**1. Introduction**

Galectins are nearly ubiquitous distributed β-galactoside binding proteins which share a common amino acid sequence, the carbohydrate recognition domain (CRD) (Barondes et al., 1994a; Cooper, 2002; Elola et al., 2007; Hirabayashi & Kasai, 1993; Hughes, 2001; Klyosov et al., 2008; Leffler et al., 2004). They are evident in vertebrates, invertebrates and also protists, implying fundamental functions of these lectins (Hirabayashi & Kasai, 1993). Some galectins are distributed in a variety of different tissues, others are more specifically expressed (Cooper, 2002).

Galectins are known to perform high diversity of functions inside the cells and in the extracellular space. They are regulators of cell cycle, inflammation, immune responses, cancer progression, cell adhesion, cell signalling events and so on. The different functions are performed either by protein-protein or by protein-glycan interactions (Almkvist & Karlsson, 2004; Danguy et al., 2002; Elola et al., 2007; Hernandez & Baum, 2002; Hughes, 2001; Ilarregui et al., 2005; Liu et al., 2002; Liu & Rabinovich, 2005; Rabinovich et al., 2002b; Rabinovich & Toscano, 2009; Vasta, 2009).

Different excellent reviews focus on the wide-spread functions of galectins such as tumor progression, cell signalling or inflammation (Garner & Baum, 2008; Hernandez & Baum, 2002; Liu et al., 2002; Liu & Rabinovich, 2005; Nangia-Makker et al., 2008; Rabinovich et al., 2002a; Rabinovich & Toscano, 2009; van den Brule et al., 2004; Vasta, 2009). Review articles discussing functions of galectins in cell adhesion events and their role as matricellular proteins for the crosslinking of extracellular matrix components have also been published (Elola et al., 2007; Hughes, 2001). The function of galectins in the assembly of the extracellular matrix as well as in cell adhesion and cell signalling processes shows their potential as mediators for cell adhesion and proliferation on biomaterial surfaces. Galectins are interesting candidates for the functionalisation of biomaterial surfaces as they can promote the primary binding event of cells to foreign materials and influence specific signalling processes. In this article we want to analyse the potential use of galectins (explained by the examples of galectin-1, -3 and -8) in biomaterial research and application.
