This invention provides for products and processes for binding to a preselected target, where the process involves contacting this target to an oligonucleotide molecule that contains one or more “non-standard” nucleotides, which are nucleotide analogs that, when incorporated into oligonucleotides (DNA or RNA, collectively xNA), present to a complementary strand in a Watson-Crick pairing geometry a pattern of hydrogen bonds that is different from the pattern presented by adenine, guanine, cytosine, and uracil. This disclosure provides an example where such an oligonucleotide molecule contains a single 2-amino-8-(1′-β-D-2′-deoxyribofuranosyl)-imidazo[1,2-a]-1,3,5-triazin-4(8H)one and a single 6-amino-5-nitro-3-(1′-β-D-2′-deoxyribofuranosyl)-2(1H)-pyridone, and where the target is a cell, and is obtained by a process of in vitro selection.