Synthesis of Apolipoprotein B Lipoparticles to DeliverHydrophobic/Amphiphilic Materials

摘要

To develop a drug delivery system (DDS), it is critical to address challenging tasks such as the delivery of hydrophobic and amphiphilic compounds, cell uptake, and the metabolic fate of the drug delivery carrier. Low-density lipoprotein (LDL) has been acknowledged as the human serum transporter of natively abundant lipoparticles such as cholesterol, triacylglycerides, and lipids. Apolipoprotein B (apo B) is the only protein contained in LDL, and possesses a binding moiety for the LDL receptor that can be internalized and degraded naturally by the cell. Therefore, synthetic/reconstituting apoB lipoparticle (rABL) could be an excellent delivery carrier for hydrophobic or amphiphilic materials. Here, we synthesized rABL in vitro, using full-length apoB through a five-step solvent exchange method, and addressed its potential as a DDS. Our rABL exhibited good biocompatibility when evaluated with cytotoxicity and cell metabolic response assays, and was stable during storage in phosphate-buffered saline at 4 °C for several months. Furthermore, hydrophobic superparamagnetic iron oxide nanoparticles(SPIONPs) and the anticancer drug M4N (tetra-O-methyl nordihydroguaiareticacid), used as an imaging enhancer and lipophilic drug model, respectively,were incorporated into the rABL, leading to the formation of SPIONPs-and M4N- containing rABL (SPIO@rABL and M4N@rABL, respectively). Fouriertransform infrared spectroscopy suggested that rABL has a similarcomposition to that of LDL, and successfully incorporated SPIONPsor M4N. SPIO@rABL presented significant hepatic contrast enhancementin T2-weighted magnetic resonance imagingin BALB/c mice, suggesting its potential application as a medicalimaging contrast agent. M4N@rABL could reduce the viability of thecancer cell line A549. Interestingly, we developed solution-phasehigh-resolution transmission electron microscopy to observe both LDLand SPIO@rABL in the liquid state. In summary, our LDL-based DDS,rABL, has significant potential as a novel DDS for hydrophobic andamphiphilic materials, with good cell internalization properties andmetabolicity.