A plug-and-play aptamer diagnostic platform based on linear dichroism spectroscopy.

Area of Science:

• Biotechnology
• Spectroscopy
• Molecular Biology

Background:

• Aptamer-based assays offer specific molecular recognition capabilities.
• Linear dichroism (LD) spectroscopy provides sensitive detection through molecular alignment.
• Filamentous bacteriophage M13 serves as a scaffold for signal amplification in biosensing.

Purpose of the Study:

• To develop a plug-and-play sandwich assay platform for aptamer-based detection.
• To utilize linear dichroism (LD) spectroscopy as a readout method for molecular targets.
• To demonstrate the platform's efficacy in detecting the protein thrombin.

Main Methods:

• Bioconjugation of a DNA linker onto M13 bacteriophage backbone.
• Assembly of aptamer-functionalized M13 bacteriophages via complementary base pairing.
• Characterization of aptamer secondary structure using circular dichroism (CD) spectroscopy.
• Confirmation of target binding using fluorescence anisotropy measurements.
• Detection of thrombin using the developed LD spectroscopy-based sandwich assay.

Main Results:

• The M13 bacteriophage scaffold facilitated strong LD signals due to its alignment in linear flow.
• The plug-and-play system successfully generated aptamer-functionalized M13 bacteriophages.
• The aptamer-based sandwich assay demonstrated high sensitivity for thrombin detection, reaching picomolar (pM) levels.
• The assay functions as a label-free, homogenous detection system.

Conclusions:

• The developed plug-and-play aptamer assay using M13 bacteriophages and LD spectroscopy is a highly effective platform for molecular detection.
• This system shows significant potential as a sensitive, label-free, and homogenous biosensing method.
• The findings highlight the versatility of M13 bacteriophages in constructing advanced aptamer-based biosensors.