Lubricin Antiadhesive Coatings Exhibit Size‐Selective Transport Properties that Inhibit Biofouling of Electrode Surfaces with Minimal Loss in Electrochemical Activity

Abstract

Electrochemical sensing is a highly effective technique for rapidly detecting and quantifying the presence of electroactive compounds in solution. However, effective sensing requires the electrode surface to be free of contamination, which makes this technique particularly susceptible to the effects of surface fouling due to the unwanted adhesion of biomolecules. Unfortunately, coating electrodes with antiadhesive molecules typically causes electrical passivation with detrimental effects upon electrochemical processes. Lubricin is a large glycoprotein found in articular joints, which self‐assembles on most substrates and exhibits excellent antiadhesive properties. This report finds that lubricin antiadhesive coatings function as a size‐selective transport barrier that physically blocks large, fouling molecules (e.g., proteins) while still allowing small molecules to diffuse into, out‐of, and within this layer more‐or‐less unimpeded. The diffuse nature of the lubricin coatings ensures the electrode retains a large, “free” surface area that facilitates efficient charge transfer. Using cyclic voltammetry to measure the oxidation/reduction of a K3[Fe(CN)6] redox couple at a gold electrode (a system particularly susceptible to fouling), this report shows that antiadhesive lubricin brush coatings can be used for highly sensitive amperometric/voltametric detection of small electroactive compounds in highly fouling solutions of proteins and blood plasma with minimal, immediate impact upon the electrochemistry.

Lubricin on Platinum Electrodes: A Low‐Impedance Protein‐Resistant Surface Towards Biomedical Implantation

“…Thus as expected, the amount of LUB immobilized on the Pt electrode surfaces increased in accordance with Pt exposure to increasing concentrations of LUB in solution. The LUB surface coverage levels obtained for Pt surfaces in this study are at least one order of magnitude higher than LUB surface coverages reported on Au surfaces . This was confirmed by performing the chronocoulometric experiments using Au electrodes (Supplementary information Figure S2).…”

“…The direct immobilization of LUB layers on surfaces has been investigated on different surfaces such as negatively charged mica, silica, polymermeric microfluidic devices, and more recently gold ,. The antifouling properties of LUB tethered to gold surfaces has also been studied electrochemically and it was shown that the LUB (native and recombinant) coatings were of sufficiently low impedance that Faradaic electrochemistry still occurred at the underlying electrodes whilst still preventing biofouling by large molecules such as bovine serum albumin . Despite these documented reports of the impressive antifouling properties of LUB, studies towards bionic implants applications are yet to be conducted.…”

Modified Electrodes for Selective Voltammetric Detection of Biomolecules

“…Recently, a self‐assembled lubricin based antiadhesive and antifouling coating was utilized as permselective surface for the small electroactive compounds. Its size selectivity lies in the telechelic brush structure transport that just allows the small size molecule to pass to transducer surface .…”

“…The assembling structure of the coating prominently controls the selectivity of the membrane. The more ordered packing of the polymer structure leads higher permselectivity with very low permeability . The electrosynthesized coatings simplify the immunoassay by providing the direct exposure of the biosensor to the unprocessed complex matrix material .…”

ZnO superhydrophobic coating via convenient spraying and its biofouling resistance

“…Consequently, protein‐resistant coatings may resist bacterial attachment and biofilm formation. Many authors use the level of protein adsorbed on a surface as a measurement tool to predict fouling . Furthermore, it is widely recognized that proteins are the main components of biofouling .…”