Rapid naked-eye acrylamide detection sensor using liquid crystal films

Overview

This technology offers a rapid, naked-eye detection method for acrylamide in water using thermotropic liquid crystal (LC) films. Acrylamide is a known contaminant of concern in drinking water and certain food products, and current analytical methods typically require laboratory instrumentation and lengthy processing. The proposed LC-based sensor is designed to deliver a visible optical response within minutes when acrylamide is present, making it suitable for field screening, environmental monitoring, and food safety applications where quick decision-making is critical.

The core value proposition is a low-cost, instrument-free detection platform that combines selectivity for acrylamide with a clear, visually interpretable output. By leveraging the sensitivity of LC ordering transitions to interfacial chemistry, the sensor can translate a molecular recognition event into a change in optical appearance that can be observed directly or captured with a simple camera.

Technical specifications

• Detection principle: Acrylamide in water selectively reacts with thiol molecules adsorbed at the surface of a thermotropic LC film through a thiol-ene click reaction under UV light.
• Transduction mechanism: The thiol-ene reaction changes the amphiphilicity of the thiols at the water-LC interface, triggering a reorientation of LC molecules at the interface that propagates through the bulk LC film.
• Visual output: The reorientation produces a change in the optical appearance of the LC film that is visible to the naked eye and can be imaged under polarized light.
• Response time: Optical changes are observed after approximately 5 minutes of UV exposure.
• Sensor format: LC films doped with thiols are infused into copper specimen grids placed on silane-functionalized glass substrates and immersed in aqueous samples containing a water-soluble photoinitiator.
• Demonstrated chemistry: The thiol-ene click reaction between acrylamide and octadecanethiol has been confirmed under UV light over 5 to 10 minutes, producing an amphiphilic product with both hydrophilic amide and hydrophobic octadecane character.
• Planned optimization: Studies will evaluate the effects of photoinitiator, thiol, and acrylamide concentrations on sensitivity and response rate.
• Companion app: A mobile application is planned to assist visual inspection and automate image analysis.

Technology readiness level

The underlying thiol-ene reaction between acrylamide and octadecanethiol has been demonstrated under UV light over 5 to 10 minutes. The team is now working to integrate this chemistry into the LC film sensing format and validate that the resulting interfacial change produces a visible optical response in the LC film. Planned experiments will use polarized light microscopy and naked-eye visualization to study the effect of photoinitiator, thiol, and acrylamide concentrations on sensor sensitivity and response rate, and to develop a companion app for automated inspection. The technology is at an early-to-mid stage of laboratory validation toward a practical acrylamide detection platform.