The duplexes include aHis-tag binding strand (tri-NTA-ODN-1, Figure 8A) and a complementary strand (ODN-2) bearinga dye of choice and a CSP ligand.54 Selectivelabeling of specific cancer cells that overexpress distinct CSPs (FR,SR, or PSMA) was achieved using three different B-probes (Figure 8B).102 The high efficiency by which the B-probes labeled the cancercells is attributed to two main factors: The first is the numerousligands covering the bacterial scaffolds, enabling the B-probes toengage in multivalent interactions with the cancer cells. The gene discussed is FOLH1; the disease is cancer.