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Voltage and Photo Induced Effects in Droplet-Interface-Bilayer Lipid Membranes

Punnamaraju, Srikoundinya
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321648604

Abstract Details

2011, PhD, University of Cincinnati, Engineering and Applied Science: Electrical Engineering.
Artificial lipid bilayers are models and mimics of biological cellular and sub-cellular membranes. Model lipid bilayers are extremely useful in understanding the physiological functions of cellular membranes and the influence of various external parameters on cellular membranes. Several approaches were developed over the past six decades for forming artificial lipid bilayers such as planar bilayer lipid membranes, supported lipid bilayers (SLB), tethered bilayer lipid membranes, and vesicles. A novel and versatile approach called droplet-interface-bilayer (DIB) was recently developed and significant contributions in DIB lipid membrane research were reported. The DIB approach involves forming a lipid bilayer by contacting two aqueous droplets, coated with lipid monolayers, against each other in a lipid-oil environment. The UC Nanolab initiated DIB research work in 2008 and results are presented in this dissertation. DIBs are characterized using several methods: optical, mechanical, electrical, and stability with time. Versatility of DIBs is demonstrated using various types and volumes of aqueous droplets, several lipids, mechanical and electrical control of DIB dimensions, formation of DIB networks, and droplet microfluidic platforms for DIB automation. This dissertation consists of three main parts. In the first part, voltage induced effects (both DC and AC) on the properties of DIB (such as lateral dimension, area, capacitance, and current) are investigated. Significant changes in the above-mentioned DIB properties vs. voltage are measured using simultaneous optical and electrical recordings on anchor-free DIBs. Mechanisms behind voltage control of DIB dimensions are investigated and formulated. Comparison is made between DIB and EWOD. Voltage controlled DIB area has potential application in active control of number of ion channels or nanopores in DIB. Single nanopore insertion studies are conducted at different voltages using alpha-hemolysin. Effect of nanopore concentration and voltage on DIB current is explored. In the second part, photo induced effects on the porosity of DIB are investigated by incorporating a mixture of photopolymerizable and non-photopolymerizable lipids in a DIB. UV-C (~ 254 nm) radiation is used for photo triggering and mechanism behind DIB porosity change with UV-C radiation is explained. This photo-induced effect is used for releasing encapsulated molecules from one droplet to the other across DIB. This approach with DIB could be useful for in-vitro drug release studies that are otherwise typically carried out using liposomes. In the third part, a droplet based digital micro fluidic platform is designed, fabricated, and tested for automating the movement of lipid monolayer coated aqueous droplets in lipid-oil bath medium inside a fluidic channel. Digital microfluidic technology primarily uses electrowetting effects and Laplace pressure to transport droplets in a channel. Low voltage operation is achieved. This approach has potential application in automating DIB formation in a fluidic channel.
Andrew Steckl, PhD (Committee Chair)
Marc Cahay, PhD (Committee Member)
Joel Fried, PhD (Committee Member)
Jason Heikenfeld, PhD (Committee Member)
David Wendell, PhD (Committee Member)
159 p.
Electrical Engineering
Droplet Interface Bilayer; Bilayer Lipid Membrane; Electrowetting; Contact Angle; Photopolymerizable Lipids; Digital Microfluidics

Recommended Citations

Citations

  • Punnamaraju, S. (2011). Voltage and Photo Induced Effects in Droplet-Interface-Bilayer Lipid Membranes [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321648604

    APA Style (7th edition)

  • Punnamaraju, Srikoundinya. Voltage and Photo Induced Effects in Droplet-Interface-Bilayer Lipid Membranes. 2011. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321648604.

    MLA Style (8th edition)

  • Punnamaraju, Srikoundinya. "Voltage and Photo Induced Effects in Droplet-Interface-Bilayer Lipid Membranes." Doctoral dissertation, University of Cincinnati, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321648604

    Chicago Manual of Style (17th edition)

ucin1321648604
405
© 2011, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.