Enhanced pyrophosphate detection: Utilizing oPD-derived carbon dots and Fe³⁺ interactions in a paper strip biosensor

Area of Science:

• Nanomaterials Science
• Biosensor Technology
• Analytical Chemistry

Background:

• Portable, cost-effective DNA biosensors are crucial for healthcare, environmental, and food safety applications.
• Existing methods often lack selectivity or require complex synthesis.
• There is a need for robust biosensing platforms with high sensitivity and specificity.

Purpose of the Study:

• To develop an innovative, environmentally friendly synthesis for carbon dots (Cdots) with high quantum yield (QY).
• To create a selective biosensing technique for Fe³⁺ ions and pyrophosphate (PPi) detection.
• To optimize Cdot synthesis and evaluate the performance of a paper-based biosensor.

Main Methods:

• Synthesized carbon dots (Cdots) using o-phenylenediamine precursor.
• Employed D-optimal response surface methodology to optimize Cdot synthesis parameters (temperature, heating time).
• Utilized a loop-mediated isothermal amplification (LAMP)/pyrophosphate (PPi) biosensing technique for DNA detection.

Main Results:

• Achieved high quantum yield (QY) Cdots (max predicted 48.8%) with specific Fe³⁺ recognition.
• Demonstrated a sensitive and specific LAMP/PPi biosensing technique with a limit of detection (LOD) of 0.079 μM.
• Characterized Cdots using HR-TEM, XRD, and FTIR, confirming their amorphous nature.

Conclusions:

• The developed Cdots and biosensing technique offer a promising platform for portable, paper-based diagnostics.
• The method shows high sensitivity, specificity, and repeatability across various conditions.
• Applicable to any DNA amplification method generating pyrophosphate (PPi), enabling broad diagnostic and monitoring applications.