Chapter 4
Reactive Thin Polymer Films
as Platforms for the Immobilization
of Biomolecules
In this chapter, spin-coated thin films of poly(N-hydroxysuccinimidyl-methacrylate)
(PNHSMA) were investigated as reactive layers for obtaining platforms for
biomolecule immobilization with high molecular loading. The surface reactivity
of PNHSMA films in coupling reactions with amino-functionalized poly(ethylene
glycol) (M n : 500 g/mol) (PEG 500 -NH 2 ) was determined by FTIR spectroscopy,
X-ray photoelectron spectroscopy (XPS), fluorescence microscopy, and ellipsometry measurements, respectively. The PEG 500 -NH 2 loading observed was about
three times higher for the polymer thin films compared to self-assembled monolayers (SAMs) of 11,11
-dithiobis(N-hydroxysuccinimidylundecanoate) (NHS-C10)
on Au. These data indicated that the coupling reactions are not limited to the outermost surface layer of the polymer films, but proceed into the surface-near regions
of the films. An increased loading was also observed by surface plasmon resonance (SPR) measurements for the covalent immobilization of amino-functionalized
probe DNA. Hybridization of fluorescently labeled target DNA was successfully
detected by fluorescence microscopy and surface plasmon resonance-enhanced fluorescence spectroscopy (SPFS), thereby demonstrating that thin films of PNHSMA
show robustness and comprise an attractive and simple platform for the immobilization of biomolecules with high densities. Finally, the successful application of
PNHSMA films as platform for biosensors for pathogen detection was demonstrated
using a protein G mediated antibody-based detection of bacteria (listeria).
4.1 Introduction
Considerable effort has been invested recently to create robust high-throughput
biosensors with improved detection sensitivity [1]. A biosensor can be defined as a
device that can convert binding events between an analyte of interest and complementary binding into an electronic signal [2]. The detection of the binding event in many
cases is based on electronic/electrochemical detection principles or employs optical
© Shanghai Jiao Tong University Press 2021
C. Feng et al., Microfabrication of Stimuli-Responsive Polymers,
https://doi.org/10.1007/978-981-33-6869-9_4
69
Reactive Thin Polymer Films
as Platforms for the Immobilization
of Biomolecules
In this chapter, spin-coated thin films of poly(N-hydroxysuccinimidyl-methacrylate)
(PNHSMA) were investigated as reactive layers for obtaining platforms for
biomolecule immobilization with high molecular loading. The surface reactivity
of PNHSMA films in coupling reactions with amino-functionalized poly(ethylene
glycol) (M n : 500 g/mol) (PEG 500 -NH 2 ) was determined by FTIR spectroscopy,
X-ray photoelectron spectroscopy (XPS), fluorescence microscopy, and ellipsometry measurements, respectively. The PEG 500 -NH 2 loading observed was about
three times higher for the polymer thin films compared to self-assembled monolayers (SAMs) of 11,11
-dithiobis(N-hydroxysuccinimidylundecanoate) (NHS-C10)
on Au. These data indicated that the coupling reactions are not limited to the outermost surface layer of the polymer films, but proceed into the surface-near regions
of the films. An increased loading was also observed by surface plasmon resonance (SPR) measurements for the covalent immobilization of amino-functionalized
probe DNA. Hybridization of fluorescently labeled target DNA was successfully
detected by fluorescence microscopy and surface plasmon resonance-enhanced fluorescence spectroscopy (SPFS), thereby demonstrating that thin films of PNHSMA
show robustness and comprise an attractive and simple platform for the immobilization of biomolecules with high densities. Finally, the successful application of
PNHSMA films as platform for biosensors for pathogen detection was demonstrated
using a protein G mediated antibody-based detection of bacteria (listeria).
4.1 Introduction
Considerable effort has been invested recently to create robust high-throughput
biosensors with improved detection sensitivity [1]. A biosensor can be defined as a
device that can convert binding events between an analyte of interest and complementary binding into an electronic signal [2]. The detection of the binding event in many
cases is based on electronic/electrochemical detection principles or employs optical
© Shanghai Jiao Tong University Press 2021
C. Feng et al., Microfabrication of Stimuli-Responsive Polymers,
https://doi.org/10.1007/978-981-33-6869-9_4
69