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Levich Institute
Steinman Hall, #1M
City College of CUNY
140th Street and Convent Avenue
New York, NY 10031

 

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212-650-8157

 

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212-650-6835

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City University of New York
City College of CUNY
Grove School of Engineering
Levich Institute Computing Services
Research Foundation of CUNY
 
 
 
 

CHARLES MALDARELLI RESEARCH

 
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Charles Maldarelli's research activities are in the areas of:

(1) The Transport of Surfactant Micellar Aggregates to an Air/Water Interface Surfactants are amphiphilic molecules containing a nonpolar hydrocarbon chain and a polar head group. When adsorbed from an aqueous solution to an air/water interface, surfactants reduce the surface tension of the interface. In aqueous solution, above a critical concentration, surfactants aggregate to form structures in which the hydrocarbon chains extend into a central core, and the polar parts of the molecule remains on the outside. Micelle solutions find many applications because they have the ability to rapidly reduce the tensions of air/water interfaces. The mechanism for this rapid reduction has remained unclear; in our research we have shown that one pathway for rapid reduction is the direct adsorption of the aggregates onto the surface, followed by the disassembly of the structure and the release of molecules along the surface. Measurements of the resonance energy transfer between micelles tagged with a fluorescent label and acceptor molecules located on the surface demonstrate that the micelles can directly adsorb onto the surface.

(2) Molecular Dynamics Studies of the Spreading of Water Over Chemically Functionalized Surfaces The ability to functionalize a surface with a particular chemistry in order to facilitate the controlled spreading of water over the surface finds applications in many areas of micro and nano fluidics. The usual method of functionalization is to graft onto the surface molecules displaying a particular chemical group which interacts with water through hydrogen bonding in order to draw water over the surface. In our research, we have used molecular dynamics simulations to understand the interactions of water nanodroplets with surfaces functionalized with different chemical groups, and to demonstrate how gradients in these groups along the surface can propel the drop along the surface.

(3) Microfluidic Particle Arrays For the High Throughput Screening of the Binding Interactions of Biomolecules Bead based microarrays are promising platforms for implementing the high throughput, multiplexed assaying of the binding interactions of biomolecules. In these arrays, each bead contains a particular probe molecule on its surface, and a code to identify this probe. Particles with different probes are mixed and subsequently bound onto a surface in a regular array. The array is then incubated with a target, and the binding of the target to particular probe molecules is identified (usually by fluorescently labeling the targets and scanning to find luminescing beads). Bead arraying is essential to the formation of these bead based microarrays, and arraying paradigms which sequester particles without reaction have the distinct advantage that they avoid chemical reaction conjugation. In our research, we have studied the design of microfluidics cell for the placement, through flow, of micron-sized particles in a two dimensional array on a planar surface as a prototype of a high througphput screening device.


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