This summer I worked with Professor Mojica to continue my study regarding the binding capacity of nanoceramics and sulfa antibiotics. We have been working on this project since the 2017-2018 school year and I presented my the beginnings of my research at the ACS 2018 meeting in New Orleans. This summer, our goal was to to expand this project by testing two new sulfa antibiotics with the goal of presenting the research at the August 2018 ACS meeting in Boston.
The basis of the issue that inspired this project is the fact that there is an abundance of antibiotics in the water system. This is due to many factors including human waste, agricultural runoff, and aquaculture. This is a fairly new issue and so far no studies have been performed that shown evidence of effects on humans. However, scientists suspect that sensitive groups including pregnant woman could be at risk. There have already been some negative effects observed in fish populations. The antibiotics have caused larger percentages of hermaphrodite fish to appear in recent generations. Modern water cleaning methods don’t remove a large portion of these antibiotics, due to the fact that these processes rely heavily on bacteria. This project intended to look at how nanoceramics can bind to certain antibiotics, in order to change their absorbance or possibly even their structure.Our idea was that if the products bind in a way that makes the antibiotics less harmful to the water system then this method could theoretically be used to more effectively treat water.
In this study, we tested four types of nano ceramics, titanium oxide, silicon oxide, magnesium oxides, and zinc oxide. Nanomaterials are extremely small particles that have at least one dimension less than 100 nanometers. These materials usually take on unique properties. In this experiment, we explored their ability to bind to different sulfa antibiotics. Sulfa antibiotics are antibiotics containing sulfonamides. The sulfa antibiotics that were tested were sulfadiazine and sulfamethizole.
In terms of our methods, we followed the same methodology that we used during the school year in which we tested sulfamethoxazole and sulfamethazine against the same nanomaterials. We began by creating a 10ppm mixture of both antibiotics in water. We then added 1mg of the four nano ceramics to antibiotics samples of 2mL and gave them an hour to bind. After filtering these solutions, we ran them through a high performance layer chromatography machine to test peak area reduction. We ran these through the machine with a mixture of 95% water 5%. We then ran these samples through a UV-vis machine in order to test for absorbance change.
We did observe changes in peak absorption after adding nanoceramics. The blue shift of maximum peak absorbance is shown for sulfamethizole with silicon oxide in Figure 1. Reduction in absorbance was observed when sulfamethizole was mixed with aluminum oxide and titanium oxide. The same trend of maximum shift can be seen with sulfadiazine and silicon oxide in figure 2. Obvious changes in the absorbance profiles were shown when Zinc oxide and silicon oxide were added to sulfadiazine. Figure 3 shows a chromatogram of the sulfamethizole solution before and after addition of a nanoceramic (zinc oxide), which shows reduction in the peak area.
A shift was observed when both antibiotics were in presence of every nanoceramic, which allows us to conclude that both sulfadiazine and sulfamethizole bind with aluminum oxide, silicon oxide, titanium oxide, and zinc oxide. The type of interaction depends on each molecule and we have not yet studied how these may affect the structure of the antibiotic. It is possible that new products form when sulfa drugs react with nanoceramics.
When I presented this research at the ACS meeting in Boston during a poster session, I was approached by a professor who was curious about the shit in sulfadiazine in the presence of silicon oxide and zinc oxide as seen in Figure 2. He pointed out that the large change in absorbance may be due to particles of nanoceramics that were too small to be filtered. Therefore, I think that if we continue this research, a control of each nanoceramic should be tested against the final products in order to check for residue of nanoceramics in the UV vis spectra.
I had a very good time participating in the undergraduate research program. Not only was I able to continue my research over the summer, but I was able to document and publish my findings through the blog. Professor Mojica was a great mentor during this process. He was extremely helpful, especially in terms of processing the final data and drawing conclusions. I feel like I am now proficient in working with a UV-Vis machine as well as a HPLC after all of his help instructing me to use them over the past year. He also helped me learn the value of getting work done efficiently, as we would run multiple tests on different machines at the same time. We hope to continue this study into the next school year in hopes of finding out more about these interactions and what products have been created.