Optimization Of Surface Chemistry On Single-walled Carbon Nanotubes For In Vivo Photothermal Ablation Of Tumors

Single-walled carbon nanotubes （SWNTs） have shown great potential in variousareas of biomedicine for their unique physical and chemical properties. However, inorder to explore the biomedical applications of SWNTs，they have to be functionalizedto acquire water solubility and biocompatibility. In this thesis, we synthesize twoseries of amphiphilic polymers (2K-PEG-PMHC₁₈，5K-PEG-PMHC₁₈) by anchoringpolyethylene glycol （PEG） of different lengths at various densities on poly（maleicanhydride-alt-1-octadecene）(PMHC₁₈). The obtained PEGylated SWNTs are watersoluble and show good biocompatibility. The blood circulation and bio-distribution ofthose PEG-PMHC₁₈-coated SWNTs in mice after intravenous injection are measuredby an established Raman spectroscopy method. It is found that heavily PEGylatedSWNTs with ultra-long blood circulation half-lives, although show high uptake in thetumor, tend to accumulate in the skin dermis. A surface coating which affords SWNTsa blood half-life of12-13h appears to be optimal to balance the tumor-to-normal organ（T/N） uptake ratios of nanotubes in major organs. Using the selected SWNT conjugate,we then carry out a pilot in vivo photothermal therapy study and observe a promisingcancer treatment. Our results highlight the importance of surface coating to the in vivobehaviors of nanomaterials in general and could provide guidelines to the future designof SWNT bioconjugates for various in vivo applications.