title: Homogeneous and selective detection of cadmium ions by forming fluorescent cadmium-protein nanoclusters.
abstract: We synthesized fluorescent Cd nanoclusters (CdNCs) through a protein-directed method, and the synthesis method was utilized for a homogeneous, ultrasensitive, and selective detection of cadmium ion (Cd2+). CdNCs were synthesized using a modified protein-directed method for developing a rapid Cd2+detection system. For rapid Cd2+detection, the reaction time was reduced by optimizing the reaction conditions such as temperature, reducing agent concentration, and protein concentration. The synthesized CdNCs had ca. 2 nm diameter and showed strong fluorescence at 485 nm under 365 nm UV light. The fluorescence of the CdNCs increased with increasing Cd2+concentrations, and the limit of detection in deionized water was 15.68 fM. This method enables the detection of Cd2+through the Cd concentration-dependent formation of fluorescent CdNCs in tap, fountain, and pond water samples with detection limits of 0.75, 7.65, and 48.2 fM, respectively. The sensitivity and specificity of our method are comparable to those of several existing methods for Cd2+detection. Furthermore, the system enables the homogeneous detection of Cd2+without separation and washing, thereby broadening its application in analytical chemistry.
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
authors.forename: Yuseon
authors.initials: Y
authors.lastname: Noh
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Jo
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
authors.forename: Hyoyoung
authors.initials: H
authors.lastname: Mun
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
authors.forename: Young-Deok
authors.initials: YD
authors.lastname: Ahn
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea. Electronic address: mkim@gist.ac.kr.
authors.forename: Min-Gon
authors.initials: MG
authors.lastname: Kim
mesh_terms: D002104:Cadmium / Q000032:analysis* / Q000737:chemistry; D060766:Drinking Water / Q000032:analysis; D005453:Fluorescence; D049329:Nanostructures / Q000032:analysis* / Q000737:chemistry; D061005:Ponds / Q000032:analysis; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D060766:Drinking Water; D011506:Proteins; D014874:Water Pollutants, Chemical; D002104:Cadmium
keywords: Cadmium; Fluorescence; Nanocluster; Protein-directed synthesis; Water