Professor & Department Chair – Inorganic Chemistry, Materials Science
Research and/or Creative Works
Research in our group is generally concerned with the rapidly emerging field of materials chemistry. This area of chemistry is directed toward understanding structure-property relationships, so that the products of chemical syntheses can be tailored for specific applications. Students in our group have the opportunity to not only work with synthetic inorganic and solid-state chemistry, but also to test the materials they have made in a variety of important applications. This application-driven aspect is a fundamental component of materials chemistry and is an important part of our group's research as well.
We generally work with nanoporous materials, with a focus on mesoporous silica. These solids, defined as having pore diameters in the range of 2 to 50 nm, have remarkable physical properties including unusually large surface areas and pore volumes. In one project, we are developing heterogeneous catalysts by two methods. In the first method, we introduce transition metals, such as Co, Cu, Mo, Ti, and V at low weight percentages, producing isolated metal sites with high activity. For example, mesoporous silica doped with as little as 1 wt% V is a highly active solid for the oxidation of organic substrates. This solid can convert aldehydes to peracids under ambient conditions using only O2 as the oxidant; interestingly, the metal is only active when silica is used as the support. The second method of developing heterogeneous catalysts involves producing solids with interconnected micropores and mesopores. Interestingly, these materials show activity that is unique from either the pure microporous or pure mesoporous phases. We probe the basis for the unique reactivities of these solids with a range of solid-state techniques including EPR, multinuclear NMR, powder XRD, TGA, and electron microscopy.
We are also working with colleagues in the UVM College of Medicine to develop mesoporous silica as a molecular delivery device. Using a spherically-shaped form of mesoporous silica called APMS, we modify the external surface of APMS particles with organic moieties to allow them to pass through cellular membranes, and we fill the internal pore volume with molecular "cargo" such as pharmaceutical drugs, DNA plasmids, or shRNA constructs. The figures below highlight some of our recent work with the anti-cancer drug doxorubicin ("DOX"). The figure on the left shows the percentage of mesothelioma cells (mesothelioma is a type of cancer caused by exposure to asbestos) in a cell culture that were killed when DOX-loaded, surface-modified APMS was applied to the cell culture. The horizontal axis shows the overall concentration of DOX in the culture, indicating that a does of 65 nM killed 53% of the cells after 48 hours. For comparison, when the same amount of DOX was applied directly to the cell culture (without APMS), the number of cells killed was not above the control. HPLC studies confirm that surface-modified APMS is able to increase the amount of DOX transferred to the cellular interior, increasing the efficacy of DOX. The figure on the right is a confocal fluorescence microscopic image of a cell culture to which surface-modified APMS have been added (after 24 hours). This shows that large numbers of surface-modified APMS (tagged with a red dye) are able to pass through cellular membranes to the cytoplasm without detrimental effects, since the cell nuclei (stained green) are still intact.
In other experiments, we have shown that the uptake and release of DNA is dependent on both the pore diameter and type of metal cation present in the solid. Current work includes a long-term study to examine the fate of APMS in vivo in mice. We hope to show that modified APMS can be used in biomedical applications that could benefit from increased molecular transfer, such as gene therapy.
Blumen, S.R.; Cheng, K.; Landry, C.C.; James, T.A.; Mossman, B.T.; Weiss, D.J.“Targeted Uptake of Bifunctionally Modified Nanoporous Particles by Malignant Mesothelioma Cells” ACS Applied Mater. Interfaces 2010, 2, 2489.
Cheng, K.; Hillegass, J.M.; Kauppinen, R.A.; Landry, C.C.; Lathrop, S.A.; Mossman, B.T.; Steinbacher, J.L. "Gd-Labeled Microparticles in MRI: In Vivo Imaging of Large Particles after Intraperitoneal Injection" Small 2010, 6, 2678.
Landry, C.C.; Livingston, S.R. “Oxidation of 2-Chloroethylethylsulfide using V-APMS" J. Mol. Catal. A 2008, 283, 52.
Landry, C.C.; Livingston, S.R. “Oxidation of a Mustard Gas Analogue Using an Aldehyde/O2 System Catalyzed by V-Doped Mesoporous Silica” J. Am. Chem. Soc. 2008, 130, 13214.
Cheng, K.; Landry, C.C. “Diffusion-Based Deprotection in Mesoporous Materials: Strategies for Differential Modification of Porous Silica Particles" J. Am. Chem. Soc. 2007, 129, 9674.
Blumen, S. R.; Cheng, K.; Ramos-Nino, M.; Taatjes, D.; Weiss, D.; Landry, C. C.; Mossman, B. T. "Unique Mechanisms of Uptake of Acid Prepared Mesoporous Spheres (APMS) by Lung Epithelial and Mesothelioma Cells," Am. J. Resp. Cell Mol. Biol. 2007, 36, 333.
Kumar, D.; Landry, C. C. "Immobilization of a Mo,V-Polyoxometalate on Cationically Modified Mesoporous Silica: Synthesis and Characterization Studies," Microporous Mesoporous Mater. 2007, 98, 309.
Solberg, S. M.; Landry, C. C. "Adsorption of DNA in Mesoporous Silica," J. Phys. Chem. B. 2006, 110, 15261.
Solberg, S. M.; Kumar, D.; Landry, C. C. "Synthesis, Structure, and Reactivity of a New Ti-Containing Mesoporous/Microporous Material," J. Phys. Chem. B 2005, 109, 24331.
Ringenbach, C. R.; Livingston, S. R.; Kumar, D.; Landry, C. C. "V-Doped APMS: Synthesis, Characterization, and Catalytic Studies on Oxidation of 2-Chloroethyl Ethylsulfide," Chem. Mater. 2005, 17, 5880.
Sorensen, A. C.; Fuller, B. L.; Eklund, A. G.; Landry, C. C. "Mo-Doped Mesoporous Silica for Thiophene HDS: Comparison of Materials and Methods," Chem. Mater. 2004, 16, 2157.
Poladi, R. H. P. R.; Landry, C. C. "Oxidation of Octane and Cyclohexane Using a New Porous Substrate, Ti-MMM-1," Microporous Mesoporous Mater. 2002, 52, 11.**cover article**
Landry, C. C.; Tolbert, S. H.; Gallis, K. W.; Monnier, A.; Stucky, G. D.; Norby, P.; Hanson, J. C. "Phase Transitions in Mesostructured Silica/Surfactant Composites. Mechanisms for Change and Applications to Materials Synthesis," Chem. Mater. 2001, 13, 1600. **cover article**
Gallis, K. W.; Landry, C. C. "Rapid Calcination of Nanostructured Silicate Composites by Microwave Irradiation," Adv. Mater. 2001, 13, 23. **cover article**
Awards and Recognition
- 2013 - University of Vermont University Scholar
- 2014 - Member, Vermont Academy of Science and Engineering
Areas of Expertise and/or Research
inorganic chemistry, materials, mesoporous materials
- Ph.D., Harvard University, Cambridge, MA, 1994
- Postdoctoral fellowship, University of California, Santa Barbara, CA, 1994-96
- (802) 656-0270