Folic acid conjugated amino acid-based star polymers for active targeting of cancer cells

Adrian Sulistio, Justin Lowenthal, Anton Blencowe, Marie N. Bongiovanni, Lydia Ong, Sally Louise Gras, Xiaoqing Zhang, Greg Qiao

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95 Citations (Scopus)


Amino acid-based core cross-linked star (CCS) polymers (poly(l-lysine) armpoly(l-cystine) core) with peripheral allyl functionalities were synthesized by sequential ring-opening polymerization (ROP) of amino acid N-carboxyanhydrides (NCAs) via the arm-first approach, using N-(trimethylsilyl)allylamine as the initiator. Subsequent functionalization with a poly(ethylene glycol) (PEG)-folic acid conjugate via thiol-ene click chemistry afforded poly(PEG-b-l-lysine) armpoly(l-cystine) core stars with outer PEG coronas decorated with folic acid targeting moieties. Similarly, a control was prepared without folic acid, using just PEG. A fluorophore was used to track both star polymers incubated with breast cancer cells (MDA-MB-231) in vitro. Confocal microscopy and flow cytometry revealed that the stars could be internalized into the cells, and higher cell internalization was observed when folic acid moieties were present. Cytotoxicity studies indicate that both stars are nontoxic to MDA-MB-231 cells at concentrations of up to 50 μg/mL. These results make this amino acid-based star polymer an attractive candidate in targeted drug delivery applications including chemotherapy.

Original languageEnglish
Pages (from-to)3469-3477
Number of pages9
Issue number10
Publication statusPublished - 10 Oct 2011
Externally publishedYes

Cite this

Sulistio, A., Lowenthal, J., Blencowe, A., Bongiovanni, M. N., Ong, L., Gras, S. L., Zhang, X., & Qiao, G. (2011). Folic acid conjugated amino acid-based star polymers for active targeting of cancer cells. Biomacromolecules, 12(10), 3469-3477.