Figure 1.

 Synthesis of mesenchymal–epithelial transition factor‐binding peptide‐click‐cRGDyk (cMBP‐click‐cRGDyk) heterodimer. Reagents and conditions: (i) 2‐(2‐[2‐Fmoc aminoethoxy]ethoxy)acetic acid, DIC, HOBT, DMF, rt, 2 h; (ii) NaN₃, water, 4°C, 16 h; (iii) DIC, HOBT, DMF, rt, 2 h; (iv) Cu(I)Br, DIPEA, DMF, propiolic cRGDyk, rt, 4 h; (v) 20% piperidine in DMF, rt, 10 min (Fmoc deprotection); (vi) triisopropylsilane, thioanisol, water, ethanedithiol, trifluoroacetic acid (2.5/2.5/2.5/2.5/90), rt, 3 h (cleavage). DIC, N,N′‐diisopropylcarbodiimide; DIPEA, N,N‐diisopropylethylamine; DMF, N,N‐dimethylformamide; HOBT, hydroxybenzotriazole.