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In recent years, nanomaterials have attracted the research intervention of experts in the fields of catalysis, energy, biomedical testing, and biomedicine with their unrivaled optical, chemical, and biological properties. From basic metal and oxide nanoparticles to complex quantum dots and MOFs, the stable preparation of various nanomaterials has always been a struggle for researchers. Microfluidics, as a paradigm of microscale control, is a remarkable platform for online stable synthesis of nanomaterials with efficient mass and heat transfer in microreactors, flexible blending of reactants, and precise control of reaction conditions. We describe the process of microfluidic preparation of nanoparticles in the last 5 years in terms of microfluidic techniques and the methods of microfluidic manipulation of fluids. Then, the ability of microfluidics to prepare different nanomaterials, such as metals, oxides, quantum dots, and biopolymer nanoparticles, is presented. The effective synthesis of some nanomaterials with complex structures and the cases of nanomaterials prepared by microfluidics under extreme conditions (high temperature and pressure), the compatibility of microfluidics as a superior platform for the preparation of nanoparticles is demonstrated. Microfluidics has a potent integration capability to combine nanoparticle synthesis with real-time monitoring and online detection, which significantly improves the quality and production efficiency of nanoparticles, and also provides a high-quality ultra-clean platform for some bioassays. [ABSTRACT FROM AUTHOR]

Nanoscale calcium carbonate and nanoscale titanium dioxide are two kinds of very important, manufactured nanomaterials which have had applications in industry for many years. The production and application of these two kinds of nanomaterials are expected to be expanded in the future. Accordingly, there is a need for better defining their characteristics contributing to performance. ISO/TC229 WG4 is the fourth working group of ISO/TC229, which is in charge for establishing the nanomaterial specifications, and the nanoscale calcium carbonate and the naonoscale titanium dioxide are the first two selected nanomaterials in this working group; the two technical specifications, ISO/WD 11931-1 and ISO/WD 11937-1, are under development. [ABSTRACT FROM PUBLISHER]

[Display omitted] • New Mo1-xWxS2 two-dimensional nanosheets were prepared by the one-pot method. • Compared with MoS2, the Raman intensity of Rhodamine 6G (10−6 M) was amplified by 1.7 times with Mo1-xWxS2 nanosheets as the substrate. • With abundant edge active sites that facilitate charge transfer, Mo1-xWxS2 nanosheets could better enhance SERS signals. A new Mo 1- x W x S 2 two-dimensional nanosheets were prepared by the one-pot method. After certain Mo atoms in MoS 2 were replaced by W ones in a hydrothermal reduction procedure, Mo 1- x W x S 2 was formed on the Mo foil. Well enhanced Mo 1- x W x S 2 nanosheets were prepared when the sodium tungstate concentration got under control. Various characterizations were carried out, which indicate that Mo 1- x W x S 2 nanosheets with good crystallinity. Compared with MoS 2 , the Raman intensity of Rhodamine 6G (10−6 M) was amplified by 1.7 times with Mo 1- x W x S 2 nanosheets as the substrate. The characteristic Raman peaks could still be clearly distinguished until the concentration of Rhodamine 6G (R6G), Methylene blue (MB) and Crystal violet (CV) down to 10−8, 10−8 and 10−7 M, respectively. With abundant edge active sites that facilitate charge transfer, Mo 1- x W x S 2 nanosheets could better enhance SERS signals of target detection molecules and get a good linear relationship exists within the concentration and Raman peak strength. In addition, R6G SERS detection also shows excellent reproducibility and long-term stability of this TMDs SERS substrate. [ABSTRACT FROM AUTHOR]

• AgNPs/MIL-101(Fe) nanocomposites is used as a Raman enhanced substrate to detect R6G. The results show that the substrate has better stability and uniformity. Its R6G Raman assignment peak position RSD = 7.55%, enhancement factor EF = 2.09 × 109. • AgNPs/MIL-101(Fe) nanocomposites as a Raman enhanced substrate can detect the lowest concentration of paraquat at 10−12 mol/L, and the Raman signal is relatively stable in different acid-base environments. Recently, in the research of Surface-enhanced Raman scattering (SERS) technology, it is found that the preparation of enhanced substrate is particularly important. In this work, the most commonly used methods were used to synthesize AgNPs and MIL-101(Fe), and AgNPs/MIL-101(Fe) nanocomposite was obtained through self-assembly of the two substances. Four different probe molecules were detected with the self-assembled substrate and compared with the results of same probe molecules with AgNPs and MIL-101(Fe) as SERS substrate separately, it was found that AgNPs/ MIL-101 (Fe) nanocomposites had a strong enhancing effect as SERS substrate. The Enhancement Factor (EF) value of 10−6 mol/L Rhodamine 6G (R6G) was calculated as 2.09 × 109, and the Raman intensities of the peak relative standard deviation (RSD) of R6G Raman attribution was calculated as 7.55%. The time stability of the material was studied and it was found that the reduced Raman signal and poor reproducibility were due to the AgNPs placement time. AgNPs/ MIL-101 (Fe) nanocomposites were used as SERS substrate to detect Paraquat with a minimum concentration of 10−12 mol/L. The signal values of Paraquat Raman detected at 10−6 mol/L in different pH environments were relatively stable. [ABSTRACT FROM AUTHOR]