Nanoparticles: Properties, applications and toxicities

We review the progress achieved during the recent five years in immunochemical biosensors (immunosensors) combined with nanoparticles for enhanced sensitivity. The initial part introduces antibodies as classic recognition elements. The optical sensing part describes fluorescent, luminescent, and surface plasmon resonance systems. Amperometry, voltammetry, and impedance spectroscopy represent electrochemical transducer methods; electrochemiluminescence with photoelectric conversion constitutes a widely utilized combined method. The transducing options function together with suitable nanoparticles: metallic and metal oxides, including magnetic ones, carbon-based nanotubes, graphene variants, luminescent carbon dots, nanocrystals as quantum dots, and photon up-converting particles. These sources merged together provide extreme variability of existing nanoimmunosensing options. Finally, applications in clinical analysis (markers, tumor cells, and pharmaceuticals) and in the detection of pathogenic microorganisms, toxic agents, and pesticides in the environmental field and food products are summarized.

Nanoparticle-Based Immunochemical Biosensors and Assays: Recent Advances and Challenges

Pesticides are essential in modern agricultural practices. Detection of pesticides is an essential step in regulating and monitoring the levels of pesticides in the environment. Even though GC/LC-MS is often the gold standard method for pesticide detection, recent technological advancements has promoted the creation of alternative techniques, such as Surface Enhanced Raman Spectroscopy (SERS), that provide added advantages such as ultrasensitive detection, faster turnover, simpler protocols, in situ sampling, on-site capability and reduced cost. In this review, a comprehensive report of recent advances in SERS detection of synthetic chemical pesticides is given. The development and applications of the SERS technique for pesticide detection in both simple and complex matrices are discussed. The main advantages of using SERS for pesticide detection are highlighted, together with its limitations. Lastly, promising future trends and applications of SERS for pesticides detection are also discussed.

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Review of surface enhanced Raman spectroscopic (SERS) detection of synthetic chemical pesticides

3D-MoS2 can adsorb organic molecules and provide multidimensional electron transport pathways, implying a potential application for environment remediation. Here, we study the degradation of aromatic organics in advanced oxidation processes (AOPs) by a 3D-MoS2 sponge loaded with MoS2 nanospheres and graphene oxide (GO). Exposed Mo4+ active sites on 3D-MoS2 can significantly improve the concentration and stability of Fe2+ in AOPs and keep the Fe3+ /Fe2+ in a stable dynamic cycle, thus effectively promoting the activation of H2 O2 /peroxymonosulfate (PMS). The degradation rate of organic pollutants in the 3D-MoS2 system is about 50 times higher than without cocatalyst. After a 140 L pilot-scale experiment, it still maintains high efficiency and stable AOPs activity. After 16 days of continuous reaction, the 3D-MoS2 achieves a degradation rate of 120 mg L-1 antibiotic wastewater up to 97.87 %. The operating cost of treating a ton of wastewater is only US$ 0.33, suggesting huge industrial applications.

Designing 3D-MoS 2 Sponge as Excellent Cocatalysts in Advanced Oxidation Processes for Pollutant Control.

Semiconductor-based surface-enhanced Raman spectroscopy (SERS) substrates represent a new frontier in the field of SERS. However, the application of semiconductor materials as SERS substrates is still seriously impeded by their low SERS enhancement and inferior detection sensitivity, especially for non-metal-oxide semiconductor materials. Herein, we demonstrate a general oxygen incorporation-assisted strategy to magnify the semiconductor substrate–analyte molecule interaction, leading to significant increase in SERS enhancement for non-metal-oxide semiconductor materials. Oxygen incorporation in MoS2 even with trace concentrations can not only increase enhancement factors by up to 100,000-fold compared with oxygen-unincorporated samples but also endow MoS2 with low limit of detection below 10−7 M. Intriguingly, combined with the findings in previous studies, our present results indicate that both oxygen incorporation and extraction processes can result in SERS enhancement, probably due to the enhanced charge-transfer resonance as well as exciton resonance arising from the judicious control of oxygen admission in semiconductor substrate. The application of non-metal-oxide semiconductor materials as surface-enhanced Raman spectroscopy (SERS) substrates is impeded by their low SERS enhancement and detection sensitivity. Here, the authors develop a general oxygen incorporation strategy to magnify these parameters.

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Semiconductor SERS enhancement enabled by oxygen incorporation

Review of Surface Enhanced Raman Scattering Applications in Forensic Science.

Surface-enhanced Raman scattering (SERS) is commonly associated with noble metal substrates. However, over the years modest Raman enhancements ( 3 × 105 enhancement in SERS signal from an organic molecule (4-mercaptopyridine) placed in the near field of a two-dimensional semiconductor molybdenum disulfide (MoS2) monolayer. This large enhancement in the SERS signal is attributed to the charge transfer (CT) state formed at the interface of the 2D semiconductor and organic molecule and is found to occur when the excitation source is chosen to be in resonance with the CT state. This approach provides a new strategy for carrying out SERS experiments on molecules with very weak Raman sig...

Cyril Muehlethaler

Papers

Review of Surface Enhanced Raman Scattering Applications in Forensic Science.

Ultrahigh Raman Enhancement on Monolayer MoS2

The application of chemometrics on Infrared and Raman spectra as a tool for the forensic analysis of paints.

Towards a validation of surface-enhanced Raman scattering (SERS) for use in forensic science: repeatability and reproducibility experiments

Discrimination and classification of FTIR spectra of red, blue and green spray paints using a multivariate statistical approach.