Protein-Resistant Behavior of Poly(ethylene glycol)-Containing Polymers with Phosphonate/Phosphate Units on Stainless Steel Surfaces

Abstract

Stainless steel is used in a large variety of food and medical applications, where it is susceptible to adsorption of proteins and other materials on its surface, ultimately leading to biofouling. Here, we report the synthesis of a copolymer bearing both poly­(ethylene glycol) (PEG)-antifouling and phosphate-containing monomers, abbreviated as poly­(PEGMA-co-MEP), to be used as an easily applied nano-coating for a stainless steel substrate. Highly tenacious films could be easily deposited by dipping the stainless steel substrate into a dilute aqueous solution of the polymer for a few minutes, which then resisted rinsing over many days. This simple attachment method, which does not need solvents, annealing, or adhesion promoters, looks to be very easy transferable into commercial applications. From quartz crystal microbalance with dissipation experiments, the films were found only about one polymer layer thick. A variety of proteins and skim milk were tested against the poly­(PEGMA-co-MEP)-coated surfaces, which showed almost a 100% reduction in binding affinity. In addition, fluorescence microscopy results showed that PEG phosphate and phosphonate-coated surfaces exhibited strong inhibition of bacterial adhesion for both Escherichia coli and Bacillus cereus over several days. Other PEG polymers containing carboxylic acids as anchoring groups were also tested and gave a somewhat worse performance.

Synthesis of fluorinated phosphorus-containing copolymers and their immobilization and properties on stainless steel

“…These results are consistent with our previous work 14,44 where phosphonate based polymer layers have shown excellent stability upon rinsing under different rinsing conditions. Similar findings were observed in a recent study by Giamblanco et al 65 where they studied the stability of poly(ethylene glycol) copolymers with phosphonate units as surface tethering groups on an iron oxide surface in water, and the resultant films appeared stable.…”

“…S10(a) † ). We showed in previous work, 14 that a PEO-phosphonate copolymer film deposited from water only formed a monolayer on stainless steel as measured by QCM-D.…”

“…The idealized process of showing the adsorption and interaction of phosphonates with stainless steel has been studied in our previous work. 14,44 The adhesion was determined to be via covalent metal-phosphonate linkages, and it assumed that the same binding is found here. The thickness could not be determined directly as in previous work as QCM-D measurements were not possible in the aggressive solvents used here.…”

“…13 Results from our previous work have shown that phosphonate based copolymers have shown stable monolayer binding to 316L stainless steel substrate under aqueous conditions. 14 As stainless steel is widely used in industry and medicine, the modification of its surface properties is of great interest. The formation of ultrathin stable monolayers has an added attraction of being able to allow heat and light transfer while affecting the binding properties of molecules such as proteins.…”

Double hydrophilic copolymers – synthetic approaches, architectural variety, and current application fields

“…Among the different polymers examined for this purpose, DHCs showed excellent antifouling effects. 357,360–362 As one example, Kousar et al 351 reported a nano-coating for a stainless steel substrate. In this work, they used copolymers based on poly(ethylene glycol) methyl ether methacrylate and 2-(meth acryloyloxy)ethyl phosphate (poly(PEGMA- co -MEP)), that was used also as an antifouling coating for covering steel surface (Fig.…”