Carbohydrate–Lectin Interaction on Graphene-Coated Surface Plasmon Resonance (SPR) Interfaces Abra Penezic & Geetanjali Deokar & Dominique Vignaud & Emmanuelle Pichonat & Henri Happy & Palaniappan Subramanian & Blaženka Gasparović & Rabah Boukherroub & Sabine Szunerits Received: 25 October 2013 /Accepted: 29 January 2014 # Springer Science+Business Media New York 2014 Abstract The paper describes the detection of carbohydrate– lectin interaction on graphene-on-metal surface plasmon res- onance (SPR) interfaces. Graphene-coated gold-based SPR interfaces were formed through the transfer of large-area graphene grown by chemical vapor deposition (CVD) on polycrystalline Cu foils. The method allowed successful trans- fer of single- and double-layered graphene sheets onto the SPR interfaces in a reproducible manner. Functionalization of the graphene interface with mannose was achieved by simple immersion into a mannose aqueous solution (100 mM), resulting in noncovalent interactions between the aromatic ring structure of graphene and mannose. The utility of the carbohydrate-modified graphene-on-gold interface for the se- lective and sensitive detection of carbohydrate–lectin interac- tions was demonstrated using model lectins from Lens culinaris (LC) and Triticum vulgaris (TV). While LC lectin binds specifically to mannopyranoside units, TV lectin has an affinity for N-acetyl glucosamine and sialic acid residues. Keywords Graphene . Surface plasmon resonance . Mannose . Lectins . Biosensors Introduction The development of carbohydrate interfaces for the study of interactions with lectins, enzymes, bacteria, and other biolog- ical relevant molecules has received much attention over the last years due to the essential role of oligosaccharides in the development and maintenance of all living systems [1–7]. Most of the early sensors rely on an end point and, thus, indirect detection of a labelled protein. Different label-free methods have lately been considered as attractive alternatives, allowing glycosignatures to be scrutinized more rapidly and more easily. Among the label-free methods available, plasmon-based techniques such as surface plasmon resonance (SPR), SPR imaging, and localized surface plasmon reso- nance (LSPR) have received the greatest attention to date in high-throughput glycan profiling [1, 4, 6–9]. The choice of the surface chemistry employed for linking glycans to the sensor surface is one of the important steps in the development of a highly performing glycan sensor. Self-assembled monolayers of thiol-functionalized carbohydrates have been widely used for decoration of SPR interfaces. The prerequisite of thiol- functionalized carbohydrate analogues is, however, often not straightforward to synthesize, and the formation of well- defined monolayers is not guaranteed [10]. Pyrrole- [1], azide- [2, 11], and alkynyl-terminated [4] glycans have been used as alternatives to thiolated glycans. Nevertheless, the requirement for prior derivatization of the carbohydrate by one or multistep sequences presents a significant hurdle for the construction of functional glycan arrays. The field would undoubtedly benefit greatly from alternative conjugation strat- egies. Among more recent scenarios, photoinduced covalent attachment of glycans to interfaces coated with photoreactive groups has been proposed [4, 5, 12, 13]. Graphene-coated SPR interfaces have been theoretically [ 14, 15 ] and experimentally [ 17–22] investigated as A. Penezic : P. Subramanian : R. Boukherroub : S. Szunerits (*) Institut de Recherche Interdisciplinaire (IRI, USR-3078), Université Lille 1, Parc de la Haute Borne, 50 Avenue de Halley, BP 70478, 59658 Villeneuve d’Ascq, France e-mail: sabine.szunerits@iri.univ-lille1.fr A. Penezic : B. Gasparović Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia G. Deokar : D. Vignaud : E. Pichonat : H. Happy Institute of Electronics, Microelectronics and Nanotechnology (IEMN), UMR-CNRS 8520, Université Lille 1, Cité Scientifique, 59655 Villeneuve d’Ascq, France Plasmonics DOI 10.1007/s11468-014-9686-3