean mass, distribution width, and multimodal feature (several population) can then be extracted out of the crude data obtained. The use of an electrospray ionization source enables the generation of multicharged ions in a soft manner allowing transfer into the gas phase of nanomaterials of different nature, composition, and morphology.
The transfer into the gas phase of ionized species provides the ability to manipulate them through the application of an electric field. The charge detection device is then used as an ion trap and the study of fragmentation upon laser irradiation at the «single-ion« level (fragments, residual parent ion, their mass and their charge states) can provide information about their structure and composition.
Another trap of cylindrical type involving the application of radio frequency electric fields allows trapping of ions in a small volume for several seconds. Selected in mass and charge, the ions can be trapped individually and their fluorescence measured after laser irradiation with the aim of correlating their fluorescence properties to their previously determined structural features. To explore these aspects, “tailor-made” functionalized metallic nanostructures with modular physicochemical characteristics are synthesized.

Nanomaterials of various size, morphology and composition, such as micelles, vesicles, composite nanoparticular systems, and biomolecular aggregates were successfully characterized by charge detection mass spectrometry. The “single-particle” approach associated with fast measurements provide reliable data ragarding sample dispersion in addition to the mean mass. The knowledge of the mean mass allowed calculation of the number of aggregation in the nanomaterials nanomaterials obtained from the self-assembly of building blocks of known mass (micelles, vesicles, protein aggregates). It has also been shown on nanoparticulate systems of anisotropic shape (particle assembly), that the measurement of the charge could be a valuable morphology probe.
The analytical tool developed has shown its reliability and robustness during its participation in a national campaign on comparison of dimensional analysis of nanomaterials organized by the Club Nanometrologie, involving academics and industrials. This action was undertaken with a view to standardizing good laboratory practices for dimensional analysis of nanomaterials.
From a more fundamental physical chemistry sight, laser coupling with the charge detection device was a world first and contributed to push the boundaries of laser dissociation methods to ultra high masses. In particular, DNA biomacromolecules activation energies were obtained and, thanks to the «single particle« approach of the device, dissociation channels have been identified based on the structure of DNA.

The interest from all collaborations woven in this project continues. From some preliminary results have emerged ambitious research projects (ANR TOPNANO and Milkyway; Labex Project IMUST MS4NanO). The developped tool offers interesting prospects for understanding the aggregation processes (self-assembly and self-organization) from the individual building blocks to the supramolecular assembly.

N. J. Warren, O. O. Mykaylyl, A. J. Ryan, M. Williams, T. Doussineau, P. Dugourd, R. Antoine, G. Portale, S. P. Armes, J. Am. Chem. Soc. 2014, DOI: 10.1021/ja511423m.

T. Doussineau, A. Anthony, O. Lambert, J.-C. Taveau, M. Lansalot, P. Dugourd, E. Bourgeat-Lami, S. Ravaine, E. Duguet, R. Antoine, J. Phys. Chem. C 2014, DOI: 10.1021/jp510081v.

T. Doussineau, P. Paletto, P. Dugourd, R. Antoine, J. Am. Soc. Mass Spectrom. 2014, DOI: 10.1007/s13361-014-1011-z.

N. Ouadah, T. Doussineau, T. Hamada, P. Dugourd, C. Bordes, R. Antoine, Langmuir 2013, 29 (46), 14074-14081.

R. Antoine, T. Doussineau, P. Dugourd, F. Calvo, Phys. Rev. A 2013, 87(1), 013435.

T. Doussineau, M. Santacreu, R. Antoine, P. Dugourd, W. Zhang, I. Chaduc, M. Lansalot, F. D’Agosto, B. Charleux, ChemPhysChem, 2013, 14(3), 603-609.

T. Doussineau, R. Antoine, M. Santacreu, P. Dugourd, J. Phys. Chem Lett. 2012, 3 (16), 2141-2145.

T. Doussineau, C.-Y. Bao, R. Antoine, P. Dugourd, W.-J. Zhang, F. D’Agosto, B. Charleux, ACS Macro Lett. 2012, 1 (3), 414-417.

T. Doussineau, C.-Y. Bao, C. Clavier, X. Dagany, M. Kerleroux, R. Antoine, P. Dugourd, Rev. Sci. Instrum. 2011, 82, 084104.

T. Doussineau, M. Kerleroux, X. Dagany, C. Clavier, M. Barbaire, J. Maurelli, R. Antoine, P. Dugourd, Rapid Commun. Mass Spectrom. 2011, 25 (5), 617-623.

Nanomaterials, nanoparticles and other engineered nanoscale constructs (ENCs) hold great promise for medical, technological and economical benefits. However, knowledge about the toxicity and environmental impact of ENCs is typically missing. Prior to any thorough study at the nanobiointerface, an exhaustive physico-chemical characterization of ENCs is of high relevance since these features can be correlated to their biological and toxicological responses. A wide variety of analytical tools exists in order to investigate the nanometrology of ENCs but no single method that can be considered complete and satisfactory. In this context, requirements for developing a new nanometrology instrument include flexibility, robustness, accuracy/reliability, multi-parameters measurability, rapid measurement as well as low cost. The PONAME project aims at developing such a new analytical tool coupling mass spectrometry and laser spectroscopy for polyscopic nanometrology. The instrument may be described according to three analytical units as followed:
i) Charge detection mass spectrometry (CD-MS) will allow, in a single event approach, the direct determination of a true and accurate mass/size distribution. In addition, study of the mass/charge relationship in these megadalton weigthed objects (ENCs, (bio)macromolecules) will be of interest in a fundamental point of view by correlating the maximum charge at a given mass to the Rayleigh limit.
ii) Laser induced photo-dissociation on single trapped megadalton ion will be carry out. This unique experiment is expected to provide relevant information on the structure, the morphology and/or surface properties of the trapped macroion of selected mass and charge.
iii) Fluorescence spectroscopy in the gas phase on single trapped macroion will also be performed. We will thus be able to determine the intrinsic optical properties of a megadalton object relatively to its mass/size, charge and structure/morphology. Such a fine analysis might solve partially contradictory results described in the literature on hybrid nanoobjects such as Au@chromophore ranging from full quenching to dramatic increase of the fluorescence.
The PONAME project appears particularly ambitious and relevant in the current context of nanotechnology. The developed instrument is expected to be highly robust and flexible towards the variability in the nature and composition of sampled objects.