Label-free DNA biosensor based on a peptide nucleic acid-functionalized microstructured optical fiber-Bragg grating.

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Molecular Biology

Background:

• Early detection of genetic mutations is crucial for diagnosing and managing diseases like cystic fibrosis (CF).
• Current diagnostic methods can be complex and time-consuming.
• Development of sensitive and specific biosensors is essential for rapid genetic analysis.

Purpose of the Study:

• To develop a novel biosensing platform for the specific detection of DNA sequences with single point mutations.
• To utilize a functionalized microstructured optical fiber-Bragg grating for enhanced sensitivity and selectivity.
• To demonstrate the potential for reusable sensing in genetic diagnostics.

Main Methods:

• Functionalization of a microstructured optical fiber-Bragg grating with peptide nucleic acid probes.
• Hybridization of target DNA sequences (CF gene mutation) within the fiber capillaries.
• Signal amplification using oligonucleotide-functionalized gold nanoparticles in a sandwich assay.
• Detection via shifts in the reflected high-order mode of the Bragg grating and fluorescence measurements.

Main Results:

• A clear shift in the Bragg grating's reflected mode was observed for a 100 nM DNA solution containing the CF mutation.
• Fluorescence measurements confirmed successful DNA hybridization.
• The sensor demonstrated high selectivity, distinguishing between mutated and wild-type DNA sequences.
• Experiments indicated the potential for sensor reuse with consistent modulation trends.

Conclusions:

• The developed optical fiber-Bragg grating sensor is effective for specific DNA target sequence detection.
• The sensor exhibits high sensitivity, selectivity, and potential for reusability.
• This approach offers a promising platform for the rapid and accurate diagnosis of genetic diseases like cystic fibrosis.