Surface-enhanced Raman scattering detection of matrix metalloproteinase-9 via an aptamer-based plasmonic ruler

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Biology

Background:

• Matrix metalloproteinase-9 (MMP-9) is vital in cancer progression, including invasion and metastasis.
• Accurate and sensitive detection of MMP-9 is crucial for cancer research but remains challenging.

Purpose of the Study:

• To develop a novel surface-enhanced Raman scattering (SERS) sensing strategy for ultrasensitive and highly selective MMP-9 detection.
• To investigate the correlation between hypoxia and MMP-9 expression in cancer cells.
• To validate the sensor's performance in clinical samples.

Main Methods:

• Fabrication of a SERS probe using magnetic/plasmonic beads co-modified with MMP-9 aptamers and methylene blue-labeled complementary DNA.
• Utilizing DNA bending mechanism for signal enhancement upon MMP-9 binding.
• Employing cell experiments to study hypoxia-induced MMP-9 expression.
• Testing the sensor with patient serum samples.

Main Results:

• The SERS sensor achieved a low detection limit of 3.67 ng/mL for MMP-9.
• Intensified hypoxia was confirmed to significantly increase MMP-9 expression.
• The sensor demonstrated high selectivity due to aptamer-target affinity.
• Results from patient sera correlated well with standard methods.

Conclusions:

• The developed DNA-bending SERS strategy offers ultrasensitive and selective MMP-9 detection.
• This method provides a new tool for cancer diagnosis and metastasis evaluation.
• The sensor shows potential for clinical application in cancer research and diagnostics.