PRL and fatty liver disease: In contrast, microneedles are popular drug carriers nowadays.[18, 19, 20, 21, 22] Through penetrating the skin, microneedles can efficiently administrate drugs, not only reducing patient pain but also showing regulated drug release kinetics.[23, 24, 25, 26, 27] Therefore, we conceived that integrating prolactin into intelligent microneedles can realize fatty liver treatment through pulsing prolactin release.