title: A liquid crystal-based sensor for the simple and sensitive detection of cellulase and cysteine.
abstract: A liquid crystal (LC)-based sensor, which is capable of monitoring enzymatic activity at the aqueous/LC interface and detecting cellulase and cysteine (Cys), was herein reported. When functionalized with a surfactant, dodecyl β-d-glucopyranoside, the 4-cyano-4'-pentylbiphenyl (5CB) displays a dark-to-bright transition in the optical appearance for cellulase. We attribute this change to the orientational transition of LCs, as a result of enzymatic hydrolysis between cellulase and surfactant. Furthermore, by adding cellulase and Cu(2+), our surfactant-LCs system performs an interesting ability to detect Cys, even though Cys could not interact with surfactant or LC directly. Alternatively, through the strong binding between Cys and Cu(2+), cellulase was able to hydrolyze surfactant in the presence of Cu(2+), leading to the transition of LCs from dark to bright. The detection limit of the LC sensor was around 1×10(-5)mg/mL and 82.5μM for cellulase and Cys, respectively. The LC-based sensor may contribute to the development of low-cost, expedient, and label-free detection for cellulase and Cys and the design strategy may also provide a novel way for detecting multiple analytes.
authors: Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, PR China.
authors: Yi
authors: Y
authors: Wang
authors: Department of Chemistry, University of Houston, Houston, TX, 77204, USA.
authors: Qiongzheng
authors: Q
authors: Hu
authors: Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, PR China; School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, PR China.
authors: Tongtong
authors: T
authors: Tian
authors: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, PR China.
authors: Yan'an
authors: Y
authors: Gao
authors: Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100, PR China. Electronic address: ylmlt@sdu.edu.cn.
authors: Li
authors: L
authors: Yu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002480:Cellulase / Q000032:analysis* / Q000378:metabolism; D003545:Cysteine / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D057230:Limit of Detection; D050866:Liquid Crystals / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D013501:Surface-Active Agents; D014867:Water; D002480:Cellulase; D003545:Cysteine
keywords: Cellulase; Cysteine; Liquid crystals; Sensor