A FRESH INSIGHT IN TO THE MICROCANTILEVER-SAMPLE INTERACTION PROBLEM: FROM ATOMIC FORCE MICROSCOPY TO BIOLOGICAL MASS DETECTION

The atomic force microscope (AFM) system has evolved into a useful tool for direct measurements of microstructural parameters and unraveling the intermolecular forces at nanoscale level with atomicresolution characterization. Current AFM imaging techniques are often based on a lumped-parameters representation of the microcantilevers and an ad-hoc methods for atomic interaction force estimation. However, the distributed nature of the structural flexibility in the microcantilever is an issue of increasing concern due to its direct influence on image resolution. Since the magnitude of the interaction force lies within the range of nano-Newtons to pico- Newtons, precise estimation of the atomic force is crucial for accurate topographical imaging. In contrast to the previously utilized lumped modeling methods, this invited paper aims at developing a general distributed-based modeling approach that reveals greater insight into the fundamental characteristics of the microcantilever-sample interaction. Following this development, the application of microcantilevers as a tool for transducing chemical and biological processes into micromechanical motion is discussed. Termed NanoMechanical Cantilever Sensors (NMCS), this announced the beginning of a new detection era for measurable chemically/biologically-induced mechanical forces. It is documented that NMCS are capable of detecting vapors, bacterial cells, proteins, and antibodies, and can provide a mechanism for DNA hybridization.

Keywords:

Atomic force microscopy , microcantilever-sample interaction , nanomechanical cantilever sensors