A nattokinase carrier bonding with polyglutamic acid peptide dendrimer for improved thrombolysis

Thrombosis has become one of the major diseases harmful to human health. The new-generation thrombolytic drug nattokinase (NK) has been used in the treatment of thrombosis because of its high safety, small side effects, and good thrombolytic effect. However, its application is limited because of its short half-life and inactivation in external environments. Therefore, it is necessary to retain the enzyme activity of NK to improve its environmental stability. In this study, NK was decorated by bonding peptide dendrimers to improve its enzymatic activity. Polyglutamic acid dendrimers of generation 2 were firstly synthesized, and then the targeting molecule arginine-glycine-aspartic acid (RGD) was linked to dendrimers by reaction of carboxyl and amino groups. Subsequently, polyglutamic dendrimer particles were bonded on the periphery of NK by chemical reaction and were used as carriers for NK. The carriers were characterized by Fourier transform infrared (FTIR) and thermogravimetric (TG) analysis, and their size and morphology were evaluated. Their enzyme activity at different pH and temperature was determined, and improved NK activity was achieved after bonding with dendrimers under acid and alkaline conditions and high temperature. Their thrombolytic properties were evaluated by in vitro and in vivo thrombolytic experiments. Effective thrombolytic effect was observed. This study indicated that the NK carrier prepared by chemical bonding may have applications in the treatment of thrombosis.