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A Combinatorial Library of Bi-functional Polymeric Vectors for siRNA Delivery In Vitro

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An Erratum to this article was published on 06 June 2013

ABSTRACT

Purpose

To apply a combinatorial chemistry approach toward the design of polymeric vectors, and to evaluate their effectiveness as siRNA delivery systems in vitro.

Methods

Poly(acrylic acid) (pAA) was synthesized via RAFT polymerization with well-controlled molecular weights (M n: 3 kDa, 5 kDa, 10 kDa and 21 kDa). A polymer library was generated from the pAA precursors by conjugating two distinct moieties, agmatine (Agm) and D-(+)-galactosamine (Gal), at various ratios. Biophysical and cellular characterization was evaluated in vitro for these polymeric vectors using MDA-MB-231-luc+ cells.

Results

A critical balance between Agm/Gal content and polymer molecular weight must be attained to achieve favorable transfection efficacies. From the library of 22 polymers, only a few had knockdown efficiencies commensurate with effective siRNA delivery, particularly those with polymer precursor M n of 5 kDa and 10 kDa. Highest protein knockdown of 84% was achieved by a polymer conjugate with a 5 kDa pAA backbone with a side chain composition of 55% Agm and 17% Gal.

Conclusions

Effective delivery of siRNA was found to be highly dependent on the molecular structure of the polymeric vector. The combinatorial approach employed provided the tools to identify optimal structural properties leading to efficient siRNA delivery for this class of vector.

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Abbreviations

Agm:

agmatine

FA:

fluoresceinamine

Gal:

D-(+)-galactosamine

M n :

number-average molecular weight

pAA:

poly(acrylic acid)

PDI:

polydispersity index

PEIb:

branched polyethyleneimine

siRNA:

small interfering RNA

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ACKNOWLEDGMENTS AND DISCLOSURES

We thank the Alfred P. Sloan Foundation Graduate Scholarship Programs and National Action Council for Minorities in Engineering (NACME), Inc. for a Sloan Fellowship (J.M.P.), the Cornell’s Learning Initiative in Medicine and Bioengineering (CLIMB) for the National Science Foundation (NSF) GK-12 Fellowship (J.M.P), and the Cornell University NMR and NBTC facilities.

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Authors and Affiliations

  1. School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, 14853, USA

    Jeisa M. Pelet & David Putnam

  2. Department of Biomedical Engineering, Cornell University, 147 Weill Hall, Ithaca, New York, 14853, USA

    David Putnam

Authors
  1. Jeisa M. Pelet
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  2. David Putnam
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Correspondence to David Putnam.

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Pelet, J.M., Putnam, D. A Combinatorial Library of Bi-functional Polymeric Vectors for siRNA Delivery In Vitro . Pharm Res 30, 362–376 (2013). https://doi.org/10.1007/s11095-012-0876-4

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  • DOI: https://doi.org/10.1007/s11095-012-0876-4

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