In the 1960s, a French artist named Jean-Pierre Sudre began experimenting with an obscure 19th-century photographic process, creating dramatic black-and-white photographs with ethereal veiling effects. Sudre christened the process “mordanҫage,” the French word for “etching.” Since then, other photographers have used and refined mordanҫage to create unique works of art. Now, Mason faculty Rebecca Jones and recent graduate, Caroline Fudala, reporting in the ACS journal Analytical Chemistry have unveiled the mysterious chemistry behind the process.
In mordanҫage, a fully developed black-and-white photograph is immersed in a solution containing copper (II) chloride, hydrogen peroxide and acetic acid. The solution bleaches the photo to a pale yellow color and partially lifts formerly black areas of the print away from the paper backing. Then, the photographer rinses off the mordanҫage solution and redevelops the print to restore the black color. When the photo is dried and pressed flat, black areas that had lifted from the paper form the veils. Caroline Fudala and Rebecca Jones wanted to better understand the chemical details of this process.
The researchers methodically studied the technique and determined that the hydrogen peroxide and acetic acid soften the photographic paper. This allows copper (II) chloride to permeate the paper and oxidize the metallic silver—which colors the dark areas of the print—to silver chloride. The softened surface layers lift off as veils. Then, during redevelopment, the veils darken when silver chloride is reduced back to metallic silver. Et voilà, a spooky photo that’s just right for a scary holiday…
Caroline Fudala and Rebecca M Jones, The Chemistry of Mordançage, a Historic Photographic Process, Analytical Chemistry (2019). DOI: 10.1021/acs.analchem.9b03205
Congratulations to Dr. Mikell Paige
Congratulations to Dr. Mikell Paige on being granted tenure and promoted to the mark of Associate Professor!!
Dr. John Schreifels Recognized at the 2019 Faculty/Staff Awards Breakfast
Dr. John Schreifels was recognized at the 2019 Faculty/Staff Awards Breakfast, which was held on April 4th, for 30 years of service at George Mason University. Congratulations!!!!
George Mason Chemistry Welcomes Dr. Chao Luo
The Department of Chemistry & Biochemistry gladly welcomes Dr. Chao Luo to the department. Dr. Luo will join us in June 2019 as an Assistant Professor of Organic Chemistry. His research lab will be on the Fairfax campus. Dr. Luo is currently a postdoctoral fellow in the Department of Chemical and Biomolecular Engineering at the University of Maryland (College Park, MD). His current work focuses on (1) structure design and material fabrication for organic alkali-ion batteries, (2) high-energy lithium sulfur batteries, and (3) all-solid-state lithium batteries. He has several years of work experience in organic materials, polymers, sulfur, selenium, porous carbon and nanostructured materials for environment and energy related applications.
Dr. Luo’s research lab will explore the use of organic/inorganic materials and new fabrication techniques to design and synthesize novel organic electrodes, porous carbon, nanostructures and their hybrid composites to address environment and energy challenges. A fundamental understanding of reaction mechanism and kinetics, investigation of structure-property correlations and development of functional structures and devices will be explored.
Dr. Luo earned a Ph.D. in Chemical Engineering (2015) from the University of Maryland (College Park, MD). He also holds a M.S. in Organic Chemistry (2011) from the Technical Institute of Chemistry and Physics, Chinese Academy of Sciences (Beijing, China) and a B.S. in Chemistry (2008) from Wuhan University (Wuhan, China).
George Mason Chemistry Welcomes Dr. Lee A. Solomon
The Department of Chemistry & Biochemistry gladly welcomes Dr. Lee A. Solomon to the department. His research lab will be on the Science & Tech campus (Manassas, VA).
- De Novo Protein Design
- Novel Protein Materials
- Molecular Biophysics
- Protein-DNA Interactions
- Enzyme Kinetics
In the Solomon lab we use protein design to study natural functions, create new protein-based materials and expand the capabilities of biology.
In nature, proteins carry out a vast array of chemical reactions with a limited set of tools. Understanding how this is done is the key to unlocking new medicines and therapies. However, studying natural proteins directly is difficult due to the high levels of complexity brought on by millions of years of evolution.
To get around this, we used artificial proteins that have been designed, not evolved. These simplified proteins do not carry any of the legacies of natural selection, making the effect of mutations easier to characterize. This approach is called de novo design. To study natural reactions, we start with simple scaffold proteins that have no function aside from folding and make stepwise mutations until we reproduce the targeted reaction. This bottom-up approach was able to successfully reproduce the oxygen binding function of myoglobin and neuroglobin in a simple 4-helix bundle. De novo design clarifies the roles of individual amino acids and chemical groups, paving the way toward powerful new catalytic reactions and biotechnologies.
We are also interested in applying de novo design to material science. Proteins can form long polymeric chains to combine their catalytic potential with the advantages of materials. We aim to generate functional and biocompatible materials to create new technologies and medicines. Again, we start with a simple system that has been designed and is not found in nature, called Peptide Amphiphiles. Small and iterative changes allow us to incorporate new functions and resolve the role of each atom we are using, while also leading to new therapies and technologies.
Education and Research Background:
Assistant Professor, George Mason University (2019- Present)
AAAS Science and Technology Policy Fellowship (2017-2018)
Postdoctoral Research: Argonne National Laboratory (2014-2017)
Postdoctoral Research: University of Chicago (2014)
Ph.D.: University of Pennsylvania (2006-2013)
B.A./M.S.: (Combined) State University of New York (SUNY) at Buffalo (2001-2006)
Pritha Roy Awarded 2018 Teacher of Distinction
Congratulations to Dr. Pritha Roy! Your contributions to the department, COS and the GMU community are certainly appreciated and noteworthy. Congratulations on your valiant efforts and thanks for all that you do to educate and inspire the next generation of STEM professionals.
