SCIENCE CHINA Materials, Volume 60, Issue 11: 1129-1144(2017) https://doi.org/10.1007/s40843-017-9022-1

Synthesis of magnetic core-branched Au shell nanostructures and their application in cancer-related miRNA detection via SERS

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  • ReceivedJan 31, 2017
  • AcceptedMar 27, 2017
  • PublishedMay 9, 2017


Magnetic core gold shell nanostructures which integrate both SERS activity and superparamagnetism are widely utilized in SERS-based detection as SERS substrates, sample separation and preconcentration operators, as well as external magnetic field controlled directional carrier. However, most of the reported gold shells coated on the magnetic cores had smooth surfaces rather than branched nanostructures with enhanced SERS activity. Here, a novel type of Fe3O4-Au core-shell nanoparticles with branched gold shell was prepared by a seed-mediated method together with the shape induction agent AgNO3, and their growth process and mechanism, properties, as well as morphologically controlled synthesis were also investigated. The branched gold coated magnetic nanoparticles (B-GMNPs) with improved SERS performance were further utilized to build superparamagnetic and SERS-active capturers by assembling tetrahedral DNA onto their surfaces for sandwich-structured detection of cancer-related biomarker miRNA-21. The experimental results indicate that highly sensitive and specific detections can be obtained by the proposed SERS sensing system including B-GMNPs and tetrahedral DNA, and the limit of detection (LOD) of miRNA-21 in serum is 623 amol L−1. These B-GMNPs can be used as good SERS substrates with the functions of external magnetic field controlled sample separation and directional enrichment for effective SERS-based biochemical sensing and detections.

Funded by

National Natural Science Foundation of China(21475064)

Sci-tech Support Plan of Jiangsu Province(BE2014719)

Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R37)

Research Innovation Program for College Graduates of Jiangsu Province(SJZZ15_0107)

Scientific Research Foundation of Nanjing University of Posts and Telecommunications(NY215075)

Priority Academic Program Development of Jiangsu Higher Education Institutions(YX03001)


This work was supported by the National Natural Science Foundation of China (21475064), Sci-tech Support Plan of Jiangsu Province (BE2014719), Program for Changjiang Scholars and Innovative Research Team in University (IRT_15R37), the Research Innovation Program for College Graduates of Jiangsu Province (SJZZ15_0107), the Scientific Research Foundation of Nanjing University of Posts and Telecommunications (NY215075), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (YX03001).

Interest statement

The authors declare that they have no conflicts of interest.

Contributions statement

Song C, Yang Y and Wang L proposed and designed the project. Yang Y, Liu B, Chao J, Zhu D participated in the design and characterization of DNA structures. Jiang X, Zhang Q and Chen Y performed the experiments. Sun Y and Yang B characterized the materials. All the authors contributed to the writing and general discussion of the paper.

Author information

Yanjun Yang is a graduate student at the Institute of Advanced Materials, Nanjing University of Posts and Telecommunications (NJUPT) under the supervision of Prof. Lianhui Wang and Prof. Chunyuan Song. She received her Bachelor’s degree from NJUPT in 2014. Her current research focuses on the development of ultrasensitive SERS sensors for multiple biochemical sensing and detections.

Xinyu Jiang is an undergraduate student at NJUPT. Currently, he is working on the Research Innovation Program for College Undergraduates of NJUPT in Prof. Wang’s lab.

Chunyuan Song received his PhD degree in optical engineering from Southeast University in 2012. He is now an associate professor at the Institute of Advanced Materials, NJUPT. His research interest focuses on the synthesis, characterization and application of plasmonic nanomaterials for surface-enhanced Raman scattering based biosensing and imaging.

Lianhui Wang obtained his PhD degree in polymeric chemistry and physics at Zhejiang University in 1998. Then he joined Prof. E. T. Kang’s group at the National University of Singapore (NUS) as a postdoctoral researcher from 1998 to 2000, followed by being a researcher and assistant professor at the Institute of Molecular and Cell Biology, NUS. Since June 2005, he joined the faculty of Fudan University as a professor and then moved to NJUPT in January 2011. Currently, he is a professor at the Institute of Advanced Materials, NJUPT. He was granted the funding of “National Distinguished Young Scholar” in 2004, and was honored as “Yangtze River Scholar Distinguished Professor” in 2011. His research group works on bioelectronics and nanobiology including the synthesis of optoelectronic nanomaterials and their applications for biochemical sensing, multimodal imaging, drug delivery and photothermo/chemo/ photodynamic therapy.


