RESUMEN
Nanoplastics, which are small plastic particles resulting from the decomposition of plastic waste, can accumulate and adsorb toxic chemicals in aquatic environments, leading to detrimental effects on the environment and human health. Consequently, there is an urgent demand for the development of an efficient method to accurately quantify and effectively remove nanoplastics. Here, we prepared a novel "cage-like" microrobot for effective dynamic capture and highly sensitive surface-enhanced Raman scattering detection of nanoplastics in situ. The microrobot utilizes water as fuel under visible light and achieves efficient capture of nanoplastics within 2 min on the basis of the stacking structure between layers and electrostatic action. The microrobot could be recovered by an external magnetic field, and the SERS activity was greatly enhanced through the coupling of multilayer hot spots, with a detection limit of 1.27 µg/mL. We built a simple device to demonstrate the feasibility of the microrobot strategy of capturing plastic in real wastewater and further extended this technology to single-use plastic cups in everyday life. Moreover, many different types of plastic spectra can also be quickly distinguished when combined with machine learning. This work provides new ideas for improving the dynamic capture and effective monitoring of nanoplastics.
RESUMEN
Peroxidase-like nanozymes have led to important progress in biosensing, but most of nanozyme sensing systems are currently established by a single-signal output mode, which is susceptible to environmental and operational factors. Thus construction of a dual-signal output nanozyme sensing system is essential for obtaining reliable and robust performance. In this study, a novel peroxidase mimicking nanozyme was developed by decorating magnetic ring-like Fe3O4 with gold nanoparticles (R-Fe3O4/Au) for the colorimetric and surface-enhanced Raman scattering (SERS) dual-mode detection of biomolecules in human serum. The R-Fe3O4/Au nanozymes served as mimetic peroxidase which can catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine by hydrogen peroxide, and concomitantly as SERS substrates for detecting the Raman signals of oxidized products, providing an effective approach to investigate the reaction kinetics of enzymes. Based on the redox reactions, the nanozymes achieved colorimetric-SERS dual-mode sensing of glutathione (GSH) and cholesterol with detection limits as low as 0.10 µM and 0.08 µM, respectively. Furthermore, the nanozymes enabled rapid detection of GSH and cholesterol in serum without any complicated sample pretreatment. The R-Fe3O4/Au catalyst still displayed excellent peroxidase activity even after repeated use for 5 times. The proposed colorimetric-SERS dual-mode sensors exhibited good accuracy and reproducibility, which provides a new avenue for exploiting multifunctional sensors and has a great application prospect in biosensing.
Asunto(s)
Técnicas Biosensibles , Nanopartículas del Metal , Colorimetría/métodos , Colorantes , Glutatión , Oro , Humanos , Peróxido de Hidrógeno , Peroxidasa , Peroxidasas/química , Reproducibilidad de los ResultadosRESUMEN
Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants, which cause serious harm to human health and ecological environment. Thus, a low-cost membrane was developed for highly effective removal and rapid surface-enhanced Raman scattering (SERS) detection of PCBs by filling esterified-sawdust (CA-SD) modified with silver nanoparticles (AgNPs) into solid phase extraction (SPE) column. SD was first modified by an esterification cross-linking strategy and then AgNPs were anchored on the CA-SD to prepare highly sensitive and reproducible SERS substrates (AgNPs/CA-SD). Due to the contraction of the surface area of the CA-SD caused by drying, the gap between the AgNPs could be reduced, thereby generating a large number of hot spots and driving more target molecules into them to obtain the enhanced SERS signals. The AgNPs/CA-SD-based SPE membrane showed excellent SERS activity with an enhancement factor of 5.98 × 108 for the R6G analysis. The proposed SERS-active SPE membrane with functionalization of mercapto-ß-cyclodextrin was further developed for the determination of PCB-77 and PCB-1 with the LODs of 1.43 × 10-9 M and 2.12 × 10-8 M, respectively. In addition, each PCB in the mixed sample could be quickly distinguished based on the characteristic peaks. The current research exhibits great potential for the simultaneous detection of multiple environmental contaminants and can meet the needs of on-site emergency detection.