Quantitative detection of a simulant of organophosphonate chemical warfare agents using liquid crystals

VanTreeck, Heidi J.; Most, Darrin R.; Grinwald, Bart A.; Kupcho, Kurt A.; Sen, Avijit; Bonds, Michael D.; Acharya, Bharat R.

doi:10.1016/j.snb.2011.05.049

Cited by 39 publications

(28 citation statements)

References 22 publications

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“…Understanding the arrangement of liquid crystals (LCs) near a substrate is important for the development of LC-based display devices, [1] chemical [2] and biological sensors [3], etc. In particular, the substrate chemical nature-mediated controlled alignment of LCs has found application in the development of biological sensors.…”

Section: Introductionmentioning

confidence: 99%

Exploitation of orientation of liquid crystals 5CB and DSCG near surfaces to detect low protein concentration

Kumar

Pattanayek

2015

Liquid Crystals

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We report the alignment of 4-cyano-4-pentylbiphenyl (5CB), a thermotropic liquid crystal (LC), and disodium chromo glycate (DSCG), a lyotropic LC, on the hydrophobic head group containing dimethyloctadecyl [3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP) and hydrophilic amine head group. Based on the texture observed using a polarised microscope for modified surfaces, we propose the alignment of the LCs on the modified surfaces. It is further supported by Fourier transform infra-red spectroscopy (FTIR) data of the corresponding system. Next, the texture under a polarised microscope for the LCs on protein bovine serum albumin adsorbed over the amine and DMOAP surfaces was observed. The difference in texture of LCs over the proteins depends on its concentration in solution. The difference is due to the amount of adsorbed proteins present on the surface. Above a critical amount of protein at the surface, the LCs show homeotropic arrangement.

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Section: Introductionmentioning

confidence: 99%

Exploitation of orientation of liquid crystals 5CB and DSCG near surfaces to detect low protein concentration

Kumar

Pattanayek

2015

Liquid Crystals

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“…The macroscopic re-orientation of the molecules in the LC film manifests as a dark appearance of the sensor placed between two crossed polarizers [Figure 2 (d)]. At the microscopic level, however, the LC molecules at the wall of the gold coated polymer pillars align perpendicular to the polymer pillars as in the case of LC-based sensors for chemical warfare simulants prepared with metal perchlorate salts [21]. …”

Section: Resultsmentioning

confidence: 99%

Liquid crystal-based sensors for selective and quantitative detection of nitrogen dioxide

Sen

Kupcho

Grinwald

et al. 2013

Sensors and Actuators B: Chemical

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A highly sensitive nitrogen dioxide (NO2) sensor based on orientational transition of a thin film of liquid crystal (LC) supported on a gold surface is reported. Transport of NO2 molecules through the LC film to the LC-gold interface induces an orientation transition in the LC film. The dynamic behavior of the sensor response exhibits a concentration-dependent response rate that is employed to generate an algorithm for quantitative determination of unknown concentrations. Sensitive, selective and reversible detection with minimal effects of environmental fluctuations suggest that these sensors can be used for quantitative NO2 detection for a number of applications.

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“…Inspired by that, bio/chemically modified substrates have been explored to control LC ordering and designed for detecting biomolecules [9][10][11][12][13][14] or chemicals [15][16][17][18][19][20]. For example, as shown in Figure 3(a), the gold substrate was first treated with a mixture of biotin-(CH 2 ) 2 [(CH 2 ) 2 O] 2 NHCO(CH 2 ) 11 SH (BiSH) and CH 3 (CH 2 ) 7 SH (C 8 SH).…”

Section: Lc-solid Interfacesmentioning

confidence: 99%

“…Apart from decorating the solid substrates with ligands for detecting proteins, it is also feasible to modify the surface with chemical receptors for chemical detection [15][16][17][18][19][20]. Figure 4 showed that depending on the surface topology and chemical composition, 5CB aligned on the plane with orientation depicted in Figure 4(c).…”

Section: Lc-solid Interfacesmentioning

confidence: 99%

Beyond displays: The recent progress of liquid crystals for bio/chemical detections

Dong

Yang

2013

Chin. Sci. Bull.

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Liquid crystals (LCs) are often known as electronic displays and have become ubiquitous in our daily life, apart from that, in the past 10 years, LCs have been investigated as exquisitely sensitive reporters for developing new molecular sensing and detection tools. The unique and primary advantage of this class of intriguing materials is the perturbation of the local ordering LCs at molecular scale by bio/chemical species can be communicated within LC molecules and extended over microns, allowing the observation of the optical signals by microscope or even the naked eye. Therefore, it provides a new platform for developing bio/chemical detection and potentially label-free sensing systems. In March 1888, a young botanist called Friedrich Reinitzer [1] first found that esters of cholesterol appeared to have two melting points between which the liquid showed iridescent colors and birefringence. Actually he discovered a new phase of matter: a liquid crystalline phase, distinguished from solids, liquids and gases that are already familiar to us [2]. Substances in this fourth state are called liquid crystals (LCs), flowing like a conventional liquid and exhibiting orientational order like a crystalline solid. In general, the molecules forming LCs are anisotropic, either rod-like or disc-like. There are two basic classes of LCs: thermotropic and lyotropic. In the thermotropic system, the liquid crystalline phase only exists within a particular temperature range, between a melting point, T m , and an upper transition temperature, T c (Figure 1). In the lyotropic system, LCs possess polar and non-polar parts within the same molecule. In a certain concentration range, molecules organize themselves into ordered structures showing LC properties. This review will not discuss lyotropes further and focus on thermotropic LCs, especially 4-cyano-4′-pentylbiphenyl (5CB), which exhibits liquid crystallinity in the nematic phase at room temperature, a simple and handy choice for constructing optical detectors performed at ambient condition. The key principle of employing LCs for molecular detection is illustrated in Figure 2. The local interruption of LC ordering at the molecular scale can be amplified to micron

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Quantitative detection of a simulant of organophosphonate chemical warfare agents using liquid crystals

Cited by 39 publications

References 22 publications

Exploitation of orientation of liquid crystals 5CB and DSCG near surfaces to detect low protein concentration

Exploitation of orientation of liquid crystals 5CB and DSCG near surfaces to detect low protein concentration

Liquid crystal-based sensors for selective and quantitative detection of nitrogen dioxide

Beyond displays: The recent progress of liquid crystals for bio/chemical detections

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