Immobilization of Antimicrobial Peptide IG-25 onto Fluoropolymers via Fluorous Interactions and Click Chemistry

Abstract

We report a practical method for biofunctionalization of fluoropolymers based on non-covalent, fluorous interactions and click chemistry which allows incorporation of biomolecules under physiological solutions. We demonstrate the method by immobilization of an antimicrobial peptide (AMP) on fluorous thin films and fluorosilicone contact lens. The fluorous surfaces were dip-coated with fluorous-tagged oligo(ethylene) chain terminated with a reactive group, such as an alkynyl group. This simple step generates a “clickable” surface. The non-covalent fluorous interaction was strong enough to allow subsequent covalent attachment of IG-25, a truncated version of the most extensively studied human AMP LL-37. The attachment was through copper-catalyzed click reaction between the alkynyl group on the surface and the azido-OEG tag at the N-terminus of IG-25. In comparison to surfaces presenting IG-25 randomly bound via carbodiimide chemistry, the surfaces presenting IG-25 tethering to the surface at the N-terminus via click chemistry displayed higher antibacterial activities against an ocular pathogen Pseudomonas aeruginosa (strain PA-O1).

Poly(l-lysine) Interfaces via Dual Click Reactions on Surface-Bound Custom-Designed Dithiol Adsorbates

“…This reaction is highly regioselective and can be performed in high yield. 17,18 Notably, this approach to assembling an array of reactive bonding sites avoids possible self-reactions associated with a single composite maleimide-terminated adsorbate. The second step involved a thiol-Michael addition of the cysteine-terminated poly-L-lysine to the maleimide and was conducted under ambient conditions; 19 this latter reaction has been used in a wide variety of materials/biomaterials applications.…”

Adding Functions to Biomaterial Surfaces through Protein Incorporation

“…for peptides involved in promoting cell adhesion. Commonly used approaches include simple adsorption onto surfaces such as multi-walled carbon nanotube sheets [317] or titanium sheets, [318] covalent attachment onto a variety of materials via EDC/NHS coupling [319] or silanization, [318] click chemistry to attach to fluorous thin films and fluorosilicone, [320] and pre-deposition of an adherent film such as polydopamine to facilitate AMP attachment. [321] A recent comparison of immobilization of AMPs on titanium using silanization with 3-aminopropyltriethoxysilane (APTES) or polymer brush-based coatings prepared by surfaceinitiated ATRP with two different silanes concluded the latter methods led to a greater reduction in bacterial attachment though this was most likely due to a higher yield of immobilized peptide attainable with the approach.…”

Modification of fluorous substrates with oligo(ethylene glycol) via “click” chemistry for long-term resistance of cell adhesion

“…Then, an ethynyl-terminated, "clickable" surface, denoted as surface B (Scheme 1) was fabricated as we previously described. 25 The resultant ethynyl-terminated EG 4 surface B was then subjected to CuAAC reaction with EG 6 -N 3 2 in the presence of Cu + catalyst, excess of sodium ascorbate to reduce Cu 2+ (rapidly formed in air) back to the catalytically active Cu + , and the ligand 3 to accelerate the CuAAC reaction to provide surface C (Scheme 1). 26 was effectively removed by washing with an EDTA solution, as indicated by the absence of the Cu 2p signal ( Figure S2) The incorporation of C 8 F 17 EG 4 and ethynyl-C 8 F 17 EG 4 molecules (surface B and D, respectively) as well as the fluorinated surface A and the clickmodified surface C was also monitored through the atomic F/C concentration ratio in the XPS spectra.…”

“…24 We recently reported a method based on CuAAC reaction for attaching fluorescent molecules, ligands (biotin) and antimicrobial peptides onto fluorous substrates via an intermediate fluorous layer terminated with an alkynyl or azido group. 25,26 For comparison, we also fabricate a fluorinated-EG 4 surface by direct immersion of the fluorinated substrate in a solution with compound 4 (C 8 F 17 -EG 4 ). Analyses of the surfaces were carried out by XPS, contact angle goniometry (CA) and bright field microscopy.…”