Pournima Morey

The last two decades have seen significant advances in the development of micro electro mechanical systems (MEMS) for use as sensors. MEMS based sensors have applications in fields of science ranging from physical and chemical sensing to biological disease diagnosis. The major advantages of MEMS sensors over conventional sensors include their potential for higher sensitivity, lower cost, smaller sample size, and label-free detection. Another important distinction is that MEMS sensors can easily be multiplexed to simultaneously detect multiple analytes. MEMS technology holds promise as the next generation of high sensitivity sensors.

  Nanolithography is the art and science of etching, writing, or printing at the nanoscopic level, in which the dimensions of characters are on the order of nanometers. The direct physical interactions between the atomic-force microscopy (AFM) tip and the sample allow local surface modification, allowing use of the AFM tip for scanning-probe lithography. Dip-pen nanolithography (DPN) differs conceptually from other scanning-probe lithography in that, rather than delivering energy to the surface, DPN directly delivers materials to the surface from an ink-coated AFM tip in a molecular printing process. DPN is a scanning probe nano patterning technique in which an atomic force microscope (AFM) tip is used to deliver molecules to a surface via a solvent meniscus, which naturally forms in the ambient atmosphere. This direct-write technique offers high resolution patterning for a number of molecular inks on a variety of substrates. DPN can be used to pattern nanostructure arrays in a massively parallel fashion. Indeed, one and two dimensional arrays of probes with numbers up to 55,000 have been already developed and proved successful in the DPN process. The use of small sample amounts in DPN should be particularly attractive to biologists for significantly lowering limits of detection of target molecules.