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CAMP
___________

is an interdisciplinary
science and engineering
endeavor dedicated to research on high-technology materials processing. This research is focused on the production, modification and conversion of matter for which "small" particles, colloidal media and / or surfaces play an important role in the process and /or properties of the final product. Presented here are some highlights of the research during CAMP's thirteenth year as a New York State Center for Advanced Technology

Figure 1. Scanning electron micrograph of barium naproxenate particles, precipitated in the presence of polyvinyl alcohol (PVA). From a paper by Corina Goia and Egon Matijevic¢, J. Colloid Interface Sci. 206 (1998) 581-591

THE Research

PARTICLE SYNTHESIS AND PROPERTIES

Uniform Particle Synthesis

Professor Egon Matijevic¢ (the Victor K. LaMer Chair in Colloid and Surface Science) pioneered the field of the preparation of monodispersed colloidal particle in a variety of chemical compositions and shapes, which have found numerous uses in modern technology and medicine. While in the past the majority of dispersions consisted of simple inorganic compounds, more recently the program has been expanded to metallic, organic, and composite particle, all obtained by precipitation in homogeneous solutions. Of particular interest is a program focusing on the medical applications of monodispersed particles. Two areas will be exemplified here.

The first deals with the preparation of uniform drug dispersions. The methods are based either on the formation of insoluble salts of active compounds, or on using the difference in solubility of a drug in miscible solvents. These techniques yielded particles of a variety of shapes, sizes, and structures. Figure 1 illustrates colloidal barium naproxenate of a rather unique structure. (Naproxenate is a well known medication for the relief of headache and other pains). The studies are also of interest in the efforts to elucidate the relationship between the steric properties of molecules to the shape of the resulting particle. The second area refers to applications in medical diagnostics. For example, Matijevic¢'s group in collaboration with the Beckman-Coulter scientists has produced exceedingly uniform nanosized semiconductor CdS in the presence of a polymer. These particles of excellent fluorescence properties are used in the cell labeling as schematically shown in Figure 2.

Another project, in collaboration with the Lincoln/MIT laboratories, involves the encapsulated inorganic resist technology (EIRT). The latter represents a fundamentally new type of the resist concept, which will be compatible with conventional resist processing. In the new method fine particles are encapsulated under a photochemically active layer, which upon exposure can modify the particle's solubility, leading to developer differentiation. The system under investigation consists of encapsulated nanosized silica, having the important advantage in the resist design, because the very small core particles will yield high resolution and also allow for spin coating from organic solvents.

Figure 2. Schematic illustration of the T4 antibody-5x-Amdex CdS conjugate and its binding to T4 + white blood cell (Amdex: aminodextran). From a paper by Ivan Sondi, Olavi Siiman, Steven Koester, and Egon Matijevic¢, Langmuir 16 (2000) 3107-3118.