A fluorescent tracer comprises: a RAFT template, comprising the residues: Glycine-Proline-Lysine-Alanine-Lysine-Glycine-Proline-Lysine-Lysine-Lysine and having a mean plane defining an upper face having four lysine residues and a lower face having one lysine residue, four identical targeting molecules comprising the amino acids: Arginine-Glycine-Aspartic acid-Phenylalanine-Lysine (RGDKf), each of the molecules being fixed to a different lysine residue of the first upper face via an oxime bond, and a fluorophore S0456 fixed to the lower face of the mean plane via a spacer arm connecting the central carbon of the sequence of double bonds of the fluorophore and the lysine amino acid of the lower face of the decapeptide via an amide bond, the spacer arm being 5-(4-hydroxyphenyl)pentanoic acid.
