A reproducible synthetic strategy was developed for facile large-scale (200 mg) synthesis of surface silanized magnetite (Fe₃O₄) nanoparticles (NPs) for biological applications. After further coupling a phosphate-specific affinity ligand, these functionalized magnetic NPs were used for the highly specific enrichment of phosphoproteins from a complex biological mixture. Moreover, correlating the surface silane density of the silanized magnetite NPs to their resultant enrichment performance established a simple and reliable quality assurance control to ensure reproducible synthesis of these NPs routinely in large scale and optimal phosphoprotein enrichment performance from batch-to-batch. Furthermore, by successful exploitation of a top-down phosphoproteomics strategy that integrates this high throughput nanoproteomics platform with online liquid chromatography (LC) and tandem mass spectrometry (MS/MS), we were able to specifically enrich, identify, and characterize endogenous phosphoproteins from highly complex human cardiac tissue homogenate. This nanoproteomics platform possesses a unique combination of scalability, specificity, reproducibility, and efficiency for the capture and enrichment of low abundance proteins in general, thereby enabling downstream proteomics applications.

Organic–inorganic hybrid perovskites attract considerable attention owing to their applications in high-efficiency solar cells and light emission. Compared with three-dimensional perovskites, two-dimensional (2D) layered hybrid perovskites have a higher exciton binding energy and potentially higher light-emission efficiency. The growth of high-quality crystalline 2D perovskites with a well-defined nanoscale morphology is desirable because they can be suitable building blocks for integrated optoelectronics and (nano)photonics. Herein, we report the facile solution growth of single-crystal microplates of 2D perovskites based on a 2-phenylethylammonium (C₆H₅CH₂CH₂NH₃⁺, PEA) cation, (PEA)₂PbX₄ (X = Br, I), with a well-defined rectangular geometry and nanoscale thickness through a dissolution–recrystallization process. The crystal structures of (PEA)₂PbX₄ are first confirmed using single-crystal X-ray diffraction. A solution-phase transport-growth process is developed to grow microplates with a typical size of tens of micrometers and thickness of hundreds of nanometers on another clean substrate different from the substrate coated with lead-acetate precursor film. Surface-topography analysis suggests that the formation of the 2D microplates is likely driven by the wedding-cake growth mechanism. Through halide alloying, the photoluminescence emission of (PEA)₂Pb(Br, I)₄ perovskites with a narrow peak bandwidth is readily tuned from violet (~410 nm) to green (~530 nm).