title: A convenient purification method for silver nanoclusters and its applications in fluorescent pH sensors for bacterial monitoring.
abstract: Herein, we report a convenient approach to purify water-soluble dihydrolipoic acid (DHLA)-capped Ag nanoclusters (Ag NCs) by pH-induced precipitation under acidic conditions. The fluorescence of Ag NCs could be completely recovered by re-dispersing the precipitate into a basic solution using DHLA and NaBH4 as stabilizing ligands and etching reagent. DHLA-Ag NCs-doped agarose hydrogels have been prepared to monitor pH with a wide range from 8.0 to 4.0. When pH decreased, the fluorescence of the hydrogels under a UV lamp decreased and completely disappeared after pH 5. The DHLA-Ag NCs-doped agarose hydrogels biosensor showed low cytotoxicity and long stability. Accordingly, a fluorescent pH sensor for bacterial monitoring has been employed based on the "OFF-ON" signal switch of the Ag NCs-agarose hydrogel.
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China.
authors.forename: Huayu
authors.initials: H
authors.lastname: Xiong
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China.
authors.forename: Huiling
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China.
authors.forename: Jichao
authors.initials: J
authors.lastname: Liang
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wen
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China.
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, China. Electronic address: wangsf@hubu.edu.cn.
authors.forename: Shengfu
authors.initials: S
authors.lastname: Wang
mesh_terms: D015373:Bacterial Typing Techniques / Q000295:instrumentation*; D003124:Colorimetry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D048168:Escherichia coli K12 / Q000302:isolation & purification*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000302:isolation & purification; D005590:Fractional Precipitation / Q000379:methods; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements / Q000295:instrumentation*; D053768:Metal Nanoparticles / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry / Q000302:isolation & purification*; D013050:Spectrometry, Fluorescence / Q000379:methods; D008063:Thioctic Acid / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D012834:Silver; D008063:Thioctic Acid; C015144:dihydrolipoic acid
keywords: Ag nanoclusters; Bacterial monitoring; Fluorescence sensor; Fluorescent pH sensor; Signal off-on