Magnetic ionic liquids: interactions with bacterial cells, behavior in aqueous suspension, and broader applications

Abstract

Previously, we demonstrated capture and concentration of Salmonella enterica subspecies enterica ser. Typhimurium using magnetic ionic liquids (MILs), followed by rapid isothermal detection of captured cells via recombinase polymerase amplification (RPA). Here, we report work intended to explore the broader potential of MILs as novel pre-analytical capture reagents in food safety and related applications. Specifically, we evaluated the capacity of thebind a wider range of human pathogens using a panel of Salmonella and Escherichia coli O157:H7 isolates, including a "deep rough" strain of S. Minnesota. We extended this exploration further to include other members of the family Enterobacteriaceae of food safety, clinical or agricultural significance. Both the Ni(II) MIL and the ([P66614 + ][Dy(hfacac)4 -]) ("Dy(III)") MIL were evaluated for their effects on cell viability and structure-function relationships behind observed antimicrobial activities of the Dy(III) MIL were determined. Next, we used flow imaging microscopy (FIM) of Ni(II) MIL dispersions made in model liquid media to examine the impact of increasing ionic complexity on MIL droplet properties as a first step towards understanding the impact of suspension medium properties on MIL dispersion behavior. Finally, we used FIM to examine interactions between the Ni(II) MIL and Serratia marcescens, providing insights into how the MIL may act to capture and concentrate Gram-negative bacteria in aqueous samples, including food suspensions. Together, our results provide further characterization of bacteria-MIL interactions and support the broader utility of the Ni(II) MIL as a cell-friendly capture reagent for sample preparation prior to cultural or molecular analyses.

Toward One‐Way Smoke: Synthesis of Copper‐Based Microclubs with Asymmetric Scattering and Absorption

“…The FlowCam is a relatively new instrument that is beginning to be used to accelerate the morphological analysis of particles and microorganisms but has yet to be widely employed in the field of colloidal synthesis. [28][29][30][33][34][35][36][37][38][39] The FlowCam uses flow imaging microscopy for the rapid acquisition of particle images, in conjunction with VisualSpreadsheet 6 software for rapid analysis of 39 geometric parameters (e.g., edge gradient, length, width, aspect ratio). Flow imaging microscopy digitally captures particles by streaming a particle-containing liquid through a microscope.…”

“…The morphology of the final product could be adjusted, and its yield optimized, by tuning the concentration of NaOH, N 2 H 4, and EDA, a process monitored by a Flow-Cam (Figure S1, Supporting Information). [28][29][30] The asymmetric properties of the microclub structure were found by simulation to create a 30% difference in scattering in opposing directions. The innovative method simplifies the synthesis and characterization process, eliminating the need for multiple steps or seed preparation, and offers an efficient pathway for the production of two-component, anisotropic copper-based microstructures with potential to be used for asymmetric vision applications.…”

Chelation-based enhancement of novel and commercially available antimicrobials against foodborne pathogens

“…It is a Gram-negative, non-sporulating and facultative anaerobic rod belonging to the family Enterobacteriaceae. This family also includes a number of other pathogens that are problematic in the food safety or clinical sectors, including Cronobacter, Klebsiella, Shigella and Salmonella, as well as the plant pathogenic genera Erwinia, Pantoea and Pectobacterium (Hice et al, 2020).…”

“…There are two types of E. coli that cause diarrheal illness, Shiga toxin-producing E. coli (STEC) and enterotoxigenic E. coli (ETEC). E. coli O157:H7 and five other STEC pathovars make up the "Big Six" ruled by the USDA to be food adulterants (Hice et al, 2020). Together, STEC are estimated to cause more than 265,000 illnesses each year in the US, with more than 3,600 hospitalizations and 30 deaths (CDC, 2012).…”