Functional Microstructures by Self-Assembly - Molecular Self-Assembly: Advances and Applications - page 390

determine cross-selectivity between Au, Pt, and the oxide. Again,
the sample was immersed in bio-GBP1 for incubation, and SAQDs
were introduced thereafter. Fluorescence microscopy revealed
that only one set of the patterned squares appeared red implying
immobilization of the SAQDs on only one kind of metal. Energy-
dispersive X-ray microanalysis (EDX) confirmed those squares to be
gold. Thus, the peptides specifically recognized and adsorbed onto
the gold surface, and directed the SAQDs to immobilize on those
predefined locations via the biotin

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streptavidin link. Therefore, it
was demonstrated for the first time that combinatorially selected
and genetically engineered GBP1 indeed preferentially adsorbs
onto its original selective substrate. Thus, it can be utilized for
selective assembly of nanoscale structures on predefined locations.
However, the mechanism or substrate recognition and selective
binding is not well understood. Polar moieties on the peptide as well
as its conformation are proposed to be responsible for its specific
adsorption characteristics [1].
Metal-specific binding and recognition may be considered one
pathway to bridge the inorganic and biological domains. The gold-
binding peptide could be employed as a molecular linker or binding
agent, or even a genetically engineered functionalized substrate
specifically bound to Au under biocompatible conditions. Moreover,
studies of the adsorption behavior of GBP1 may offer essential
information for the investigation of mechanisms behind peptide (or
protein)

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inorganic substrate interactions.

12.2.2 Two-Dimensional Self-Assembly of

1-Pyrylphosphonic Acid

1-Pyrylphosphonic acid (PYPA), an amphiphilic aromatic acid, is
used to form a 2D supramolecular laminate architecture on a solid
support via spin coating. The effects of processing parameters such as
solvent, concentration, and substrate were studied to determine the
mechanism of the self-assembly process. Atomic force microscopy
(AFM), scanning tunneling microscopy (STM), X-ray diffraction
(XRD), and Fourier transform infrared spectroscopy (FTIR) were
used to analyze the morphology and internal structure of the PYPA
architecture. In addition, UV

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vis absorption and fluorescence
spectroscopy were carried out on the deposited structures.
Three other molecules, diethyl 1-pyrylphosphonate (PYPDEt),