Photo-responsive and NGR-mediated multifunctional nanostructured lipid carrier for tumor-specific therapy.

A novel nanostructured lipid carrier (NLC) modified with photon-sensitive cell penetrating peptides (psCPP) and Asn-Gly-Arg (NGR) was designed to enhance paclitaxel (PTX)-targeted delivery and antitumor effect. The NGR moiety selectively binds to CD13-positive tumors. On other hand, the psCPP moiety enhance specific cancer cellular uptake after rapidly cleaving the two-photon excitation-responsive protective group, in this case, illumination in the presence of near-IR (NIR) light at the tumor site. The dual-modified NLC (psCPP/NGR-NLC) were prepared by emulsification method, and the concentrations of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol 2000-psCPP (DSPE-PEG2000 -psCPP) and DSPE-PEG5000 -NGR in the NLC were chosen to be 4% and 1% (molar ratio), respectively. The mean particle size of the psCPP/NGR-NLC was about 100 nm, and the drug entrapment efficiency was more than 90%. Stability study showed that the prepared NLCs were physically and chemically stable at 2°C-8°C up to 1 month. Cellular uptake results demonstrated that the proposed psCPP/NGR-NLC had an enhancement of cancer cell recognition and specific uptake. Pharmacokinetic study showed that the prepared psCPP/NGR-NLC possessed the long-circulation characteristic with the t1/2 of 6.112 ± 0.304 h. Pharmacodynamics results confirmed that, with the aid of NIR illumination and NGR, the tumor inhibition ratio of psCPP/NGR-NLC group was significantly higher than the other PTX groups.