Letter

Biocompatibility and antifouling: is there really a link? Christophe Blaszykowski1, Sonia Sheikh2, and Michael Thompson1,2,3 1

Econous Systems Inc., Toronto, Ontario, Canada Department of Chemistry, St. George Campus, University of Toronto, Toronto, Ontario, Canada 3 Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada 2

Introduction Predictably endowing materials with biocompatibility still is a challenge at the beginning of the 21st century. Deleterious biological reactions are the result of cellular processes initiated by surface-activated proteins, which upon adsorption restructured to expose cryptic bioactive sites. One can read however that antifouling – the ability of a surface to prevent proteins from adsorbing and accumulating – would constitute a prerequisite to biomaterial inertia. We argue and propose herein that the key to achieving biocompatibility is not to try and minimize the amount of adsorbed proteins, but the degree of unfolding that relevant ones (i.e., those able to trigger a cellular process) may experience upon co-adsorption with other, bystander proteins. Deleterious consequences of protein–material interaction Most medical equipment/devices are fabricated from materials foreign to the human body. Upon contact with bodily fluids, these exogenous materials spontaneously acquire a layer of proteins on their surface [1,2]. Cellular adhesion then may follow [1,2]. Reliably preventing this sequence of events from occurring is however paramount in devising biocompatible medical equipment and implantable (biosensor) devices with full functionality and long life expectancy. In fact, protein adsorption (fouling) is a problematic, ubiquitous phenomenon – a genuine biotechnological plague [3] – that may stimulate deleterious biological processes orchestrated by the immune and coagulation systems [4,5]. For example, serious complications can occur due to the formation of hazardous thromboemboli if blood coagulates upon contact with the multicomponent circuitry of bypass machines that circulate blood during cardiopulmonary surgery [5,6]. Another case is the ‘foreign body reaction’, a detrimental immune response that accompanies normal wound healing following the implantation of a medical device [7,8]. A misidentified ‘Holy Grail’ Intuitively, it is reasonable to think that minimizing the amount of adsorbed proteins, for example by imposing antifouling surface chemistry [3], should go a long way Corresponding author: Blaszykowski, C. ([email protected]). 0167-7799/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.tibtech.2013.11.002

towards biocompatibility. It is thus not surprising that tremendous efforts have been, and continue to be, made to engineer ‘stealth’ organic coatings able to resist protein accumulation from blood-based fluids (i.e., plasma and serum), as reviewed elsewhere [3]. This quest only recently culminated in the development of ultrathin (

Biocompatibility and antifouling: is there really a link?

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