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A Label-Free Diamond Microfluidic DNA Sensor Based on Active Nitrogen-Vacancy Center Charge State Control
Marie Krečmarová1, Michal Gulka1,2,3, Thijs Vandenryt2,4
1Department of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, Sítna sq. 3105, 27201 Kladno, Czech Republic.
ACS Applied Materials & Interfaces
|April 14, 2021
Summary
We developed a novel label-free biosensor using diamond nitrogen-vacancy (NV) centers and electrochemistry. This sensor detects charged molecules like DNA optically by monitoring NV charge state changes.
Area of Science:
- Quantum sensing
- Nanotechnology
- Diamond-based devices
Background:
- Nitrogen-vacancy (NV) centers in diamond offer unique quantum properties for sensing.
- Electrochemical microfluidic systems enable precise control and detection of biochemical reactions.
- Label-free detection methods are crucial for sensitive and direct molecular analysis.
Purpose of the Study:
- To propose and demonstrate a novel label-free biosensor concept.
- To integrate NV quantum centers with an electrochemical microfluidic flow cell.
- To achieve optical detection of charged molecules, specifically DNA.
Main Methods:
- Fabrication of a boron-doped diamond electrochemical microfluidic flow cell.
- Utilizing NV centers' charge state manipulation via electrochemical potential and molecular interaction.
- Employing confocal photoluminescence microscopy for NV charge state readout.
- Characterizing biochemical reactions using electrochemical impedance spectroscopy.
Main Results:
- Demonstrated label-free optical detection of DNA molecules.
- Successfully shifted NV center charge states (NV- to NV0/NV+) using a cationic polymer.
- Restored NV center charge state (NV-) upon immobilization of DNA, enabling detection.
- Confirmed the potential for electrochemical impedance spectroscopy to characterize reactions.
Conclusions:
- The developed device enables label-free biosensing by manipulating NV center charge states.
- This integrated approach offers a versatile platform for detecting charged molecules.
- Potential applications include DNA detection and nuclear magnetic resonance spin sensing.
