Process for preparing a surface coated by crosslinked polyelectrolyte multilayer films as a biomimetic reservoir for proteins

1. A process for coating a surface, comprising the following steps:

(a) sequentially depositing on a surface at least one layer of alternate adsorbed polyelectrolytes to provide a coated surface presenting complementary amino and carboxylic reactive groups, wherein a first (or conversely second) polyelectrolyte is a cationic polymer comprising said amino groups and a second (or conversely first) polyelectrolyte is an anionic polymer comprising said carboxylic groups,

(b) reacting said complementary reactive groups of the coated surface in the presence of a coupling agent, as to form amide bonds between said complementary reactive groups giving rise to a cross-linked polyelectrolyte multilayer film, and

(c) treating said cross-linked polyelectrolyte multilayer film with a protein containing solution as to incorporate said protein on and inside said cross-linked polyelectrolyte multilayer film, wherein the obtained polyelectrolyte multilayers film has a thickness ranging from 500 nm to 20 μm.

2. The process according to claim 1 , wherein the protein of step (c) is:

a) a growth factor type protein; or

b) BMP-2 or SDF-1.

3. The process according to claim 1 , wherein the obtained polyelectrolyte multilayer film has a thickness ranging from

1 μm to 10 μm.

4. The process according to claim 2 , wherein the growth factor type protein is BMP-2 and the concentration of BMP-2 in the solution is such that the amount of BMP-2 incorporated in the film, obtained after step (c), varies from:

a) 50 ng/cm 2 to 20 μg/cm 2 ;

b) 0.2 μg/cm 2 to 10 μg/cm 2 ; or

c) 1 μg/cm 2 to 6 μg/cm 2 .

5. The process according to claim 2 , wherein the growth factor type protein is SDF-1 and the concentration of SDF-1 in the solution is such that the amount of SDF-1 incorporated in the film, obtained after step (c), varies from:

a) 50 ng/cm 2 to 20 μg/cm 2 ;

b) 0.2 μg/cm 2 to 10 μg/cm 2 ; or

c) 0.3 μg/cm 2 to 6 μg/cm 2 .

6. The process according to claim 1 , wherein the anionic polymer comprising a carboxylic group is selected from the group consisting of polyacrylic acid, polymethacrylic acid, poly(glutamic) acid, polyuronic acid, glycosaminoglycans, poly(aspartic acid), and mixtures thereof.

7. The process according to claim 1 , wherein the anionic polymer comprising carboxylic groups is hyaluronic acid or a salt thereof.

8. The process according to claim 1 , wherein the cationic polymer comprising amino groups is selected from the group consisting of poly(lysine), poly(diallyldimethylammonium chloride), poly(allylamine), poly(ethylene)imine, chitosan, poly(arginine), poly(ornithine), poly(histidine), poly(mannoseamine) and mixtures thereof.

9. The process according to claim 1 , wherein the cationic polymer comprising amino groups is poly(lysine).

10. The process according to claim 1 , wherein the polyelectrolyte multilayer film is a Polylysine/HA film.

11. The process according to claim 1 , wherein said polyelectrolyte multilayer film is a Polylysine/HA-HEP or Polylysine/HEP film.

12. The process according to claim 1 , wherein the coupling agent is a compound of formula (I):

RN═C═NR′  (I),

wherein R and R′, which are identical or different, represent an alkyl or aryl group.

13. The process according to claim 1 , wherein the coupling agent is 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC).

14. The process according to claim 1 , wherein step (b) is carried out also in the presence of at least one N-hydroxysuccinimide compound.

15. The process according to claim 1 , wherein step (b) is carried out also in the presence of at least one N-hydroxysuccinimide compound and said N-hydroxysuccinimide compound is selected from the group consisting of N-hydroxysulfosuccinimide para-nitrophenol and dimethylaminopyridine.

16. The process according to claim 1 , wherein step (a) comprises steps selected from the group consisting of dipping, dip-coating, rinsing, dip-rinsing, spraying, inkjet printing, stamping, printing and microcontact printing, wiping, doctor blading and spin coating.

17. The process according to claim 1 , wherein step (a) involves coating and rinsing steps.