A 3D-Printed Scaffolded Hydrogel Microneedle Array Biosensor for Real-Time, Continuous Monitoring

Area of Science:

• Biomedical Engineering
• Materials Science
• Analytical Chemistry

Background:

• Hydrogel biosensors are promising for real-time biomarker tracking but lack mechanical strength for skin penetration.
• Hydrated hydrogels struggle to access interstitial fluid (ISF) due to poor mechanical properties.

Purpose of the Study:

• To develop a microneedle-array biosensor (MAB) patch for continuous and reversible in vivo sensing.
• To overcome the mechanical limitations of hydrogels for effective skin insertion and ISF access.

Main Methods:

• Developed a 3D-printed scaffold to support a hydrated hydrogel mesh functionalized with DNA aptamer switches.
• Tuned aptamer switch design and hydrogel mesh size for detecting cortisol and adenosine triphosphate.
• Integrated a cortisol-sensing MAB with a portable optical detector for in vivo measurements.

Main Results:

• Demonstrated successful detection of exogenous cortisol and adenosine triphosphate.
• Validated the biocompatibility and in vivo utility of the MAB patch in live rats.
• Achieved submicromolar detection levels for cortisol in real-time ISF measurements.

Conclusions:

• The MAB platform provides essential mechanical support for skin insertion while maintaining hydrogel sensing functionality.
• This novel biosensor enables continuous, real-time in vivo monitoring of biomarkers like cortisol.
• The MAB patch represents a versatile solution for advanced biosensing applications.