Magnetite-Supported Gold Nanostars for the Uptake and SERS Detection of Tetracycline

Abstract

Magnetite nanoparticles (MNPs) decorated with gold nanostars (AuNSs) have been prepared by using a seed growth method without the addition of surfactants or colloidal stabilizers. The hybrid nanomaterials were investigated as adsorbents for the uptake of tetracycline (TC) from aqueous solutions and subsequent detection using surface-enhanced Raman scattering (SERS). Several parameters were investigated in order to optimize the performance of these hybrid platforms on the uptake and SERS detection of TC, including variable pH values and the effect of contact time on the removal of TC. The spatial distribution of TC and AuNS on the hybrid composites was accomplished by coupling SERS analysis with Raman imaging studies, allowing also for the determination of the detection limit for TC when dissolved in ultrapure water (10 nM) and in more complex aqueous matrices (1 μM). Attempts were also made to investigate the adsorption modes of the TC molecules at the surface of the metal NPs by taking into account the enhancement of the Raman bands in these different matrices.

Dendrimer‐Based Gold Nanostructures for SERS Detection of Pesticides in Water

“…389, 845 and 1035 cm –1 ) along with the enhancement of the Raman band at 1376 cm –1 . Previous reports have suggested that the enhancement of the band at 1376 cm –1 is due to the proximity of the methyl CH 3 and CN groups (Table ) to the surface of metal nanoparticles Note that a detection limit of 10 n m in thiram was achieved by considering this Raman feature as a diagnosis band (1376 cm –1 ). Although for this analyte concentration the band has low intensity, it was assessed as distinct from the background noise.…”

“…Several differences are noticeable by comparing the conventional Raman spectrum of thiram with the corresponding SERS spectrum. These differences arise mostly because in the SERS spectrum the spectroscopic fingerprints result from thiram adsorbed on the Au surfaces . The most pronounced difference is the absence of certain vibrational bands (e.g.…”

“…For example, the dendritic structure of the polymer, which mimics natural structures such as tree roots, can be regarded as a means for the selective entrapment of chemical species to be detected at the surface of the metallic nanoparticles. This synergistic behavior, together with the well‐known colloidal stability of these systems in aqueous solutions, can be exploited in surface techniques such as the SERS analysis of trace levels of water contaminants , , . However, the research reported on the use of colloidal dendrimer based plasmonic nanostructures for SERS analysis is relatively scarce .…”

An integrated approach for trace detection of pollutants in water using polyelectrolyte functionalized magneto-plasmonic nanosorbents

“…Our interest in this field, prompted us to develop magnetic nanosorbents for SERS detection of TC. A first attempt involved the use of Fe 3 O 4 decorated with star shaped colloidal Au NPs 40 . While these systems have shown great potential in terms of SERS detection, the results also indicated the need for improvements mainly concerning the long term colloidal stability that allows adsorption studies for this analyte.…”

NaYF4:Yb,Tm@TiO2 core@shell structures for optimal photocatalytic degradation of ciprofloxacin in the aquatic environment

“…The widespread use of antibiotics in humans, animals and aquaculture results in vast residuals in aquatic environments. 1,2 The persistence of antibiotic residues may cause a series of problems in ecosystems and public health because of the poor biodegradability of antibiotics. 3 Therefore, the removal of antibiotic residues in aquatic environments is of great concern in environmental protection.…”