title: "RaMassays": Synergistic Enhancement of Plasmon-Free Raman Scattering and Mass Spectrometry for Multimodal Analysis of Small Molecules.
abstract: SiO2/TiO2core/shell (T-rex) beads were exploited as "all-in-one" building-block materials to create analytical assays that combine plasmon-free surface enhanced Raman scattering (SERS) and surface assisted laser desorption/ionization (SALDI) mass spectrometry (RaMassays). Such a multi-modal approach relies on the unique optical properties of T-rex beads, which are able to harvest and manage light in both UV and Vis range, making ionization and Raman scattering more efficient. RaMassays were successfully applied to the detection of small (molecular weight, M.W. <400 Da) molecules with a key relevance in biochemistry and pharmaceutical analysis. Caffeine and cocaine were utilized as molecular probes to test the combined SERS/SALDI response of RaMassays, showing excellent sensitivity and reproducibility. The differentiation between amphetamine/ephedrine and theophylline/theobromine couples demonstrated the synergistic reciprocal reinforcement of SERS and SALDI. Finally, the conversion of L-tyrosine in L-DOPA was utilized to probe RaMassays as analytical tools for characterizing reaction intermediates without introducing any spurious effects. RaMassays exhibit important advantages over plasmonic nanoparticles in terms of reproducibility, absence of interference and potential integration in multiplexed devices.
authors.affiliation: INSTM and Chemistry for Technologies Laboratory, Mechanical and Industrial Engineering Department (DIMI), University of Brescia, via Branze 38, 25123 Brescia, Italy.
authors.forename: Ivano
authors.initials: I
authors.lastname: Alessandri
authors.affiliation: INSTM and Chemistry for Technologies Laboratory, Mechanical and Industrial Engineering Department (DIMI), University of Brescia, via Branze 38, 25123 Brescia, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Vassalini
authors.affiliation: INSTM and Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Bertuzzi
authors.affiliation: INSTM and Chemistry for Technologies Laboratory, Mechanical and Industrial Engineering Department (DIMI), University of Brescia, via Branze 38, 25123 Brescia, Italy.
authors.forename: Nicolò
authors.initials: N
authors.lastname: Bontempi
authors.affiliation: INSTM and Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Memo
authors.affiliation: INSTM and Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Gianoncelli