Chemical Journal of Chinese Universities ›› 2012, Vol. 33 ›› Issue (09): 2099-2105.doi: 10.3969/j.issn.0251-0790.2012.09.039

• Polymer Chemistry • Previous Articles     Next Articles

Enzymatic Degradation of Biocompatible Block Polyelectrolyte Micelles in Aqueous Solutions

MAO Jun, BO Shu-Qin, JI Xiang-Ling   

  1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
  • Received:2012-11-21 Online:2012-09-10 Published:2012-08-14
  • Contact: 相玲 姬 E-mail:xlji@ciac.jl.cn

Abstract:

Enzymatic degradation behavior of biocompatible block polyelectrolyte poly(L-lactide)-b-poly[2-(dimethylamino)ethyl methacrylate](PLLA-b-PDMAEMA) micelles in aqueous solutions at two different temperatures (25.0℃, 36.8℃) and two different pH values (pH=4.9, 7.4) was investigated by laser light scattering (LLS) and atomic force microscopy (AFM). It is found that there is an enzyme inactivation time during the degradation process. Before this time, the degradation mechanism of PLLA-b-PDMAEMA micelles follows a one-by-one process. After this time, the degraded micelles with cracks or tunnels in their cores aggregate into large micelles to minimize their surface area exposed to the solvent, therefore minimize the free energy of the micelles. After increasing temperature, the activity of the enzyme increases, and the degradation rate of micelles is much faster. At pH=4.9, the coronas of the micelles are stretched due to the electrostatic repulsion, because of which the degradation rate of micelles is faster at pH=4.9 than that at pH=7.4.

Key words: Block polyelectrolyte, Micelle, Enzymatic degradation, Biocompatibility

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