SICM + AVI Series
There are three instrumentation setups in the Baker Group that make use of the AVI-200 active vibration isolation system. Our studies are mainly focused on scanned probe microscopy, where is a nanopipette filled with electrolyte is used to either map the local ion current of a given sample or to obtain acurrent-voltage characteristic over a given surface.Shown in Figure 1 (Left) is our experimental setup for the imaging technique known as SICM (Scanning Ion Conductance Microscopy), which was specially designed for sub-micrometer resolution imaging of soft and non-conductive materials bathed in electrolyte. During imaging process we found that our image resolution was limited by background noise. The noise sources include ambient vibration from the floor or pumps and other machinery. Figure 1 (Right) shows custom instrumentation set-up for characterizing current-voltage response by bringing a nanopipette closely towards a substrate. Studies based on this setup showed that vibration isolation was required since characterized current-voltage curves obtained when in close proximity to a surface indicate that vibration from nanopipette probe is not negligible.
We asked Herzan for help with a solution to make our instrument perform better considering all the above measurements we did are recorded in a mechanically noisy environment. Environmental noise has been significantly curtailed with incorporation of a Herzan active vibration isolation system.
- Ion Current Measurement Utilizing Nanopipettes
- Scanning Ion Conductance Microscopy (SICM) and custom instrumentation setup for characterizing current-voltage response by bringing a nanometer scale pipette in close proximity to a surface.
- Baker Group, Chemistry Department, Indiana University, Bloomington.
Figure 2. SICM image of a nanopore membrane with improved resolution after AVI-200 vibration isolation system. Figue 2 (a) shows higher background noise as compared with Figure 2 (b). Figure 3 describes comparison of improved current-voltage curves after AVI-200.
Lane Baker is an Assistant Professor of Chemistry at Indiana University Bloomington. Niya Sa, currently a 4th year graduate student in Baker Group. Chiao-chen Chen, currently a 5th year graduate student in Baker Group.