Christina Bauer

Assistant Professor
Department of Chemistry

562.907.4200, ext.4420
cbauer@whittier.edu 

Academic History

B.S., Bloomsberg University
Ph.D., University of Arizona

Professor Christina Bauer graduated from Bloomsburg University, PA in 1999, receiving a ACS-accredited Bachelor’s in Chemistry.  Here, research regarding ab initio studies of cis-trans isomerization of diglycine in water.  At the University of Arizona and Georgia Institute of Technology, Bauer studied the synthesis and structure-assembly relationships of metal nanoparticles and their coupling with two- photon organic dyes under the direction of Joseph Perry, receiving a Ph.D. in physical chemistry from U of A in 2005. Here, various nanomaterial synthetic and characterization methods were used, as well as advanced spectroscopies and two-photon microfabrication.  A brief time was spent at Ventana Medical Systems, Inc, where Bauer investigated the bioconjugation of metal and semiconductor nanoparticles (quantum dots) for use in tissue staining and fluorescence imaging. As a postdoctoral appointee at Sandia National Laboratories in 2005, Bauer studied bio-inspired routes to the formation of silica nanoparticles in confined environments and the synthesis of novel fluorescent metal organic frameworks (MOFs) for optical and radiation sensing studies. 

Bauer also served as a guest lecturer at Clark Atlanta University (a historically black college and university (HBCU) in Atlanta, GA.  Finally, at UCLA, Bauer was the recipient of a NSF Discovery Corps Fellowship, entitled, “Nanomaterials: Bridging the Achievement Gap.” Here, Bauer continued research in synthesis, characterization, and sensing via fluorescent hybrid nanoparticle composites and the development and study of metal organic frameworks (MOFs).  Also, as part of this fellowship, demonstrations and lectures were developed and presented to community colleges and Los Angeles area high school teachers.

Selected publications

"Laser and Electron-Beam Induced Growth of Nanoparticles for 2 & 3D  Metal Patterning."  F. Stellacci, C.A. Bauer, T. Meyer-Friedrichsen, W. Wenseleers, V. Alain, S.M. Kuebler, S.J.K. Pond, Y. Zhang, S.R. Marder, J.W. Perry, Adv. Mater., 2002: (14),  p.194-198 (cover paper).

“Silica Particle Formation in Confined Environments via Bioinspired Polyamine Catalysis at Near-Neutral pH,C.A. Bauer, D. Robinson, B.A. Simmons, Small, 2007: (3), p. 58-62.

“Influence of Connectivity and Porosity on Ligand-Based Luminescence in Zinc Metal-Organic Frameworks,” C. A. Bauer, T. V. Timofeeva, T. B. Settersten, B. D. Patterson, V. H. Liu, B. A. Simmons, M. D. Allendorf, J. Am. Chem. Soc., 2007: (171), p.7136-7144.

“Dependence of Amine-Accelerated Silicate Condensation on Amine Structure.” D. B. Robinson, J.L. Rognlien, C.A. Bauer, B. A. Simmons, J. Mater. Chem. 2007: (17), p.2113-2119.

“Mechanical Properties of Cubic Zinc Carboxylate IRMOF-1 Metal-Organic Framework Crystals.”  D. F. Bahr, J. A. Reid, W. M. Mook, C. A. Bauer, R. Stumpf, A. J. Skulan, N. R. Moody, B. A. Simmons, M. M. Shindel, and M. D. Allendorf, Phys. Rev. B, 2007: (76), 184106.

Special Issue - The Nanoscience Revolution, “Relationship Between Structure and Solubility of Thiol-Protected Silver Nanoparticles and Assemblies," C. A. Bauer, F. Stellacci, J. W. Perry, Topics in Catalysis, 2008: (49), p.32-41.

“Scintillating Metal Organic Frameworks: A New Class of Radiation Detection Materials.”  F. P. Doty, C. A. Bauer, A. J. Skulan, M. D. Allendorf, Adv. Mater. 2009: (21), p.95-101.

 Invited review article - “Luminescent Metal Organic Frameworks,” M. D. Allendorf*, C.A. Bauer*, R.K. Bhakta, R.A. Houk, Chem. Soc. Rev. 2009: (38), p. 1330-1352 .

