Preface
vii
toward primary amino groups. Biomolecule microarrays were thus conveniently
fabricated in a two-step procedure. The hybridization of target DNA to immobilized
probe DNA in micropatterns proved the concept of reactive µCP on activated polymer
films for obtaining robust patterned platforms for biomolecule immobilization and
screening.
Three different lithographic approaches to produce chemical patterns on ultrathin PS 690 -b-PtBA 1210 films were introduced in Chap. 7, which were expanded to
obtain patterns of biomolecules with (sub)micrometer feature sizes. In approach (A),
PS 690 -b-PtBA 1210 films were homogeneously hydrolyzed and subsequently activated
with NHS. Fluoresceinamine and BSA were patterned and covalently bound on the
activated polymer films in sequential direct molecular transfer steps using reactive
µCP. NHS functionalized polymer films were also patterned with PEG 500 -NH 2 by
reactive µCP in approach (B). The PEG layer was used as antifouling layer to prevent
the non-specific adsorption of (bio)molecules in the subsequent covalent coupling
step of fluoresceinamine and BSA carried out in solution. The area selective immobilization was also successfully demonstrated for 25-mer probe DNA, as shown by
the fluorescence microscopic detection of the hybridization of dye-labeled target
DNA. In approach (C), the polymer films were first locally hydrolyzed with trifluoroacetic acid that was locally applied on the films using acid-soaked PDMS stamps.
A detailed study of the reactive µCP mechanism led to the conclusion that ink
spreading and diffusion must be controlled for faithful pattern transfer, in particular
on the sub-micrometer level. In addition, it was found that patterns with micrometerscale dimensions could be fabricated by using stamps with >10 µm dimensions
by controlling the spreading of trifluoroacetic acid. Thus, ultrahigh density patterns
could be conveniently fabricated.
In Chap. 8, nanofabrication and the subsequently selective immobilization
of (bio)molecules on reactive PS 690 -b-PtBA 1210 ultrathin films were studied. As
revealed by AFM and spectroscopic techniques, the surface exposed PtBA islands in a
matrix of unreactive PS. The films were then hydrolyzed with trifluoroacetic acid and
activated with NHS. The domain selective immobilization of fluoresceinamine on the
films was globally analyzed by fluorescence microscopy and was also investigated
on the nanometer scale by AFM adhesion force mapping in the force/volume mode.
Finally, the area selective functionalization of BSA and polyamidoamine (PAMAM)
dendrimers on nanopatterned block copolymer thin films on the micrometer and submicrometer scales was carried out by reactive microcontact printing and the dip-pen
nanolithography technique, respectively, to yield surfaces that are patterned with
(bio)molecules on multiple length scales. Therefore, the polymer thin film platforms
and patterning approaches investigated here provide the opportunity to study a broad
variety of surface-mediated biological recognition processes in the future.
In Chap. 9, the development of novel bio-inspired surfaces with hierarchical
micro- and nanoscale topographic structures for efficient capture and release of circulating tumor cells (CTCs) is reported. The three-dimensional hierarchically structured
surfaces were facilely fabricated by replicating the natural micro- and nanostructures
of rose petals onto polydimethylsiloxane (PDMS) substrates. These rose petal derived
surfaces were further modified with epithelial cell adhesion molecule antibodies
vii
toward primary amino groups. Biomolecule microarrays were thus conveniently
fabricated in a two-step procedure. The hybridization of target DNA to immobilized
probe DNA in micropatterns proved the concept of reactive µCP on activated polymer
films for obtaining robust patterned platforms for biomolecule immobilization and
screening.
Three different lithographic approaches to produce chemical patterns on ultrathin PS 690 -b-PtBA 1210 films were introduced in Chap. 7, which were expanded to
obtain patterns of biomolecules with (sub)micrometer feature sizes. In approach (A),
PS 690 -b-PtBA 1210 films were homogeneously hydrolyzed and subsequently activated
with NHS. Fluoresceinamine and BSA were patterned and covalently bound on the
activated polymer films in sequential direct molecular transfer steps using reactive
µCP. NHS functionalized polymer films were also patterned with PEG 500 -NH 2 by
reactive µCP in approach (B). The PEG layer was used as antifouling layer to prevent
the non-specific adsorption of (bio)molecules in the subsequent covalent coupling
step of fluoresceinamine and BSA carried out in solution. The area selective immobilization was also successfully demonstrated for 25-mer probe DNA, as shown by
the fluorescence microscopic detection of the hybridization of dye-labeled target
DNA. In approach (C), the polymer films were first locally hydrolyzed with trifluoroacetic acid that was locally applied on the films using acid-soaked PDMS stamps.
A detailed study of the reactive µCP mechanism led to the conclusion that ink
spreading and diffusion must be controlled for faithful pattern transfer, in particular
on the sub-micrometer level. In addition, it was found that patterns with micrometerscale dimensions could be fabricated by using stamps with >10 µm dimensions
by controlling the spreading of trifluoroacetic acid. Thus, ultrahigh density patterns
could be conveniently fabricated.
In Chap. 8, nanofabrication and the subsequently selective immobilization
of (bio)molecules on reactive PS 690 -b-PtBA 1210 ultrathin films were studied. As
revealed by AFM and spectroscopic techniques, the surface exposed PtBA islands in a
matrix of unreactive PS. The films were then hydrolyzed with trifluoroacetic acid and
activated with NHS. The domain selective immobilization of fluoresceinamine on the
films was globally analyzed by fluorescence microscopy and was also investigated
on the nanometer scale by AFM adhesion force mapping in the force/volume mode.
Finally, the area selective functionalization of BSA and polyamidoamine (PAMAM)
dendrimers on nanopatterned block copolymer thin films on the micrometer and submicrometer scales was carried out by reactive microcontact printing and the dip-pen
nanolithography technique, respectively, to yield surfaces that are patterned with
(bio)molecules on multiple length scales. Therefore, the polymer thin film platforms
and patterning approaches investigated here provide the opportunity to study a broad
variety of surface-mediated biological recognition processes in the future.
In Chap. 9, the development of novel bio-inspired surfaces with hierarchical
micro- and nanoscale topographic structures for efficient capture and release of circulating tumor cells (CTCs) is reported. The three-dimensional hierarchically structured
surfaces were facilely fabricated by replicating the natural micro- and nanostructures
of rose petals onto polydimethylsiloxane (PDMS) substrates. These rose petal derived
surfaces were further modified with epithelial cell adhesion molecule antibodies