A fluorescent polymer, comprising a linear semitelechelic statistical copolymer to which at least one fluorescent label is bound in an amount in the range of from 0.4 to 12 mol %, based on the number of monomer units, wherein the linear semitelechelic statistical polymer comprises polyacrylamide, polymethacrylamide, or poly( N -(2-hydroxypropyl)methacrylamide, wherein from 0.4 to 12 mol % of monomer units in the linear semitelechelic statistical copolymer are replaced by monomer units of general formula wherein R is selected from the group consisting of a straight or branched carbon alkylenyl chain with a number of carbons from 1 to 6; wherein R may be further substituted with one or more identical or different natural amino acid side chains; Y is selected from the group consisting of a bond, -C(=O)-NH-, -NH-C(=O)-, -NH-C(=S)-NH-; wherein the molecular weight M n of the linear semitelechelic copolymer is in the range of from 10,000 to 100,000 g/mol; and wherein the fluorophore has a molecular weight in the range of from 350 to 1,500 g/mol, an excitation wavelength in the range of from 300 to 850 nm and an emission wavelength in the range of from 350 to 1,200 nm, and is covalently bound to the monomer unit of general formula of the linear semitelechelic copolymer via terminal amine or thiocyanate or N-hydroxysuccinimide ester, wherein the groups formed following the fluorophore binding are subsequently part of the group Y; and wherein the fluorescent polymer contains at one end of the polymer chain a functional group for binding to a protein structure, which functional group is selected from the group comprising esters, preferably N-hydroxysuccinimide ester or (C1-C4)alkyl esters, amides, preferably thiozolidine-2-thione amide, maleimide, azide, propargyl, preferably the functional group is azide or maleimide. wherein the linear semitelechelic statistical polymer comprises polyacrylamide, polymethacrylamide, or poly( N -(2-hydroxypropyl)methacrylamide, wherein from 0.4 to 12 mol % of monomer units in the linear semitelechelic statistical copolymer are replaced by monomer units of general formula wherein R is selected from the group consisting of a straight or branched carbon alkylenyl chain with a number of carbons from 1 to 6; wherein R may be further substituted with one or more identical or different natural amino acid side chains; Y is selected from the group consisting of a bond, -C(=O)-NH-, -NH-C(=O)-, -NH-C(=S)-NH-; wherein the molecular weight M n of the linear semitelechelic copolymer is in the range of from 10,000 to 100,000 g/mol; and wherein the fluorophore has a molecular weight in the range of from 350 to 1,500 g/mol, an excitation wavelength in the range of from 300 to 850 nm and an emission wavelength in the range of from 350 to 1,200 nm, and is covalently bound to the monomer unit of general formula of the linear semitelechelic copolymer via terminal amine or thiocyanate or N-hydroxysuccinimide ester, wherein the groups formed following the fluorophore binding are subsequently part of the group Y; and wherein the fluorescent polymer contains at one end of the polymer chain a functional group for binding to a protein structure, which functional group is selected from the group comprising esters, preferably N-hydroxysuccinimide ester or (C1-C4)alkyl esters, amides, preferably thiozolidine-2-thione amide, maleimide, azide, propargyl, preferably the functional group is azide or maleimide.