Development of a label-free, rapid biosensor for early detection of metabolic syndrome biomarkers using electrochemical impedance spectroscopy and aptamer-based recognition

Project Abstract

The global burden of metabolic syndrome (MetS) necessitates rapid, accurate, and cost-effective diagnostic tools for early intervention. This study presents a label-free, rapid electrochemical impedance spectroscopy (EIS) biosensor leveraging aptamer-based recognition to detect key MetS biomarkers in a single assay, enabling straightforward translation to point-of-care settings. The biosensor employs a gold electrode surface modified with a meticulously engineered thiolated aptamer library that targets clinically relevant biomarkers including fasting glucose, triglycerides, high-density lipoprotein (HDL) cholesterol, blood pressure proxy signals, and inflammatory cytokines associated with MetS progression. Aptamer immobilization is optimized through a mixed self-assembled monolayer (SAM) to balance probe accessibility with antifouling properties, while a passivating polymer layer minimizes non-specific adsorption from complex biological matrices such as serum and whole blood. Principally, the platform operates on label-free EIS measuring changes in charge transfer resistance (Rct) and interfacial capacitance upon biomarker-aptamer binding, producing highly sensitive impedance fingerprints without the need for secondary labels or enzymatic amplification. We introduce a differential measurement strategy using a reference aptamer to enhance specificity and suppress background signals, achieving a robust limit of detection in the low picomolar to nanomolar range for targeted MetS markers. The sensor architecture integrates microfluidic delivery to enable minimal sample volumes (?10 µL) and rapid assay times (<15 minutes) while maintaining reproducibility across multiple fabrications. Data analytics incorporate equivalent circuit modeling and machine learning-assisted signal deconvolution to distinguish overlapping impedance responses from multiple biomarkers, thereby enabling multiplexed readouts on a single chip. A rigorous optimization protocol examines critical parameters, including aptamer density, SAM composition, electrolyte composition, pH, temperature, and applied potential windows, to maximize signal-to-noise ratio and dynamic range. Analytical performance is validated in spiked human plasma and serum, followed by preliminary testing with clinical samples from individuals diagnosed with MetS components. Specificity is assessed against structurally similar non-target proteins and common interferents, demonstrating minimal cross-reactivity. Stability and repeatability studies confirm sensor reliability over a 14-day period under refrigerated storage and multiple regenerative cycles using mild chemical resets. The novelty of this work lies in the integration of aptamer-based recognition with a label-free EIS readout in a multiplexed, miniaturized platform suitable for point-of-care use, enabling early detection and routine monitoring of metabolic syndrome risk. The anticipated impact includes reduced need for invasive diagnostics, shorter turnaround times, and the potential to tailor personalized intervention strategies based on rapid biomarker profiling. This study provides a scalable blueprint for translating aptamer-EIS biosensing into clinical decision support, aligning with precision medicine goals for metabolic disorders.

Project Overview

What This Project Is About

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The project explores a simple, fast way to detect early signs of metabolic syndrome in people using a tiny sensor. The sensor can read specific molecules in blood or other fluids without needing dyes or labels. It uses two main ideas: a special DNA-like molecule (an aptamer) that sticks to the target biomarker, and a method that measures electrical responses (electrochemical impedance) to see if binding happened. The goal is a quick, accurate test that could be used in clinics or at the point of care.

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The Problem It Addresses

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Objectives of the Project

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1. Identify key metabolic syndrome biomarkers to target with the sensor.
2. Develop an aptamer that binds specifically to those biomarkers.
3. Fabricate a simple electrochemical sensor surface compatible with aptamer binding.
4. Demonstrate label-free detection using electrochemical impedance measurements.
5. Evaluate sensitivity, specificity, and detection limits in model samples.

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What You Will Do Step by Step

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1) Research background on metabolic syndrome biomarkers and aptamers. 2) Design or select aptamers that bind chosen targets. 3) Prepare sensor surfaces and immobilize aptamers. 4) Calibrate the sensor with known biomarker solutions. 5) Measure electrical responses to binding events. 6) Test with real-like samples to assess practicality. 7) Analyze data to determine accuracy and limits of detection. 8) Discuss potential improvements and real-world use.

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Expected Outcome

A working label-free biosensor that can rapidly indicate the presence of metabolic syndrome biomarkers with clear electrical signals, along with data on performance and potential clinical impact. This could lead to faster screenings and better early intervention strategies.