In vitro Function Study of Different Negative Charge Pullulan Nanoparticles for Sentinel Lymph Node Angiography

Backgroud: Many dyes or radioactive markers used for sentinel lymph node (SLN) have the shortcomings of false positive and radiation injury. Indocyanine green (ICG) seems to have a lower false positive rate and tissue damage, without a clear field of vision during the operation. Methods: For the shortcomings, we successfully synthesized three anionic pullulan materials, changed the degree of hydrophobic for size controlling (< 50nm) to prepare CHP nanoparticles (NPs) and changed the succinyl degree to prepare CHPC NPs with different negative surface potential. Results: The size of those NPs were less than 50nm under (transmission electron microscope) TEM, with hydrodynamic size of 90.67±2.2nm of CHP, 105.8±1.7nm of CHPC1 and 115.9±2.3nm of CHPC2. Moreover, the Zeta potential of CHP, CHPC1 and CHPC2 were -1.9±0.2mV, -9.6±0.3mV and -19.4±0.7mV. The size of ICG-loading CHP, CHPC1 and CHPC2 NPs increased to 109.4±2.7nm, 113.8±1.2nm and 30.6±3.5 nm, as the zeta potential decreased to -2.7±0.4mV, -12.5±1.6mV and -23.1 ±1.2mV. With the increasing degree of succinyl, the size increased and the zeta potential decreased. At the same time, the higher degree of succinyl drug-loading NPs have lower release and have increased the stability of ICG. We found that the blank-NPs had no significant toxicity to normal cells (HSF), as the ICG@CHP group had larger toxicity than the CHPCs and control. Moreover, the cellular uptake was decreased with the increased degree of succinyl. Conclusion: In this study, we successfully prepared CHPC2 carriers with the maximum negative surface charge, for follow-up research and providing new ideas for SLN.