Enhanced Optical Biosensing by Aerotaxy Ga(As)P Nanowire Platforms Suitable for Scalable Production

ABSTRACT: Sensitive detection of low-abundance biomolecules is central for diagnostic applications. Semiconductor nanowires can be designed to enhance the fluorescence signal from surface-bound molecules, prospectively improving the limit of optical detection. However, to achieve the desired control of physical dimensions and material properties, one currently uses relatively expensive substrates and slow epitaxy techniques. An alternative approach is aerotaxy, a high-throughput and substrate-free production technique for high-quality semiconductor nanowires. Here, we compare the optical sensing performance of custom-grown aerotaxyproduced Ga(As)P nanowires vertically aligned on a polymer substrate to GaP nanowires batch-produced by epitaxy on GaP substrates. We find that signal enhancement by individual aerotaxy nanowires is comparable to that from epitaxy nanowires and present evidence of single-molecule detection. Platforms based on both types of nanowires show substantially higher normalized-to-blank signal intensity than planar glass surfaces, with the epitaxy platforms performing somewhat better, owing to a higher density of nanowires. With further optimization, aerotaxy nanowires thus offer a pathway to scalable, low-cost production of highly sensitive nanowire-based platforms for optical biosensing applications.

Automated summary

Sensitive detection of low-abundance biomolecules is crucial for diagnostic applications. This study compares the optical sensing performance of semiconductor nanowires produced by aerotaxy and epitaxy techniques. It demonstrates that aerotaxy nanowires show comparable signal enhancement and can achieve single-molecule detection, offering a potential pathway for scalable and low-cost production of highly sensitive nanowire-based platforms for optical biosensing applications. The platforms based on both types of nanowires exhibit higher signal intensity compared to planar glass surfaces, with epitaxy platforms performing slightly better due to higher nanowire density.