Aptamer-Based Scanning Electrochemical Microscopy for Specific and Localized Detection of Analyte Concentration

Area of Science:

• Electroanalytical Chemistry
• Biosensor Technology
• Scanning Electrochemical Microscopy (SECM)

Background:

• Scanning electrochemical microscopy (SECM) offers high spatial resolution for localized analyte detection.
• Current SECM applications are limited to redox-active analytes, with few biosensor strategies utilizing enzymes.
• There is a need for broader applicability of SECM in biosensing and localized chemical analysis.

Purpose of the Study:

• To introduce and demonstrate aptamer-based (AB)-SECM as a novel imaging probe.
• To showcase the localized detection of dopamine and adenosine triphosphate (ATP) using AB-SECM.
• To validate the capability of AB-SECM for precise probe positioning and chemical analysis at the microscale.

Main Methods:

• Fabrication and characterization of a model micropore system for analyte release.
• Utilized amperometric feedback mode of SECM for probe positioning via approach curves.
• Employed aptamer-functionalized electrodes as imaging probes for constant height AB-SECM imaging with square wave voltammetry (SWV).

Main Results:

• Successfully demonstrated localized detection of dopamine and ATP released from micropores.
• AB-SECM images revealed higher analyte concentrations directly above micropore openings.
• Confirmed the ability of AB-SECM to maintain a known probe-sample distance and map analyte distribution.

Conclusions:

• Aptamer-based (AB)-SECM provides a versatile platform for localized electrochemical detection.
• This technique overcomes limitations of traditional SECM by enabling biosensor integration.
• AB-SECM holds significant potential for adaptation in single-cell level chemical analysis.