Abstract
An insulator-based dielectrophoresis (iDEP) is a label-free method that has been extensively utilized for manipulation of nanoparticles, cells, and biomolecules. Here, we present a new iDEP approach that can rapidly trap nanoparticles at the close proximity of a glass nanopipette’s tip by applying 10 V/cm direct current (DC) across the pipette’s length. The trapping mechanism was systemically studied using both numerical modeling and experimental observations. The results showed that the particle trapping was determined to be controlled by three dominant electrokinetic forces including dielectrophoretic, electrophoretic and electroosmotic force. Furthermore, the effect of the ionic strength, the pipette’s geometry, and the applied electric field on the entrapment efficiency was investigated. To show the application of our device in biomedical sciences, we demonstrated the successful entrapment of fluorescently tagged liposomes and unlabeled plasma-driven exosomes from the PBS solution. Also, to illustrate the selective entrapment capability of our device, 100 nm liposomes were extracted from the PBS solution containing 500 nm polystyrene particles at the tip of the pipette as the voltage polarity was reversed.
Highlights
IntroductionIn the last few decades, considerable efforts have been made to develop new miniaturized technologies for particle manipulation, pre-concentration, and sorting using the optical[1,2,3], magnetic[4,5,6], acoustic[7,8,9], and dielectrophoretic (DEP)[10,11,12,13,14,15,16,17,18] schemes
An alternative insulator-based dielectrophoresis (iDEP) approach was initially introduced by the Klenerman group[36], as significantly lower voltage was applied across a glass nanopipette; The small conical geometry of the nanopore induced a strong non-uniform electric field (E-field) which created a DEP trapping zone inside of the pipette near the tip region[36,37,38]
The simulation and experimental results indicated that the entrapment was governed by the net electrokinetic force induced on the particles; and the entrapment mechanism and yield are dependent on the polarity of the applied voltage, the size and the geometry of pipette, and the ionic strength of the solution
Summary
In the last few decades, considerable efforts have been made to develop new miniaturized technologies for particle manipulation, pre-concentration, and sorting using the optical[1,2,3], magnetic[4,5,6], acoustic[7,8,9], and dielectrophoretic (DEP)[10,11,12,13,14,15,16,17,18] schemes. An alternative iDEP approach was initially introduced by the Klenerman group[36], as significantly lower voltage was applied across a glass nanopipette; The small conical geometry of the nanopore induced a strong non-uniform E-field which created a DEP trapping zone inside of the pipette near the tip region[36,37,38] This method has been used for trapping DNA molecules and proteins, by backfilling the nanopipette with a solution containing the target analytes and concentrating them inside the pipette as an AC field was applied[36,37,38,39]. To show the biomedical application of our device, small extracellular vesicles (exosomes) extracted from plasma of healthy donors, re-suspended in PBS solution, were trapped and pre-concentrated under two minutes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
