Size-dependent translocation and lymphatic transportation of polymeric nanocarriers post intraperitoneal administration

Intraperitoneal (i.p.) administered nanomedicine has been widely applied in the clinical treatment of intra-abdominal diseases and preclinical pharmacological investigations. However, current understandings about the in vivo fate of i.p.-administered drug remains controversial owing to lack of reliable investigation tools. This work presents a nanoparticle-labeling strategy based on aggregation-caused quenching (ACQ) probes in the second near-infrared (NIR-II) window, which can eliminate the interference of unbound probes and allow for non-invasive tracking of nanoparticles in deep tissues. Our results strongly evidence a size-dependent absorption and biodistribution of the i.p.-administered polymeric nanocarriers (PNs) with particle sizes ranging from 30 to 1000 nm both in vivo and ex vivo, and moreover provide a clear visualization of lymphatic transportation and lymph node retention of integral PNs. Importantly, our findings suggest that small particles (<= 30 nm) are favorable in systemic therapies due to their rapid absorption and high concentration (>19 %ID mL(-1)) in circulation, while large particles (over 1000 nm) are meant for localized treatment of abdominal diseases. Besides, the high retention of 200 nm nanoparticles within lymph nodes indicates their promising role in cancer vaccines and lymphatic diseases including lymph node metastasis.