NSF-MRI: Development of Sub-Angstrom Amplitude Atomic Force Microscope for Biological and Liquid Environments

Wayne State University, Detroit MI

Investigators

Abstract

A grant has been awarded to Wayne State University under the direction of Dr. Peter Hoffmann to design and construct a new, innovative Atomic Force Microscope (AFM) to study cells and biomolecules. AFM is a technique where a sharp tip mounted on a cantilever spring is scanned across or approached towards a surface in order to image and measure mechanical properties at the nanoscale. The technique has been used for over a decade in measurements of biological structures. However, current AFM's have fundamental design issues that limit their usefulness. These include low sensitivity and inherent non-linearities. As a result, AFM's have not reached their full potential in biological research. The purpose of this grant is to design a radically different AFM system that avoids these limitations from the start and is specifically built to perform unprecedented high-resolution imaging and nano-mechanical measurements of biological samples. The most important features of this new instrument will be the use of a fiber-optic interferometer to measure the deflection of the cantilever (boosting sensitivity by a factor 100), non-contact operation (for non-invasive imaging), and the use of ultra-small amplitudes (< 1 Angstrom = the size of a single hydrogen atom), which will linearize force measurements. The development of this new instrument will have a tremendous impact on our understanding of cells and cell membranes. Research that will be conducted with this new instrument includes: (1) behavior of transmembrane proteins (proteins that are located in the cell membrane), which play important roles in cell signaling, (2) mechanical properties of fetal membranes, part of a project to address prematurity in humans, and (3) basic research of hydrophobicity and other forces in model systems that mimic cell membranes and their components to gain better understanding of these fundamental building blocks of life. The instrument will add a significant component to the research infrastructure here at Wayne State University, and is expected to be used for a number of ground-breaking interdisciplinary research projects ranging from biology, medicine, materials science to industrial applications (nanotribology). Results of the work will be communicated to the general public via planned outreach events in Detroit area science museums and schools, part of a currently implemented program consisting of science lectures for the general public.