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

Abstract

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.

Fabrication of tunable hierarchical MXene@AuNPs nanocomposites constructed by self-reduction reactions with enhanced catalytic performances

“…However, it is still challenging to design and obtain MXene-based composites via facile and effective self-assembly. Alternatively, Au nanostructures and nanocomposites have shown important applications in cancer-related detection, selective photocatalysts and controlled drug release [42][43][44][45]. It is expected that a combination of MXene-based composites with gold na-noparticles could be especially advantageous, owing to controllable nanostructures and enhanced catalytic properties.…”

A Tailor-Made Protocol to Synthesize Yolk-Shell Graphene-Based Magnetic Nanoparticles for Nanomedicine

“…In order to overcome magnetic nanoparticle limitations, such as toxicity, self-aggregation and a low rate of bio-functionalization, many composite magnetic nanosystems have been developed in the last decade for nanomedicine [1,2]. These nanostructures are usually developed by having a magnetic core covered with a metal or a non-metal structure, such as gold [3][4][5], silica [6,7], polymers [8][9][10], among others. In general, this core-shell approach allows for, besides protection of the magnetic core,…”

Analysis of Biomolecules Based on the Surface Enhanced Raman Spectroscopy

“…To improve the sensitivity of the SERS detection, the sandwich strategy was also employed in detecting miRNA. A novel type of Fe 3 O 4 -Au core-shell NPs with branched gold shell integrated SERS activity and superparamagnetism was designed to form the sandwich structure for the detection of miRNA-21 as shown in Figure 3 B [ 20 ]. The LOD of miRNA-21 in serum was as low as 623 aM that indicated the branched nanostructures were also appropriate for SERS detection beside of smooth surfaces nanostructures.…”

“…Due to the synergistic effects, many nanohybrids were designed with non-metallic material, such as SiO 2 [ 17 ] and graphene oxide (GO) [ 18 ]. Numerous complex structures were designed to enhance the SERS signal, containing hexagonal-packed lotus seedpod like array substrate [ 19 ], Fe 3 O 4 -Au core-shell NPs with branched gold shell [ 20 ] and Si nanopillars (SiNPLs)@silver nanoparticles (AgNPs) [ 21 ], etc.…”