Reivindicaciones

1. A silicon particle selected from the group consisting of a type I silicon particle and a type II silicon particle, wherein the type I silicon particle comprises: a. a silicon body, b. a silica surface surrounding the silicon body, wherein the silica surface is functionalized by at least one functional group, and wherein said functional group is capable of setting up a bond with an enzymatically metabolizable compound, c. an enzymatically metabolizable compound, wherein said compound is linked to (i) said silica surface through said functional group and to (ii) a targeting moiety, and d. a targeting moiety, wherein said moiety is linked to the particle through said enzymatically metabolizable compound, and wherein the type II silicon particle comprises: a. a silicon body, b. a silica surface surrounding the silicon body, wherein the silica surface is functionalized by at least one functional group, and wherein said functional group is capable of setting up a bond with a targeting moiety, and c. a targeting moiety, wherein said moiety is directly linked to said functionalized silica surface. 2. The particle according to claim 1, wherein said silica surface is functionalized by reaction with a compound selected from the group comprising an halosilane, an organosilane, a silanol, a siloxane, an aminosilane, a mercaptosilane and a glycidoxysilane. 3. The particle according to claim 1 or 2, wherein said silica surface is functionalized by reaction with aminopropylsilane (APS). 4. The particle according to any one of claims 1 to 3, wherein said enzymatically metabolizable compound is selected from the group comprising a carbohydrate, a lipid, a peptide, a protein and a nucleic acid. 5. The particle according to claim 4, wherein said enzymatically metabolizable carbohydrate is a glucopyranoside. 6. The particle according to any one of claims 1 to 5, wherein said targeting moiety is a molecule able to specifically recognize and bind to a cell receptor of a target cell, wherein said targeting moiety is selected from the group comprising an antibody or an antigen binding fragment thereof, a binding structure, an aptamer, a peptide or a small molecule. 7. A process for the preparation of a particle according to any of claims 1 to 6, selected from the group consisting of "Process I" and "Process II", - wherein Process I comprises: i) contacting a silicon particle comprising a silicon body and a functionalized silica surface with an enzymatically metabolizable compound under conditions suitable for binding the compound to the functionalized silica surface; and ii) contacting the product resulting from step i) with a targeting moiety under conditions suitable for binding the targeting moiety to the compound bound to the functionalized silica surface, and - wherein Process II comprises contacting a silicon particle comprising a silicon body and a functionalized silica surface with a targeting moiety under conditions suitable for binding the targeting moiety to the functionalized silica surface. 8. A composition comprising at least a particle according to any of claims 1 to 6 and a suitable medium. 9. A pharmaceutical composition comprising a therapeutically effective amount of a particle according to any of claims 1 to 6 and a pharmaceutically acceptable excipient. 10. The pharmaceutical composition according to claim 9, which further comprises an anti-cancer agent. 11. The particle according to any of claims 1 to 6, or the pharmaceutical composition according to claim 9 or 10, for use in medicine. 12. The particle according to any of claims 1 to 6 for use in the prevention and/or treatment of cancer. 13. The particle for use according to claim 12, wherein prevention and/or treatment of cancer comprises killing tumor cells. 14. The particle for use according to claim 12 or 13, wherein the cancer is selected from the group consisting of breast cancer, colon cancer, gastric cancer, lung cancer, gall bladder cancer, colorectal cancer, bone cancer, sarcoma, esophageal cancer, head and neck carcinomas, ovarian cancer, prostate cancer, liver cancer, melanoma, glioma and neuroblastoma.