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Issue 10, 2012
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Star polypeptides by NCA polymerisation from dendritic initiators: synthesis and enzyme controlled payload release

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Abstract

Well-defined star polypeptides were successfully synthesised by initiation of γ-benzyl-L-glutamate N-carboxyanhydride (NCA) from polypropylene imine (PPI) dendrimers. The dendrimer generation and the dendrimer to NCA ratio were systematically varied to afford a range of star shaped architectures with a maximum of 8 to 64 poly(γ-benzyl-L-glutamate) (PBLG) arms. High molar masses up to 500 000 g mol−1 were achieved that were otherwise unobtainable for the analogous linear polypeptides in the absence of the dendrimer core. By deprotection the PBLG star polypeptides were converted into poly(L-glutamic acid) (PGA) star polypeptides. Various concentrations of rhodamine B could be loaded into the polypeptide star architectures dependent on the number of PGA arms and the length of the grafted polypeptide chain produced. Furthermore, the polypeptidic nature of PGA-grafted dendrimers ensures their responsiveness, through controlled degradation, to the target enzyme thermolysin. An enzyme-responsive release mechanism was devised and demonstrated in which rhodamine B payload was released upon incubation with thermolysin but not the control enzyme chymotrypsin. The rate and extent of rhodamine B release was dependent on the composition of the hybrid material, which can be readily tuned to provide highly specific temporal and spatial controlled release.

Graphical abstract: Star polypeptides by NCA polymerisation from dendritic initiators: synthesis and enzyme controlled payload release

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Publication details

The article was received on 10 May 2012, accepted on 02 Jul 2012 and first published on 30 Jul 2012


Article type: Paper
DOI: 10.1039/C2PY20327H
Citation: Polym. Chem., 2012,3, 2825-2831
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    Star polypeptides by NCA polymerisation from dendritic initiators: synthesis and enzyme controlled payload release

    M. Byrne, P. D. Thornton, S. Cryan and A. Heise, Polym. Chem., 2012, 3, 2825
    DOI: 10.1039/C2PY20327H

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