This invention regards the contrast medium which includes the colloidal solution, and the aforementioned colloidal solution which contain the nano- particle which it disperses is stabilized by the igai gluing protein imitation dispersed stabilization medicines and the aforementioned dispersed stabilization medicine because the nano- particle is made to disperse to water medium. In detail, as for the aforementioned igai gluing protein imitation dispersed stabilization medicine, polyethylene imine - graft - (polyethylene glycol poridopa) is. The aforementioned graft polymer consists of two parts, one is the polyethylene imine which connects the polyethylene glycol organism compatibility macromolecule which possesses affinity in water medium (polyethylene glycol grafted polyethyleneimine), in addition one is poridopa which possesses affinity on the surface of the nano- particle (poly DOPA). With the aforementioned quality, the stabilization medicine has the feature where the nano- particle is dispersed stably in water medium.< Selective figure >Figure 1本発明は、ナノ粒子を水性媒質に分散させるためのイガイ類接着タンパク質模倣分散安定化剤、前記分散安定化剤により分散安定化したナノ粒子を含有するコロイド溶液、及び前記コロイド溶液を含む造影剤に関する。より詳細には、前記イガイ類接着タンパク質模倣分散安定化剤は、ポリエチレンイミン-グラフト-(ポリエチレングリコール;ポリドーパ)である。前記グラフトポリマーは、二つの部分からなり、一つは、水性媒質に親和性を有するポリエチレングリコール系生体適合性高分子を結合したポリエチレンイミン(polyethylene-glycol grafted polyethyleneimine)であり、また一つは、ナノ粒子の表面に親和性を有するポリドーパ(poly DOPA)である。前記特性により、安定化剤は、水性媒質中にナノ粒子が安定的に分散される特徴を有する。【選択図】図1
