Robust label-free microRNA detection using one million ISFET array.

Area of Science:

• Biotechnology
• Nanotechnology
• Molecular Biology

Background:

• Current DNA/RNA detection methods often rely on fluorescence labeling and require laboratory settings.
• There is a significant need for cost-effective, label-free, and rapid biomolecule detection methods with minimal resource use.
• Electrical detection methods utilizing the inherent charge of biomolecules present a promising avenue for biosensing.

Purpose of the Study:

• To develop and demonstrate a high-density label-free sensor array for nucleic acid detection.
• To utilize Ion Sensitive Field Effect Transistors (ISFETs) for sensitive and robust detection of specific nucleic acid sequences.
• To validate the sensor's performance in distinguishing target molecules from non-complementary sequences.

Main Methods:

• Fabrication of a 1024x1024 array of Ion Sensitive Field Effect Transistors (ISFETs).
• Functionalization of the ISFET array with Peptide Nucleic Acid (PNA) probes.
• Detection of miRNA Let-7b through hybridization with target molecules and measurement of drain current changes.
• Assessment of sensor response to mismatched and non-complementary target sequences.

Main Results:

• Robust detection of miRNA Let-7b at concentrations as low as 1 nM using the ISFET array.
• Statistically significant smaller changes in drain current observed for mismatched or non-complementary targets.
• Demonstrated high reliability and robustness of the high-density sensor array with P values <0.0001.
• Successful label-free detection of nucleic acid molecules.

Conclusions:

• The developed ISFET array offers a reliable and robust platform for label-free nucleic acid detection.
• This technology provides a sensitive alternative to traditional fluorescence-based assays.
• Potential applications include high-throughput genotyping, pathogen detection, and cell-free DNA analysis.