Many methods have been reported for the formation of sulfide nanoparticles by the reaction of metallic salts with sulfide chemical sources in aqueous solutions or organic solvents. Here, we report the formation of sulfide nanoparticles in dimethylsulfoxide (DMSO) by boiling metallic salts without sulfide sources. The sulfide sources are generated from the boiling of DMSOand react with metallic salts to form sulfide nanoparticles. In this method DMSOfunctions as a solvent and a sulfide source as well as a stabilizer for the formation of the nanoparticles. The recipe is simple and economical making sulfide nanoparticles formed in this way readily available for many potential applications.

Rare earth compound nanowires have currently attracted booming interests and become hotspot in diverse fields such as bioimaging and semiconductor devices. In this review, we primarily focus on recent progress in materials synthesis of rare earth compound nanowires. Many methods including template synthesis, hydrothermal method, high temperature organic solvents synthesis, electrospinning and chemical vapor deposition have been used to synthesize rare earth compound nanowires. Then, we further briefly review the phyciochemical properties and applications of rare earth compound nanowires in the past decades. The studies revealed that doping and shell encapsulation are efficient means to optimize the optical properties including emission wavelength and quantumn efficiency. These rare earth compound nanowires exhibit great potential in multimodal biological theranostics and future optoelectronic devices due to their abundant 4f electronic configurations resutled novel physicochemical properties.

For decades, the sandwich assay has been a mainstay in the fields of biodetection, clinical diagnostics, environmental monitoring, and quality control in various industries. By eliminating the requirement of labeling the molecular target, the sandwich assays usually require the simultaneous binding of the recognition probe and signaling probe, which makes them extremely specific. Likewise, because signaling is typically coupled to an enzyme catalytic or amplified signaling mechanism, the sandwich assay usually achieves impressive sensitivity of detection. Along with progress in chemistry, biotechnology, and nanotechnology, the sandwich assay has been extensively developed. For example, the sandwich assay has been employed successfully for the detection of a spectrum of targets, including pathogens, proteins, nucleic acids, small molecules, and ions. The signaling mechanism has also been extensively expanded from radiolabeling to more readily detectable readouts such as enzyme catalysis, fluorescence, or electricity. Furthermore, the basic sandwich architecture has been adapted into a supersandwich platform, which usually further amplifies the signal and pushes the detection limit down. To date, thousands of papers have been published on the sandwich assay. However, to our best knowledge, no such review paper summarizing the developments and future goals of this field yet exists. Thus, we present a critical review of the literature on the sandwich assay in the past 10 years to summarize and comment upon its development and advances, concentrating mainly on recent developments in nanobiotechnology.