Finding Cells That Will Make What You Want

Graduate student Jamie Link in the Center for the Science and Engineering of Materials at the California Institute of Technology has developed a method for identifying cells that will make new materials that normal cells just won’t make. Bacterial cells that can use azidohomoalanine (1) in place of one of the natural amino acids, can be detected by labeling their surfaces with the biotin-alkyne reagent 2 (Scheme 1). Labeled cells remain intact, and can be sorted from normal, unlabeled cells with good selectivity (Figure 1). Under the auspices of the Center, Jamie is using such “cell-surface display” methods to screen for E. coli cells that activate amino acids that carry novel side chain functionality that is useful in materials design. There are many reactions other than that shown in Scheme 1 that should be amenable to this approach.

Scheme 1. Surface labeling of E. coli via Cu(I)-catalyzed cycloaddition.

Jamie’s research is part of a multidisciplinary effort directed toward developing cellular systems that can make new materials for use in medicine and biotechnology.

Figure 1. Flow cytometry of (A) normal cells, (B) cells labeled with a small amount of 1, (C) cells labeled with a large amount of 1, (D) a mixed population of labeled and unlabeled cells.