Emanuele Barborini
Tethis SpA, Italy
Title: Nanostructured surfaces for on-plate processing of biological samples in MALDI mass spectrometry
Biography
Biography: Emanuele Barborini
Abstract
Matrix-assisted laser desorption/ionization mass spectrometry (MALDIMS) is a powerful analytical tool endowed with the capability to analyze in short time several classes of biomolecules (e.g. peptides, proteins, nucleic acids) as well as micro-organisms (e.g. bacteria), up to whole histological sections. However, MALDI-MS effectiveness may be hampered by the complexity of the sample itself or by the presence of contaminants. This requires a many-steps pre-analysis processing of the samples, which is carried out in-vial. Nanostructured surfaces can be exploited to transfer sample processing (e.g. secondary cleaning, enzymatic cleavage) from vials directly to the MALDI plate. Here we show the use of Cluster Beam Deposition [1,2] to deposit patterned nanostructured films, made of ultrafine TiO2 nanoparticles (top image), onto suitable substrates for MALDI-MS. Material nanoporosity (due to nanoparticle soft-assembling) and bio-affinity play a synergic role in sample capturing. Super-hydrophilicity induced in TiO2 by UV irradiation [3] ensures uniform spreading in the case of liquid samples as well as optimal adhesion in the case of histological sections. Hydrophobic barrier at the border of the super-hydrophilic nanostructured areas acts as an effective confinement structure for droplets (bottom image), allowing reliable on-plate sample processing. In comparison with standard in-vial approach, on-plate processing avoids the loss of sample fractions due to cleaning or to the sticking on vials plastic surfaces, and improves the management of scanty samples in general. Regarding histological samples, the nanostructured film improves tissue adhesion and avoids detachment, tearing and shrinking, during processing (e.g. dehydration, delipidation, fixation). Improved adhesion can also benefit pharmaco-kinetic studies, where any tissue treatment is a-priori excluded [4]. The use of nanostructured films and surface-engineering concepts for the development of advanced plates in MALDI-MS may contribute to further fuel the spreading of this powerful analytical technique in clinical proteomic as well as biomedical and healthcare areas in general, with the ultimate benefit for patients.