A rapid dual-mode SERS/FL cytosensor assisted via DNA Walker-based plasmonic nanostructures

Area of Science:

• Nanotechnology and Nanoscience
• Biomedical Engineering
• Analytical Chemistry

Background:

• Surface-enhanced Raman scattering (SERS) biosensors are crucial for ultrasensitive detection of circulating tumor cells (CTCs) and cancer diagnosis.
• Challenges exist in the rapid and precise preparation of SERS plasmonic nanostructures for biosensing applications.

Purpose of the Study:

• To develop a DNA-assisted, dual-mode (SERS/Fluorescent) cytosensor for enhanced detection of circulating tumor cells (CTCs).
• To overcome the limitations in swift and precise preparation of SERS plasmonic nanostructures.

Main Methods:

• Synthesis of Au@Ag nanoparticle multimers (Au@AgNMs) with DNA self-assembly and in-situ deposition to create plasmonic nanostructures with tunable nano-gaps.
• Optimization of nano-gap distance for simultaneous SERS enhancement and fluorescence quenching.
• Utilized MUC1 aptamer for specific CTC recognition, strand displacement reaction (SDR), and DNA Walker-based signal amplification.

Main Results:

• Achieved a limit of detection (LOD) as low as 5 cells/mL in SERS mode and 21 cells/mL in fluorescence (FL) mode.
• Demonstrated that SERS mode provides high precision, while FL mode allows for rapid quantitative analysis.
• Successfully developed a dual-mode cytosensor for CTC detection.

Conclusions:

• The developed DNA-assisted plasmonic nanostructures enable a dual-mode cytosensor for ultrasensitive CTC detection.
• This dual-mode approach offers both high precision (SERS) and rapid quantification (FL) for cancer diagnosis.
• The cytosensor facilitates early detection and precise treatment strategies for cancers and infectious diseases.