Quantification of multiple disease-related micro-RNAs (miRNAs) is of great significance for clinical diagnosis. Based on the simultaneous multiple element detection ability of inductively coupled plasma−mass spectrometry (ICP−MS) and good specificity of multicomponent nucleic acid enzymes (MNAzymes), a novel and simple method based on the MNAzyme amplification strategy and lanthanide labeling coupled with ICP− MS detection was proposed for the sensitive and simultaneous detection of three miRNAs . Specifically, a probe consisting of streptavidin-modified magnetic beads (SA-MBs) and three DNA substrates labeled with lanthanide tags ( 159 Tb/ 165 Ho/ 175 Lu) was constructed. In the presence of target miRNAs, three pairs of MNAzymes were assembled where each pair was hybridized with the corresponding miRNA, and then the substrates on the SA-MBs were cleaved by the activated MNAzymes, continuously releasing the fragment with lanthanide tags. The released lanthanide tags in the supernatant were collected after magnetic separation and analyzed by ICP−MS, realizing the simultaneous quantification of multiple miRNAs. The correlation of the lanthanide tag signal with the miRNA concentration fitted well in a linear model in the range of 50−1000 pmol L −1 (miRNA-21) and 50−2000 pmol L −1 (miRNA-155 and miRNA-10b). The limits of detection for three miRNAs were 11−20 pmol L −1 , with the relative standard deviations of 2.2− 2.7%. The recoveries of target miRNAs in the human serum and HepG-2 cells were in the range of 87.2−111% and 93.3−111%, respectively. Overall, the method is ideal for the simultaneous quantification of multiple miRNAs with advantages of low spectral interference, high sensitivity, good selectivity, and strong resistance to the complex matrix.

The adsorption/desorption behavior of mobile solute molecules at a solution-crystal interface has been explored using crystals of model protein hen egg-white lysozyme (HEWL) and fluorescent-labeled HEWL (F-HEWL) molecules. We have tracked the transient processes occurring during adsorption/desorption of identical F-HEWL molecules on a tetragonal HEWL crystal surface by single-molecule visualization using a total internal reflection fluorescent microscope and pulsed discontinuous laser illumination. We found an induction period (∼70 min) after which the number density of F-HEWL molecules adsorbed mainly on steps increased linearly with the adsorption time. We show direct evidence that the residence time of molecules on the crystal surface gradually increases during the transition process from a solute species to the crystal after successive multistep processes.

The unique characteristics of the local surface plasmon resonance (LSPR) effect endows heterostructure nanocomposite of noble metal (NM) nanoparticles and semiconducting materials with dramatically enhanced light absorption, charge separation and surface activity. In addition, they boost the development of research in photocatalytic fields including artificial photosynthesis, degradation of pollutants and deactivation of microorganisms. The advantages of using LSPR to improve the photocatalytic activity of semiconductor-based materials as well as the design and synthesis of NM nanoparticles with LSPR for photocatalytic applications have been widely studied in recent years and a great number of research works have been published in these areas. This review will introduce the concept of heterostructure nanocomposite, the basis of LSPR, controlled synthesis and the recent research progress involving applications of LSRP in artificial photosynthesis, degradation of pollutants and deactivation of microorganisms.

Inductively coupled plasma–mass spectrometry (ICP–MS) with elemental labeling is a promising strategy for multiplex microRNA (miRNA) analysis. However, it is still challenging for specific analysis of multiple miRNAs with high homology, and the development of multiplex assays is always limited by the complexity of the sequence design. Herein, a simple and direct ICP–MS-based assay was developed for the simultaneous detection of three miRNAs by combining the lanthanide labeling strategy with entropy-driven catalytic (EDC) amplification. Owing to the specificity of EDC for nucleic acid recognition, it is able to differentiate miRNAs with single-base mutation in each EDC circuit. A universal biotin-labeled DNA strand was designed to hybridize with the DNA substrates for three EDC circuits, targeting miRNA-21, miRNA-155, and miRNA-10b, respectively. All the substrates were loaded on the surface of streptavidin magnetic beads. In the presence of target miRNA, the EDC reaction was initiated, and EDC substrates were dissociated, continuously releasing reporter strands that were labeled with lanthanides (Tb/Ho/Lu). After magnetic separation, the supernatant containing the released reporter strands was introduced into an ICP–MS system for simultaneous detection of 159Tb/165Ho/175Lu and quantification of miRNA-21, miRNA-155, and miRNA-10b, respectively. The limits of detection were 7.4, 7.5, and 11 pmol L–1 for miRNA-21, miRNA-155, and miRNA-10b, respectively. Overall, this study provides a powerful strategy for simultaneous quantification of multiple miRNAs, with the advantages of flexible probe design, good sensitivity, and excellent specificity.