received by the International Bureau on 19 November 2015 (19.1 1 .2015)

Cell-instructing composition comprising:

a platelet lysate with an initial concentration of 1-2 million platelets/ L, diluted between 1-1500 times, depending on some protein incorporation that may desirable to be improved or reduced; and with a pH between 2 and 11, in order to facilitate incorporation of some protein (s) according to their isoelectric point and subsequent overall charge;

at least one substrate; and

at least one positive or negative polyelectrolyte for stabilization and/or binding of the platelet lysate; assembled layer-by-layer.

Cell-instructing composition according to claim 1, wherein the polyelectrolyte is alginate, chitosan, carrageenan, and heparin, or combinations thereof.

Cell-instructing composition according to the previous claims, wherein the polyelectrolyte is a sulphated polyelectrolyte .

Cell-instructing composition according to any one of the previous claims, comprising a bilayer of platelet lysate and carrageenan.

Cell-instructing composition according to any one of the previous claims, comprising 10 tetra-layers of two bilayers of carrageenan, one of chitosan and one of platelet lysate.

6. Cell-instructing composition according to any one of the previous claims, wherein said composition is in the form of a film, a coating or a fibrillar structure.

7. Layer-by-layer assembling process for obtaining the cell-instructing composition described in claims 1-6, comprising the following steps:

a) dipping a substrate into a polyelectrolyte solution for at least 30 seconds at 0-60°C;

b) dipping the substrate into a rising solution preferably composed by the same liquid phase of the other solutions for at least 30 seconds between 0-60°C;

c) dipping the substrate into a platelet lysate solution for at least 30 seconds between 0- 60°C;

d) dipping the substrate into a rising solution preferably composed by the same liquid phase of the other solutions for at least 30 seconds between 0-60°C; or

e) repeating the set of layers between at least 1- 6 times.

8. Layer-by-layer assembling process according to claim 7, comprising steps a) , b) , c) and d) followed by

- dipping the substrate into a polyelectrolyte solution for at least 30 seconds at 0-60°C, dipping the substrate into a rising solution preferably composed by the same liquid phase of the other solutions for at least 30 seconds between 0-60°C, dipping the substrate into other polyelectrolyte solution for at least 30 seconds at 0-60°C and dipping the substrate into a rising solution preferably composed by the same liquid phase of the other solutions for at least 30 seconds between 0-60°C, and

- repeating the set of layers between at least 1-10 times .

9 . Layer-by-layer assembling process according to the previous claims, wherein the polyelectrolyte is alginate, chitosan, carrageenan, and heparin, or combinations thereof.

10. Layer-by-layer assembling process according to claim 9, wherein the polyelectrolyte is a sulphated polyelectrolyte .

11. Layer-by-layer assembling process according to any one of claims 7 to 10, comprising at least one additional step selected from: layer-by-layer modification, physical or chemical modification, irradiation, freeze- drying or sterilization.

12. Cell-instructing composition according to any one of claims 1-6 for use in regenerative medicine, providing a controlled display of multiple proteins, which are able to synergistically enhance or trigger a specific cell behavior.

13. Cell-instructing composition according to any one of claims 1-6 for use in tissue engineering applications, providing a controlled display of multiple proteins, which are able to synergistically enhance or trigger a specific cell behavior.

1 . Medical device coated with the cell-instructing composition described in any one of claims 1-6 for use in regenerative medicine.

15. Medical device coated with the cell-instructing composition described in any one of claims 1-6 for use in tissue engineering applications.