The composition of the invention comprises: (a) polyethylene glycol with a molecular weight comprised between 20000 (20 K) and 50000 (50 K), at a weight/volume concentration comprised between 0.5 and 15%; (b) a non-ionic surfactant of general formula (I) where n is comprised between 5 and 40, and said surfactant being at a volume/volume concentration comprised between 0.1% and 2.0%; and (c) one or more ingredients selected from a liquid carrier, a binder and an additive suitable for printing.The composition of the invention is used for printing molecules of biological interest.