Electrochemical aptamer-based biosensors

Electrochemical Aptamer-Based Biosensors

Diagram of an electrochemical aptamer-based sensor.

Electrochemical aptamer-based biosensors, often referred to as E-AB sensors, are a class of biosensors that utilize aptamers as the recognition element and electrochemical methods for signal transduction. These sensors are designed to detect a wide range of analytes, including small molecules, proteins, and even whole cells, with high specificity and sensitivity.

Principles of Operation

E-AB sensors operate on the principle of specific binding interactions between the target analyte and the aptamer. Aptamers are short, single-stranded nucleic acids (either DNA or RNA) that can fold into unique three-dimensional structures, allowing them to bind selectively to their target molecules. This binding event induces a conformational change in the aptamer, which is transduced into an electrochemical signal.

The electrochemical signal is typically measured using techniques such as cyclic voltammetry, differential pulse voltammetry, or electrochemical impedance spectroscopy. These methods allow for the detection of changes in current, potential, or impedance that occur as a result of the aptamer-target interaction.

SELEX Process

Illustration of the SELEX process used to develop aptamers.

The development of aptamers for use in E-AB sensors involves a process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX). SELEX is an iterative process that selects aptamers with high affinity and specificity for a given target. The process begins with a large library of random nucleic acid sequences, which are exposed to the target molecule. Sequences that bind to the target are isolated, amplified, and subjected to further rounds of selection to enhance their binding properties.

Applications

E-AB sensors have a wide range of applications in various fields, including:

• Medical Diagnostics: They are used for the detection of biomarkers associated with diseases such as cancer, cardiovascular diseases, and infectious diseases.
• Environmental Monitoring: E-AB sensors can detect pollutants and toxins in environmental samples, providing a tool for monitoring water and air quality.
• Food Safety: These sensors are employed to detect contaminants and pathogens in food products, ensuring food safety and quality.
• Biodefense: E-AB sensors can be used to detect biological warfare agents and other hazardous substances.

Advantages

E-AB sensors offer several advantages over traditional biosensors, including:

• High Specificity: The use of aptamers allows for highly specific binding to target molecules, reducing the likelihood of false positives.
• Reusability: Many E-AB sensors can be regenerated and reused multiple times, making them cost-effective.
• Rapid Response: These sensors provide real-time detection and rapid response times, which are crucial for many applications.
• Miniaturization: E-AB sensors can be miniaturized, allowing for the development of portable and point-of-care diagnostic devices.

Related Pages

• Biosensor
• Aptamer
• Electrochemistry
• Systematic Evolution of Ligands by Exponential Enrichment