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Custom Modification of AFM Tips for Fast, High Force Resolution Single-Molecule Force Spectroscopy

Published

Author(s)

Aric W. Sanders, Jaevyn Faulk, Devin T. Edwards, Thomas T. Perkins

Abstract

In addition to providing the ability to image on the nanoscale, atomic force microscopy (AFM) has the ability to measure small (pN) forces at a single point. This ability has led to new insights into conformation changes in biological molecules; in particular, single-molecule force spectroscopy (SMFS) is a powerful tool to investigate folding in proteins. Ideally, one could observe folding in proteins at fast time scales, in the microsecond range, with both short-term force precision and long-term force stability. Traditionally, to achieve minimize force drift one must sacrifice temporal resolution and a large AFM cantilever with low spring constant but slow time response is chosen. When speed is required, one choses a smaller cantilever, which because of fabrication constraints has a higher spring constant and hence a increased force drift. Recently, it has been shown that by modifying a commercially available cantilever with focused ion beam (FIB) milling, small AFM cantilevers can be softened to reduce force drift, without sacrificing temporal resolution. The resulting cantilevers offer state-of-the-art force stability and precision, with temporal resolution ~100 μs. To further improve the performance of modified AFM cantilevers, different FIB modification strategies need to be developed to improve yield and extend the technique to ultra-small cantilevers, which offer temporal resolution ~1 μs.We present several modification strategies each which decrease the stiffness of the resultant cantilevers while retaining fast response times. Additionaly, we explore techniques that improve the yield of the process.
Proceedings Title
Microscopy and Microanyalsis
Conference Dates
August 2-6, 2015
Conference Location
portland, OR

Keywords

AFM, Canitlever, FIB, Single Molecule Force Spectroscopy, JILA

Citation

Sanders, A. , Faulk, J. , Edwards, D. and Perkins, T. (2015), Custom Modification of AFM Tips for Fast, High Force Resolution Single-Molecule Force Spectroscopy, Microscopy and Microanyalsis, portland, OR, [online], https://doi.org/10.1017/S1431927615008867 (Accessed January 18, 2022)
Created September 5, 2015, Updated November 10, 2018