ABSTRACT

Basic Information

Abstract Number: 1280 - 1
Author Name: Florika Caling Macazo - University of Maryland Baltimore County
Session Title: SEAC - The Student Session in Electroanalysis
Event Type: Organized Contributed Sessions
Event Title: Developing an Innovative Bio-Inspired Scanning Probe Microscopy (Bio-SPM) Approach to Map Specific Molecular Flux

Presider Name:Stephen MaldonadoCo-Author:Ryan J White
Affiliation:University of Michigan Affiliation:University of Maryland Baltimore County

Date: Tuesday, March 8, 2016
Start Time: 01:30 PM (Slot #1)
Location: B401

Abstract Content

Successful reports on the utility of nanopore sensing and scanning ion conductance microscopy (SICM) in studying physiological systems are great motivations to pursue studies involving coupling of these two techniques to encompass broader applications. In this study, we combined the imaging ability of SICM with the sensitivity of protein nanopore sensing to develop a new, bio-inspired scanning ion conductance microscopy (bio-SICM) technique capable of quantitatively mapping specific molecular flux across membranes. We established the framework of this analytical platform using [alpha]-hemolysin ([alpha]HL) as a representative protein nanopore to map [beta]-cyclodextrin ([beta]CD) flux across a synthetic membrane. We fabricated [alpha]HL-based probes and used an in-house SPM to generate approach curves employing the distance-dependent current response as feedback. Continuous monitoring of the current fluctuations suggests successful detection of [beta]CD binding events as evidenced by typical current blockades (60 – 80%) for a single [alpha]HL channel inserted into a lipid bilayer. To demonstrate molecular flux imaging, we raster-scanned the [alpha]HL-based probe over a 25-[micro]m pore glass substrate, while recording the lateral positions and current fluctuations caused by the [beta]CD flux. Specifically, we utilized the frequency of [beta]CD single binding events occurring at a single [alpha]HL pore to generate a concentration profile of the [beta]CD flux across the membrane. When further optimized, we believe that this will provide a simple analytical methodology that is generalizable, which will lay the groundwork for pursuing other molecular flux-related studies especially in the areas of neuroscience and biology (e.g. mapping ATP flux from astrocyte cells).