National Cancer Institute believes that the research coming out of the University of California, Santa Barbara, in which scientists have developed a nanoparticulate formulation of cisplatin, could potentially offer an effective way to deliver higher doses of drugs to cancer cells and overcome cellular resistance:
Reporting its work in the journal Langmuir, a team of investigators led by Ratnesh Lal, Ph.D., of the University of California, Santa Barbara, describes its development and characterization of a nanoscale liposome capable of ferrying cisplatin across the cell membrane of tumor cells. Using atomic force microscopy (AFM), the researchers were able to fully characterize the size distribution, drug encapsulation efficiency, stability, and cell uptake of their cisplatin liposomes.
The investigators identified several key physical characteristics, all easily measured using AFM, that enabled them to accurately measure cisplatin encapsulation in the liposomes. Past efforts by many research groups to encapsulate cisplatin within a liposome were judged unsuccessful, in part because of the difficulty in tracking the efficiency of drug encapsulation. In this case, the researchers found that the stiffness of any given liposome, measured using AFM force mapping, correlated with the amount of cisplatin encapsulated within that liposome.
By adding a fluorescent label to the liposomes, the investigators were able to monitor uptake by ovarian cancer cells growing in culture and to track their cell-killing properties. These studies showed that the cisplatin-loaded liposomes crossed the cell membrane in large numbers. More importantly, massive cell death occurred as a result, particularly when the cells were treated with smaller cisplatin-loaded liposomes, i.e., those with diameters less than 250 nanometers.