Thiazole orange-carboplatin triplex-forming oligonucleotide (TFO) combination probes enhance targeted DNA crosslinking

We report a new class of carboplatin-TFO hybrid that incorporates a bifunctional alkyne-amine nucleobase monomer called AP-C3-dT that enables dual ‘click’ platinum(ii) drug conjugation and thiazole orange fluorophore coupling. Thiazole orange enhances the binding of Pt(ii)-TFO hybrids and provides an intrinsic method for monitoring triplex formation. These hybrid constructs possess increased stabilisation and crosslinking properties in comparison to earlier Pt(ii)-TFOs, and demonstrate sequence-specific binding at neutral pH. © 2023 The Royal Society of Chemistry.