Peptide-Assisted Design of Precision Polymer Sequences: On the Relevance of the Side-Chain Sequences and the Variability of the Backbone.

Functional sequences of monodisperse, sequence-defined oligo(amide-urethane)s are designed based on a peptide sequence as blueprint. The translation of a discrete side-chain functionality sequence from a known peptide-based solubilizer of the photosensitizer meta-tetra(hydroxyphenyl)-chlorin, into a non-peptidic precision polymer backbone is demonstrated. The resulting peptidomimetic precision polymers retain the functions of the parent peptide sequence, showing analogues sensitivity toward single monomer mutations/exchanges and even exceeding the parent peptide equivalent by reaching up to 69% higher payload capacities and more favored release kinetics.

Digging into the Sequential Space of Thiolactone Precision Polymers: A Combinatorial Strategy to Identify Functional Domains.

Functional sequences of precision polymers based on thiolactone/Michael chemistry are identified from a large one-bead one-compound library. Single-bead readout by MALDI-TOF MS/MS identifies sequences that host m-THPC that is a second generation photo-sensitizer drug. The corresponding Tla/Michael-PEG conjugates make m-THPC available in solution and drug payload as well as drug release kinetics can be fine-tuned by the precision segment.

PEGylated Precision Segments Based on Sequence-Defined Thiolactone Oligomers.

A straightforward access route to multifunctional block copolymers, combining a poly(ethylene glycol) (PEG) block and a monodisperse segment with discrete monomer sequence based on thiolactone chemistry, is described. Exploiting an inverse conjugation strategy on a PEG preloaded poly(styrene) synthesis resin enables the convenient introduction of a predefined PEG-block at the α-terminus of thiolactone-based sequence-defined oligomers. Reaction conditions for the stepwise, submonomer synthesis at polar solid supports are optimized, using sequential synthesis on a model resin that enables to isolate and determine the purity of the oligomer segments by liquid chromatography-electrospray ionization mass spectrometry analysis. The reaction conditions are used to synthesize PEGylated 5mer precision polymers with defined monomer sequence in good yields and high purity to offer an interesting platform of macromolecules with potential for biomedical applications.

Responsive Thiolactone-Derived N-Substituted Poly(Urethane-Amide)s.

AB' type monomers containing a thiolactone unit and vinyl ether moiety have been prepared with high yields. Aminolysis of the thiolactone moiety generates the corresponding thiol in situ, and upon UV-irradiation, radical polyaddition occurs in the same medium, yielding linear poly(amide-urethane)s with different side chain residues and (Poly(Ethylene Oxide)) PEO-like backbone. Moreover, these unique polymers feature lower critical solution temperature behavior in water. Systematic modification of the responsive polymers reveals the influence of the variation of the side chains and the backbone structure on the corresponding solubility properties. In selected cases, multiresponsive polymers have been developed, which also respond to pH and metal concentration.