Function - spacer - lipid (FSL) constructs are amphiphilic molecules that are able to disperse in water and then self-assemble into cell membranes or onto solid surfaces. Modification of a biological or non-biological surface is very easy and achieved by simple contact of the surface with an appropriately buffered solution containing one or more FSLs. When the functional head group of the FSL is a glycan, glycan modified surfaces can be rapidly formed. Once cells, viruses, or solid surfaces are FSL modified with either simple or complex glycans, they can be used in vitro and/or in vivo to measure interactions with cells, viruses, antibodies, and lectins. FSLs have already been used in a variety of techniques including antibody specificity mapping, antibody/toxin neutralization, diagnostic assays, immune system manipulation, and animal modeling of transfusion reactions. FSLs offer the easiest and fastest method available to achieve a glycan-modified surface.