Fig. 1: Establishment of the whole-cell-based CAM discovery platform in liquid medium.

a Schematic of the strategy for facilitating precise DNA conjugation between specific cells through synthetic cell-cell adhesion. Bacteria expressing diverse nanobodies (Nb) and conjugative cells with surface antigens (Ag) are involved. b The whole-cell-based selection platform is designed to identify nanobody CAMs targeting specific antigens of interest. Conjugative cells expressing the target antigen and cells displaying the nanobody library are employed. ① Within a liquid culture, contact-dependent DNA conjugation is enhanced through strong binding between cognate nanobodies and antigen pairs (both labeled in blue). ② After conjugation, antibiotics are used to eliminate conjugative cells and recipients expressing non-nanobody binders. ③ After a single round of selection, transconjugants carrying nanobodies with a relatively strong binding affinity toward the target antigens are enriched. c Conjugation frequencies (transconjugants/total recipients) of conjugative plasmids (pGenR, pAmpR, and pTmpR) were assessed under both solid and liquid growth conditions for a 6 h duration. E. coli S17-1 serves as the conjugative donor strain, and MG1655 serves as the recipient strain. d Conjugation frequency of pGenR under the liquid growth condition. Recipient cells expressing nanobodies were co-cultured with donor cells displaying cognate or orthogonal antigens. Data are presented as means ± SD. n = 3 biological replicates with three technical replicates each. Asterisks indicate statistically significant differences between the indicated mean values (p < 0.05, two-tailed t-test). See also Supplementary Fig. 1. Source data are provided as a Source Data file.