Discipline: Ecology Environmental and Earth Sciences
Subcategory: Materials Science
Kenneth M. Serrano - University of Puerto Rico, Mayaguez, PR
Co-Author(s): John Lopez, Zuleika Oquendo, Ariana Torres, Karimar Amador, Karla Romero, Genesis Reyes, Edwin Ramos, Luis Olmo, Oscar Suarez , University of Puerto Rico, Mayaguez, PR
Lack of sufficient fresh water is a worldwide concern, as 1.2 billion people lack access to a clean drinking water source. Hence, innovative ways need to be discovered to purify contaminated water using cost-effective technologies. Moreover, chitosan, a polysaccharide made of ?1-4 linked d-glucosamine and N-acetyl-d-glucosamine, can form a gel with antibacterial and flocculent properties. Furthermore, titanium dioxide, a photocatalyst activated by ultraviolet (UV) light, forms reactive oxygen species that disrupt bacterial cell membranes resulting in cell death. This research evaluates the effect of TiO2 embedded in chitosan on the growth of Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive). We synthesized the biocomposite films by mixing chitosan, deionized water, and TiO2 into a single homogenous solution. Ultrasonic, magnetic, and mechanical agitators allowed obtaining a fine mix, which was then treated at 55°C for 48 hours. At the same time, E. coli and S. aureus populations were incubated at 37 °C to be later used in the test. The biocomposite films were characterized via scanning electron microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy to gather information about the functional group, bonding type and the nature of the biocomposite. To evaluate their antibacterial capacity, a growth curve analysis was completed under different testing parameters. We activated TiO2 with UV light, and, as expected, it caused a lower bacterial growth than the control groups. Afterward, films bearing different TiO2 concentrations were exposed to UV light along with the two types of bacteria. Preliminary results revealed that the chitosan/TiO2 biocomposite can lower the concentration of live bacteria in the sample. This material is supported by NSF under grant N? 1345156 (CREST program).
Funder Acknowledgement(s): This material is supported by NSF under grant # 1345156 (CREST program).
Faculty Advisor: Dr. Oscar Suarez, firstname.lastname@example.org
Role: In this research I assume the role of filter designer and lead mechanical engineer. I have used PTC CREO and Siemens NX for the design work. I have developed two design models, which meet with the parameters established. Also, I have been actively working synthesizing the chitosan/TiO2 biocomposite, exposing it to both bacteria, and studying its effect through a growth curve analysis.