A conjugate comprising: (a) at least one polymer comprising: at least two polymer arms each comprising a plurality of monomers each independently selected from the group consisting of methacrylate, acrylate, acrylamide, methacrylamide, styrene, vinyl-pyridine, vinyl-pyrrolidone and vinyl-ester, wherein each monomer comprises a phosphorylcholine moiety, an initiator fragment linked to a proximal end of each polymer arm, wherein the initiator moiety is suitable for radical polymerization, and an end group linked to a distal end of each polymer arm, wherein the at least one polymer has a molecular weight of 50 kDa to 1,500 kDa and a polydispersity index of less than 2; and (b) at least one functional agent comprising a bioactive agent or a diagnostic agent, linked to the initiator fragment or the end group, wherein the bioactive agent is selected from the group consisting of a protein, a drug, an antibody, an antibody fragment, a single domain antibody, an avimer, an adnectin, diabodies, a vitamin, a cofactor, a polysaccharide, a carbohydrate, a steroid, a lipid, a fat, a peptide, a polypeptide, a nucleotide, an oligonucleotide, a polynucleotide, and a nucleic acid, and the diagnostic agent is selected from the group consisting of a radiolabel, a contrast agent, a fluorophore and a dye. (a) at least one polymer comprising: at least two polymer arms each comprising a plurality of monomers each independently selected from the group consisting of methacrylate, acrylate, acrylamide, methacrylamide, styrene, vinyl-pyridine, vinyl-pyrrolidone and vinyl-ester, wherein each monomer comprises a phosphorylcholine moiety, an initiator fragment linked to a proximal end of each polymer arm, wherein the initiator moiety is suitable for radical polymerization, and an end group linked to a distal end of each polymer arm, wherein the at least one polymer has a molecular weight of 50 kDa to 1,500 kDa and a polydispersity index of less than 2; and at least two polymer arms each comprising a plurality of monomers each independently selected from the group consisting of methacrylate, acrylate, acrylamide, methacrylamide, styrene, vinyl-pyridine, vinyl-pyrrolidone and vinyl-ester, wherein each monomer comprises a phosphorylcholine moiety, an initiator fragment linked to a proximal end of each polymer arm, wherein the initiator moiety is suitable for radical polymerization, and an end group linked to a distal end of each polymer arm, wherein the at least one polymer has a molecular weight of 50 kDa to 1,500 kDa and a polydispersity index of less than 2; and (b) at least one functional agent comprising a bioactive agent or a diagnostic agent, linked to the initiator fragment or the end group, wherein the bioactive agent is selected from the group consisting of a protein, a drug, an antibody, an antibody fragment, a single domain antibody, an avimer, an adnectin, diabodies, a vitamin, a cofactor, a polysaccharide, a carbohydrate, a steroid, a lipid, a fat, a peptide, a polypeptide, a nucleotide, an oligonucleotide, a polynucleotide, and a nucleic acid, and the diagnostic agent is selected from the group consisting of a radiolabel, a contrast agent, a fluorophore and a dye.