Supplementary information

Supporting data are available in the online version of the paper.


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  • Figure 1

    Characterizations of the S-GMNPs and B-GMNPs. (a–c) SEM images of the nanoparticles synthesized by ×1 Au shell growth solution, ×2 Au shell growth solution, and ×2 Au shell growth solution with 10 μL AgNO3, respectively; (d–f) corresponding TEM images of the three nanoparticles showing in (a–c); (g) absorption spectra; (h) averaged SERS spectra of 4-MBA obtained from the three nanoparticles; (i) SERS intensities of 4-MBA at 1080 cm–1 corresponding to the three nanoparticles respectively (n=10).

  • Scheme 1

    (a) Sketch maps of the preparation of B-GMNPs and S-GMNPs; (b) construction of tetrahedral DNA; (c) sandwich-structured strategy by using tetrahedral DNA modified B-GMNPs and SERS tags to assay cancer-related biomarker miRNA-21.

  • Figure 2

    Detailed characterizations of the B-GMNPs. (a) SEM image of a single B-GMNP; (b) TEM image of a single B-GMNP; (c) SAED pattern of a whole B-GMNP; (d) HRTEM image obtained from the circle area marked in (b) and the corresponding SAED pattern (inset). (e) XRD patterns of Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2@Au seeds, and Fe3O4@SiO2@Au, respectively. Diffraction peaks of gold ★, amorphous SiO2 ◆, and Fe3O4 ●. (f) Hysteresis loop of the B-GMNPs and a photograph of the magnetic separation (inset).

  • Figure 3

    The GMNPs synthesized by three different dosages of growth solutions, one fold (×1) (a), two folds (×2) (b), and three folds (×3) (c). SEM images (a–c), TEM images (d–f), absorption spectra (g), SERS spectra (h), and SERS intensity of 4-MBA (i) at 1080 cm–1 corresponding to the three kinds of GMNPs, respectively (n=10).

  • Figure 4

    (a–h) TEM and SEM images of the B-GMNPs prepared by different dosages of AgNO3 solution, (a) and (b) 10 μL, (c) and (d) 20 μL, (e) and (f) 30 μL, (g) and (h) 50 μL, respectively. (i) Corresponding absorption spectra. (j) Averaged SERS spectra of 4-MBA obtained from the four products, respectively. (k) SERS intensities of 4-MBA at 1080 cm–1 corresponding to the four SERS spectra shown in (j) (n=10).

  • Figure 5

    (a–e) Time-evolution TEM images, 10, 20, 30, 50 min and 14 h, respectively. (f) Time-evolution absorption spectra.

  • Figure 6

    Scheme of the growth process of B-GMNPs.

  • Figure 7

    (a) Native PAGE (10%) analysis of the formation of DNA tetrahedron structure. 20 bp Ladder (lane M), four ssDNAs (lane 1–4), DNA hybridizations of two ssDNAs (lane 5–10), DNA hybridizations of three ssDNAs (lane 11–14), and DNA tetrahedron (lane 15); (b) native PAGE (8%) analysis of sandwich assay with DNA tetrahedron. Lane 1 represents ABC for a reference, lane 2 for DNA tetrahedron, lane 3 for DNA tetrahedron+target, lane 4 for DNA tetrahedron+target+probe DNA, lane 5 for target, lane 6 for probe DNA.

  • Figure 8

    SERS assays for miRNA-21 in human serum. (a) Concentration-dependent SERS spectra; (b) linear fitting of the peak intensity at 1331 cm–1 as a function of concentration of miRNA-21; (c) specificity assessment: SERS spectra obtained from blank, noncomplementary miRNA-486, single-base mismatched miRNA, miRNA-21 and the mixture of three miRNA-21/375/486 (1 nmol L−1); (d) corresponding peak intensities at 1331 cm–1 (n=10).

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