Atomically flat surfaces
of single-crystalline Au nanoplates can maximize the functionality
of biomolecules, thus realizing extremely high-performance biosensors.
Here, we report both highly specific and supersensitive detection
of C-reactive protein (CRP) by employing atomically flat Au nanoplates.
CRP is a protein biomarker for inflammation and infection and can
be used as a predictive or prognostic marker for various cardiovascular
diseases. To maximize the binding capacity for CRP, we carefully optimized
the Au nanoplate-Cys3-protein G-anti-CRP structure by observing atomic
force microscopy (AFM) images. The optimally anti-CRP-immobilized
Au nanoplates allowed extremely specific detection of CRP at the attomolar
level. To confirm the binding of CRP onto the Au nanoplate, we assembled
Au nanoparticles (NPs) onto the CRP-captured Au nanoplate by sandwich
immunoreaction and obtained surface-enhanced Raman scattering (SERS)
spectra and scanning electron microscopy (SEM) images. Both the SERS
and SEM results showed that we completely eliminated the nonspecific
binding of Au NPs onto the optimally anti-CRP-immobilized Au nanoplate.
Compared with the anti-CRP-immobilized rough Au film and the randomly
anti-CRP-attached Au nanoplate, the optimally anti-CRP-immobilized
Au nanoplate provided a highly improved detection limit of 10–17 M. In this study, it was validated that ultraclean
and ultraflat Au nanoplates can maximize the sensing capability of
CRP. We expect that these Au nanoplates will enable the feasible detection
of many important biomarkers with high specificity and high sensitivity.
Multivalent immunoprobes can improve the sensitivity of biosensors because increased valency can strengthen the binding affinity between the receptor and target biomolecules. Here, we report surface-enhanced Raman scattering (SERS)-based immunoassays using multivalent antibody-conjugated nanoparticles (NPs) for the first time. Multivalent antibodies were generated through the ligation of Fab fragments fused with Fc-binding peptides to immunoglobulin G. This fabrication method is easy and fast because of the elimination of heterologous protein expression, high degrees of antibody modifications, and covalent chemical ligation steps. We constructed multivalent antibody−NP conjugates (MANCs) and employed them as SERS immunoprobes. MANCs improved the sensitivity of SERS-based immunoassays by 100 times compared to standard antibody−NP conjugates. MANCs will increase the feasibility of practical SERS-based immunoassays.
Correction for ‘Bioaccumulation of polystyrene nanoplastics and their effect on the toxicity of Au ions in zebrafish embryos’ by Wang Sik Lee et al., Nanoscale, 2019, DOI: 10.1039/c8nr09321k.
A silver nanoparticle is one of the representative engineered nanomaterials with excellent optical, electrical, antibacterial properties. Silver nanoparticles are being increasingly used for medical products, water filters, and cosmetics, etc. However, silver nanoparticles are known to cause adverse effects on the ecosystem and human health. To utilize silver nanoparticles with minimized negative effects, it is important to understand the behavior of silver nanoparticles released to the environment. In this study, we compared toxicity behaviors of citrate-stabilized silver nanoparticles with polyethylene glycol coated silver nanoparticles in two different ionic environments, which are aquatic environments for developing zebrafish embryo. Depending on the composition of the ionic environment, citrate-stabilized silver nanoparticles and polyethylene glycol coated silver nanoparticles exhibited different behaviors in dissolution, aggregation, or precipitation, which governed the toxicity of silver nanoparticles on zebrafish embryos.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.