Biotin-dT is a deoxythymidine nucleotide base attached to biotin through a long-chain alkyl spacer arm. Biotin-dT is typically used to label an oligonucleotide with biotin at an internal base position, though it can also be used for 5’- and 3’-end labeling as well. Internal biotin-labeling is necessary when an oligo needs to be captured or immobilized, but both ends are unavailable. A good example of this is the use of internal biotin-labeling to facilitate the immobilization of a molecular beacon on a glass slide (1). The internal labeling strategy can also be used to label a hybridization detection probe with several biotins to enhance detection of a target sequence with anti-biotin antibodies attached to colored particles (2), fluorescent dyes, or enzymes.
1. Fang, X., Liu, X., Schuster, S., Tan, W. Designing a novel molecular beacon for surface immobilized DNA hybridization studies. J. Am. Chem. Soc. (1999), 121: 2921-2922.
2. Dineva, M.A., Candotti, D., Fletcher-Brown, F., Allain, J-P., Lee, H. Simultaneous Visual Detection of Multiple Viral Amplicons by Dipstick Assay.J. Clin. Microbiol. (2005), 43: 4015-4021.