A synthetic protocol for the preparation of heterobiofunctional protein-polymer conjugates Is described. A chain transfer agent, S,S-bis (a,a -dimethyl-a -acetic acid) trithiocarbonate was functionalized with a?-pyridyl disulfide (PDS) groups, Subsequently, one of the PDS groups was covalently attached to bovine serum albumin (BSA) at the specific free thiol group on the cysteine residue through a disulfide linkage. The second PDS group remained intact, as it was found to be inaccessible to further BSA functionallzation. The BSA-macroreversible addition-fragmentation chain transfer (RAFT) agent was then used to prepare BSA-polymer conjugates via in situ polymerization of oligo (ethyleneglycol) acrylate and W-(2hydroxypropyl) methacrylamide using an ambient temperature initiator, 4,4 -azobis [2,9-imidazolin-2-ethyl)propane] dihydrochloride in an aqueous medium. Sodium dodecyl sulphate Polyacrylamide gel electrophoresis (SDS-PAGE) confirmed that the in situ polymerization occurred at the protein surface where the RAFT agent was attached and the molecular weights of the BSA-polymer conjugates were found to increase concomitantly with monomer conversion and polymerization time. After polymerization the remaining terminal PDS groups were then utilized to attach thiocholesterol and a flurophore, rhodamine B to the protein-polymer conjugates via disulfide coupling, UV-Vis and fluorescence analyses revealed that 80 of the protein conjugates were found to retain integral PDS end groups for further attachment to free thiol-tethered precursors.
|Pages (from-to)||1399 - 1405|
|Number of pages||7|
|Journal||Journal of Polymer Science, Part A: Polymer Chemistry|
|Publication status||Published - 2010|