rXXXX American Chemical Society A dx.doi.org/10.1021/bm101547d | Biomacromolecules XXXX, XXX, 000–000 ARTICLE pubs.acs.org/Biomac Bactericidal Microparticles Decorated by an Antimicrobial Peptide for the Easy Disinfection of Sensitive Aqueous Solutions Thomas Blin, † Viswas Purohit, † J  er^ ome Leprince, ‡ Thierry Jouenne, † and Karine Glinel* ,§ † Laboratoire Polym eres, Biopolym eres, Surfaces, UMR 6270 & FR 3038, Universit  e de Rouen, Bd Maurice de Broglie, 76821 Mont Saint Aignan, France ‡ Laboratoire de Diff erenciation et Communication Neuronale et Neuroendocrine, INSERM U982, PRIMACEN, IFRMP23, Universit  e de Rouen, Place Emile Blondel, 76821 Mont Saint Aignan, France § Institute of Condensed Matter and Nanosciences - Bio & Soft Matter, Universit  e Catholique de Louvain, Croix du Sud 1/4, 1348 Louvain-la-Neuve, Belgium b S Supporting Information ’ INTRODUCTION There is a considerable interest in the development of innovative techniques to remove or to kill micro-organisms present in aqueous solutions, not only for drinking water but also for sanitizing biomedical, pharmaceutical, and cosmetic formulations. 1-3 Indeed, some of these complex formulations contain sensitive bioactive products that can be denatured by the usual disinfecting methods such as temperature treatment. Alternatively, chemical disinfecting methods have been devel- oped based on the addition of water-soluble antimicrobial agents such as chlorine, ozone, antibiotics, or poly(quaternary ammo- nium) salts, depending on the application. 1 Although the effec- tiveness of these substances against micro-organisms is largely proven, their use is controversial. Indeed, it has been revealed in the last two decades that chemical disinfectants, such as chlorine used for water treatment, induce the formation of harmful byproducts. 4 In the case of drinking water production, for instance, it has been shown that these compounds can react with various constituents of natural water to form carcinogens and toxic derivatives. 5 The antibiotics are also not recommended because of their role in the emergence of multiresisting patho- gens. 6 As for poly(quaternary ammonium) salts like chitosan, they are also not completely satisfying because of their rather limited antimicrobial activity spectrum. 7 To overcome these shortcomings related to water-soluble antimicrobial substances, processes based on water-insoluble materials have been recently developed. These materials consist essentially of insoluble particles such as polymeric latexes, clay platelets, glass fibers, ceramic particles, or polyelectrolyte cap- sules coated by a conventional bactericidal agent immobilized by adsorption or chemical grafting. 8-11 The idea is to fabricate drug- supported particles that are able to kill bacteria by surface contact and that can be removed by filtration, centrifugation, or decanta- tion. Despite their effectiveness, such post-treatments are time- consuming, not practical, and even more expensive. In this con- text, nanomaterials such as silver, titanium oxide, or zinc oxide nanoparticles have been gaining considerable attention within the past few years because of their highly efficient bactericidal properties. Nevertheless, although the antibacterial activity of these nanosubstances such as silver has been well-known since antiquity, 12 several studies have recently pointed out the envir- onmental and health risks related to the extensive use of these nanoparticles. 13,14 Besides the conventional antimicrobial agents, a new class of substances, called antimicrobial peptides (AMPs), have recently emerged as a very promising alternative. 15,16 These natural peptides, which are components of the immune natural defense system of various living organisms, exert their activity by Received: December 21, 2010 Revised: January 26, 2011 ABSTRACT: Silica and paramagnetic silica microparticles are surface-modified by an antibacterial macromolecular coating. For this, a hydrophilic copolymer brush based on oligo(ethylene glycol) methacrylates is grown on the particle surface by surface-initiated ATRP. Then, Magainin-I, a natural antimicrobial peptide, is grafted onto the hydroxyl groups of the brush through a heterolinker. The grafting of the peptide is evidenced by fluorescence microscopy and X-ray photoelectron spectroscopy. Moreover, culturability and viability assays per- formed in the presence of the magainin-grafted particles prove their bactericidal properties. The rapid recovery of the bactericidal particles based on paramag- netic silica and suspended in solution is shown under magnetization. Such particles offer the advantage to treat efficiently various sensitive aqueous solutions while avoiding any dissemination of bactericidal substances in the environment. As a consequence, they are of a great interest for various applications in medical, cosmetic, or biomedical fields.