PROBLEM TO BE SOLVED: To provide a nanoparticle-containing dispersion liquid that permeates through a biological membrane quickly with a high chemical potential.SOLUTION: The present invention provides a nanoparticle dispersion liquid, wherein, nanoparticles, which comprise protein that can take in water molecules as a component, and have their internal pressure (P) exceeding 10 atm, are dispersed in hydrous solvent.SELECTED DRAWING: NoneCOPYRIGHT: (C)2017,JPO&INPIT【課題】高い化学的ポテンシャルより迅速に生体膜に浸透するナノ粒子分散液を提供すること。【解決手段】水分子を取り込むことができるタンパク質を構成成分とするナノ粒子であって、ナノ粒子の内圧(P‘)が10atmを超えるナノ粒子が含水溶媒中に分散されていることを特徴とするナノ粒子分散液。【選択図】なし