Utilization of Glycosyltransferases for the Synthesis of a Densely Packed Hyperbranched Polysaccharide Brush Coating as Artificial Glycocalyx

Abstract

Densely packed polysaccharide brushes consisting of α-d-glucose residues were grafted from modified silicon substrates. Potato phosphorylase was herein used to grow linear polysaccharide chains from silicon tethered maltoheptaose oligosaccharides using glucose-1-phosphate as donor substrate. The combined use of potato phosphorylase and Deinococcus geothermalis branching enzyme resulted in a hyperbranched brush coating as the latter one redistributes short oligosaccharides from the α(1–4)-linked position to the α (1–6)-linked position in the polysaccharide brush. The obtained grafting density of the brushes was estimated on 1.89 nm–2 while the thickness was measured with ellipsometric techniques and determined to be between 12.2 and 20.2 nm.

Enzymatic Synthesis of Amylose Brushes Revisited: Details from X‐Ray Photoelectron Spectroscopy and Spectroscopic Ellipsometry

“…While on the gold/cysteamine surface extended MH units can be assumed, the lower density obtained on Si wafer/APDMES can envisage the presence of some coiled units that makes them inaccessible for further polymerization. The degree of polymerization of the amylose brushes can be estimates as previously reported …”

“…The degree of polymerization of the amylose brushes can be estimates as previously reported. [32] A first proof of the successful brush growth was provided from the XPS spectra after the enzymatic polymerization. In detail, the XPS results did not reveal any contribution either from sulfur 2p 3/2 or from gold 4f 7/2 core level regions.…”

“…[25][26][27][28][29] Interestingly, the first surface-initiated enzymatic polymerization ever reported was the synthesis of amylose brushes on planar and spherical surfaces [30,31] and this approach was extended recently by the synthesis of amylopectin brushes via an enzymatic ''grafting from'' procedure. [32] However, to date a proper surface chemistry characterization of these systems is still missing.…”

Synthesis of Telechelic and Three-Arm Polytetrahydrofuran-block-amylose

“…Reductive amination using NaBH 3 CN as a reducing agent can be used to couple maltoheptaose to the synthesized telechelic amine terminated PTHF. The resulting maltoheptaose‐ b ‐PTHF ‐b ‐maltoheptaose is expected to be able to act as a primer for the enzymatic polymerization of glucose‐1‐phosphate (G 1 P) to prepare amylose‐ b ‐PTHF‐ b ‐amylose . In this case, potato phosphorylase is used as a biocatalyst for the enzymatic polymerization (Scheme ).…”

Synthesis of Hyperbranched Glycoconjugates by the Combined Action of Potato Phosphorylase and Glycogen Branching Enzyme from Deinococcus geothermalis

“…The presence of an acceptor substrate (or primer) is essential for PP and makes this enzyme ideal for the preparation of bioconjugates as the primer can be chemically bound to the synthetic polymer or substrate of choice. Via this concept, amylose-like polymer chains were already grown from: Si surface [20], polystyrene [21,22], PEG [2] and Si particles [23]. The inspiring work of Pfannemüller resulted in a series of (multi)functional primers and diblock copolymers that were subsequently used as acceptor substrate for PP [24][25][26][27].…”