Hybridizing Carbon-Based Dot-Capped Manganese Dioxide Nanosheets and Gold Nanoparticles as a Highly Sensitive Surface-Enhanced Raman Scattering Substrate

Abstract

Surface-enhanced Raman Scattering (SERS) is a sensitive and nondestructive technique that provides fingerprint structural information of molecules. Designing and constructing sensitive and stable SERS substrates is of great significance for the application of the technique. In this study, single-layer carbon-based dots (CDs) are used as capping agents to synthesize gold nanoparticles (AuNPs/CDs) and manganese dioxide nanosheets (MnO2/CDs), which are then hybridized through a simple cocentrifugation method. After the hybridization, the monodispersive AuNPs/CDs aggregate obviously into some clusters exhibiting strong SERS activity due to the electromagnetic “hot spots” effect, and the MnO2/CDs also show outstanding SERS activity due to the charge-transfer resonance effect. The obtained nanohybrids (MnO2/CDs/AuNPs) with robust chemical stability combine well with the electromagnetic enhancement of AuNPs/CDs and chemical enhancement of MnO2/CDs, leading to an ultrahigh enhancement factor of 3.9 × 108. Based on the novel SERS substrate, a sensitive and rapid sensing system for the detection of malachite green is developed, with a low detection limit of 1 × 10–9 M. This work provides a valuable model for designing and fabricating high-performance SERS substrates.

An Immunosensor Using Electroactive COF as Signal Probe for Electrochemical Detection of Carcinoembryonic Antigen

“…TEM (Figure f) and AFM (SI Figure S9) images verified that lots of AuNPs with a diameter of about 2.7 nm was immobilized on COFTFPB-Thi evenly, which provided a platform for the loading of Ab2 through Au–S bond. High-resolution TEM (HRTEM) image showed regular lattice fringes with a space of 0.235 nm which was ascribed to the (111) crystal plane of Au (Figure g). , Selective area electron diffraction pattern (SAED) proved the AuNPs was polycrystalline (SI Figure S10). AFM image confirmed successful preparation of Ab2/AuNPs/COFTFPB-Thi because the size of particles was increased to 6.5 nm (Figure h).…”

“…High-resolution TEM (HRTEM) image showed regular lattice fringes with a space of 0.235 nm which was ascribed to the (111) crystal plane of Au (Figure 2g). 46,47 Selective area electron diffraction pattern (SAED) proved the AuNPs was polycrystalline (SI Figure S10). AFM image confirmed successful preparation of Ab2/AuNPs/COFTFPB-Thi because the size of particles was increased to 6.5 nm (Figure 2h).…”

Carbon-based dot-capped gold nanoparticles hybridized with manganese dioxide for enhanced photodynamic cancer therapy

“…32 However, it was difficult to directly observe the CDs capped on the AuNPs by HRTEM due to the low contrast degree. 33 They could only be vaguely identified on the surface of small particles of AuNPs (Fig. S4, ESI †).…”

Photo-Assisted Robust Anti-Interference Self-Powered Biosensing of MicroRNA Based on Pt–S Bonds and the Inorganic–Organic Hybridization Strategy

“…In addition, the immobilization of DNA probes played a vital role in the stability and anti-interference ability of the as-constructed sensors, in which Au–S bonds can be a general strategy to realize efficient immobilization. − However, the Au–S bond was sensitive to complicated conditions, especially biothiols, which could lead to accidental shedding of surface ligands or nonspecific release of target molecules. , By contrast, the stability of Pt–S bonds was higher than that of Au–S bonds. Liu et al reported that gold nanoparticle@Pt (AuNP@Pt) with Pt shell on the surface of AuNP could form highly stable biological conjugates and preserve the properties of AuNPs, which efficiently avoids the interference of biological mercaptan in cells …”