High-sensitivity DNA biosensor based on optical fiber taper interferometer coated with conjugated polymer tentacle

Area of Science:

• Optoelectronics
• Nanotechnology
• Biomedical Sensing

Background:

• Accurate detection of single-stranded DNA (ssDNA) is crucial for various biological and medical applications.
• Existing methods for ssDNA detection often require labeling, which can be complex and costly.
• Development of sensitive, label-free biosensors is an active area of research.

Purpose of the Study:

• To present a sensitive bio-probe for in situ detection of unlabeled single-stranded DNA targets.
• To utilize an optical microfiber taper interferometer coated with a conjugated polymer for enhanced sensing capabilities.

Main Methods:

• Fabrication of an optical microfiber taper interferometer.
• Coating the interferometer with a highly ordered porous conjugated polymer.
• Utilizing the polymer's 'tentacle' effect for π-π conjugated interaction with ssDNA, altering the microfiber's surface refractive index.
• Translating refractive index changes into wavelength shifts of the interference fringe.

Main Results:

• The developed sensor demonstrates high sensitivity to DNA concentration.
• Achieved a DNA concentration sensitivity of 2.393 nm/log M.
• Exhibited a lowest detection limit of 10(-10) M or even lower for ssDNA targets.

Conclusions:

• The optical microfiber taper interferometer biosensor offers a sensitive and label-free approach for ssDNA detection.
• The conjugated polymer coating effectively enhances the sensor's ability to capture and detect ssDNA.
• This technology holds promise for in situ, real-time monitoring of DNA in various applications.