Two AIE-Ligand-Based 2-D Luminescent Metal-Organic Frameworks as Fe3+ Sensors.

The design and synthesis of high-performance sensors are very important but remain great challenges. In this work, a new aggregation-induced-emission (AIE) molecule 4,4'-(((9H-fluoren-9-ylidene)methylene)bis(4,1-phenylene))dipyridine (L) was successfully synthesized and first developed as a functional ligand to construct two isomorphic metal-organic frameworks (MOFs) [M(L)(OBBA)]n [M2+ = Cd2+ (1), Co2+ (2); H2OBBA = 4,4'-oxybisbenzoic acid]. They adopt [M2(COO)4] flywheel clusters, OBBA2- bridges, and terminal L ligands as building units to form isomorphic 2-D networks with Lewis base active cites (uncoordinated pyridyl N). Both 1 and 2 exhibit excellent water, pH, and thermal stabilities and extremely efficient Fe3+ sensing abilities in the water environment. The quenching constants and detection limits reach the best levels reported so far. The sensing mechanism of 1 and 2 toward Fe3+ is studied in depth, and the difference in their sensing performance is also explained.

Perspective on fluorescence cell imaging with ionophore-based ion-selective nano-optodes.

Inorganic ions are ubiquitous in all kinds of cells with highly dynamic spatial and temporal distribution. Taking advantage of different types of fluorescent probes, fluorescence microscopic imaging and quantitative analysis of ion concentrations in cells have rapidly advanced. A family of fluorescent nanoprobes based on ionophores has emerged in recent years with the potential to establish a unique platform for the analysis of common biological ions including Na+, K+, Ca2+, Cl-, and so on. This article aims at providing a retrospect and outlook of ionophore-based ion-selective nanoprobes and the applications in cell imaging.

Phase transfer of fatty acids into ultrasmall nanospheres for colorimetric detection of lipase and albumin.

Colorimetric detection of fatty acids during biological interactions is extremely difficult since they are optically silent. Here, fatty acids are found to function as ion-exchangers in ultrasmall polymeric nanospheres to facilitate the protonation of chromoionophores, causing a vivid color change between red and blue. With an excellent detection limit of 1.8 µg mL-1 for oleic acid, colorimetric assays for lipase and albumin are developed with quick response, high sensitivity, and low cost.

Ruthenium bipyridine complexes as electrochemiluminescent transducers for ionophore-based ion-selective detection.

We report here a method to determine target ion concentrations (with Na+ as a model) based on ionophores and electrochemiluminescence (ECL). Ruthenium bipyridine complexes were released from thin polymeric films (plasticized poly(vinyl chloride) also containing a sodium ionophore) into the sample solution following an explicit ion-exchange process (between Na+ and the ruthenium complex). Two signal transducers, tris(2,2'-(pCF3)bipyridine)ruthenium(II) (Ru(p-CF3-bpy)32+) and tris(2,2'-bipyridyl)dichlororuthenium(II) (Ru(bpy)32+), were examined using the sensing film, with the latter providing a more sensitive detection range (ca. 1 to 100 µM) than that of the more hydrophobic one (0.01 to 1 mM). While the ionophore (Na+ ionophore X) offered excellent selectivity to the method, the ruthenium complexes made the measurements independent of the sample pH. Furthermore for complex biological samples such as blood serum, an indirect approach of measuring the ECL of the remaining ruthenium complexes helps avoid background matrix interference to the ECL production at the working electrode, making the ECL method more attractive for real complex samples.

Rapid Equilibrated Colorimetric Detection of Protamine and Heparin: Recognition at the Nanoscale Liquid-Liquid Interface.

Demand for rapid quantitation of polyions such as heparin and protamine are ever growing. Previous paper-based and polymeric optical and electrochemical sensing devices required more than several hours for signal stabilization. Therefore, signals were acquired with fixed sample exposure time modes, which was time-consuming and technically demanding. We present here for the first time the optical detection of protamine and heparin in equilibrium mode with emulsified nanospheres. The method significantly shortens the response time from hours to typically less than 10 s and offers tunable, sensitive, and colorimetric detection within the clinically relevant range (10 to 100 mg/L) for heparin. The improved characteristics are attributable to the small size of the nanospheres (ca. 50 nm in diameter) as well as the reversible recognition at the nanoscale liquid-liquid interface. Detection of the anticoagulant heparin was also successfully demonstrated in human blood serum background.

Downregulation of microRNA-145 promotes epithelial-mesenchymal transition via regulating Snail in osteosarcoma.

Metastasis is the principal cause of cancer death and occurs through multiple, complex processes. Epithelial to mesenchymal transition (EMT) is an important process during embryonic development and has also been hypothesized to exhibit a significant role in cancer cell invasion and metastasis. MicroRNAs (miRNAs) are a class of widespread noncoding RNAs. In recent years, many studies have shown that miRNAs could influence the signaling pathways and downstream events that define EMT on a molecular level. However, the exact role and mechanisms of miR-145 in EMT of osteosarcoma (OS) was unknown. In the present study, miR-145 was downregulated in OS tissues and cell lines and it was shown that miR-145 expression was closely correlated with advanced tumor progression in patients of OS. In addition, miR-145 upregulation by miR-145 agomir significantly inhibited MG63 cells invasion and migration ability. MiR-145 was reported to be able to inhibit EMT in cancers. Following the examination of changes in cell epithelial and mesenchymal markers, it was found that upregulation of miR-145 strongly reversed EMT in MG63 cells. Meanwhile, the expression of Snail, a strong E-cadherin transcription repressor was also attenuated by miR-145 agomir. Furthermore, the decreased EMT and invasion and metastasis caused by miR-145 agomir could be restored by Snail siRNA. In conclusion, the results demonstrated that miR-145 could mediate EMT by targeting Snail and miR-145 might be a novel EMT regulating transcription factor that involved in the progression of OS. The specific drugs targeting miR-145-mediated EMT process might be new promising cancer therapies.

[Early microsurgical treatment of upper obstetrical brachial plexus injury].

OBJECTIVE: To search for the operation timing and methods for obstetrical brachial plexus injury (OBPI). METHODS: Thirty-two children with upper OBPI were treated by microsurgical procedure from October 1997 to April 2001. The average age of patients was 10 months, ranged from 3 months to 24 months; of them, 19 were below 6 months while 13 were over 6 months. Surgical procedure included neurolysis(n = 12), coaptation after resection of the neuroma without function (n = 7), phrenic nerve transfer to anterior cord of upper trunk or musculocutaneous nerve (n = 7) and intercostal nerves transfer to musculocutaneous nerve(n = 6). The children underwent operation with microsurgical technique and 7/0 or 9/0 nylon was used for nerve suture. RESULTS: Thirty cases were followed up for 21 months postoperatively; the excellent and good rate was 76.7% (23/30). The results of the children under 6 months were better than those over 6 months. CONCLUSION: The microsurgical operation might be considered at the age of 3-6 month infants who had shown little or no improvement in elbow flexion. Neurolysis and nerve coaptation are superior to neurotization. The appropriate procedure should be selected according to the findings of exploration.