Analysis of Bacteriophages with Insulator-Based Dielectrophoresis

Abstract

Bacterial viruses or phages have great potential in the medical and agricultural fields as alternatives to antibiotics to control nuisance populations of pathogenic bacteria. However, current analysis and purification protocols for phages tend to be resource intensive and have numbers of limitations, such as impacting phage viability. The present study explores the potential of employing the electrokinetic technique of insulator-based dielectrophoresis (iDEP) for virus assessment, separation and enrichment. In particular, the application of the parameter “trapping value” (Tv) is explored as a standardized iDEP signature for each phage species. The present study includes mathematical modeling with COMSOL Multiphysics and extensive experimentation. Three related, but genetically and structurally distinct, phages were studied: Salmonella enterica phage SPN3US, Pseudomonas aeruginosa phage ϕKZ and P. chlororaphis phage 201ϕ2-1. This is the first iDEP study on bacteriophages with large and complex virions and the results illustrate their virions can be successfully enriched with iDEP systems and still retain infectivity. In addition, our results indicate that characterization of the negative dielectrophoretic response of a phage in terms of Tv could be used for predicting individual virus behavior in iDEP systems. The findings reported here can contribute to the establishment of protocols to analyze, purify and/or enrich samples of known and unknown phages.

Insulator Based Dielectrophoresis: Micro, Nano, and Molecular Scale Biological Applications

“…Currently, the most recent report on iDEP based virus manipulation is the work of Adriana et al [ 104 ] who assessed bacterial virus (phage) separation and enrichment with iDEP traps ( Figure 5 ) on structurally and inherently distinct, phages of P. chlororaphis phage 201ϕ2-1, P. aeruginosa phage ϕKZ, S. enterica phage SPN3US, and it was determined that the virion trapping occurred at lower voltages in devices with circular insulating posts compared to oval-shaped ones ( Figure 5 d) since these generate lower DEP forces than the latter. The results indicated that virus behavior in the iDEP system could be predicted based on the trapping response of the phage.…”

“…Therefore, iDEP is actively being investigated to manipulate various types of viruses and develop innovative high throughput diagnostic devices due to the selective nature of applied trapping voltages on viruses. The findings encountered by Adriana et al [ 104 ] shed light on one such application of iDEP for analyses and separation of phage mixtures. Tables S3 and S4 (Supplementary Materials) further highlight iDEP publications and device patents on various virus manipulation work.…”

“… Virion enrichment with iDEP traps [ 104 ]. ( a ) Transmission electron microscope (TEM) image of Salmonella (SPN3US-infected).…”

“…( d ) Circle posts: (i) SPN3US virions at 1200 V, (ii) P. aeruginosa phage ϕKZ at 1100 V, and (iii) 1100 V applied on P. chlororaphis phage 201ϕ2-1. Oval posts: (iv) SPN3US virion at 800 V, (v) P. aeruginosa phage ϕKZ at 750 V and (vi) P. chlororaphis phage 201ϕ2-1 at 750 V. [ 104 ]. ©Reprinted (adapted) with an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium.…”

AC Electroosmosis Effect on Microfluidic Heterogeneous Immunoassay Efficiency

“…DEP is applied, for instance, to control particles and detect cancer cells from the blood [14]. DEP is greatly used in biological applications for the separation of virus particles [15,16], the separation of nanoparticles [17], droplet manipulation [18], and trapping and manipulation of single cells and particles [19]. Dielectrophoresis (DEP) and alternating current electrothermal (ACET) flow are also combined to realize continuous particle trapping, switching, and sorting [20].…”