title: Graphene oxide quantum dots@silver core-shell nanocrystals as turn-on fluorescent nanoprobe for ultrasensitive detection of prostate specific antigen.
abstract: We report a fluorescent turn-on nanoprobe for ultrasensitive detection of prostate specific antigen (PSA) based on graphene oxide quantum dots@silver (GQDs@Ag) core-shell nanocrystals. The success of this work relies on the assembly of quantities of GQDs in one GQDs@Ag probe, which makes the ratio of probe to target significantly increased and thus enables the fluorescent signal enhancement. When the silver shell was removed via oxidative etching using hydrogen peroxide (H2O2), the incorporated GQDs could be readily released and the whole process caused little change to their fluorescence performance. We tested the probe for the ultrasensitive detection of PSA based on the sandwich protocol of immunosensors. In particular, magnetic beads (MBs) were employed to immobilize anti-PSA antibody (Ab1) and acted as a separable capture probe, while GQDs@Ag was used as detection probe by linking antibody (Ab2). The developed immunosensor showed a good linear relationship between the fluorescence intensity and the concentration of PSA in the range from 1 pg/mL to 20 ng/mL with a detection limit of 0.3 pg/mL. The immunosensor used for the analysis of clinical serum samples exhibited satisfactory results, which demonstrated its potential for practical diagnostic applications. This method provides a possible solution to the application of GQDs in immunosensing and could be potentially extended to other similar systems.
authors.affiliation: College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, PR China.
authors.forename: Haimeng
authors.initials: H
authors.lastname: Pei
authors.affiliation: College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, PR China.
authors.forename: Shuyun
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, PR China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Yang
authors.affiliation: College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, PR China.
authors.forename: Rongmei
authors.initials: R
authors.lastname: Kong
authors.affiliation: Leadernano Tech. L.L.C., Jining, Shandong 272000, PR China.
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, PR China. Electronic address: fengliquhn@hotmail.com.
authors.forename: Fengli
authors.initials: F
authors.lastname: Qu
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005456:Fluorescent Dyes; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D008297:Male; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010087:Oxides / Q000737:chemistry; D017430:Prostate-Specific Antigen / Q000097:blood*; D045663:Quantum Dots; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*
chemical_list: D014408:Biomarkers, Tumor; D005456:Fluorescent Dyes; D010087:Oxides; D012834:Silver; D006108:Graphite; D017430:Prostate-Specific Antigen
keywords: Fluorescent immunoassay; GQDs@Ag; Graphene oxide quantum dots; Magnetite; Prostate specific antigen