title: Well-defined aminooxy terminated N-(2-hydroxypropyl) methacrylamide macromers for site specific bioconjugation of glycoproteins.
abstract: Syntheses and characterization of aminooxy terminated polymers of N-(2-hydroxyproyl) methacrylamide (HPMA) of controlled molecular weight and narrow molecular weight distribution are presented here. Design of a chain transfer agent (CTA) containing N-tert-butoxycarbonyl (t-Boc) protected aminooxy group enabled us to use reversible addition-fragmentation (RAFT) polymerization technique to polymerize the HPMA monomer. An amide bond was utilized to link the aminooxy group and the CTA through a triethylene glycol spacer. As a result, the aminooxy group is linked to the poly(HPMA) backbone through a hydrolytically stable amide bond. By varying the monomer to initiator ratios, polymers with targeted molecular weights were obtained. The molecular weights of the polymers were determined by gel permeation chromatography (GPC) and mass spectrometry (ESI and MALDI-TOF). The t-Boc protecting group was quantitatively removed to generate aminooxy terminated poly(HPMA) macromers. These macromers were converted to rhodamine B terminated poly(HPMA) by reacting N-hydroxysuccinimide (NHS) ester of the dye with the terminal aminooxy group to form a stable alkoxyamide bond. Utility of these dye-labeled polymers as molecular probes was evaluated by fluorescence microscopy by studying their intracellular uptake by renal epithelial cells. These aminooxy terminated poly(HPMA) were also tested as biocompatible carriers to prepare chemoselective bioconjugates of proteins using transferrin (Tf) as the protein. Oxidation of the sialic acid side chains of Tf generated aldehyde functionalized protein that was reacted with aminooxy terminated poly(HPMA), which resulted in protein-polymer bioconjugates carrying oxime linkages. These bioconjugates were characterized by gel electrophoresis and MALDI-TOF mass spectrometry.
authors: Polymer & Biomaterial R&D, Sanofi-Genzyme R&D Center, Genzyme Corporation-A Sanofi Company, 270 Albany Street, Cambridge, Massachusetts 02139, United States. Pradeep.Dhal@genzyme.com
authors: Pradeep K
authors: PK
authors: Dhal
authors: Steven C
authors: SC
authors: Polomoscanik
authors: Diego A
authors: DA
authors: Gianolio
authors: Patrick G
authors: PG
authors: Starremans
authors: Michelle
authors: M
authors: Busch
authors: Kim
authors: K
authors: Alving
authors: Bo
authors: B
authors: Chen
authors: Robert J
authors: RJ
authors: Miller
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010091:Oximes / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000138:chemical synthesis / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D006023:Glycoproteins; D008689:Methacrylates; D010091:Oximes; D011109:Polymethacrylic Acids; C011533:Duxon; C032802:hydroxypropyl methacrylate