"Thermoreversible and Injectable ABC Polypeptoid Hydrogels: Controlling" by Sunting Xuan, Chang-Uk Lee et al.

Faculty Publications

Title

Thermoreversible and Injectable ABC Polypeptoid Hydrogels: Controlling the Hydrogel Properties through Molecular Design

Authors

Sunting Xuan, Department of Chemistry and Macromolecular Studies Group, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Chang-Uk Lee, Department of Chemistry and Macromolecular Studies Group, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Cong Chen, Department of Biological and Agricultural Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Andrew B. Doyle, Department of Biological and Agricultural Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Yueheng Zhang, Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States.
Li Guo, Department of Chemistry and Macromolecular Studies Group, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Vijay T. John, Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States.

Document Type

Article

Publication Date

2-9-2016

Abstract

A series of ABC triblock copolypeptoids [i.e., poly(-allyl glycine)--poly(-methyl glycine)--poly(-decyl glycine) (AMD)] with well-defined structure and varying composition have been synthesized by sequential primary amine-initiated ring-opening polymerization of the corresponding N-substituted -carboxyanhydride monomers (Al-NCA, Me-NCA, and De-NCA). The ABC block copolypeptoids undergo sol-to-gel transitions with increasing temperature in water and biological media at low concentrations (2.5-10 wt %). The sol-gel transition is rapid and fully reversible with a narrow transition window, evidenced by the rheological measurements. The gelation temperature () and mechanical stiffness of the hydrogels are highly tunable: in the 26.2-60.0 °C range, the storage modulus (') and Young's modulus () in the 0.2-780 Pa and 0.5-2346 Pa range, respectively, at the physiological temperature (37 °C) can be readily accessed by controlling the block copolypeptoid composition and the polymer solution concentration. The hydrogel is injectable through a 24 gauge syringe needle and maintains their shape upon in contact with surfaces or water baths that are kept above the sol-gel transition temperature. The hydrogels exhibit minimal cytotoxicity toward human adipose derived stem cells (hASCs), evidenced from both alamarBlue and PicoGreen assays. Furthermore, quantitative PCR analysis revealed significant up-regulation of the gene and down-regulation of gene, suggesting that the hydrogel exhibit biological activity in inducing chondrogenesis of hASCs. It was also demonstrated that the hydrogel can be used to quantitatively encapsulate water-soluble enzymes (e.g., horseradish peroxidase) by manipulating the sol-gel transition. The enzymatic activity of HRP remain unperturbed after encapsulation at 37 °C for up to 7 d, suggesting that the hydrogel does not adversely affect the enzyme structure and thereby the enzymatic activity. These results suggest that the polypeptoid hydrogel a promising synthetic platform for tissue engineering or protein storage applications.

Publication Source (Journal or Book title)

Chemistry of materials : a publication of the American Chemical Society

First Page

727

Last Page

737

Recommended Citation

Xuan, S., Lee, C., Chen, C., Doyle, A. B., Zhang, Y., Guo, L., & John, V. T. (2016). Thermoreversible and Injectable ABC Polypeptoid Hydrogels: Controlling the Hydrogel Properties through Molecular Design. Chemistry of materials : a publication of the American Chemical Society, 28 (3), 727-737. https://doi.org/10.1021/acs.chemmater.5b03528

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