Analyzing Nanoparticle Levels in Blood
With the race to develop nanoparticle-based therapeutics and imaging agents for cancer applications moving at full speed, a small but growing group of researchers is quietly developing the methods that are needed to fully characterize a wide variety of nanoscale materials and then detect and quantify their presence in blood and other human tissues. One such effort, headed by King Chan, Ph.D., of the National Cancer Institute, and Anil Patri, Ph.D., of the Nanotechnology Characterization Laboratory, has now developed a straightforward method for analyzing two types of the fullerene nanoparticle.
Reporting its work in the journal Electrophoresis, this research team used capillary electrophoresis, a standard laboratory tool, to analyze a wide variety of concentrations of carboxyfullerene, a water-soluble nanoparticle related to buckyballs, and dendrofullerene, a larger, hybrid nanoparticle combining the features of a buckyball with the highly branched polymer chains found in dendrimers. Several research groups are developing these two nanoparticles for human biomedical applications.
For their analysis, the researchers explored the use of two different variants of capillary electrophoresis: capillary zone electrophoresis (CZE), the simplest and fastest form of capillary electrophoresis, and micellar electrokinetic chromatography (MEKC), a slightly more complex and slower version of the basic electrophoresis method that uses an added surfactant to increase separation among closely related molecules. These studies showed that the simpler CZE technique was both faster and more successful at separating and quantifying both types of nanoparticles that had been spiked into human serum samples. Furthermore, CZE was capable of producing a signal proportional to nanoparticle concentrations ranging from 0 to 500 micrograms per milliliter. The lower limit of detection ranged from 0.5 to 6 micrograms per milliliter.
This work, which was supported by the National Cancer Institute's Alliance for Nanotechnology in Cancer, is detailed in the paper "Analysis of fullerene-based nanomaterials in serum matrix by CE." An abstract of this paper is available through PubMed.