Properties of silver and copper nanoparticle-containing aqueous solutions and evaluation of their in vitro activity against Candida albicans and Staphylococcus aureus biofilms

dc.contributor.advisorGuo, Ruyan
dc.contributor.advisorLopez-Ribot, Jose L.
dc.contributor.authorMontes Aguirre, Melissa Mariluz
dc.contributor.committeeMemberBhalla, Amar
dc.contributor.committeeMemberTang, Liang
dc.descriptionThis item is available only to currently enrolled UTSA students, faculty or staff. To download, navigate to Log In in the top right-hand corner of this screen, then select Log in with my UTSA ID.
dc.description.abstractMost microorganisms grow on surfaces as biofilms rather than as individual planktonic cells, and cells within biofilms show high levels of resistance against antimicrobial drugs. Thereby biofilm formation complicates treatment and contributes to high morbidity and mortality rates associated with infections. This study explores the physical, optical, and nano-structural properties of selected nanoparticles dispersed in aqueous solutions (nanoparticulate colloidal water or nanofluids) and examines their in vitro activity against microbial biofilms. Silver and copper nanofluids of various concentrations were prepared and studied. Their surface energies, surface charge and surface plasmonic resonance properties were obtained using contact angle measurement, zeta potential and optical spectrometer, respectively. The temperature dependence of the surface plasmon resonance behavior was also determined for the selected nanoparticulate aqueous solutions. A model of biofilm formation on the wells of microtiter plates was used to determine the in vitro activity of the nanoparticle preparations against both fungal (Candida albicans) and bacterial (Staphylococcus aureus) biofilms. Scanning electron microscopy (SEM) was used to observe the nanoparticle interactions with microbial cells. Results show that silver nanofluid has higher surface energy than that of the copper, the surface energy increases as the concentration of silver nanoparticles increases; and both nanoparticles in liquid are positively charged. The interaction between silver nanoparticles and water molecules produces notable changes on the usual temperature properties of water. Altogether, effectiveness of silver nanoparticle-containing liquids in controlling biofilm formation is observed and reported. For a given size of silver nanoparticles studied, it is found that the effective concentrations of silver nanoparticles against microbial biofilms are far lower than their cytotoxic concentrations, indicating an overall safety and a good therapeutic index thus substantial application potential.
dc.description.departmentElectrical and Computer Engineering
dc.format.extent78 pages
dc.subject.classificationBiomedical engineering
dc.subject.lcshSilver compounds
dc.subject.lcshCandida albicans
dc.subject.lcshStaphylococcus aureus
dc.titleProperties of silver and copper nanoparticle-containing aqueous solutions and evaluation of their in vitro activity against Candida albicans and Staphylococcus aureus biofilms
dcterms.accessRightspq_closed and Computer Engineering of Texas at San Antonio of Science


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