Aptamer-Functionalized Magnetic Ti3C2 Based Nanoplatform for Simultaneous Enrichment and Detection of Exosomes.

Exosomes are nanovesicles secreted by cells, which play a crucial role in various pathological processes. Exosomes have shown great promise as tumor biomarkers because of the abundant secretion during tumor formation. The development of a convenient, efficient, and cost-effective method for simultaneously enriching and detecting exosomes is of utmost importance for both basic research and clinical applications. In this study, an aptamer-functionalized magnetic Ti3C2 composite material (Fe3O4@Ti3C2@PEI@DSP@aptamer@FAM-ssDNA) is prepared for the simultaneous enrichment and detection of exosomes. CD63 aptamers are utilized to recognize and capture the exosomes, followed by magnetic separation. The exosomes are then released by cleaving the disulfide bonds of DSP. Compared to traditional methods, Fe3O4@Ti3C2@PEI@DSP@aptamer@FAM-ssDNA exhibited superior efficiency in enriching exosomes while preserving their structural and functional integrity. Detection of exosome concentration is achieved through the fluorescence quenching of Ti3C2 and the competitive binding between the exosomes and a fluorescently labeled probe. This method exhibited a low detection limit of 4.21 × 104 particles mL-1, a number that is comparable to the state-of-the-art method in the detection of exosomes. The present study demonstrates a method of simultaneous enrichment and detection of exosomes with a high sensitivity, accuracy, specificity, and cost-effectiveness providing significant potential for clinical research and diagnosis.

Biohybrid Molecule-Based Photocatalysts for Water Splitting Hydrogen Evolution.

The problems of resource depletion and environmental pollution caused by the excessive use of fossil fuels greatly restrict the rapid development of human technology and industry, which has led to a high demand for the development of new and clean energy sources. Hydrogen, due to its high calorific value and environmentally friendly combustion products, is undoubtedly a very promising energy carrier. The current methods of industrial hydrogen production are mainly water electrocatalytic decomposition or fossil fuels conversion, which also results in the waste of other energy sources. Since only one-step is involved during the conversion from solar to chemical energy and thus unnecessary energy waste is avoided, solar energy photocatalytic decomposition of water provides a more viable method for hydrogen production. The utilization of biohybrid molecules, which are widely available in nature and environmentally friendly, further reduce the cost of such photocatalytic systems. This Review discusses the research progress on hydrogen production using biohybrid molecules for photocatalytic hydrogen evolution. The basic reaction mechanism, general types and system structures about biohybrid molecule-based photocatalysts are summarized. The current challenges and prospects in the research of water splitting hydrogen evolution by biohybrid molecules photocatalysts are presented.

Biohybrid Organic Heterostructure Based on Chlorophyll-Bacteriochlorophyll Aggregates for Ecofriendly Hydrogen Production.

Hydrogen energy is an abundant, clean, sustainable and environmentally friendly renewable energy source. Therefore, the production of hydrogen by photocatalytically splitting water on semiconductors has been considered in recent years as a promising and sustainable strategy for converting solar energy into chemical energy to replace conventional energy sources and to solve the growing problem of environmental pollution and the global energy crisis. However, highly efficient solar-driven photocatalytic hydrogen production remains a huge challenge due to the poor visible light response of available photocatalytic materials and the low efficiency of separation and transfer of photogenerated electron-hole pairs. In the present work, organic heterojunction structures based on bacteriochlorophyll (BChl) and chlorophyll (Chl) molecules were introduced and used for solar-driven photocatalytic hydrogen production from water under visible light. Also, noble metal-free photocatalyst was successfully constructed on Ti3 C2 Tx nanosheets by simple successive deposition of Chl and BChl, which was used for the photocatalytic splitting water to hydrogen evolution reaction (HER). The results show that the optimal BChl@Chl@Ti3 C2 Tx composite has a high HER performance with 114 µmol/h/gcat , which is much higher than the BChl@Ti3 C2 Tx and Chl@Ti3 C2 Tx composites.

Chlorophyll-Based Organic Heterojunction on Ti3 C2 Tx MXene Nanosheets for Efficient Hydrogen Production.

The Z-scheme process is a photoinduced electron-transfer pathway in natural oxygenic photosynthesis involving electron transport from photosystem II (PSII) to photosystem I (PSI). Inspired by the interesting Z-scheme process, herein a photocatalytic hydrogen evolution reaction (HER) employing chlorophyll (Chl) derivatives, Chl-1 and Chl-2, on the surface of Ti3 C2 Tx MXene with two-dimensional accordion-like morphology, forming Chl-1@Chl-2@Ti3 C2 Tx composite, is demonstrated. Due to the frontier molecular orbital energy alignments of Chl-1 and Chl-2, sublayer Chl-1 is a simulation of PSI, whereas upper layer Chl-2 is equivalent to PSII, and the resultant electron transport can take place from Chl-2 to Chl-1. Under the illumination of visible light (>420 nm), the HER performance of Chl-1@Chl-2@Ti3 C2 Tx photocatalyst was found to be as high as 143 µmol h-1 gcat -1 , which was substantially higher than that of photocatalysts of either Chl-1@Ti3 C2 Tx (20 µmol h-1 g-1 ) or Chl-2@Ti3 C2 Tx (15 µmol h-1 g-1 ).

Extracellular signal-regulated kinase 5 in the cerebrospinal fluid-contacting nucleus contributes to morphine physical dependence in rats.

The cerebrospinal fluid-contacting nucleus (CSF-CN) may influence actual composition of the CSF for non-synaptic signal transmission via releasing or absorbing bioactive substances, which distributes and localizes in the ventral periaqueductal central gray of the brainstem. Previous studies demonstrated that CSF-CN was involved in neuropathic pain and morphine dependence. Thus, to identify whether extracellular signal-regulated kinase 5 (ERK5) distributed in the CSF-CN and its function on the formation and development of morphine physical dependence, morphine withdrawal-like behavioral test and immunofluorescent technique were used in this research. Morphine was subcutaneously injected by an intermittent and escalating procedure to induce physical dependence, which was measured by withdrawal symptoms. In this study, we found that horseradish peroxidase-conjugated toxin subunit B/p-ERK5 double-labeled neurons expressed in the CSF-CN of normal rats. ERK5 signaling pathway was remarkably activated by naloxone-precipitated withdrawal in the CSF-CN. Moreover, selective attenuation of p-ERK5 expression in the CSF-CN by lateral ventricle injection of BIX02188 could significantly relieve morphine withdrawal symptom. These findings confirmed that the activation of p-ERK5 in the CSF-CN might contribute to morphine physical dependence.