Label-Free Extended Gate Field-Effect Transistor for Sensing Microcystin-LR in Freshwater Samples.

Area of Science:

• Biosensor technology
• Nanomaterials science
• Environmental toxicology

Background:

• Microcystin-LR (MC-LR) is a potent cyanotoxin causing significant health risks.
• Existing MC-LR detection methods can be complex and time-consuming.
• There is a need for rapid, selective, and user-friendly MC-LR monitoring tools.

Purpose of the Study:

• To develop a label-free biosensor for the selective detection of MC-LR.
• To utilize aptamer-modified multi-walled carbon nanotube extended gate field-effect transistors (MWCNT-EG-FET) for enhanced sensitivity.
• To provide a rapid and easy-to-use platform for MC-LR detection in freshwater.

Main Methods:

• Fabrication of an aptamer-functionalized MWCNT-EG-FET biosensor.
• Utilizing a custom DNA aptamer for specific MC-LR binding.
• Measuring electrical resistance changes upon MC-LR interaction for detection.

Main Results:

• The biosensor achieved label-free and selective detection of MC-LR.
• Detection limit of 0.134 ng/mL and analytical sensitivity of 0.024 ng/mL were obtained.
• Rapid detection of MC-LR in freshwater samples was accomplished within 5 minutes.

Conclusions:

• The developed MWCNT-EG-FET biosensor offers a sensitive, selective, and rapid method for MC-LR detection.
• The sensor's design allows for easy replacement of the sensitive membrane, reducing costs.
• This technology shows promise for integrated lab-on-chip systems for environmental monitoring.