Gold Nanobipyramid Hotspot Aggregation-Induced Surface-Enhanced Raman Scattering for the Ultrasensitive Detection of...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• MicroRNA-221 (miRNA-221) is a biomarker implicated in various cancers.
• Ultrasensitive detection of miRNA-221 is crucial for early disease diagnosis and monitoring.
• Existing biosensing methods often face limitations in sensitivity and specificity.

Purpose of the Study:

• To develop a novel surface-enhanced Raman scattering (SERS) biosensor for ultrasensitive detection of miRNA-221.
• To enhance SERS signal through hotspot aggregation induced by gold nanobipyramids (Au NBPs) assembled by tetrahedral DNA nanostructures (TDNs).
• To validate the biosensor's performance in biological samples for potential clinical applications.

Main Methods:

• Construction of a SERS biosensor utilizing Au NBPs and hotspot aggregation.
• Assembly of multiple Au NBPs using TDNs to amplify SERS signals.
• Integration of Exo-III assisted target cycle amplification and TDN-induced catalytic hairpin assembly (CHA) for signal amplification.
• Detection of miRNA-221 using methylene blue (MB) as a Raman reporter molecule.

Main Results:

• The assembled multiple Au NBPs significantly enhanced SERS signals compared to single Au NBPs.
• The biosensor achieved a wide linear detection range for miRNA-221 from 1 fM to 10 nM.
• An ultra-low limit of detection (LOD) of 0.59 fM was obtained for miRNA-221.
• The biosensor demonstrated practical applicability by detecting miRNA-221 in MHCC-97L and MCF-7 cell lysates.

Conclusions:

• The developed HAI-SERS biosensor offers a highly sensitive and effective platform for miRNA detection.
• Hotspot aggregation strategies using DNA nanostructures can significantly boost SERS sensitivity.
• This approach holds promise for biomarker detection and advancing disease diagnosis.