Development of tLyP-1 functionalized nanoliposomes with tunable internal water phase for glioma targeting

tLyP-1 peptide is verified to recognize neuropilin (NRP) receptors overexpressed on the surface of both glioma cells and endothelial cells of angiogenic blood vessels. In the present study, tLyP-1 was conjugated with DSPE-PEG2000 to prepare tLyP-1-DSPE-PEG2000, which was further employed to prepare tLyP-1 functionalized nanoliposome (tLyP-1-Lip) to achieve enhancing target of glioblastoma. Process parameters were systematically studied to investigate the feasibility of tuning the internal water phase of nanoliposomes and encapsulating more Temozolomide (TMZ). The particle size, Zeta potential, and encapsulation efficiency of tLyP-1-Lip/TMZ were fully characterized in comparison with conventional nanoliposomes (Lip-TMZ) and PEGylated nanoliposomes (PEG-Lip/TMZ). The release behaviors of TMZ from PEG-Lip/TMZ and tLyP-1-Lip/TMZ are similar and slower than TMZ-Lip in acidic solutions. The tLyP-1-Lip/TMZ demonstrated the strongest cytotoxicity in comparison with TMZ-Lip and PEG-Lip/TMZ in both U87 and HT22 cells, and displayed the highest cellular internalization. The pharmacokinetic studies in rats revealed that tLyP-1-Lip/TMZ showed a 1.4-fold (p < 0.001) increase in AUC_{INF_obs} and a 1.4-fold decrease (p < 0.01) in clearance compared with PEG-Lip/TMZ. We finally confirmed by in vivo imaging that tLyP-1-Lip were able to penetrate the brains and tumors of mice.