Sensing High 17β-Estradiol Concentrations Using a Planar Microwave Sensor Integrated with a Microfluidic Channel

Area of Science:

• Environmental Science
• Analytical Chemistry
• Sensor Technology

Background:

• Endocrine-disrupting chemicals (EDCs) like 17β-estradiol (E2) pose global environmental and health risks.
• E2 can cause endocrine system malfunctions and reproductive disorders in humans and animals.
• Accurate detection of E2 is crucial for environmental safety and risk assessment.

Purpose of the Study:

• To develop a rapid, sensitive, low-cost, and simple sensor for detecting E2 contamination.
• To present a planar microwave sensor integrating a Peano fractal geometry with a narrow slot complementary split-ring resonator (PF-NSCSRR) and a microfluidic channel.
• To validate the sensor's performance through simulations and empirical measurements.

Main Methods:

• A planar microwave sensor was designed using a microstrip transmission line loaded with a PF-NSCSRR and a microfluidic channel.
• E2 solutions were analyzed using the sensor within a 0.5-3.5 GHz frequency range.
• Sensor performance was evaluated by measuring changes in transmission coefficient (S21) and resonance frequency (Fr) with varying E2 concentrations.

Main Results:

• The sensor demonstrated a wide linear detection range (0.001–10 mM) and high sensitivity (1746.98 dB/mM for S21, 40 GHz/mM for Fr at 0.01 mM).
• Compared to non-slotted sensors, the proposed PF-NSCSRR sensor showed a 6.08% increase in sensitivity and a 40.72% higher quality factor.
• The sensor requires small sample volumes (1.37 µL) and offers fast measurements with a compact, easily fabricated structure.

Conclusions:

• The developed planar microwave sensor provides a highly sensitive and efficient method for E2 detection.
• Its compact design, low cost, and simple operation make it suitable for environmental, human, and animal sample analysis.
• The sensor effectively addresses the need for rapid and reliable detection of E2 contamination.