Enabling Indium Channels for Mass Cytometry by Using Reinforced Cyclam-Based Chelating Polylysine
Laura Grenier, Maryline Beyler, Taunia Closson, Nick Zabinyakov, Alexandre Bouzekri, Yefeng Zhang, Jothir Mayanantham Pichaandi, Mitchell A. Winnik, Peng Liu, Olga Ornatsky, Vladimir Baranov, Raphaël Tripier
Abstract
The synthesis of a polylysine polymer functionalized with the previously reported astonishingly inert [In(cb-te2pa)]+ chelate was performed. A biotin end group allowed the conjugation to biotinylated beads by the intermediary of a fluorescein isothiocyanate/neutravidin receptor. High quality imaging mass cytometry trials, based on 115In detection were performed to highlight the behavior of the material. Anti-CD20 antibody was labeled by the so-obtained In(III)-modified polylysine using the biotin/neutravidin interaction. Ramos (CD20[+]) and HL-60 (CD20[−]) cell lines were costained with the In(III)-modified bioconjugate by finding the best staining conditions. Both immunofluorescence microscopy (IF-M) and mass cytometry analyses confirmed the specific binding of anti-CD20 onto Ramos cells. CyTOF histograms constructed on the 115In detection allowed us to define and to separate, with a good signal-to-noise ratio, two populations (Ramos and HL-60). The inertness of In(III)-MCP-NAv over a three-month storage period was proved by performing new functionality tests involving Jurkat cells (CD20[−]) and multiparametric trials involving the 115In channel. The results ensure a promising future use of the previously announced [In(cb-te2pa)]+ complex-based polymers for mass cytometry.