Sub-attomolar HIV-1 DNA detection using surface-enhanced Raman spectroscopy.

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Analytical Chemistry

Background:

• Accurate and sensitive detection of Human Immunodeficiency Virus type 1 (HIV-1) DNA is crucial for diagnosis and monitoring.
• Existing methods may lack the sensitivity required for early or low viral load detection.
• Surface-Enhanced Raman Spectroscopy (SERS) offers potential for ultrasensitive molecular detection.

Purpose of the Study:

• To develop a novel, highly sensitive assay for detecting HIV-1 DNA.
• To utilize multilayer metal-molecule-metal nanojunctions (NJs) and SERS for signal amplification.
• To achieve subattomolar detection limits and single base mismatch discrimination.

Main Methods:

• Fabrication of multilayer metal-molecule-metal nanojunctions using gold nanoparticles (Au NPs).
• Development of a two-step detection mechanism involving capture probes and detection units.
• Application of SERS for signal transduction and amplification.
• Utilizing distance-dependent electromagnetic enhancement (EM) of SERS.

Main Results:

• The assay successfully detected HIV-1 DNA at concentrations as low as 10(-19) M.
• The developed platform demonstrated the ability to discriminate single base mismatches in DNA sequences.
• The nanojunctions created SERS "hot spots" and reduced the distance between Au NPs and Raman labels, significantly enhancing the signal.

Conclusions:

• The developed SERS-based nanojunction platform provides a highly sensitive and specific method for HIV-1 DNA detection.
• This assay holds promise for improved diagnostics and monitoring of HIV-1 infection.
• The multi-metal-molecule-metal NJs approach offers a versatile strategy for ultrasensitive biosensing applications.