MicroLED biosensor with colloidal quantum dots and smartphone detection.

Area of Science:

• Biophotonics
• Nanotechnology
• Analytical Chemistry

Background:

• Developing portable and sensitive bioanalytical tools is crucial for point-of-care diagnostics.
• Existing fluorescence detection methods often require bulky and expensive equipment.
• Smartphone integration offers a promising platform for accessible bioassay detection.

Purpose of the Study:

• To develop a spatially multiplexed fluorescence sensor using smartphone detection.
• To leverage total internal reflection fluorescence (TIRF) principles for enhanced sensitivity.
• To demonstrate the sensor's capability for detecting low concentrations of biomolecules.

Main Methods:

• Utilized bioconjugated quantum dots as fluorescent tags.
• Employed a blue-emitting gallium nitride micro-light-emitting diode (µLED) array for excitation.
• Integrated the µLED array with a glass slide waveguide for TIRF.
• Analyzed fluorescence signals using the red, green, and blue channels of a smartphone camera.
• Validated the system using a biotin-streptavidin assay on a functionalized glass slide.

Main Results:

• Achieved spatially multiplexed fluorescence measurements.
• Successfully separated excitation light from fluorescence signals using smartphone RGB channels.
• Demonstrated detection of streptavidin conjugated quantum dots down to 8 nM concentration.
• Confirmed the feasibility of smartphone-based fluorescence detection for bioassays.

Conclusions:

• The developed smartphone-based fluorescence sensor enables sensitive and spatially multiplexed bioassays.
• The integration of µLEDs and TIRF principles with smartphone detection offers a cost-effective and portable analytical solution.
• This technology has potential applications in various fields, including diagnostics and environmental monitoring.