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.

A novel near-infrared light responsive microcapsule system, gold nanorod-covered DOX-loaded hollow CaCO₃ microcapsule (AuNR-HM-DOX) is developed for cancer therapy. The hollow CaCO₃ microcapsules were prepared based on the self-assembly between chitosan and sodium alginate on CaCO₃ particles via layer-by-layer technique, and then covered with gold nanorods to obtain the microcapsule system. Upon near-infrared (NIR) irradiation, microcapsule with gold nanorods can convert the absorbed NIR light into heat. Meanwhile, doxorubicin (DOX), a chemotherapy drug, is loaded into the microcapsule system via electrostatic adsorption for combined photothermal therapy and chemotherapy. Properties of AuNR-HM-DOX including grain diameter, optical spectra were characterized. Confocal fluorescence imaging was performed to observe the morphology of the capsules and existence of DOX in the core, confirming the successful loading of DOX. The release of DOX from the capsules under continuous NIR irradiation was investigated to evaluate the temperature responsiveness of AuNR-HM-DOX. Results indicate that AuNR-HM-DOX microcapsules possess uniform particle size and high light responsiveness. The combination of chemical and physical therapy of AuNR-HM-DOX features great potential as an adjuvant therapeutic alternative material for combined cancer therapy.