Skip to Content
MilliporeSigma
  • A thermoresponsive biodegradable polymer with intrinsic antioxidant properties.

A thermoresponsive biodegradable polymer with intrinsic antioxidant properties.

Biomacromolecules (2014-10-09)
Jian Yang, Robert van Lith, Kevin Baler, Ryan A Hoshi, Guillermo A Ameer
ABSTRACT

Oxidative stress in tissue can contribute to chronic inflammation that impairs wound healing and the efficacy of cell-based therapies and medical devices. We describe the synthesis and characterization of a biodegradable, thermoresponsive gel with intrinsic antioxidant properties suitable for the delivery of therapeutics. Citric acid, poly(ethylene glycol) (PEG), and poly-N-isopropylacrylamide (PNIPAAm) were copolymerized by sequential polycondensation and radical polymerization to produce poly(polyethylene glycol citrate-co-N-isopropylacrylamide) (PPCN). PPCN was chemically characterized, and the thermoresponsive behavior, antioxidant properties, morphology, potential for protein and cell delivery, and tissue compatibility in vivo were evaluated. The PPCN gel has a lower critical solution temperature (LCST) of 26 °C and exhibits intrinsic antioxidant properties based on its ability to scavenge free radicals, chelate metal ions, and inhibit lipid peroxidation. PPCN displays a hierarchical architecture of micropores and nanofibers, and contrary to typical thermoresponsive polymers, such as PNIPAAm, PPCN gel maintains its volume upon formation. PPCN efficiently entrapped and slowly released the chemokine SDF-1α and supported the viability and proliferation of vascular cells. Subcutaneous injections in rats showed that PPCN gels are resorbed over time and new connective tissue formation takes place without signs of significant inflammation. Ultimately, this intrinsically antioxidant, biodegradable, thermoresponsive gel could potentially be used as an injectable biomaterial for applications where oxidative stress in tissue is a concern.

MATERIALS
Product Number
Brand
Product Description

Lysine hydrochloride, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
2,2′-Azobis(2-methylpropionitrile), recrystallized from methanol, 99%
Sigma-Aldrich
Linoleic acid, ≥99%
Sigma-Aldrich
2,2′-Azobis(2-methylpropionitrile), 98%
Sigma-Aldrich
N-Isopropylacrylamide, 97%
Sigma-Aldrich
Linoleic acid, technical, 58-74% (GC)
Sigma-Aldrich
2,2′-Azobis(2-methylpropionitrile), SAJ first grade, ≥98.0%
Sigma-Aldrich
Linoleic acid, liquid, BioReagent, suitable for cell culture
Sigma-Aldrich
Glycerol 1,3-diglycerolate diacrylate, technical grade
Supelco
Linoleic acid, analytical standard
Sigma-Aldrich
N-Isopropylacrylamide, ≥99%
Citric acid, anhydrous, European Pharmacopoeia (EP) Reference Standard
USP
Citric acid, United States Pharmacopeia (USP) Reference Standard
Supelco
L-Lysine monohydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
Citric acid, Anhydrous, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Citric acid, anhydrous, free-flowing, Redi-Dri, ACS reagent, ≥99.5%
Supelco
Citric acid, certified reference material, TraceCERT®, Manufactured by: Sigma-Aldrich Production GmbH, Switzerland
Sigma-Aldrich
Citric acid, meets analytical specification of Ph. Eur., BP, USP, E330, anhydrous, 99.5-100.5% (based on anhydrous substance)
Sigma-Aldrich
Citric acid, 99%
Sigma-Aldrich
Citric acid, anhydrous, suitable for cell culture, suitable for plant cell culture
Sigma-Aldrich
L-Lysine monohydrochloride, reagent grade, ≥98% (HPLC)
Sigma-Aldrich
2-Hydroxybutyric acid sodium salt, 97%
Sigma-Aldrich
Citric acid, SAJ first grade, ≥99.5%
Supelco
L-Lysine hydrochloride solution, 100 mM amino acid in 0.1 M HCl, analytical standard
Sigma-Aldrich
Citric acid, ≥99.5%, FCC, FG
Sigma-Aldrich
Citric acid, ACS reagent, ≥99.5%
Sigma-Aldrich
L-Lysine monohydrochloride, from non-animal source, meets EP, JP, USP testing specifications, suitable for cell culture, 98.5-101.0%
Sigma-Aldrich
Citric acid, BioUltra, anhydrous, ≥99.5% (T)
Sigma-Aldrich
L-Lysine monohydrochloride, BioUltra, ≥99.5% (AT)
Sigma-Aldrich
L-Lysine monohydrochloride, SAJ special grade, ≥99.0%