Oral Administration of Fluorescent NPs

Healthy male C57BL/6 mice aged 6–8 weeks were purchased from the Animal Center of the Chinese Academy of Sciences (Beijing, China). The animal experiments were performed at Experimental Animal Center of School of Pharmacy of Wenzhou Medicine University, and were approved by Experimental Animal Ethics Committee of School of Pharmacy of Wenzhou Medicine University (ID Number: wydw2021-0140). We synthesized Sulfo-cyanine-5 NHS ester labeled LIRA (Cy5-LIRA) and Rhodamine B isothiocyanate-conjugated zein (RITC-zein) as reported [45 (link)], followed by the preparation of double fluorescence-labeled NPs. The mice were fasted overnight with free access to water and randomly divided into four groups. The solutions of LIRA/CA Complex, LIRA/CA@Zein/RLs, LIRA@Zein/RLs, and LIRA/CA@Zein were administrated orally at a dose of 0.4 mg kg⁻¹. After 2, 6, 12, and 24 h, the mice were sacrificed and organs were taken out, washed, and imaged (In Vivo Xtreme, Bruker).