Salomé Poyer

A Simple Post‐Polymerization Modification Method for Controlling Side‐Chain Information in Digital Polymers

A three-step post-polymerization modification method was developed for the design of digitally encoded poly(phosphodiester)s with controllable side groups. Sequence-defined precursors were synthesized, either manually on polystyrene resins or automatically on controlled pore glass supports, using two phosphoramidite monomers containing either terminal alkynes or triisopropylsilyl (TIPS) protected alkyne side groups. Afterwards, these polymers were modified by stepwise copper-catalyzed azide-alkyne cycloaddition (CuAAC). The terminal alkynes were first reacted with a model azide compound, and after removal of the TIPS groups, the remaining alkynes were reacted with another organic azide. This simple method allows for quantitative side-chain modification, thus opening up interesting avenues for the preparation of a wide variety of digital polymers.

2D Sequence-Coded Oligourethane Barcodes for Plastic Materials Labeling

Mixtures of uniform sequence-defined oligourethanes are evaluated as 2D molecular barcodes for labeling three different commodity polymers, namely polystyrene, polyvinylchloride and polyethylene terephthalate. Six different oligourethanes are synthesized by solid-phase iterative synthesis and are coded using a binary monomer alphabet. High-resolution mass spectrometry studies indicate that all oligomers are uniform and sequence-defined. However, instead of using them as individual coded chains, oligomers with different chain-length, mass and sequence are mixed into intentionally polydispersed libraries. In particular, a three-component library and a four-component library are created to encode a 2-bytes model binary sequence. These 2D-coded libraries are incorporated in all commodity plastics via a simple solvent casting procedure. Furthermore, in all cases, the oligomer mixtures can be extracted from the host polymer films and deciphered by mass spectrometry, thus opening interesting avenues for anti-counterfeiting and traceability applications.

Cleavable Binary Dyads: Simplifying Data Extraction and Increasing Storage Density in Digital Polymers

Digital polymers are uniform macromolecules that store monomer-based binary sequences. Molecularly stored information is usually extracted from the polymer by a tandem mass spectrometry (MS/MS) measurement, in which the coded chains are fragmented to reveal each bit (i.e. basic coded monomer unit) of the sequence. Here, we show that data-extraction can be greatly simplified by favoring the formation of MS/MS fragments containing two bits instead of one. In order to do so, digital poly(alkoxyamine phosphodiester)s, containing binary dyads in each repeat unit, were prepared by an orthogonal solid-phase approach involving successive phosphoramidite and radical-radical coupling steps. Three different sets of monomers were considered to build these polymers. In all cases, four coded building blocks-two hydroxy-nitroxides and two phosphoramidite monomers-were required to build the dyads. Among the three studied monomer sets, one combination allowed synthesis of uniform sequence-coded polymers. The resulting polymers led to clear dyad-containing fragments in MS/MS and could therefore be efficiently decoded. Additionally, an algorithm was created to detect specific dyad fragments, thus enabling automated sequencing.

Sequence-coded ATRP macroinitiators

Sequence-coded oligourethanes were tested as macroinitiators for the atom transfer radical polymerization (ATRP) of styrene. These oligomers were synthesized by solid-phase orthogonal iterative chemistry and transformed into ATRP initiators using a three-step modification procedure. A controlled radical polymerization behavior was observed with these macroinitiators, thus opening interesting opportunies for the synthesis of macromolecular architectures containing sequence-defined segments.

Photocontrolled Synthesis of Abiotic Sequence-Defined Oligo(Phosphodiester)s

A photoregulated phosphoramidite iterative process is studied for the synthesis of non-natural, digitally encoded oligo(phosphodiester)s. The oligomers are prepared using two reactive phosphoramidite monomers containing a 2-(2-nitrophenyl)propoxycarbonyl (NPPOC) protected OH group. The stepwise synthesis is performed on an OH-functional soluble polystyrene support, which allows recycling by precipitation in a nonsolvent. Repeating cycles involving phosphoramidite coupling, oxidation of phosphite to phosphate, and NPPOC deprotection by light irradiation at λ = 365 nm are performed in order to prepare oligomers with different lengths and sequences. Synthesis is conducted on a micromolar scale and good recycling yields are obtained in all cases. The use of a soluble polymer support allows an in-depth characterization of the NPPOC photo-deprotection step by 1 H NMR, UV spectroscopy, and size exclusion chromatography, and thus identification of optimal synthesis conditions. After cleavage from the support, the oligo(phosphodiester)s are characterized by tandem mass spectrometry, which confirms preparation of uniform sequence-coded oligomers.

Abiotic Sequence-Coded Oligomers as Efficient In Vivo Taggants for the Identification of Implanted Materials

Sequence-defined oligourethanes were tested as in vivo taggants for implant identification. The oligomers were prepared in an orthogonal solid-phase iterative approach and thus contained a coded monomer sequence that can be unequivocally identified by tandem mass spectrometry (MS/MS). The oligomers were then included in small amounts (1 wt %) in square-centimeter-sized crosslinked poly(vinyl alcohol) (PVA) model films, which were intramuscularly and subcutaneously implanted in the abdomen of rats. After one week, one month, or three months of implantation, the PVA films were explanted. The rat tissues exposed to the implants did not exhibit any adverse reactions, which suggested that the taggants are not harmful and probably not leaching out from the films. Furthermore, the explanted films were immersed in methanol, as a solvent for oligourethanes, and the liquid extract was analyzed by mass spectrometry. In all cases, the oligourethane taggant was detected, and its sequence was identified by MS/MS.