Discipline: Nanoscience
Subcategory: Chemistry (not Biochemistry)
Session: 4
Room: Park Tower 8216
David Medina-Suarez - University of Puerto Rico in Ponce
Co-Author(s): Sonia J. Bailon-Ruiz, University of Puerto Rico, Ponce.
Nanotechnology has drawn the attention of the scientific community, because of the wide variety of applications that can be done with it, from food packaging to targeted drug delivery; the use of nanoparticles has been a breakthrough in science. Silver nanoparticles have unique properties due to the oscillation of electrons in the superficial plasmon. These nanostructures have been used in different applications nanomedicine such as: targeted drug delivery, sensing and imaging, anti-fungal, anti-cancerous and biosensors. One of the most pressing matters in the world is the rapid growth in which pathogenic bacteria are resisting medications such as Penicillin. People in the science community fear the day when we no longer can use these antibiotics, because the resistance of bacteria became too great, leaving us defenseless against any type of pathogens and possibly causing a catastrophe. However, we theorize that the solution to this problem is in the use of silver nanoparticles, given that there has not been a documented bacterial adaptation strategy that could give them resistance to AgNPs. The purpose of this study is to find how the water-stable silver nanoparticles interact with different strains, including Gram negative and Gram-positive bacteria. The main objectives of our research were the following: 1) Synthesize eater stable silver nanoparticles using the Turkey method, 2) Characterize silver nanoparticles and 3) Test potential bactericidal activity of silver nanoparticles. We synthesized our silver nanoparticles using sodium citrate as a reducing agent and then concentrated the product with centrifugation. After synthesizing the silver nanoparticles, their optical properties were characterized by Ultraviolet-visible spectroscopy (UV-Vis); crystalline structure was evaluated with Electron Diffraction (ED) and X-Ray Diffraction (XRD); morphology was assessed by High Resolution Transmission Electron Microscopy (HR-TEM); and Fourier Transform Infra-Red Spectroscopy (FTIR) was used to indicate functional groups involved in the nanoparticle capping. Cultures were prepared with agarose and inoculated with the following bacterial strains: Bacillus cereus (Gram +), Micrococcus luteus (Gram +), Staphylococcus aureus (Gram +), Escherichia coli (Gram -), Citrobacter freundii (Gram -), Enterobacter aerogenes (Gram -), Klebsiella pneumoniae (Gram -), Proteus mirabilis (Gram -), Proteus vulgaris (Gram -) and Serratia marcescens (Gram -). Each petri dish was divided in two sections, one holding prescription gentamicin as positive control and the other section containing the silver nanoparticle treatment. Preliminary tests showed an inhibition diameter that surpassed 1.0 cm in all bacterial strains. We expect our silver nanoparticles to have a potential antibacterial activity towards all types of bacteria, due to oxidation of silver (Ag0 to Ag+). The silver ions (+1) would be damaging the microbial cell membrane and consequently killing the Gram-positive and Gram-negative bacteria. Future works will be focused on the study of different sizes of Ag NPs to evaluate the relationship between the particle size and the antibacterial activity. References: Keshari, A. K., Srivastava, R.., Singh, P., Yadav, V. B. & Nath, G. 2018. Antioxidant and Antibacterial Activity of Silver Nanoparticles Synthesized by Cestrum Nocturnum. Journal of Ayurveda and Integrative Medicine. Zheng, K., Setyawati, M. I., Leong, D. T., Xie, J. 2018. Antimicrobial Silver Nanomaterials. Coordination Chemistry Reviews, 357, 1-17. Liu, G., Haiqi, G., Li, K., Xiang, J., Lan, T., Zhang, Z. 2018. Fabrication of Silver Nanoparticle Sponge Leather with Durable Antibacterial Property. Journal of Colloid and Interface Science, 514, 338-348.
Funder Acknowledgement(s): PRLSAMP; UPRP Institutional funders
Faculty Advisor: Sonia J. Bailon-Ruiz, sonia.bailon@upr.edu
Role: I was involved in the synthesis and concentration of the spherical silver nanoparticles. I also worked with the optical and functional group characterizations of these synthesis, which were evaluated by UV-Vis Light Spectroscopy and Fourier Transform Infrared Spectroscopy, respectively. Lastly, I also worked in the agar plate preparations, bactericidal tests and gram stains.