title: Development of aptamer-conjugated magnetic graphene/gold nanoparticle hybrid nanocomposites for specific enrichment and rapid analysis of thrombin by MALDI-TOF MS.
abstract: Simple, rapid and sensitive analysis of thrombin (a tumor biomarker) in complex samples is quite clinical relevant and essential for the development of disease diagnosis and pharmacotherapy. Herein, we developed a novel method based on aptamer-conjugated magnetic graphene/gold nanoparticles nanocomposites (MagG@Au) for specific enrichment and rapid analysis of thrombin in biological samples using MALDI-TOF-MS. At first, gold nanoparticles were compactly deposited on PDDA functionalized magnetic graphene through electrostatic interaction. Afterwards, aptamer was easily conjugated to gold nanoparticles via Au-S bond formation. The as-made aptamer-conjugated nanocomposites took advantage of the magnetism of magnetic graphene, the high affinity and specificity of aptamer, facilitating a high-efficient separation and enrichment of thrombin. More importantly, due to the large surface area of the hybrid substrate, the average coverage density of aptamer achieved 0.34 nmol/mg, which enhanced the thrombin binding capacity and the recovery of thrombin in real samples. In turn, the enriched thrombin attributed to the sensitive output of MALDI-TOF mass spectrometry signal, 0.085 ng μL(-1) (2.36 nM) thrombin could be detected. This proposed method has a relatively wide linear relation ranging from 0.1 ng μL(-1) to 10 ng μL(-1), and satisfactory specificity. The proposed high-throughput method based on MALDI-TOF MS is expected to the application in the disease biomarker detection and clinical diagnosis.
authors.affiliation: Department of Chemistry and Institutes of Biomedical Science, Fudan University, Shanghai 200433, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: Department of Chemistry and Institutes of Biomedical Science, Fudan University, Shanghai 200433, China. Electronic address: chdeng@fudan.edu.cn.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Deng
authors.affiliation: Department of Chemistry and Institutes of Biomedical Science, Fudan University, Shanghai 200433, China.
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Zhang
mesh_terms: D052158:Aptamers, Peptide / Q000737:chemistry*; D014408:Biomarkers, Tumor / Q000097:blood / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D016014:Linear Models; D053768:Metal Nanoparticles / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D011095:Polyethylenes / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D055672:Static Electricity; D013917:Thrombin / Q000737:chemistry*
chemical_list: D052158:Aptamers, Peptide; D014408:Biomarkers, Tumor; D011095:Polyethylenes; D000644:Quaternary Ammonium Compounds; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride; D006046:Gold; D006108:Graphite; D013917:Thrombin
keywords: Aptamer; MALDI-TOF mass spectrometry; Magnetic graphene/gold nanoparticles nanocomposites; Selective enrichment; Thrombin detection