Surface Zwitterionization of Expanded Poly(tetrafluoroethylene) via Dopamine-Assisted Consecutive Immersion Coating

Abstract

Expanded polytetrafluoroethylene (ePTFE) is one of the materials widely used in the biomedical field, yet its application is being limited by adverse reactions such as thrombosis when it comes in contact with blood. Thus, a simple and robust way to modify ePTFE to be biologically inert is sought after. Modification of ePTFE without high-energy pretreatment, such as immersion coating, has been of interest to researchers for its straightforward process and ease in scaling up. In this study, we utilized a two-step immersion coating to zwitterionize ePTFE membranes. The first coating consists of the codeposition of polyethylenimine (PEI) and polydopamine (PDA) to produce amine groups in the surface of the ePTFE for further functionalization. These amine groups from PEI will be coupled with the epoxide group of the zwitterionic copolymer, poly(GMA-co-SBMA) (PGS), via a ring-opening reaction in the second coating. The coated ePTFE membranes were physically and chemically characterized to ensure that each step of the coating is successful. The membranes were also tested for their thrombogenicity via quantification of the blood cells attached to it during contact with biological solutions. The coated membranes exhibited around 90% reduction in attachment with respect to the uncoated ePTFE for both Gram-positive and Gram-negative strains of bacteria (Staphylococcus aureus and Escherichia coli). The coating was also able to resist blood cell attachment from human whole blood by 81.57% and resist red blood cell attachment from red blood cell concentrate by 93.4%. These ePTFE membranes, which are coated by a simple immersion coating, show significant enhancement of the biocompatibility of the membranes, which shows promise for future use in biological devices.

Thermoresponsive Polymer Brushes for Switchable Protein Adsorption via Dopamine‐Assisted Grafting‐To Strategy

“…[50,53,54] The poly(DA) layer can be simply deposited from aqueous solutions, does not require harsh pretreatment by, for example, plasma activation or strong acid, and the free amine groups present can conveniently be used for reactions with several chemical functional groups, including epoxides, [55] which thus also allow polymer attachment. [56][57][58] The epoxide functionality can be introduced to polymer chains as end group functionality or by incorporation of epoxide-containing monomers during the polymerization step. [59,60] We thus hypothesized that a block copolymer design that combines a short poly(glycidyl methacrylate) (poly(GMA)) segment with a longer thermoresponsive polymer segment would provide for effective covalent attachment of a fully characterizable, thermoresponsive block copolymers to poly(DA)-functionalized surfaces.…”

Zwitterionic Biomaterials

“…301 Therefore, Yoneyama et al further increased the content of PMEH in the SPU/PMEH blend to 10 wt % and prepared the SPU/PMEH(10) coated vascular graft, which showed no thrombus and pseudointima formation 8 weeks after implantation. 302 Following MPC, other zwitterionic polymers have also been developed as coatings for artificial vascular grafts, such as SBMA copolymers 303 and SB modified starch, 304 starch coating via thiol−ene click chemistry, which facilitated the adhesion, proliferation, and migration of human umbilical vein endothelial cells (HUVECs) onto the vascular grafts. 304 In addition to synthetic polymers, Zheng et al designed two triblock functional proteins, cofp-MZY and cofp-MZR, as the coating materials.…”

“…Following MPC, other zwitterionic polymers have also been developed as coatings for artificial vascular grafts, such as SBMA copolymers and SB modified starch, which all showed improved hemocompatibility compared with uncoated grafts. Yao et al further conjugated REDV peptide to the SB-starch coating via thiol–ene click chemistry, which facilitated the adhesion, proliferation, and migration of human umbilical vein endothelial cells (HUVECs) onto the vascular grafts .…”

Intervention of Polydopamine Assembly and Adhesion on Nanoscale Interfaces: State‐of‐the‐Art Designs and Biomedical Applications

“…Polydopamine (PDA) is a bioinspired synthetic analogue of naturally occurring melanin, which contains catechol, quinone, imine, amine functional groups and -conjugated structures. [46] While the abundant functional groups make the material surface hydrophilic, [47][48][49] the fascinating -conjugated structures of PDA endow it with favorable photoelectrical activity that was universally possessed by conjugated polymers. [50][51][52] Specifically, the comproportionation equilibrium between the quinone, hydroquinone, and semiquinone (SQ) forms can generate free protons in the form of hydronium ions which can drift and diffuse through the matrix by hopping (the Grötthus mechanism [53] ), leading to a solid-state proton conducting behavior.…”