Toward Protein-Repellent Surface Coatings from Catechol-Containing Cationic Poly(2-ethyl-2-oxazoline)

Abstract

Inspired by mussel proteins that enable surface binding in harsh marine environments, we envisioned a platform of protein-repellent macromolecules based on poly(2-ethyl-2-oxazoline) carrying catechol and cationic functional groups. To facilitate surface attachment, catechol units were installed by copolymerizing a functional comonomer, i.e., 2-(3,4-dimethoxyphenyl)-2-oxazoline, in a gradient fashion. Cationic units were introduced by partial acidic hydrolysis. The surface affinity of these polymers was probed using a quartz crystal microbalance with dissipation monitoring (QCM-D), and it was found that polymers with catechol units had a strong tendency to form surface-bound layers on different substrates, i.e., gold, iron, borosilicate, and polystyrene. While the neutral catechol-containing polymers showed strong, but uncontrolled binding, the ones with additional cationic units were able to form defined and durable polymer films. These coatings were able to prevent the attachment of different model proteins, i.e., bovine serum albumin (BSA), fibrinogen (FI), or lysozyme (LYZ). The herein-introduced platform offers straightforward access to nonfouling surface coatings using a biomimetic approach.

Recent Advances in Antifouling Surface Polymer Brushes

“…By tuning the composition and structure, the physical properties such as hydrophilicity or thermal responsiveness of POx can be manipulated, allowing for tailored modulation of biomaterial interactions . Surface POx brushes can be presented with linear, − bottlebrush or comblike, ,− and cyclic structures. , Both the chemical structures and molecular topologies of surface POx brushes are found to be closely related to their interfacial properties. ,, Tang et al reported the synthesis of poly­(2-alkyl-2-oxaoline) brushes by surface-initiated ATRP of a series of oligo­(2-alkyl-2-oxazoline) methacrylate macromonomers from gold surfaces modified with thiolated ATRP initiators . Through using the SPR, they investigated the resistance of the polymer brushes to the attachment of proteins such as BSA, fibronectin, and FBS.…”

Multifunctional coatings hinging on the catechol/amine interplay

“…[16] On the other hand, in the last decade coatings inspired to the same chemistry, but using different starting materials have been explored and their potential assessed for different applications. [17][18][19][20][21][22][23][24][25] The versatile chemistry of catechols make different mode of interaction with amine components possible ranging from covalent-type via Michael-type addition or Schiff-base formation to non-covalent electrostatic and cation-π ones.…”

“…On the other hand, in the last decade coatings inspired to the same chemistry, but using different starting materials have been explored and their potential assessed for different applications [17–25] …”