A survey of state-of-the-art surface chemistries to minimize fouling from human and animal biofluids

Abstract

Upon contact with bodily fluids, synthetic materials spontaneously acquire a layer of various species (most notably proteins) on their surface. The concern with respect to biomedical equipment, implants or devices resides in the possibility for biological processes with potentially harmful effects to ensue. In biosensor technology, the issue with this natural fouling phenomenon is that of non-specific adsorption to sensing platforms, which generates an often overwhelming interference signal that prevents the detection, not to mention the quantification, of target analytes present at considerably lower concentration. To alleviate this ubiquitous, recurrent problem - this genuine biotechnological plague - considerable research efforts have been devoted over the last few decades to engineer antifouling coatings. Extensive literature now exists that describes stealth organic adlayers capable of reducing fouling surface coverage Γ down to a few ng cm(-2)- however from biotechnologically irrelevant buffered solutions free or nearly depleted of any potentially interfering species. Regrettably indeed, few coatings are known to display/retain such level of performance when exposed to otherwise more complex, real-life biosamples (even diluted). Herein, we comprehensively review the state-of-the-art surface chemistries developed to date (January 2015) to minimize fouling from 8 such uncomparatively more challenging biological media (blood plasma, blood serum, cell lysate, cerebrospinal fluid, egg, milk, saliva, and urine) - whether of human or animal origin. Literature search for another 25 biological milieux generated no (exploitable) hit. Also discussed in this Review are the identification of the species responsible for fouling, and the dependence of antifouling properties on biosample source variability.

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

“…Excellent fouling resistance has been recently reported for ultra‐low fouling polymer brushes 2. Examples include nonionic poly(2‐hydroxyethyl methacrylate), poly(3‐hydroxypropyl methacrylate), poly( N ‐(2‐hydroxypropyl)methacrylamide) (pHPMAA), zwitterionic poly(carboxybetaine)‐based (pCB) brushes such as poly(carboxybetaine methacrylamide) (pCBMAA) and poly(carboxybetaine acrylamide) (pCBAA), or recently developed random copolymers combining zwitterionic and nonionic moieties such as p(CBMAA‐ co ‐HPMAA) 1,2,5,6. These platforms are characterized by diverse physicochemical surface properties including structure, architecture, thickness, rigidity, wettability, surface charge, packing density, or swelling properties; all of these parameters have been shown to have an impact on resulting surface resistance to fouling from complex media and biological activity of immobilized biorecognition elements 5,7.…”

“…[1,2,5,6] These platforms are characterized by diverse physicochemical surface properties including structure, architecture, thickness, rigidity, wettability, surface charge, packing density, or swelling properties; all of these parameters have been shown to have an impact on resulting surface resistance to fouling from complex media and biological activity of immobilized biorecognition elements. [5,7] Therefore, it is expected that these factors may also significantly influence behavior of living cells in the proximity of such coatings. In fact, when the cells are seeded on such surfaces, the coatings will act as an analogue of extracellular matrix and thus will have a substantial impact on cells, conveying physical and chemical stimuli, and influencing cellular shape, actin cytoskeleton organization, and transcription activity.…”

Label-Free Sandwich Imaging Ellipsometry Immunosensor for Serological Detection of Procalcitonin

“…The other challenge is the nonspecific adsorption from the serum 13,14 . Although many works have focused on developing anti-fouling immunosensor substrates 15 , the non-specific adsorption still haunts in practice and its interference cannot be eliminated completely in the serological detection 13 .…”

Plasmonic Hepatitis B Biosensor for the Analysis of Clinical Saliva

“…Arguably, the key problem in the analysis of clinically relevant samples by plasmonic biosensors is the fouling of their metallic surface with tethered ligands for specific capture of target analyte. 19,20 To solve this problem, research in surface chemistries and architectures was pursued to decrease or completely eliminate the adverse effect of fouling and thereby maximize the efficiency. The most widely used surface modifications are based on poly(ethylene glycol) (PEG), for example, self-assembled monolayers (SAM) terminated with short oligoethylene glycol (OEG).…”