Particles of cross-linked proteins and polysaccharides with hydroxamic groups for chelating metals and their uses notably in cosmetics

A particle selected from a micro-particle and/or a nanoparticle having a surface, which comprises, at least on the surface thereof, a wall composed of a mixture of at least one protein and of at least one polysaccharide which are cross-linked in a reaction medium by interfacial cross-linking with a polyfunctional acylating cross-linking agent which forms at least amide and ester bonds, and optionally anhydride bonds, with amine, hydroxyl or carboxyl functions of the protein and of the polysaccharide, said protein and said polysaccharide being present in said at least cross-linked wall in a relative weight ratio of at least 0.5/0.1 of reaction medium, to provide to said cross-linked wall resistance to degradation by hydroxylamine in an alkaline medium, said particles comprising hydroxamic groups on the surface thereof for chelating metal ions.

A particle selected from a micro particle and/or a nanoparticle having a surface, which comprises, at least on the surface thereof, a wall composed of a mixture of at least one protein and of at least one polysaccharide which are cross-linked in a reaction medium by interfacial cross-linking with a polyfunctional acylating cross-linking agent which forms at least amide and ester bonds, and optionally anhydride bonds, with amine, hydroxyl or carboxyl functions of the protein and of the polysaccharide, said protein ranging between 0.5 and 2.5 weight % and said polysaccharide ranging between 0.1 and 10 weight % with respect to the reaction medium, to provide to said cross-linked wall resistance to degradation by hydroxylamine in an alkaline medium, said particles comprising hydroxamic groups on the surface thereof for chelating metal ions.

A method of preparing particles selected from micro particles and/or nanoparticles having a surface which comprises a first step wherein an interfacial cross-linking is carried out in a reaction medium comprising a mixture of at least one protein and of at least one polysaccharide, with a polyfunctional acylating cross-liking agent to obtain said particles comprising, at least on the surface thereof, amide, ester and optionally anhydride functions, said protein and said polysaccharide being present in said at least cross-linked wall in relative weight proportions sufficient to provide to said cross-linked wall resistance to degradation by hydroxylamine in an alkaline medium, and, in a second step, these cross-linked particles are reacted with hydroxylamine in an alkaline medium to cause rupture at least of ester bonds and optionally anhydride bonds with the linking of hydroxamic groups, which particles are recovered, said particles being there by capable of carrying out the chelation of metal ions.

A method of preparing particles selected from micro particles and/or nanoparticles having a surface which comprises a first step wherein an interfacial cross-linking is carried out in a reaction medium comprising a mixture of at least one protein and of at least one polysaccharide, with a polyfunctional acylating cross-linking agent to obtain said particles comprising, at least on the surface thereof amide, ester and optionally anhydride functions, said protein and said polysaccharide being present in said at least cross-linked wall in a relative weight ratio of at least 0.5/0.1 of reaction medium, and, in the second step, these cross-linked particles are reacted with hydroxylamine in an alkaline medium to cause a rupture at least of ester bonds and optionally anhydride bonds with the linking of hydroxamic groups, which particles are recovered, said particles being thereby capable of carrying out the chelation of metal ions.

A method of preparing particles selected from micro-particles and/or nanoparticles having a surface which comprises a first step wherein an interfacial cross-linking is carried out in a reaction medium comprising a mixture of at least one protein and of at least one polysaccharide, with a polyfunctional acylating cross-linking agent to obtain said particles comprising, at least on the surface thereof amide, ester and optionally anhydride functions, said protein ranging between 0.5 and 2.5 weight % and said polysaccharide ranging between 0.1 and 10 weight % with respect to the reaction medium, and, in a second step, these cross-linked particles are reacted with hydroxylamine in an alkaline medium to cause a rupture at least of ester bonds and optionally anhydride bonds with the linking of hydroxamic groups, which particles are recovered, said particles being thereby capable of carrying out the chelation of metal ions.