Macrophage as cellular vehicles for delivery of nanoparticles

Treatment of malignant brain tumors continues to challenge scientists and clinicians alike. Location of these tumors within the central nervous system (CNS), which is considered a "privileged" organ, can prevent the penetration of chemotherapeutic agents through the blood–brain barrier (BBB). To overcome this limitation, nanoparticles are taken up and transported by macrophage and then delivered directly into the CNS. In this study, we used macrophage to uptake the folate-targeted bifunctional micelles loaded with near-infrared (NIR) dye ICG-Der-01 and investigate the dynamic bio-distributions of macrophage after intravenous injection into tumor-bearing mice. In vitro cellular experiments by confocal microscopy indicated that the uptake of micelles in macrophage was greatly enhanced due to the folate receptor overexpression. Dynamic bio-distributions of macrophage showed a rapid clearing rate through the liver intestine pathway. In conclusion, macrophage could potentially be used as nanoparticle drug carriers and require further investigation.