Flexible sensor patch for continuous carbon dioxide monitoring.

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Accurate carbon dioxide (CO2) monitoring is crucial across various scientific disciplines.
• Traditional CO2 sensors like the Severinghaus electrode have limitations in terms of complexity and fabrication.
• Emerging optochemical sensors offer simpler detection but often involve intricate preparation and control issues.

Purpose of the Study:

• To develop a facile and repeatable method for fabricating optical carbon dioxide (CO2) sensors.
• To create a flexible, user-friendly CO2 sensor suitable for in-line monitoring in biological applications.
• To demonstrate the sensor's efficacy in quantifying CO2 levels in cell culture media.

Main Methods:

• Utilized polydimethylsiloxane (PDMS) as a flexible matrix for the CO2 sensor.
• Incorporated 1-hydroxypyrene-3,6,8-trisulfonate (HPTS), a pH-sensitive dye, as the sensing material.
• Developed a simple droplet-loading and curing process for sensor fabrication, requiring minimal technical expertise.

Main Results:

• Achieved a straightforward CO2 sensor fabrication process completed within approximately 2 hours.
• Demonstrated successful in-line CO2 quantification in cell culture media within the 0-20 kPa range.
• Generated a highly accurate standard curve (R² = 0.998) with a resolution of 0.5 kPa (3.7 mm Hg).

Conclusions:

• The developed PDMS-based optical CO2 sensor offers a simple, repeatable, and cost-effective alternative to existing technologies.
• The sensor is autoclavable, possesses a long working lifetime, and is suitable for sterile applications.
• This flexible, easily manufactured sensor presents a significant advancement for optical carbon dioxide measurement across diverse fields.