Design and synthesis of digitally encoded polymers that can be decoded and erased.

Biopolymers such as DNA store information in their chains using controlled sequences of monomers. Here we describe a non-natural information-containing macromolecule that can store and retrieve digital information. Monodisperse sequence-encoded poly(alkoxyamine amide)s were synthesized using an iterative strategy employing two chemoselective steps: the reaction of a primary amine with an acid anhydride and the radical coupling of a carbon-centred radical with a nitroxide. A binary code was implemented in the polymer chains using three monomers: one nitroxide spacer and two interchangeable anhydrides defined as 0-bit and 1-bit. This methodology allows encryption of any desired sequence in the chains. Moreover, the formed sequences are easy to decode using tandem mass spectrometry. Indeed, these polymers follow predictable fragmentation pathways that can be easily deciphered. Moreover, poly(alkoxyamine amide)s are thermolabile. Thus, the digital information encrypted in the chains can be erased by heating the polymers in the solid state or in solution.

Convenient Routes to Efficiently N-PEGylated Peptides.

Efficient routes to N-terminal PEGylated peptides are described. Alternative supports such as superparamagnetic core-shell nanoparticles as colloidal supports and end-functional poly(styrene) as homogeneous supports improve the available solid-phase supported coupling strategies preserving ease of purification. Poly(ethylene glycol) (PEG)-peptide bioconjugates are obtained in high yield despite the use of nearly stoichiometric PEGylation agents with respect to the supported peptides.

"Inverse" synthesis of polymer bioconjugates using soluble supports.

Well-defined cleavable or non-cleavable soluble polystyrene supports were prepared by atom transfer radical polymerization and utilized for the iterative synthesis of functional hexapeptides. This approach allowed rapid and efficient liquid phase synthesis of peptide-polymer conjugates.

Reversible pH-controlled switching of poly(methacrylic acid) grafts for functional biointerfaces.

Responsive polymeric brushes of poly(methacrylic acid) (PMAA) were grafted from silicon surfaces using controlled surface-initiated atom-transfer radical polymerization (SI-ATRP). The growth kinetics of PMAA was investigated with respect to the composition of the ATRP medium by grafting the polymer in mixtures of water and methanol with different ratios. The dissociation behavior of the polymer layers was characterized by FTIR titration after incubating the polymer-grafted substrates in PBS buffer solutions with different pH values. PMAA layers show a strong pH-dependent behavior with an effective pK(a) of the bulk polymer brush of 6.5 ± 0.2, which is independent of the polymer brush thickness and methanol content of the ATRP grafting medium. The pH-induced swelling and collapse of the grafted polymer layers were quantified in real time by in situ ellipsometry in liquid environment. Switching between polymer conformations at pH values of 4 and 8 is rapid and reversible, and it is characterized by swelling factors (maximum thickness/minimum thickness) that increase with decreasing the methanol content of the SI-ATRP medium.