A surface graft polymerization process on chemically stable medical ePTFE for suppressing platelet adhesion and activation

Abstract

An effective surface grafting method for chemically inert and elaborately porous medical expanded-polytetrafluoroethylene (ePTFE) was developed. Although surface graft polymerization onto basic polymeric biomaterials has been widely studied, successful modification of the ePTFE surface has been lacking due to its high chemical resistance. Herein, we succeeded in surface graft polymerization onto ePTFE through glycidyl methacrylate (GMA) as a bridge linkage following argon (Ar) plasma treatment. The epoxy group of GMA was expected to react with the peroxide groups produced on ePTFE by Ar plasma exposure, and its methacrylic groups can copolymerize with various monomers. In the present study, we selected 2-methacryloyloxyethyl phosphorylcholine (MPC) as a model monomer and the blood compatibility of modified ePTFE was evaluated. Two sequences of surface grafting were compared. In a two-step graft polymerization, GMA was first immobilized onto Ar plasma treated ePTFE, and then MPC was polymerized. In a one-step graft copolymerization, MPC and GMA were mixed and copolymerized simultaneously onto Ar plasma treated ePTFE, resulting in a poly(MPC-co-GMA) (PMG) graft surface. The roughness of the node-and-fibril structure of ePTFE was reduced by the uniform polymer layer, and the modified ePTFE had a good hydrophilic nature even after being stored in an aqueous environment for 30 days. The indispensable GMA in graft polymerization improved the surface grafting on ePTFE. The one-step and two-step graft polymerization methods could decrease the number of adhered platelets, and almost inhibit platelet activation. We concluded that graft polymerization with the GMA linker provides a novel strategy to modify the chemically inert ePTFE surfaces for functionalizing as new medical devices.

Development of a Simplified Radiation-Induced Emulsion Graft Polymerization Method and Its Application to the Fabrication of a Heavy Metal Adsorbent

“…To solve the problem concerning the dissolved oxygen during emulsion graft polymerization as mentioned in “Introduction,” we introduced a new method, SREG, as shown in Scheme 1. GMA was chosen as a grafting agent, as it could be easily converted to structures having various functions [21,22,23,24,25,26,27]. The process is as follows: (a) The preirradiated PE/PP fabric was set in the commercially available sealed glass jar, made up of the glass lid, the rubber packing, and the jar itself.…”

Modification of relevant polymeric materials for medical applications and devices

“…The surface modification of PUs for medical purposes has been directed towards increasing the biocompatibility, enzyme immobilization or cell adhesion (Ahmad, 2018; Figure 3, demonstrated improved resistance to protein adsorption and good resistance to platelet adhesion, indicating enhanced surface haemocompatibility (Liu, Munisso, et al, 2018).…”

“…Polydimethylsiloxane (PDMS) is an organosilicon polymer, which is also commonly known as silicone rubber, and its general structure is F I G U R E 2 Urethane and polyurethane structures F I G U R E 3 Representation of the grafting PEG onto SPEU synthesized by Liu, Munisso, et al (2018) for avoiding protein adsorption improving haemocompatibility represented in Figure 6. The development of biomedical devices and materials based on PDMS has been vastly explored due to its high biocompatibility, hydrophobicity and useful mechanical properties such as its glass transition temperature (Tg) and high moduli (Abbasi, Mirzadeh, & Katbab, 2001).…”

“…The modification of PU with these polymers has been performed by conventional chemistry, using coupling reactions (Liu, Munisso, et al, 2018), free‐radical polymerization (Calvete, Holguín, & Luna, 2015), plasma‐induced polymerization (Fujimoto, Inoue, & Ikada, 1993; Myung, Yeom, Jang, Choi, & Cho, 2005; Shourgashti, Khorasani, & Khosroshahi, 2010), UV radiation (Zia, Zuber, Mahboob, Sultana, & Sultana, 2010) and with other non‐conventional mechanisms (Guan, Gao, Feng, & Sheng, 2000).…”

“…Small molecules, peptides and other polymers have been grafted into different variations of polyurethane matrices. For example, segmented poly(ester‐urethane) (SPEU) was modified with poly(ethylene glycol) (PEG) via condensation and Michael addition reactions using chemical linkers to favour PEG attach, and the final SPEU‐PEG, represented in Figure 3, demonstrated improved resistance to protein adsorption and good resistance to platelet adhesion, indicating enhanced surface haemocompatibility (Liu, Munisso, et al, 2018).…”