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