Polymer Brushes on GaAs and GaAs/AlGaAs Nanoheterostructures: A Promising Platform for Attractive Detection of Legionella pneumophila

Abstract

This work reports on the potential of polymer brushes (PBs) grown on GaAs substrates (PB-GaAs) as a promising platform for the detection of Legionella pneumophila (Lp) . Three functionalization approaches of the GaAs surface were used, and their compatibility with antibodies against Lp was evaluated using Fourier transform infrared spectroscopy and fluorescence microscopy. The incorporation of PBs on GaAs has allowed a significant improvement of the antibody immobilization by increased surface coverage. Bacterial capture experiments demonstrated the promising potential for enhanced immobilization of Lp in comparison with the conventional alkanethiol self-assembled monolayer-based biosensing architectures. Consistent with an eightfold improved capture of bacteria on the surface of a PB-functionalized GaAs/AlGaAs digital photocorrosion biosensor, we report the attractive detection of Lp at 500 CFU/mL.

Applications of surface‐grafted polymer brushes with various architectures

“…The modification of polymer side-or end-groups is crucial in the preparation of sensing systems as it allows the incorporation of molecular recognition systems into the polymer layer. The post-polymerization functionalization includes the incorporation of nanoparticles (e.g., gold nanoparticles 82 ), and attachment of biomolecules with an affinity towards specific targets: vitamins, 82 proteins, 83 antibodies, 84,85 aptamers, [86][87][88] or enzymes. 90 The exemplary structures of recently reported PB-based biosensors, including the important postpolymerization modifications with recognition elements, analytes, and detection methods are summarized in Table 2.…”

“…Depending on the detection method for a given sensor, a broad variety of substrates has been used for construction of PBbased biosensors, such as semiconductors (silicon, 82,83 GaAs 84 ), surface plasmon resonance (SPR) chips, 85,86 glass microfluidic plates for construction of Lab-on-Chip devices, 87,88 quartz crystal microbalance (QCM) gold chips 89 or gold electrodes. 90 Commonly, polymer chains are grafted from such surfaces using SI-ATRP, 82,83,85,87,89,90 with some modifications to the traditional technique, such as ARGET-ATRP 84 or photoinduced ATRP. 86 The most commonly used polymers are stimuli-responsive polymers, 82,90 hydrophilic, zwitterionic polymers with antifouling properties 85 and other polymers with pedant groups convenient for further modifications (e.g., poly(methacrylic acid) (PMAA) 83 or PGMA 84 ).…”

“…90 Commonly, polymer chains are grafted from such surfaces using SI-ATRP, 82,83,85,87,89,90 with some modifications to the traditional technique, such as ARGET-ATRP 84 or photoinduced ATRP. 86 The most commonly used polymers are stimuli-responsive polymers, 82,90 hydrophilic, zwitterionic polymers with antifouling properties 85 and other polymers with pedant groups convenient for further modifications (e.g., poly(methacrylic acid) (PMAA) 83 or PGMA 84 ). For more advanced applications, random 86 or block 90 copolymers or even terpolymer 89 brushes were synthesized to combine the advantages of different functional units (e.g., antifouling and reactive side groups).…”

“…83 It was shown that the 3D architecture of PB enables binding a higher number of antibodies with higher surface area coverage when compared to conventional self-assembled monolayers (SAMs). 84 Additionally, the binding of bioactive compounds to PB limited unwanted conformational strains or changes leading to shielding of active sites or denaturation, which influences the biosensor performance 84,86 and stability. 86,87 Moreover, the possibility of designing the chemical composition of the polymer chains allowed to compensate the negative charge introduced by aptamer or antibody implementation, 86,89 which prevented the non-specific interaction with the ingredients of the analyzed matrix.…”

“…), as well as wide possibilities of post‐polymerization functionalization resulting in numerous ways of achieving desirable characteristics of such nanocoatings. Depending on the detection method for a given sensor, a broad variety of substrates has been used for construction of PB‐based biosensors, such as semiconductors (silicon, 82,83 GaAs 84 ), surface plasmon resonance (SPR) chips, 85,86 glass microfluidic plates for construction of Lab‐on‐Chip devices, 87,88 quartz crystal microbalance (QCM) gold chips 89 or gold electrodes 90 . Commonly, polymer chains are grafted from such surfaces using SI‐ATRP, 82,83,85,87,89,90 with some modifications to the traditional technique, such as ARGET‐ATRP 84 or photoinduced ATRP 86 .…”