Reivindicaciones
1. A bioconjugate comprising a photosensitizer unit and an elastin-like polypeptide conjugated thereto, said elastin-like polypeptide containing at least one occurrence of a monomeric unit having the formula (A): Xaa<1>PXaa<2>Xaa<3>G (A) wherein P represents a prolyl residue, G represents a glycyl residue, Xaa<2> represents a glycyl residue or an alanyl residue and: - either Xaa<1> represents a valyl residue and Xaa<3> represents a sulfur-containing amino acid residue having a side chain of formula -(CH<2>)<z>-S-R', wherein z is equal to 1 or 2 and R' represents a linear, branched and/or cyclic C1-C22 hydrocarbon radical, saturated and/or unsaturated, aromatic or not, optionally substituted, optionally interrupted by one or more heteroatoms and/or by one or more groups comprising at least one heteroatom or group comprising at least one heteroatom, - or Xaa<3> represents a valyl residue and Xaa<1> represents a sulfur-containing amino acid residue having a side chain of formula -(CH<2>)<z>-S-R', wherein z is equal to 1 or 2 and R' is as defined above. 2. A bioconjugate according to claim 1, wherein R' represents a C1-C3 alkyl group. 3. A bioconjugate according to claim 1 or 2, wherein, in formula (A): - either Xaa<1> represents a valyl residue and Xaa<3> represents an amino acid residue selected in the group consisting of a methionyl residue, a S-alkyl-homocysteinyl residue and a S-alkyl-cysteinyl residue, - or Xaa<3> represents a valyl residue and Xaa<1> represents an amino acid residue selected in the group consisting of a methionyl residue, a S-alkyl-homocysteinyl residue and a S-alkyl-cysteinyl residue, 4. A bioconjugate according to any of claims 1 to 3, wherein said photosensitizer is selected in the group consisting of phthalocyanines, porphyrins, bodipy-based photosensitizers and methylene blue. 5. A bioconjugate according to any of claims 1 to 4, wherein said photosensitizer unit is covalently attached to said elastin-like polypeptide by a linker. 6. A bioconjugate according to any of claims 1 or 5, wherein said elastin-like polypeptide is conjugated to said photosensitizer unit at its N-terminal end. 7. A bioconjugate according to any of claims 1 to 6, wherein said elastin-like polypeptide has the formula (B): Z-[VPXaa<2>Xaa<3>G]<x>-OH (B) wherein x is an integer between 1 and 200 Z represents a peptide fragment comprising 1 to 20 amino acid residues, V represents a valyl residue, P represents a prolyl residue, G represents a glycyl residue, Xaa<2> represents a glycyl residue or an alanyl residue, and Xaa<3> represents a variable amino acid residue selected from the group consisting of a valyl residue and a sulfur-containing amino acid residue having a side-chain of formula -(CH<2>)<z>-S-R', z and R' being as defined in claim 1 or 2, Xaa<3> being such that the molar ratio valyl residue/sulfur-containing amino acid residue in the [VPXaa<2>Xaa<3>G]<x> peptide fragment is between 0/1 and 10/1. 8. A bioconjugate according to claim 7, wherein, in the formula (B), Z represents a peptide fragment having the amino acid sequence MW. 9. A bioconjugate according to any of claims 1 to 8, wherein said elastin-like polypeptide has an amino acid sequence selected in the group consisting of sequences: MGTELAAASEFTHMW[VPGMG]<20> (SEQ ID No: 9), MW[VPGVGVPGMG(VPGVG)<2>]<5> (SEQ ID No: 10), MW[VPGVGVPGMG(VPGVG)<2>]<10> (SEQ ID No: 11), MW[VPGVGVPGMG(VPGVG)<2>]<15> (SEQ ID No: 12) and MW[VPGVGVPGMG(VPGVG)<2>]<20> (SEQ ID No: 13). 10. A bioconjugate according to any of claims 1 to 9, wherein said photosensitizer unit is a phthalocyanine unit having the general formula (V'): <img class="EMIRef" id="ad0a7dac-1d9b-4f59-a151-d67f384eefa3-ib0047" /> wherein M represents a metal or metalloid atom, R<2>, R<3>, R<4>, R<5> and R<6>, which may be identical or different, each represent: a hydrogen atom, -COOH, -C≡C-COOH, -CH=CHCOOH, an alkyl group, linear or branched, having from 1 to 12 carbon atoms, -OR<7>, -SR<7> or -NR<7>R<8>, wherein R<7> and R<8>, which may be identical or different, each represent a hydrogen atom, an alkyl group, linear or branched, having from 1 to 12 carbon atoms, or a phenyl group optionally substituted by one or more R<9> groups independently selected from the group consisting of an alkyl group, linear or branched, having from 1 to 12 carbon atoms, -OR<10>, -SR<10>, and -NR<11>R<12>, wherein R<10>, R<11> and R<12>, which may be identical or different, each represent a hydrogen atom or an alkyl group, linear or branched, having from 1 to 12 carbon atoms, or one or both pairs R<3> and R<4>, and R<5> and R<6>, are attached to adjacent carbon atoms and form, together with the ring to which they are attached, an aromatic fused ring system, and R<1> represents a covalent bond involved in the attachment of said phthalocyanine unit to said elastin-like polypeptide. 11. A method of preparing a bioconjugate according to any of claims 1 to 10, characterized in that it comprises: - modifying the N-terminal end of an elastin-like polypeptide containing at least one occurrence of a monomeric unit having the formula (A): Xaa<1>PXaa<2>Xaa<3>G (A), wherein P, G, Xaa<1>, Xaa<2> and Xaa<3> are as defined in any of claims 1 to 3, to introduce a terminal alkyne group, - functionalizing a photosensitizer molecule to introduce an azide group, - and realizing a Huisgen's copper(I)-catalyzed alkyne-azide cycloaddition reaction between the elastin-like polypeptide so modified and the photosensitizer so functionalized. 12. A bioconjugate according to any of claims 1 to 10 for its use for the treatment of a disease, in particular for the treatment of a skin disease or an ocular disease, by photodynamic therapy. 13. A bioconjugate for its use as claimed in claim 12, wherein said bioconjugate is administered by injection in a targeted site of the body of a subject to be treated. 14. A pharmaceutical composition comprising a bioconjugate according to any of claims 1 to 10 in a pharmaceutically acceptable vehicle. 15. A pharmaceutical composition according to claim 14, in a form that is suitable for parenteral administration to a subject.
