Electrografting of mixed organophosphonic monolayers for SI-ATRP of 2-methacryloyloxyethyl phosphorylcholine

Abstract

Nitinol (NiTi), one of the most important alloys for biomedical applications, is still hampered by its surface nickel inclusions, making it sensitive to pitting corrosion and leading therefore to the release of potentially carcinogenic Ni 2+ ions. In this work, we assess the impact of the combination of electrografted mixed self-assembled monolayers (SAMs) on NiTi followed by a polymer coating formed by surfaceinitiated atom transfer radical polymerization (SI-ATRP). The molecular ratio of 11-(2-bromoisobutyrate)-undecyl-1-phosphonic acid (BUPA) to 11-decylphosphonic acid (C 10 P) on the electroassisted elaboration of the (BUPA/C 10 P)-NiTi-SAMs has been optimized. A small amount of BUPA (20%) appears to be the most promising condition, as it provides an efficient corrosion resistance and promotes the SI-ATRP of 2-methacryloyloxyethyl methacrylate (MPC). This confers to the surface hydrophilic properties and corrosion resistance close to those NiTi-SAMs when long polymerization times are used (‡ 6 h).

A Comparative Study of the Electro-Assisted Grafting of Mono- and Bi-Phosphonic Acids on Nitinol

“…The (electro)grafting of bisphopshonic acid derivatives thus appear to be a promising alternative for mixed monolayers, which were previously used for the grafting of bulky polymerization initiators [44]. In this context, a monolayer made of a polymerization initiating specie deriving from HEP 2 or MIP 2 needs to be investigated.…”

“…Some molecules of interest present bulky terminal functions, which can lead to disordered and less protective layers. The use of mixed monolayers resulting from the co-adsorption of two organophosphonic acid derivatives differing in length and/or terminal functional groups has been shown to improve the corrosion resistance as well as the layer organization [41][42][43][44]. The present experimental work investigates the grafting on NiTi of short tail mono-and bi-phosphonic acid derivatives, which could be an alternative to the mixed monolayers approach, to find the most efficient anchoring group to be used in molecules of biological interests.…”

Unravelling Surface Modification Strategies for Preventing Medical Device‐Induced Thrombosis

“…For example, individual MPC molecules can form a monolayer or bilayer film via weak hydrophobic or van der Waal interactions, which obviously limits by the inherent instability. [ 204 ] Similarly, the disulfide‐modified PC was self‐assembled by the high affinity of gold substrate. [ 205 ] Other routes could be accounted for the incorporation of MPC groups alongside the polymethacrylate and polyurethane‐based polymers or the in situ polymerization of MPC into biomimetic film, which proposed more stable and stealth coatings.…”

Nanofabrication Techniques in Large-Area Molecular Electronic Devices

“…In addition to the fabrication of exceptionally robust monolayers for molecular electronics applications, this technique is an affordable methodology to reach specific improvements in surface functionalization for an extensive variety of substrates. For example, mixed monolayers made of organophosphonic derivatives have been electrografted onto nitinol (NiTi), which is an alloy often employed in the biomedical field, in order to prevent the release of the possibly carcinogenic Ni 2+ ions [327]. Kim et al [143] modified a GLAD-ITO substrate by the electrografting of a porphyrin diazonium salt, showing the possibility to introduce molecular functionalities, such as photo-activity Numerous examples can be found in the literature reporting molecular electronic devices based on the electrografting of diazonium salts.…”