“Diastereoselective Heterogeneous Bromination of Stilbene in a Porous Metal-Organic Framework S.C. Jones, C.A. Bauer*, J. Am. Chem. Soc.  2009: (131), p. 12516–12517.

Invited book chapter – “Luminescent Metal Organic Frameworks" in Application of MOFs, Wiley, Farrusseng, David (ed.), 1st.Ed. - July 2011, Part V.

"Homo- and heterometallic luminescent 2-D stilbene metal-organic frameworks" Bauer CA, Jones SC, Kinnibrugh TL, Tongwa P, Farrell RA, Vakil A, Timofeeva TV, Khrustalev VN, Allendorf MD.Dalton Trans. 2014 Feb 21;43(7):2925-35. 

Professor Christina Bauer’s research goals are focused towards the development of luminescent, nanostructured materials for the manipulation of light and for chemical sensing.  There is a fundamental need for efficient, portable, and tunable light emitting materials to support the development of technologies in many fields, from medicine (e.g. tissue imaging) to homeland security (e.g. radiation detection). To advance beyond the current state-of-the-art, improvements in the sensitivity, stability, and control of such materials are required and nanomaterials are a potential solution.  This work involves structural design, chemical synthesis, and physical characterization, and in some cases utilizes green chemistry techniques in order to reduce environmental impact. Bauer’s research will find direct application in sensing, and may also prove useful in other areas such as in light-emitting diodes, or as biomarkers in biomedical research.

 

Project 1Project 1:  Development of Luminescent Metal Organic Frameworks with properties tailored for high intensity, tunable light output.  Metal organic frameworks (MOFs) are crystalline, infinite networks assembled by strong coordination between metal ions or clusters and organic linker groups, providing a robust and a geometrically well-defined structure, which often maintains permanent porosity.  Bauer’s research has shown that structures with the same basic building blocks but with different overall structures can result in tunable emission colors, which are more photostable than traditional fluorescent molecules.  This enables the materials to behave as sensors and as scintillators, allowing for discrimination between small molecules and between different types of incident. In addition, modification of the organic linker after incorporation into the MOF crystal was found to afford new materials that are not possible to achieve from common synthetic approaches. Building from this work, I will develop new strategies for control over solid state emission of light using MOF materials as a versatile platform to achieve this aim.

 

Project 2: Biomimetic Silica Composite Materials for sensing and sequestration of CO2.         Biomimetic chemistry offers a potential route for obtaining controllable, functional nanoporous structures. In nature, ornate silica materials are formed catalytically by polyamines at room temperature and under neutral conditions with control over multiple length scales (from micrometers to nanometers) by diatoms (see figure). The polyamines remain intimately incorporated within the structures and require full dissolution of the silica matrix for their removal. Inspired by this chemistry, Bauer has utilized polyethyleneimine (PEI), which mimics naturally-occurring biological polymers, to prepare silica particles from silicic acid at room temperature under a variety of pH conditions (Bauer, et. al. Small, 2007, 3, p. 58).  Currently, Bauer is exploring methods for incorporation of fluorescent molecules into the polymer to develop silica composite nanoparticles which are stable and may be used in similar applications as traditional organic dyes. However, these nanoparticles offer significant advantages, as they are brighter and more photostable because the silica matrix provides a protective "shield" around the fluorophore.  Bauer will also apply these particles as filtration agents that may potentially bind large amounts of carbon dioxide reversibly.  That is, these can be used in exhaust systems to soak up significant amount of CO2, owing to the nanoporosity of the particles, which can be recycled via a heating process.

 

Project 3: Structure of Silver Nanocrystals and Study of Silver Biotoxicity. The structure of silver alkanethiol-capped silver nanocrystals is still questionable, as the understanding of the stability to air and the sulfur-silver bond has not been fully elucidated.  Previous studies performed by Bauer and others have suggested the possibility of a mechanism whereby the surface of the particle is stripped of an atomic metal layer and forms a metal-alkanethiolate polymer as a by-product.  Bauer’s group is working to characterize these before and after air exposure.  They are also beginning investigation into structure/property relationships between silver nanostructure and their antimicrobial properties. It is known that silver nanomaterials display antimicrobial properties, as they are currently being used in band-aids, catheters, and antimicrobial coatings.  However, the effect of the size and shape of the nanoparticle and the speed/efficacy of microbe destruction remains unknown.