Nanoparticles for tracing acupuncture Meridians and Bonghan ducts

Nanoparticles are increasingly used in various fields, especially in biomedical research such as enzyme immobilization, contrast enhancing media, and imaging of cellular and molecular structures. We report on the use of fluorescent magnetic nanoparticles for tracing acupuncture meridians and their anatomical structures, that is, Bonghan ducts. By injecting nanoparticles into the acupuncture points (LR9) of mice we observed them at other acupoints (LR3) of the same liver meridian, which implied the propagation of nanoparticles along the meridian. Another use of nanoparticles was injecting them into a Bonghan corpuscle and observing them to flow along the Bonghan duct on the surface of mammalian internal organs. The third application was injecting them into lymph nodes so that Bonghan ducts inside lymphatic vessels were detected and visualized by the fluorescence of nanoparticles. Confocal laser scanning microscope images of cryo-sectioned specimens showed that the nanoparticles were preferentially taken up by Bonghan ducts. Transmission electron microscope images revealed the nanoparticles captured in the extra cellular matrix of Bonghan ducts.