Method for preparing polybiotinylated compounds

A compound having the formula (I):

• where
• X is biotin or
• Y is biotin or
• Z is biotin or
• V is biotin or
• B is NH2 or H,
• AA is a trifunctional molecule derivative when B is NH2 or a bifunctional molecule derivative when B is H,
• AA1 to AA4 are each independently a trifunctional molecule derivative,
• G0 to G5 are each independently an arm comprising a (—CH2—CH2—O) unit,
• n0 to n5 are each independently a whole number between 1 and 8 and
• T is a maleimide group, a carboxylic acid group or an antiligand.