Ultrasensitive colorimetric biosensor for BRCA1 mutation based on multiple signal amplification strategy.

Area of Science:

• Nanomaterials Science
• Biosensor Technology
• Biomedical Engineering

Background:

• Colorimetric biosensors offer advantages like low cost and simplicity but often suffer from limited sensitivity.
• Detecting breast cancer-associated BRCA1 mutations is crucial for early diagnosis and genetic screening.
• Existing biosensor amplification strategies require improvement for enhanced detection limits.

Purpose of the Study:

• To develop a highly sensitive colorimetric biosensor for detecting breast cancer-associated BRCA1 mutations.
• To implement a three-step signal amplification strategy using nanomaterials for improved detection.
• To evaluate the biosensor's sensitivity, selectivity, and potential for clinical application.

Main Methods:

• A sandwich-type construction was designed using capture units, signal units (immobilized on nanomaterials), and target DNA.
• Signal amplification was achieved in three steps: 0D gold nanoparticles (AuNPs), AuNPs on 2D graphene oxide (GO), and finally AuNPs on Bi2Se3 nanosheets.
• The catalytic reduction of 4-nitrophenol (4-NP) by AuNPs was used as the colorimetric readout.

Main Results:

• The three-step amplification strategy achieved a nearly 10^10-fold signal enhancement.
• The developed Bi2Se3-AuNPs biosensor demonstrated a low detection limit of 10^-18 M.
• The biosensor exhibited excellent selectivity, clearly distinguishing single-base mismatches and non-complementary sequences.

Conclusions:

• The novel colorimetric biosensor achieves ultra-high sensitivity and selectivity for BRCA1 mutation detection.
• The three-step signal amplification strategy significantly overcomes the sensitivity limitations of traditional colorimetric biosensors.
• This advanced biosensor holds significant promise for clinical applications in cancer genetic screening and early diagnosis.