Nanometer-Scale Mapping of Chemically Distinct Domains at Well-Defined Organic Interfaces Using Frictional Force Microscopy

Immunosensing Platforms Using Spontaneously Adsorbed Antibody Fragments on Gold

“…Moreover, the friction image confirms a compositional difference between the grids and the squares, with the squares having a higher friction than the grids. Several laboratories, [43][44][45] including our own, 46 have recently shown that the friction observed at the microcontact formed between a high surface free energy Si 3 N 4 tip (i.e., an uncoated tip) and a sample with high surface free energy is larger than the friction observed for a sample with low surface free energy. Since the uncoated gold squares have a higher surface free energy than the fluorinated grids, 12 it follows that the exposed gold squares of the photopatterned surfaces should exhibit a higher friction than the fluorinated grids.…”

Exploration of Simple Analytical Approaches for Rapid Detection of Pathogenic Bacteria

“…The spacer region plays an important role in the stability to the monolayer through van der Waals interactions. The terminal group largely controls interfacial properties, as it can be tailored through the [156][157][158] We studied different functional group terminated SAMs in Chapter 1 for the creation of an immunosensing platform for E. coli 0157:H7. The following paragraphs will briefly discuss a specific system utilized in Chapter 1 and 2 that involves the formation of monolayers from A^-hydroxysuccinimidyl-terminated molecules, e.g., dithio-bis(succinimidyl propionate) (DSP), a disulfide coupling agent that can be employed for the covalent attachment of molecules containing primary amines (e.g., proteins) to gold.…”

Structural and functional imaging with carbon nanotube AFM probes

“…The forces applied to the tip during retraction are due to the interactions of tip and sample molecules. Force spectroscopy has been used to measure a variety of interactions including the intermolecular adhesion between fundamental chemical groups (Frisbie et al, 1994;Green et al, 1995;Vezenov et al, 1997), the unfolding of protein molecules (Rief et al, 1997), antigen-antibody interactions (Hinterdorfer et al, 1996), and DNA stretching and unbinding (Noy et al, 1997a).…”

“…Key results obtained from past studies include (1) resolution of the packing and often subunit arrangement of membrane proteins Scheuring et al, 1999;Shao et al, 1996), (2) determination of the overall structures of protein-DNA complexes (Bustamante and Rivetti, 1996), and (3) elucidation of dynamic processes (Kasas et al, 1997;Guthold et al, 1999). In addition, in chemical force microscopy (CFM), it has been shown that the AFM tip can be modified to present well-defined chemical or biological functionality, which provides specific chemical contrast as well as topography (Frisbie et al, 1994;Fujihira and Ohzono, 1999;Green et al, 1995;Noy et al, 1997b;Vezenov et al, 1997). These capabilities of AFM suggest a great potential to impact many areas of structural biology, although to date the impact on major structural and dynamic problems has been much less than that achieved by electron microscopy as well as X-ray diffraction and NMR.…”