Outstanding teaching is an integral part of Mason’s mission and is deserving of significant recognition. The Teaching Excellence Awards are both institutional recognition and a monetary acknowledgement of the significant work that faculty members devote to course planning and preparation; curriculum development; and innovative teaching, advising, and mentoring.
The Chemistry and Biochemistry department has received 3 Teaching Excellence and 3 Teachers of Distinction Awards.
George Mason Chemistry welcomes Dr. Hao Jing
The Department of Chemistry & Biochemistry gladly welcomes Dr. Hao Jing as the newest member of the department. Dr. Jing will join us in January 2018 as an Assistant Professor of Physical Chemistry. His research lab will be in Planetary Hall. Dr. Jing is currently a postdoctoral fellow in the Department of Chemistry & Biochemistry at UCLA investigating nanoscale optical sensors based on plasmonic and rare-earth upconversion nanoparticles (UCNPs) for voltage sensing and neural activities recording. He previously completed an industrial postdoctoral project at nanoComposix Inc. (San Diego, CA), where he designed and fabricated nanoparticles with various morphologies and optical properties and performed nanoparticle surface functionalization capable of targeting biomolecules. Dr. Jing earned a Ph.D. in Physical Chemistry (2015) from the University of South Carolina, with a focus on Nanoscience. He also holds a M.S. in Organic Chemistry (2011) from the University of South Carolina, a M.S. in Inorganic Chemistry (2009) from Fudan University (China), and a B.E. in Polymers (2004) from Qingdao University of Science & Technology (China).
Dr. Shahamat Khan receives Lifetime Achievement AwardCongratulations to our own, Dr. Shahamat Khan, for being one of the two recipients of the Albert Nelson Marquis Lifetime Achievement Award for 2017! Only two persons are recognized during each year for having achieved “career longevity and demonstrated unwavering excellence in their chosen fields”. Dr. Khan is the editor of two journals that have home addresses in our department:
- Journal of Environmental Science and Health, Part A; Toxic/Hazardous Substances & Environmental Engineering
- Journal of Environmental Science and Health, Part B; Pesticides, Food Contaminants, Agricultural Wastes
Mason researchers create a bioprospecting tool to hunt for Komodo dragon peptides
George Mason University researchers have developed a new bioprospecting tool to help them find promising Komodo dragon peptides that are germ-fighting powerhouses, according to new research in the Journal of Proteome Research.
The federal government’s Defense Threat Reduction Agency (DTRA) funded the research with a $7.57 million contract for the George Mason team to analyze peptides used by such “extreme animals” as Komodo dragons and American alligators to defend against infection, potentially leading to new drugs and strategies to fight infection and protect the warfighter from bacterial bioweapons.
The rampant spread of antibiotic resistance threatens our ability to treat what were once routine infections, and there is an urgent need for new antibiotics. These evolutionarily ancient reptiles could be a new source for antibiotics—they dine on carrion and live in bacteria-rich environments but rarely fall ill.
“Nature can provide great templates and models for the development of new drugs against these hard-to-kill bacteria,” said Monique van Hoek, a professor with Mason’s National Center for Biodefense and Infectious Diseases, who along with chemistry professor Barney Bishop founded Antimicrobial Discovery Research in the College of Science.
The team, led by Bishop, van Hoek, and Joel Schnur, needed to invent a new way to find potent peptides present in the blood of these animals, which could provide the basis for new antibiotics. These peptides are small proteins that contribute to the body’s first line of immune defense against infection.
With the help of Dr. Kent Vliet at the University of Florida and the St. Augustine Alligator Farm Zoological Park in Florida, the Mason researchers acquired samples of blood collected from a Komodo dragon named Tujah, who lives at the park. Their analysis of the dragon’s blood revealed a complex mixture of promising peptides, many of which were fragments of larger proteins.
Bishop’s approach to capturing and enriching peptides from plasma is a critical step in their peptide discovery process, and it has allowed the team to identify peptides that are undetectable using conventional methods.
Bishop and his team developed custom-made microparticles to isolate peptides with specific physical characteristics. The antimicrobial peptides they were after were small and combined both positively charged and “greasy” elements. So they created particles that were negatively charged to attract their positively charged peptide counterparts like magnets, and they contained “greasy” components in order to complement the “greasy” parts of the peptides.
Once caught by the microparticles, the peptides were analyzed using a mass spectrometer, which tells researchers the peptides’ sizes and molecular weights. The mass spectrometer also blasts apart the peptides to give researchers an in depth look at the molecular puzzle, allowing them to determine the amino acid sequences of the peptides.
“The people who like sequencing peptides in this way also seem to like puzzles,” Bishop said.
Van Hoek and Bishop developed a gated testing process to determine whether peptides met their specific performance criteria and identify those peptides that would move on for further evaluation. They looked for bacteria-killing peptides that inhibited bacterial growth. In this paper, the team describes applying their new approach to the identification and performance testing of peptides from the Komodo dragon, and they report a series of nested peptides that showed activity against the bacteria Pseudomonas aeruginosa and Staphylococcus aureus.
Along with the Komodo dragon and American alligators, the Mason team has also investigated other large reptiles, including salt-water crocodiles, Chinese alligators, and Siamese crocodiles. They’re on the hunt for more peptides with the potential to be developed into new antibiotics. The five-year grant wraps up in February.
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