Isabelle L. Lagadic

Inorganic Chemistry and Materials Chemistry

Assistant Professor of Chemistry

Postdoctoral Fellow, Kansas State University, 1995
Ph.D., University Paris-Sud, Orsay, France, 1994
B.S. / M.S. University Paris-Sud, Orsay, France, 1991

Phone: 860-486-3215
Email : isabelle.lagadic@uconn.edu

PDF version of Lagadic research summary

FUNCTIONAL ORGANIC-INORGANIC MATERIALS

Research Overview

Our research interests relate to the rapidly growing field of functional hybrid materials and focus on combining organic and inorganic precursors in order to create interesting and useful organic-inorganic hybrid silicate materials. These functional materials combine several properties: a high thermal and mechanical stability imparted by the silicate framework, and surface properties that can be tailored to the anticipated applications by varying the functionality of the organic components.
We are particularly interested in organically functionalized ordered porous silicates prepared by direct co-polymerization reactions between inorganic precursors and different functionalized organotrialkoxysilanes of general formula: (RO)3-Si-X, where R is an alkyl group and X (represented by ? below) a functional group such as –(CH2)3SH, –(CH2)3NH2, etc. The resulting organic-inorganic hybrid exhibit either a porous layered structure similar to that of clay minerals (1) or an hexagonal mesoporous structure (2), with the organic functionalities lining the inside of the interlayer spaces or the pore walls. The functionalized galleries or pores can then act as "nanoreactors" or "nanoreservoirs" where a variety of reactions can take place depending on the anticipated applications.

(1) Layered Organosilicates	(2) Mesoporous Organosilicates

Students working in the group are exposed to a variety of scientific areas, such as materials and nanoscale sciences, inorganic, organic and analytical chemistry, and acquire a broad knowledge of various techniques. They not only synthesize and characterize novel functional materials, but also have the opportunity to investigate the performances of these materials in important applications. The interdisciplinary nature of the research also offers the possibility of collaborative partnerships with other research groups.

Engineering Porous Silicates and Organosilicates for Controlled Drug Delivery

In these projects, our objective is to design functional mesoporous silicates that can act as carriers for the controlled and/or sustained release of various drugs, such as poorly water-soluble anti-inflammatory drugs (e.g. ibuprofen, naproxen) or anticancer agents (e.g. doxorubicin). Our preliminary results show that impregnation of ibuprofen and naproxen onto mesoporous silicates and their amino-functionalized derivatives to a drug-loading capacity up to 300 mg of drug per gram of solid leads to an improved solubility of these drugs. In addition, the strong interactions between the drug molecules and the amino-functionalized solids result in a sustained release of the drugs over up to 30 hours (Figure 1).

Figure 1: Release of ibuprofen from ibuprofen-loaded amino-functionalized mesoporous silicate in simulated body fluid (pH = 7.4)

Functional Organoclays as Metal Ion Adsorbents

In this project, we prepared a thiol-functionalized organoclays (Mg-MTMS) by direct alkaline co-polymerization between MgCl2 and (CH3O)3Si-(CH2)3-SH. The hybrid material obtained exhibits the layered structure of the natural clay, talc, and a high loading of SH groups pending from the layers into the interlayer galleries. We investigated the effectiveness of Mg-MTMS for the adsorption of aqueous ions Hg2+, Pb2+, Cd2+ and Pd2+ (Figure 2). We found that Mg-MTMS exhibits very high uptake capacities fro these ions (Figure 3). Our research efforts are now directed toward the investigation of synthetic methods for the direct preparation of organoclays with various functions.

Figure 2: Schematic representation of Pb2+ ions onto Mg-MTMS. The organoclay solid undergoes a distinctive color change upon Pb2+ ion adsorption	Figure 3: In low concentration solutions, 99% of metal ions are removed by Mg-MTMS