Articles by Rachel Komorek in JoVE
In Situ Characterization of Shewanella oneidensis MR1 Biofilms by SALVI and ToF-SIMS Rachel Komorek1, Wenchao Wei1, Xiaofei Yu2, Eric Hill1, Juan Yao1, Zihua Zhu2, Xiao-Ying Yu1 1Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, 2Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory This article presents a method for growing a biofilm for in situ time-of-flight secondary ion mass spectrometry for chemical mapping in its hydrated state, enabled by a microfluidic reactor, System for Analysis at the liquid Vacuum Interface. The Shewanella oneidensis MR-1 with green fluorescence protein was used as a model.
In Situ Characterization of Boehmite Particles in Water Using Liquid SEM Juan Yao1, Bruce W. Arey1, Li Yang1, Fei Zhang1, Rachel Komorek1, Jaehun Chun1, Xiao-Ying Yu1 1Earth & Biological Sciences Directorate, Pacific Northwest National Laboratory We present a procedure for real-time imaging and elemental composition analysis of boehmite particles in deionized water by in situ liquid Scanning Electron Microscopy.
Other articles by Rachel Komorek on PubMed
Characterization of Syntrophic Geobacter Communities Using ToF-SIMS Biointerphases. Aug, 2017 | Pubmed ID: 28821212 The aggregation of syntrophic Geobacter metallireducens and Geobacter sulfurreducens is beneficial for enhancing direct interspecies electron transfer (DIET). Although DIET was suspected to occur on the microbial community surface, the surface chemical speciation of such cocultured communities remains unclear. In order to better understand surface interactions related to DIET, the authors characterized a series of samples associated with syntrophic G. metallireducens and G. sulfurreducens using surface sensitive time-of-flight secondary ion mass spectrometry (ToF-SIMS). Principal component analysis was used in spectral analysis. Our results show that the syntrophic Geobacter aggregates are significantly different from their planktonic cells, indicating a distinct chemical composition (i.e., amino acids, fatty acids, and lipids) and structure formed on their surface. Among these characteristic components, amino acid fragments dominated in the variance, suggesting the importance of proteins in the coculture. Additionally, the quorum sensing signal molecule N-butyryl-l-homoserine lactone was observed in cocultured Geobacter aggregates, implying its role in syntrophic growth and aggregate formation. Furthermore, the electron acceptor organism G. sulfurreducens was shown to be the dominant species in syntrophic communities that drove the syntrophic growth. These results demonstrate that unique chemical compositions distinguish syntrophic Geobacter aggregates from planktonic cells and suggest that ToF-SIMS may be a promising tool to understand the syntrophic mechanism and investigate interspecies electron transfer pathways in complex biofilms.
Recent Developments in the Synthesis, Properties, and Biomedical Applications of Core/shell Superparamagnetic Iron Oxide Nanoparticles with Gold Biomaterials Science. Sep, 2017 | Pubmed ID: 28901350 In the last decade, magnetic nanoparticles (MNPs), especially superparamagnetic iron oxide nanoparticles (SPIONs), have immensely promoted the advancement of diagnostics and theranostics in the biomedical field. The unique properties of the SPIONs-core and the functional gold (Au)-shell together (SPIONS/Au core/shell or CS) have a wide range of biomedical applications including, but not limited to, magnetic resonance imaging (MRI), dual modality MRI/computed tomography (CT), photo-induced and magnetic fluid hyperthermia (MFH), drug delivery, biosensors, and bio-separation. Researchers have made much effort to develop synthesis strategies for size control and surface modifications to achieve the desired properties of these CSs for applications in in vitro and in vivo studies. This review highlights recent developments in the synthesis and biomedical applications of SPIONs/Au CSs, including γ-Fe2O3/Au (maghemite), Fe3O4/Au (magnetite), and MFe2O4/Au (M = divalent metal ions) in the past seven years. More importantly, current trends of SPIONs/Au in relation to the biochemical industry are surveyed. Finally, we outline the developmental needs of SPIONs/Au from the perspective of material synthesis and their novel applications in disease diagnosis and treatment in the near future.