Control of Liquid Crystal Microarray Optical Signals Using a Microspectral Mode Based on Photonic Crystal Structures

Abstract

Herein, a novel liquid crystal microarray (LCM) film with optical regulation ability is first constructed by combining liquid crystals (LC) and the highly ordered microporous structure of inverse opal photonic crystals (IOPhCs). The LCM films are fabricated by infiltrating LC molecules into the LC polymer with the structure of IOPhCs, and their properties are very different from those without the LC. Interestingly, the optical property of LCM films can be controlled by changing the orientation of LC molecules, which varies with the interfacial force. In combination with polarization images, spectral reflection peak, circular dichroism spectra, potential difference, and fluorescence images of LCM films, the mechanism of this change is investigated. It is found that the exposed basic group of single-stranded DNA is the key to the change of the optical property of LC microarrays. Meanwhile, the optical signals of LC microarrays based on the PhCs provide a novel LC signal mode for an LC sensing system (microspectral signal mode), and it can be recorded by a fiber-optic spectrometer, which is a great improvement on LC sensing signals. Therefore, the LC microarray sensing signal can be used for accurate analysis of targets by the change of the reflection peak intensity of PhCs. When the LC molecules are induced by different aptamers, the LC microarray sensing interface can be further used for the determination of different targets, such as cocaine and Hg 2+ . The research on LCM films is of significant value for the development of LC sensing technology and also shows great application prospects in biochemical sensing fields.

Bioinspired bioassay platforms derived from colloidal crystals with topological shapes

“…Compared with colloidal crystal particles, colloidal crystal films have larger scales; therefore, they are more visual and promising in application scenarios. [166][167][168][169][170][171][172][173][174][175][176][177] To date, many strategies have been used for preparing colloidal crystal films, including electrophoresis, [178] vertical deposition, [179][180][181][182] and horizontal deposition. [183,184] Besides, the array of NCP colloidal nanoparticles or colloidal crystal particles can also be fabricated as film shapes.…”

Construction and Research of Multiple Stimuli-Responsive 2D Photonic Crystal DNA Hydrogel Sensing Platform with Double-Network Structure and Signal Self-Expression

“…Over the past decades, the development of photonic crystal (PhC) provides a new idea for the realization of label-free determination of targets. PhC is a unique optical material with a special ordered structure, which is formed by periodic arrangement of materials with different dielectric constants. , The optical signal of PhC can be manipulated by adjusting the structure of itself (such as effective refractive index and lattice spacing). − By introducing a PhC array into a hydrogel, the change of the hydrogel volume will cause a movement of the lattice spacing of the PhC array and lead to a change of the diffraction signal. − The constructed responsive PhC hydrogels sensing platforms show many advantages in the sensing field based on this excellent optical property. − And this provides a possibility for the construction of a label-free and signal self-expressing hydrogel sensing platform.…”

Partial induced reorientation of 5CB in a liquid crystal microarray and a signal-on sensing assay for the detection of aflatoxin B1

“…Recently, a new LC microarray (LCM) sensing interface combining the birefringence of LCs and the highly ordered microporous structure and unique optical property of inverse opal photonic crystals (IOPhCs) has been designed for the first time and reported by our group. 15 The optical properties of photonic crystals (PhCs) originate from the alternate ordered arrangement of two materials with different refractive indexes, and can be regulated by particle spacing or the refractive index of the material. 16 Therefore, the optical properties of LCM films based on PhCs can be controlled by a change in the refractive index of the LC resulting from an orientation change of the LC molecules, and the optical signals can be recorded in the reflection spectrum.…”

“…Herein, a signal-on LCM biosensor is developed using an LCM interface fabricated from inverse opal LC polymer (IO-LCP) films and LC molecules. According to the induction mechanism of ssDNA for LC molecules in LCM films, 15 an LCM biosensor with a signal-on strategy is designed through the release of ssDNA from dsDNA AFB1 driven by the addition of AFB1. The released ssDNA will induce 5CB in the LCM films to convert from the disordered to the ordered arrangement, and clear optical signals were observed in the LCM films by the naked eye.…”

“…As proven in a previous study, the optical properties of LCM films can be modulated by single-stranded nucleic acid (ssDNA) but not double-stranded nucleic acid (dsDNA). 15 This is because the exposed base groups of ssDNA have an interaction force with the cyano groups of the LC molecules (5CB), and this interaction force changes the orientation of the LC molecules from disordered to ordered. According to the physical properties of the LCs, the ordered LC molecules have a uniform refractive index, which satisfies the conditions required for Bragg diffraction of the PhCs.…”