CAMP December Newsletter: Page 4
Clarkson University Professor Igor Sokolov Synthesizes the Brightest Fluorescent Nanoparticles Continued from page3
Transmission electron microscopy (TEM) image of an ultrabright fluorescent mesoporous silica nanoparticle.
Sokolov’s process physically entraps a large number of organic fluorescent molecules inside nanoporous silica particles, which can be 20 to 50 nanometers in diameter, while preventing the molecules from leaking.
As an example of their brightness, the fluorescence of 40-nanometer particles is 34 times brighter than the brightest water-dispersible (15-30 nanometer) quantum dots, and seem to be the brightest nanoparticles created so far.
In 2007, Sokolov and his team discovered a method of making the brightest ever synthesized fluorescent silica micro (non-nano) particles. Various attempts to decrease the size of the particles down to the nanoscale led to the particles that were bright but not ultrabright. The problem was in the dye leakage. It took the group several years to finally synthesize the ultrabright nanoparticles. See Figure 1.
Professor Sokolov and postdoctoral fellow Eun-Bum Cho (now an Assistant Professor at Seoul National University of Science and Technology) and Ph.D. student Dmytro Volkov developed the process, which gives the desired nanoparticles. The group, which now includes postdoctoral fellow Shajesh Palantavida, is currently looking at the development of the particles suitable for biomedical labeling.
The research was partially supported by the National Science Foundation and the U.S. Army Research Laboratory’s Army Research Office. It was performed in Clarkson’s Nanoengineering and Biotechnology Laboratories Center (NABLAB), a unit led by Sokolov and established to promote cross-disciplinary collaborations within the University.
NABLAB includes more than a dozen faculty members who apply the expertise of Clarkson scholars to cancer cell research, fine particles for bio and medical applications, the synthesis of smart materials, the advancement of biosensors, and more.
Syntheses of core particles encapsulated in shells having a wide variety of sizes, shapes and compositions, and of core particles functionalized with covalently attached organic moieties, is the traditional forte of the CAMP team mentored by Sr. University Professor Richard Partch. These particles have found successful application in composite, electronic, environmental, imaging, lighting, medical, printing, optical limiting and thermal management areas of technology. Current and upcoming challenges for his team of students led by Research Technicians Tania Tannahill and Deborah Shipp include: tribological evaluation of clay-like flakes used to lubricate gun barrels; synthesis and PCR analysis of DNA oligomer and other organics attached to doped silica particles to sense explosives; synthesis of hollow polymer latex spheres for new printing applications and for actuated release of neutralizer of air-born toxins; coating thermally conducting AlN core with fluorinated polymer to enhance thermal conductivity of rubber composites; processing of metal nanoflakes and metal oxides nanospheres having infrared, visible and/or bispectral obscurant properties; and preparation of particulate and fibrous metal oxides with templated pores or attached receptors for controlled release of therapeutics or sequestration of toxins in water.