Jonathan Mwizerwa - Georgia Gwinnett College
Co-Author(s): Veolonda Peoples and Mamie T. Coats, Alabama State University, Montgomery, AL
Streptococcus pneumoniae is a major cause of mortality in children and adults. Despite their best efforts, scientists have not been able to develop vaccines that cover all serotypes of S. pneumoniae. The ideal disease control method would also address antibiotic resistance in the bacterium. The need for an innovative solution has brought the field of nanobiotechnology research to the spotlight. Studies have shown that ZnO nanoparticles (NPs) exhibit significant antibacterial activity and are not toxic to human cells. The efforts of this study were aimed towards examining the effects of ZnO nanoparticles on the viability of S. pneumoniae known strain D39 and cancerous human lung epithelial cells known as A1549. The size and shape of the ZnO nanoparticles were 40 nm and spherically shaped, respectively. A killing assay ran on agar plates was used to determine the MBC of the ZnO nanoparticle aqueous solutions. 2.5, 1.25, .625, .3125, 15625 and 0 g/mL were the concentrations of ZnO nanoparticle aqueous solutions to be assessed using the killing assay. The standard MTT assay protocol was used to examine the effects of ZnO nanoparticles on the viability of A549 cells. Differing concentrations of 5, 2.5, 1.25, .625, .3125, and 0 mg/mL ZnO in aqueous solutions were tested in replicates of 3. The standard resazurin and microdilution assay protocol was used to examine the effects of ZnO nanoparticles on the viability of D39 cells. Analysis of the killing assay results found the MBC of the ZnO nanoparticles to be .0625 g/mL. The microtoxicity assay results revealed that ZnO NPs can be toxic to human cells at concentrations of .3125, .625, and 1.25 mg/mL. Analysis of the microdilution assay results showed a decrease in D39 viability as the concentration of ZnO NPs increased. Our data is to be interpreted with reluctance due to the low number of replications. Also, the results were in line with previous studies claiming that ZnO NPs are toxic to bacterial but cells, but were not in congruence with studies claiming that ZnO NPs do not harm human cells. In the future, lower dosages will be used to produce results similar to the claims of previous studies that revealed the antibacterial effects of ZnO NPs. Additional studies will address the mechanism of inhibition by ZnO using qPCR.
Funder Acknowledgement(s): This work was supported by NSF-REU (DBI-1358923) to Komal Vig (PI) and by NSFCREST (HRD-1241701) to Shree S. Singh (PI).
Faculty Advisor: Komal Vig, firstname.lastname@example.org
Role: I completed the whole procedure myself. I was provided the lab space, lab equipment, and materials by Alabama State University as part of a summer internship. The procedure was taught and provided to me by a faculty mentor on the campus.