5.1 Introduction
93
In the previous chapter, spin-coated thin films of reactive poly(Nhydroxysuccinimidyl-methacrylate) (PNHSMA) films were introduced as new
(bio)reactive thin film platforms [7]. A broad range of molecules can be directedly
deposited on these films in a simple way through covalent bond formation. Several
advantages were found for this active homopolymer, such as high reactivity, high
loading, and tunable film thickness. However, one drawback of this polymer was
found, that is, short shelf life due to the high sensitivity of the NHS ester groups to
humidity [8].
As shown in this chapter, PS 690 -b-PtBA 1210 diblock copolymer thin films with
reactive t-butyl acrylate (tBA) ester groups were developed to be used as an alternative polymer-based potential bioplatform. Such polymer films show increased
stability under typical processing condition due to the presence of a water insoluble
PS block. The tunable film thickness, the reactive PtBA skin layer (see Chap. 3),
and the stability under a wide range condition render PS 690 -b-PtBA 1210 diblock
copolymer a promising biointerface platform for studying protein immobilization
and cell adhesion.
5.2 Investigation of the Surface Chemistry
of PS 690 -b-PtBA 1210 Films
The hydrolysis of reactive tBA groups in the PtBA skin layer in 3 M aqueous HCl and
its kinetics have already been discussed in Chap. 3. In this current chapter, the surface
hydrolysis of PS 690 -b-PtBA 1210 films is investigated under different conditions in
order to maximize the degree of hydrolysis and thereby degree of functionalization
of PS 690 -b-PtBA 1210 block copolymer films. Functionalization of the polymer films
with BSA, PLL, as well as 25mer probe DNA will be then treated. Finally, the
interaction of K562 and pancreatic cancer cells with derivatized PS 690 -b-PtBA 1210 is
discussed.
5.2.1 Surface Hydrolysis of PS 690 -b-PtBA 1210 Films
The hydrolysis reaction under different conditions, the functionalization of the PtBA
skin layer, and the subsequent immobilization of amino-functionalized molecules
are shown in Scheme 5.2.
As extension of the work reported in Chap. 3, the possibly different hydrolysis
behavior of PS 690 -b-PtBA 1210 films in HCl gas and in neat trifluoroacetic acid was
investigated. The FTIR transmission spectra of the films on oxidized silicon under
different acid conditions are shown in Fig. 5.1. For comparison, we show data for the
maximum possible degree of hydrolysis for all three different conditions. The spectrum of the unreacted films (0 min) shows some characteristic and intense adsorptions
93
In the previous chapter, spin-coated thin films of reactive poly(Nhydroxysuccinimidyl-methacrylate) (PNHSMA) films were introduced as new
(bio)reactive thin film platforms [7]. A broad range of molecules can be directedly
deposited on these films in a simple way through covalent bond formation. Several
advantages were found for this active homopolymer, such as high reactivity, high
loading, and tunable film thickness. However, one drawback of this polymer was
found, that is, short shelf life due to the high sensitivity of the NHS ester groups to
humidity [8].
As shown in this chapter, PS 690 -b-PtBA 1210 diblock copolymer thin films with
reactive t-butyl acrylate (tBA) ester groups were developed to be used as an alternative polymer-based potential bioplatform. Such polymer films show increased
stability under typical processing condition due to the presence of a water insoluble
PS block. The tunable film thickness, the reactive PtBA skin layer (see Chap. 3),
and the stability under a wide range condition render PS 690 -b-PtBA 1210 diblock
copolymer a promising biointerface platform for studying protein immobilization
and cell adhesion.
5.2 Investigation of the Surface Chemistry
of PS 690 -b-PtBA 1210 Films
The hydrolysis of reactive tBA groups in the PtBA skin layer in 3 M aqueous HCl and
its kinetics have already been discussed in Chap. 3. In this current chapter, the surface
hydrolysis of PS 690 -b-PtBA 1210 films is investigated under different conditions in
order to maximize the degree of hydrolysis and thereby degree of functionalization
of PS 690 -b-PtBA 1210 block copolymer films. Functionalization of the polymer films
with BSA, PLL, as well as 25mer probe DNA will be then treated. Finally, the
interaction of K562 and pancreatic cancer cells with derivatized PS 690 -b-PtBA 1210 is
discussed.
5.2.1 Surface Hydrolysis of PS 690 -b-PtBA 1210 Films
The hydrolysis reaction under different conditions, the functionalization of the PtBA
skin layer, and the subsequent immobilization of amino-functionalized molecules
are shown in Scheme 5.2.
As extension of the work reported in Chap. 3, the possibly different hydrolysis
behavior of PS 690 -b-PtBA 1210 films in HCl gas and in neat trifluoroacetic acid was
investigated. The FTIR transmission spectra of the films on oxidized silicon under
different acid conditions are shown in Fig. 5.1. For comparison, we show data for the
maximum possible degree of hydrolysis for all three different conditions. The spectrum of the unreacted films (0 min) shows some characteristic and intense adsorptions