Copolymer Brush-Based Ultralow-Fouling Biorecognition Surface Platform for Food Safety

Abstract

Functional polymer coatings that combine the ability to resist nonspecific fouling from complex media with high biorecognition element (BRE) immobilization capacity represent an emerging class of new functional materials for a number of bioanalytical and biosensor technologies for medical diagnostics, security, and food safety. Here, we report on a random copolymer brush surface - poly(CBMAA-ran-HPMAA) - providing high BRE immobilization capacity while simultaneously exhibiting ultralow-fouling behavior in complex food media. We demonstrate that both the functionalization and fouling resistance capabilities of such copolymer brushes can be tuned by changing the surface contents of the two monomer units: nonionic N-(2-hydroxypropyl) methacrylamide (HPMAA) and carboxy-functional zwitterionic carboxybetaine methacrylamide (CBMAA). It is demonstrated that the resistance to fouling decreases with the surface content of CBMAA; poly(CBMAA-ran-HPMAA) brushes with CBMAA molar content up to 15 mol % maintain excellent resistance to fouling from a variety of homogenized foods (hamburger, cucumber, milk, and lettuce) even after covalent attachment of BREs to carboxy groups of CBMAA. The poly(CBMAA 15 mol %-ran-HPMAA) brushes functionalized with antibodies are demonstrated to exhibit fouling resistance from food samples by up to 3 orders of magnitude better when compared with the widely used low-fouling carboxy-functional oligo(ethylene glycol) (OEG)-based alkanethiolate self-assembled monolayers (AT SAMs) and, furthermore, by up to 2 orders of magnitude better when compared with the most successful ultralow-fouling biorecognition coatings - poly(carboxybetaine acrylamide), poly(CBAA). When model SPR detections of food-borne bacterial pathogens in homogenized foods are used, it is also demonstrated that the antibody-functionalized poly(CBMAA 15 mol %-ran-HPMAA) brush exhibits superior biorecognition properties over the poly(CBAA).

Modulation of Living Cell Behavior with Ultra‐Low Fouling Polymer Brush Interfaces

“…The set of surfaces prepared for the purpose of this study included the state‐of‐art ultra‐low fouling brushes of zwitterionic pCBAA and pCBMAA, nonionic pHPMAA, and p(CBMAA‐ co ‐HPMAA) copolymers with randomly distributed monomer units 30. A scheme of the polymer brush structures is shown in Figure 1 .…”

“…The brushes of pCBMAA, pCBAA, and random copolymers of CBMAA‐HPMAA were synthesized on homogenous gold‐coated substrates using surface‐initiated atom transfer radical polymerization procedure as described elsewhere giving a resulting wet thickness of ≈75 nm,30,48 see also Supporting Information. The model microarray substrates containing squared (50 µm × 50 µm and a spacing of 50 µm) and circular patterns (with a diameter of 20 µm and a spacing of 50 µm) were prepared via an optical lithography.…”

“…The brushes based on zwitterionic pCB, nonionic pHPMAA, and random p(CBMAA‐ co ‐HPMAA) copolymers with the comparable wet thickness were employed. In case of p(CBMAA‐ co ‐HPMAA), we take the advantage of easily tunable surface properties achieved by adjusting the molar feed ratio of the monomers with statistically distributed monomer units in the brush structure 30. The tendency of the cell growth, cellular shaping, cytoskeleton distribution, and clustering were analyzed using the high‐resolution spinning disk confocal microscopy.…”

Bioactive Antifouling Surfaces by Visible‐Light‐Triggered Polymerization

“…A good bioactive antifouling layer balances two objectives, namely, maximizing immobilization of bioreceptors and minimizing the nonspecific adsorption of proteins . However, a significant amount of immobilized bioreceptors itself increases the nonspecific adsorption of proteins, due to fouling nature of bioreceptors on their own, as well as due to the changes in antifouling brush structure . In contrast, a low amount of immobilized bioreceptors might decrease the biosensing capabilities of the bioactive surfaces, but better maintains the antifouling properties of the polymer brushes.…”

Plasmonic Hepatitis B Biosensor for the Analysis of Clinical Saliva

“…This value corresponds to about a monolayer as was reported for proteins exhibiting similar molecular weight. 30 Comparable surface mass density has been shown previously for SAM-based architectures, however, the resistance to fouling was largely impaired. 31 …”