Microfluidic production of chromonic liquid crystal microspheres and shells for food safety and freshness

Chromonic liquid crystals (CLCs) have recently received a lot of attention due to their spontaneous self-assembly in supramolecular columnar structures. Chromonics are widely studied because they are biocompatible, and it is possible to induce a chirality by adding suitable chiral moieties. The chirality can be enhanced confining them in curved geometries with a consequent impact on the aggregate’s lengths and torsion.

The goal of this work is playing with chirality and anchoring phenomena to produce well-defined periodic texture in chromonics confined in curved geometries, to be used as temperature sensors for monitoring the cold chain. Indeed, these periodic topologies are particularly sensitive to temperature, whose variation induces irreversible change, easily detected by optical methods. CLCs confinement in curved geometries such as microspheres and shells can be obtained by microfluidic techniques that, compared to conventional methods, allow a gentle and controlled formation of microspheres and shells with a consequent production of monodisperse solutions.

Among chromonics, food dyes as Sunset Yellow (SSY) and drugs as the well-known anti-asthmatic cromolyn (DSCG) were chosen for this work.