Structure-regulated enhanced Raman scattering on a semiconductor to study temperature-influenced enantioselective identification.

Surface-enhanced Raman scattering (SERS) spectroscopy is an effective technique that can reveal molecular structure and molecular interaction details. Semiconductor-based SERS platforms exhibit multifaceted tunability and unique selectivity to target molecules as well as high spectral reproducibility. However, the detection sensitivity of semiconductors is impeded by inferior SERS enhancement. Herein, a surface and interference co-enhanced Raman scattering (SICERS) platform based on corrugated TiO2 nanotube arrays (c-TiO2 NTs) was developed, and the coupling of structural regulation and photo-induced charge transfer (PICT) effectively optimized the SERS performance of the semiconductor substrate. Due to the regularly oscillating optical properties of the c-TiO2 NTs, well-defined interference patterns were generated and the local electric field was significantly increased, which greatly promoted both the electromagnetic mechanism and PICT processes. The c-TiO2 NTs were subsequently applied as a highly sensitive SICERS substrate to investigate the mechanism of temperature influence on enantioselective identification. This identification process is related to the existence of temperature-sensitive hydrogen bonds and π-π interaction. This work demonstrates a simply prepared, low-cost, and sensitive SERS substrate that enables better investigation into molecular identification.

Designing ultrafine PdCo alloys in mesoporous silica nanospheres with peroxidase-like activity and catalase-like activity.

Nanomaterial-based artificial enzyme mimetics have attracted increasing attention because of their robust stability, adjustable activity, and cost-effectiveness. In this study, we developed a simple and effective method for the synthesis of highly dispersed ultrafine PdCo alloys with peroxidase- and catalase-like activities. The aberration-corrected transmission electron microscopy analysis verified that the cyanogel precursor in the mesoporous silica nanospheres (MSNs) was converted to PdCo alloy in NH3 at a high temperature. The PdCo alloy was homogenously distributed in MSNs as ultrafine and monodispersed particles. By selectively removing the Co species from the binary alloy through an acid-leaching approach, the role of each component in the enzyme-like mimetics was systematically studied. Using glutathione (GSH) as the model analyte, the potential application of PdCo@MSNs in GSH detection from complex cell media was confirmed via colorimetric assay. The ultrafine alloy size, double mimetic activities, and abundant loading space of PdCo@MSNs make them promising not only in clinical diagnosis but also in overcoming hypoxia-induced photodynamic therapy resistance in tumor treatment.

Pt nanoparticle-coupled WO2.72 nanoplates as multi-enzyme mimetics for colorimetric detection and radical elimination.

Nanomaterials that exhibit enzyme-like activity (nanozymes) have attracted significant attention due to their potential for applications in analytical tests and in the biological field. In this study, an enzyme-like nanomaterial is developed by coupling Pt nanoparticles with WO2.72 (Pt/WO2.72). The resultant nanocomposite nanomaterial exhibits peroxidase activity and catalase activity. Moreover, owing to the presence of W6+ and W5+ in WO2.72, Pt/WO2.72 nanoplates demonstrate promise as scavengers of hydroxyl radicals. The Pt/WO2.72 composite nanoplates exhibit excellent peroxidase-like activity for the sensitive colorimetric detection of H2O2 and blood glucose. These Pt/WO2.72 nanoplates are thought to be a promising tool for broad potential applications in biomedicine, biotechnology, and environmental chemistry. Pt nanoparticles anchored WO2.72 nanoplates (Pt/WO2.72) as a multienzyme-like mimetics exhibits peroxidase activity and catalase activity. Furthermore, this composite can be acted scavengers of hydroxyl radicals.