Self-assembled serum albumin-poly(L-lactic acid) nanoparticles: a novel nanoparticle platform for drug delivery in cancer

We developed a new self-assembled bovine serum albumin-poly(L-lactic acid) nanoparticle platform for anticancer drug delivery made from a bovine serum albumin-poly(L-lactic acid) polymer conjugate. Depending on the ratio of bovine serum albumin (BSA) to poly(L-lactic acid) (PLLA), these conjugates self-assemble into uniform spherical nanoparticles with different sizes. Then, BA-loaded BSA-PLLA nanoparticles (BSA-PLLA/BA NPs) were prepared by using BSA-PLLA conjugates as prototype materials, and betulinic acid (BA) as a model drug. In vitro cytotoxicity studies with human lung cancer cell lines (A549) and murine Lewis lung carcinoma (LLC) cell lines suggested that the BSA-PLLA/BA NPs were significantly superior to the model drug BA in antitumor activity and the BSA-PLLA NPs were non-toxic. Compared to free BA, the BSA-PLLA/BA NPs provided significantly higher blood circulation half-time of free BA (5.02-fold). The antitumor effect of the BSA-PLLA/BA NPs in a mouse tumor xenograft model showed much better tumor inhibition efficacy and fewer side effects than that of free BA. It may be attributed to the preferential tumor accumulation and increases the solubility of the drug in water, strongly supporting their use as high-performance carriers for anti-cancer therapy.