Banana DNA derivatives as homeotropic alignment layers in optical devices.

In this study, deoxyribonucleic acid (DNA) from bananas was extracted and functionalized and used for the first time as a homeotropic alignment layer for liquid crystals (LCs). Our research was aimed at extracting and investigating DNA from bananas via the synthesis and study of DNA complexes with various surfactants to examine the usefulness of such a complex as an alignment layer in electro-optical transducers. We proposed a simple and eco-friendly synthesis of the DNA complexes isolated from bananas with surfactants, so we transformed the DNA isolated from bananas into a functionalized alignment layer. A biopolymer alignment layer like deoxyribonucleic acid (DNA) from a banana complexed with a cationic surfactant is an excellent alternative to a commonly used but toxic polyimide alignment layer. DNA-based materials are promising for photonic applications and biosensors because of their excellent optical and physical properties, biodegradability, and low production cost. The novelty of the research lies in the potential use of these materials as biodegradable biopolymer alignment layers for optical devices instead of conventional polymers, which are usually harmful for the environment.

Protein Determination with Molecularly Imprinted Polymer Recognition Combined with Birefringence Liquid Crystal Detection.

Liquid crystal-based sensors offer the advantage of high sensitivity at a low cost. However, they often lack selectivity altogether or require costly and unstable biomaterials to impart this selectivity. To incur this selectivity, we herein integrated a molecularly imprinted polymer (MIP) film recognition unit with a liquid crystal (LC) in an optical cell transducer. We tested the resulting chemosensor for protein determination. We examined two different LCs, each with a different optical birefringence. That way, we revealed the influence of that parameter on the sensitivity of the (human serum albumin)-templated (MIP-HSA) LC chemosensor. The response of this chemosensor with the (MIP-HSA)-recognizing film was linear from 2.2 to 15.2 µM HSA, with a limit of detection of 2.2 µM. These values are sufficient to use the devised chemosensor for HSA determination in biological samples. Importantly, the imprinting factor (IF) of this chemosensor was appreciable, reaching IF = 3.7. This IF value indicated the predominant binding of the HSA through specific rather than nonspecific interactions with the MIP.

Traveling Wave Rotary Micromotor Based on a Photomechanical Response in Liquid Crystal Polymer Networks.

The photomechanical response of liquid crystal polymer networks (LCNs) can be used to directly convert light energy into different forms of mechanical energy. In this study, we demonstrate how a traveling deformation, induced in a liquid crystal polymer ring by a spatially modulated laser beam, can be used to drive the ring (the rotor) to rotate around a stationary element (the stator), thus forming a light-powered micromotor. The photomechanical response of the polymer film is modeled numerically, different LCN molecular configurations are studied, and the performance of a 5.5 mm diameter motor is characterized.