Polarizer-Free Dye-Doped Liquid Crystal Sensors with High Precision

Area of Science:

• Materials Science
• Analytical Chemistry
• Biotechnology

Background:

• Liquid crystals (LCs) are widely used in sensors, detecting chemical and biological stimuli through surface-induced ordering.
• Traditional LC sensors often rely on transducing analyte-triggered changes in LC orientation using polarized light.
• Quantifying out-of-plane LC orientation can be challenging due to simultaneous in-plane orientation changes.

Purpose of the Study:

• To introduce a novel sensing approach using dichroic dye-doped LCs (DDLC) and unpolarized light for precise quantification of LC orientation.
• To benchmark the performance of the DDLC method against conventional polarizer-based LC sensors.
• To demonstrate the DDLC approach's utility in detecting analyte concentration gradients.

Main Methods:

• Development of a sensing system combining DDLC with unpolarized light and a photodiode.
• Benchmarking against polarizer-based methods using a model amphiphilic analyte in aqueous solution.
• Evaluation of sensitivity, dynamic range, and precision in detecting analyte concentration gradients.

Main Results:

• The DDLC approach significantly reduced the coefficient of variation from 300% to less than 5%.
• Analytical sensitivity increased from 0.16 to 3.73 μM⁻¹, with an expanded dynamic range.
• The DDLC method distinguished concentration differences as small as 0.03 μM/μm, outperforming conventional methods.

Conclusions:

• The DDLC sensor offers superior sensing performance, including enhanced sensitivity and precision.
• The simplified implementation, without the need for polarizers, facilitates broader deployment of LC sensors.
• This technology holds promise for applications like high-throughput screening in chemical formulations.