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16. Cascade Structured Plasmonic Liquid Crystal Biosensor for the Rapid Detection of Harmful Bacteria Dispersed in Potable Water

Author

Sforza, Maria Laura, Petronella, Francesca, De Biase, Daniela, Zaccagnini, Federica, Lim, Seok‐In, Butt, Usman Akhtar, d'Alessandro, Antonio, Godman, Nicholas P., Evans, Dean R., McConney, Michael, Jeong, Kwang‐Un, and De Sio, Luciano

Abstract

Pathogenic microorganisms contaminating potable water are a serious water quality concern because they have severe consequences for human and environmental health. Managing water contamination requires the availability of fast and highly sensitive point‐of‐use detection systems responsive to a wide concentration range. In the present work, this goal is achieved by realizing a cascade‐structured biosensor that exploits innovative stimuli‐responsive materials such as gold nanorods (AuNRs) and photosensitive nematic liquid crystals (NLCs). The cascade structure is fabricated by interfacing a glass substrate in a back‐to‐front arrangement, hosting an array of bioactivated AuNRs and an NLC cell. The AuNRs array integrates microfluidic channels, allowing direct water sampling and the analysis of reduced water volumes with high sensitivity. The biosensor combines in the same device two independent optical transducers: a bioactive AuNRs array (plasmonic biosensor), sensitive to refractive index alterations, and an NLC cell that detects the presence of pathogens by responding to light intensity variations. The plasmonic biosensor performs exceptionally well for very low concentrations of bacteria. In contrast, the NLC biosensor works for high‐concentration bacteria, thus providing a cascade‐like detection system able to detect bacteria in a wide concentration range from 10 to 109CFU mL−1. A new early warning system that detects the presence of harmful pathogens dispersed in potable water is realized by harnessing the capabilities of antibody‐functionalized gold nanorod arrays and light‐sensitive liquid crystals, providing a robust and efficient detection mechanism.

Published
2024
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20. Phase behaviors and structures of a symmetrically tapered biphenylamide

Author

Hwang, Seok-Ho, Park, Soo-Jin, Kim, Hak Yong, Kuo, Shiao-Wei, Lee, Seung Hee, Lee, Myong-Hoon, and Jeong, Kwang-Un

Subjects
Amides -- Properties, Amides -- Structure, Amides -- Research, Hydrogen bonding -- Research, X-rays -- Diffraction, X-rays -- Usage, Chemicals, plastics and rubber industries
Published
2009

21. Phase transitions and structures of novel pyrenes potentially useful in photovoltaic applications

Author

Leng, Siwei, Wex, Brigitte, Chan, Li Hsin, Graham, Matthew J., Jin, Shi, Jing, Alexander J., Jeong, Kwang-Un, Horn, Ryan M. Van, Sun, Bin, Zhu, Meifang, Kaafarani, Bilal R., and Cheng, Stephen Z. D.

Subjects
Benzopyrene -- Structure, Benzopyrene -- Properties, Benzopyrene -- Research, Benzopyrene -- Usage, Phase transformations (Statistical physics) -- Research, X-rays -- Diffraction, X-rays -- Usage, Chemicals, plastics and rubber industries
Published
2009

36. Dependence of Retardation Dispersion on the Ultraviolet Polarization Direction During Photopolymerization of Self-organized Smectic Reactive Mesogen Molecules

Author

Jeong, Jinyoung, Choi, Yu-Jin, Jeong, Kwang-Un, and Lee, Ji-Hoon

Abstract

We investigated the dependence of the retardation dispersion on the polarization direction of ultraviolet (UV) light during the photopolymerization of self-organized smectic reactive mesogen (RM) molecules. RM retarder film that was photopolymerized with UV light linearly polarized parallel to the layer plane showed negative dispersion (ND) of retardation for a wide range of UV polymerization temperatures. On the other hand, film that was photopolymerized with unpolarized UV light showed negative dispersion in a narrow range of UV polymerization temperatures. With a certain UV polymerization temperature, the dispersion of retardation was converted from positive to negative, depending on the UV polarization.

Published
2018

41. Columnar Structures from Asymmetrically Tapered Biphenylamide

Author

Park, Soo-Jin, primary, Hwang, Seok-Ho, additional, Kim, Namil, additional, Kuo, Shiao-Wei, additional, Kim, Hak Yong, additional, Park, Seul-Ki, additional, Kim, Young-Jin, additional, Nah, Changwoon, additional, Lee, Joong Hee, additional, and Jeong, Kwang-Un, additional

Published
2009
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45. Self-assembly of chemically linked rod-disc mesogenic liquid crystals.

Author

Jeong KU, Jing AJ, Monsdorf B, Graham MJ, Harris FW, and Cheng SZ

Abstract

A series of new molecular discs (RDn, here n is the number of carbon atoms between the rod and disc mesogens) was synthesized via the chemical attachment of six cyanobiphenyl calamitic (rod) mesogens (R) linked to the triphenyl discotic (disc) mesogen (D) with a series of six alkyl chain linkages (n = 6-12). In this study, phase structures, transitions, and liquid crystalline (LC) behavior of the RD12 compound with 12 carbon atoms in each alkyl chain linkage between the rod and disc mesogens were investigated. Differential scanning calorimetry, polarized light microscopy, wide-angle X-ray diffraction (WAXD), and selected area electron diffraction (SAED) allowed us to identify three ordered phases below the isotropization temperature: nematic (N) LC and K1 and K2 crystalline phases. On the basis of the structural results obtained via 2D WAXD experiments on oriented samples and SAED experiments on single crystals, the K1 crystalline unit cell was determined to be triclinic with the dimensions of a = 1.36 nm, b = 1.45 nm, c = 2.11 nm, alpha = 85 degrees, beta = 100 degrees, and gamma = 50 degrees. The K2 phase was metastable with respect to the K1 phase. It also possessed a triclinic unit cell with a = 1.40 nm, b = 1.51 nm, c = 1.92 nm, alpha = 87 degrees, beta = 117 degrees, and gamma = 62 degrees. Molecular packing models for the crystalline phases were proposed on the basis of the diffraction results. In the whole range of ordered structures, it was found that RD12 molecular discs are intercalated. Both triphenyl discotic mesogens and cyanobiphenyl calamitic mesogens are completely interdigitated.

Published
2007
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