Protein Modification with Amphiphilic Block Copoly(2-oxazoline)s as a New Platform for Enhanced Cellular Delivery

Jing Tong, Robert Luxenhofer, Xiang Yi, Rainer Jordan, Alexander V. Kabanov

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Several homopolymers, random copolymers and block copolymers based on poly(2-oxazoline)s (POx) were synthesized and conjugated to horseradish peroxidase (HRP) using biodegradable and nonbiodegradable linkers. These conjugates were characterized by amino group titration, polyacrylamide gel electrophoresis (PAGE), isoelectric focusing, enzymatic activity assay and conformation analysis. The conjugates contained on average from about one to two polymer chains per enzyme. From 70% to 90% of enzymatic activity was retained in most cases. Circular dichroism (CD) analysis revealed that HRP modification affected the secondary structure of the apoprotein but did not affect the tertiary structure and heme environment. Enhanced cellular uptake was found in the conjugates of two block copolymers using both MDCK cells and Caco-2 cells, but not in the conjugates of random copolymer and homopolymer. Conjugation with a block copolymer of 2-methyl-2-oxazoline and 2-butyl-2-oxazoline led to the highest cellular uptake as compared to other conjugates. Our data indicates that modification with amphiphilic POx has the potential to modulate and enhance cellular delivery of proteins.
Original languageEnglish (US)
Pages (from-to)984-992
Number of pages9
JournalMolecular Pharmaceutics
Issue number4
StatePublished - Jun 15 2010
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUK-F1-029-32
Acknowledgements: This study was supported by the United States National Institutes of Health (NIH) RO1 Grant NS051334, the United States Department of Defense (DoD) USAMRMC 06108004 and the Nanomaterials Core Facility of the Nebraska Center of Nanomedicine supported by NIH COBRE Grant RR021937 (all awarded to A.V.K.). R.L. is also thankful to the Deutsche Akademischen Austauschdienst (DAAD) for a postdoctoral fellowship and to the King Abdullah University of Science and Technology (KAUST) Award No. KUK-F1-029-32 for partial salary support. Likewise X.Y. has been in part supported by the American Heart Association (AHA) Midwest Predoctoral Fellowship 0910040G. We also gratefully acknowledge Professor Luis Marky (College of Pharmacy, UNMC) for kind assistance in CD experiments.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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