Development and characterization of PLA nanodispersion as a potential ultrasound contrast agent for cancer site imaging

In this study, a poly (D,L-lactic acid) (PLA) nanodispersion system was designed for targeting and imaging of cancer sites. Nanoparticles between 120 nm and 200 nm would allow delivery into the cancer site specifically via the enhanced permeability and retention (EPR) effect Also, by reducing reticuloendothelial system (RES) uptake and renal excretion, the nanoparticles would have longer circulation time under physiological conditions with minimal side effects. This advantageous system was prepared by a modified solvent diffusion method. Camphor, which upon removal by sublimation makes the nanoparticles hollow enabling gas introduction, was added to offer echogenicity to the particles. Dynamic light scattering (DLS) results demonstrated that these nanoparticles have approximately 200 nm size with unimodal distribution. Atomic force microscopy (AFM) results showed that the nanoparticles have a spherical shape and supported DLS results. These particles containing Sulfur hexafluoride (SF₆) gas have shown 7.5 dB enhancements at 5 MHz frequency. Thus, we can conclude that this PLA nanodispersion system has the potential for creating a multifunctional particle acting as a cancer targeting molecule, an ultrasound contrast agent, and further a drug carrier.