Nanowire Nanosensors for Highly Sensitive and Selective Detection of Biological and Chemical Species

TLDR

Semiconductor nanowires enable sensitive, label‑free, real‑time detection of diverse chemical and biological species, promising array‑based screening and in‑vivo diagnostics. Boron‑doped silicon nanowires were engineered into highly sensitive, real‑time electrical sensors, with biotin and antigen functionalization enabling picomolar streptavidin detection and reversible, concentration‑dependent antibody binding. Amine‑ and oxide‑functionalized SiNWs exhibited pH‑dependent conductance linear over a large dynamic range, explained by surface charge changes during protonation/deprotonation, and reversible binding of the metabolic indicator Ca²⁺ was also demonstrated.

Abstract

Boron-doped silicon nanowires (SiNWs) were used to create highly sensitive, real-time electrically based sensors for biological and chemical species. Amine- and oxide-functionalized SiNWs exhibit pH-dependent conductance that was linear over a large dynamic range and could be understood in terms of the change in surface charge during protonation and deprotonation. Biotin-modified SiNWs were used to detect streptavidin down to at least a picomolar concentration range. In addition, antigen-functionalized SiNWs show reversible antibody binding and concentration-dependent detection in real time. Lastly, detection of the reversible binding of the metabolic indicator Ca 2+ was demonstrated. The small size and capability of these semiconductor nanowires for sensitive, label-free, real-time detection of a wide range of chemical and biological species could be exploited in array-based screening and in vivo diagnostics.