Contents: (Small 2/2013)

The cover shows the modifi cation of living cells with single-stranded DNA oligonucleotides. The method described by C. M. Niemeyer and co-workers on page 255 takes advantage of covalent modifi cation of carbohydrate residues of membrane proteins, which are abundant on the surface of eukaryotic cells. Cis-diols of these carbohydrates are oxidatively cleaved to generate a carbonyl group, which undergoes a chemoselective oxime ligation with aminooxybiotin to produce biotinylated proteins. These are targeted by streptavidin covalently conjugated with DNA oligonucleotides. This method outperforms alternative chemistries for DNA coupling to cell surfaces because of its high labeling effi cacy, specifi city, and low impact on cell viability.