Real-Time Interaction of Mixed Species Biofilm With Silver Nanoparticles Using QCM-D

Connie Walden, Lauren Greenlee, Wen Zhang

Research output: Contribution to journalArticlepeer-review


This study presents a novel approach to probe in situ, real-time changes in mixed-species biofilms via quartz crystal microbalance with dissipation (QCM-D). The viscoelasticity of a model wastewater biofilm was monitored by QCM-D, and quantitative changes in both measured frequency, ∆f, and dissipation, ∆D, reflected biofilm structural changes in the presence of silver nanoparticles (Ag-NPs). Complimentary results from confocal laser scanning microscopy confirmed biofilm attachment and the presence of live cells. A step-input experiment with increasing concentrations of Ag-NPs (127, 666, 1160, 1632 ppb) was performed. A Voigt model analysis of QCM-D results shows differing biofilm viscoelastic behavior as a function of Ag-NP concentration. The step input response of ∆D/∆f ratio showed that Ag-NPs cause a structural pattern of firmness at low concentrations (up to 666 ppb), and less rigidity of attached mass at higher concentrations (up to 1632 ppb) for the mixed species biofilm studied.

Original languageEnglish (US)
Pages (from-to)49-53
Number of pages5
JournalColloids and Interface Science Communications
StatePublished - Jan 2019

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry
  • Materials Chemistry


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