Light Induced Surface Corrosion of Gallium Arsenide for Immobilization of Oligonucleotide Probes

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

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.

Polymer Brush-GaAs Interface and Its Use as an Antibody-Compatible Platform for Biosensing

Despite evidence showing that polymer brushes (PBs) are a powerful tool used in biosensing for minimizing nonspecific interactions, allowing for optimization of biosensing performance, and the fact that GaAs semiconductors have proven to have a remarkable potential for sensitive biomolecule detection, the combination of these two robust components has never been considered nor evaluated as a platform for biosensing applications. This work reports different methodologies to prepare and tune PBs on the GaAs interface (PB-GaAs) and their potential as useful platforms for antibody grafting, with the ultimate goal of demonstrating the innovative and attractive character of the PB-GaAs interfaces in the enhanced capture of antibodies and control of nonspecific interactions. Three different functionalization approaches were explored, one "grafting-to" and two "grafting-from," in which atom transfer radical polymerization (ATRP) was performed, followed by their corresponding characterizations. Demonstration of the compatibility of Escherichia coli (E. coli) and Legionella pneumophila (Lp) antibodies with the PB-GaAs platform compared to the results obtained with conventional biosensing architectures developed for GaAs indicates the attractive potential for operation of a sensitive biosensor. Furthermore, these results showed that by carefully choosing the nature and preparation methodology of a PB-GaAs interface, it is possible to effectively tune the affinity of PB-GaAs-based sensors toward E. coli and Lp antibodies ultimately demonstrating the superior specificity of the developed biosensing platform.