Hyperchromatic structural color for perceptually enhanced sensing by the naked eye

Area of Science:

• Nanotechnology
• Optical Engineering
• Biomedical Diagnostics

Background:

• Colorimetric sensors offer low-cost, on-demand diagnostics but struggle with sensitivity to small sample changes.
• Existing methods often rely on broadband illumination and highly responsive materials, limiting dynamic color variation.
• Achieving strong chromatic and luminance changes for sensitive detection remains a significant challenge.

Purpose of the Study:

• To develop a general colorimetric sensing technique that overcomes limitations of current chromatic and luminance-based methods.
• To demonstrate a novel approach combining structural color optical filters with a multichromatic laser illuminant.
• To achieve ultrasensitive and perceptually enhanced chromatic color changes for label-free biosensing.

Main Methods:

• Utilized structural color optical filters as sensing elements.
• Employed a multichromatic laser illuminant to enhance color variations.
• Experimentally demonstrated the technique for label-free biosensing, focusing on refractive index changes and surface attachment.

Main Results:

• Achieved ultrasensitive and perceptually enhanced chromatic color changes.
• Demonstrated naked-eye detection of approximately 3 pg/mm² of analyte, surpassing surface plasmon resonance sensors.
• Enabled spatially resolved biosensing in large-area, lithography-free sensing films.

Conclusions:

• The developed technique overcomes performance limitations of existing colorimetric sensors.
• Highlights the critical roles of illuminant choice and structural color filter design.
• Offers a promising pathway for high-performance, rapid, portable diagnostic sensors in diverse applications.