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  • Single step synthesis and characterization of thermoresponsive hyaluronan hydrogels.

Single step synthesis and characterization of thermoresponsive hyaluronan hydrogels.

Carbohydrate polymers (2012-09-04)
Matteo D'Este, Mauro Alini, David Eglin
ABSTRACT

An efficient and scale-up ready single-step synthesis for the conjugation of thermoresponsive polymers to hyaluronic acid (HA) was established. Jeffamines(®) (JFM) and poly(N-isopropylacrylamide) (PNIPAM) were grafted to HA via direct amidation mediated by 1,1'-carbonyldiimidazole activation. The temperature-induced gelation of the semi-synthetic co-polymers was characterized by rheology as a function of the temperature and by differential scanning calorimetry (DSC). A HA-JFM conjugate with sol-gel transition in a physiologically relevant temperature range was identified. The grafting of PNIPAM resulted in the drastic change of the main rheological properties of native HA, revealing the hydrophobic non-covalent nature of the interactions between the thermoresponsive brushes in the gel state. Owing to the reversibility of these interactions and the sharpness of the transition, the HA-PNIPAM conjugates are suitable candidates for the incorporation of drugs, cells or ceramic materials for different biomedical applications.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Poly(N-isopropylacrylamide), Mn ~40,000
Sigma-Aldrich
Poly(N-isopropylacrylamide), carboxylic acid terminated, average Mn 10,000
Sigma-Aldrich
Poly(N-isopropyl acrylamide), NHS ester end functionalized, average Mn 5,000