A Target-Triggered Emission Enhancement Strategy Based on a Y-Shaped DNA Fluorescent Nanoprobe with Aggregation-Induced Emission Characteristic for microRNA Imaging in Living Cells.

DNA self-assembled fluorescent nanoprobes have been developed for bio-imaging owing to their high resistance to enzyme degradation and great cellular uptake capacity. In this work, we designed a new Y-shaped DNA fluorescent nanoprobe (YFNP) with aggregation-induced emission (AIE) characteristic for microRNA imaging in living cells. With the modification of the AIE dye, the constructed YFNP had a relatively low background fluorescence. However, the YFNP could emit a strong fluorescence due to the generation of microRNA-triggered AIE effect in the presence of target microRNA. Based on the proposed target-triggered emission enhancement strategy, microRNA-21 was detected sensitively and specifically with a detection limit of 122.8 pM. The designed YFNP showed higher bio-stability and cell uptake than the single-stranded DNA fluorescent probe, which has been successfully applied for microRNA imaging in living cells. More importantly, the microRNA-triggered dendrimer structure could be formed after the recognition of target microRNA, achieving a reliable microRNA imaging with a high spatiotemporal resolution. We expect that the proposed YFNP will become a promising candidate for bio-sensing and bio-imaging.

A Benzil- and BODIPY-Based Turn-On Fluorescent Probe for Detection of Hydrogen Peroxide.

Faced with rising threats of terrorism, environmental and health risks, achieving sensitive and selective detection of peroxide-based explosives (PEs) has become a global focus. In this study, a turn-on fluorescent probe (BOD) based on benzil (H2O2-recognition element) and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivative (fluorophore) was developed to sensitively and specifically detect hydrogen peroxide (H2O2). The synthesized BOD had a very weak fluorescence due to intramolecular donor-excited photo-induced electron transfer (d-PET) effect; however, it could emit a strong fluorescence since H2O2 selectively oxidized the benzil moiety and released free BODIPY fluorophore (BOD-COOH). As a result, the proposed BOD detected H2O2 in linear detection ranged from 25 to 125 µM with a detection limit of 4.41 µM. Meanwhile, the proposed BOD showed good selectivity toward H2O2, which is not affected by other common reactive oxygen species (ROS) and ions from explosive residues. In addition, a blue shift from 508 to 498 nm was observed in the absorption spectra upon addition of H2O2. More importantly, the BOD was successfully applied for rapid detection of H2O2 vapor with good sensitivity (down to 7 ppb), which holds great potential for practical use in public safety, forensic analysis and environmental monitoring.

Association of the GLI gene with ventricular septal defect after the susceptibility gene being narrowed to 3.56 cM in 12q13.

BACKGROUND: Our previous research has suggested that genes around D12S1056 in 12q13 may confer susceptibility to ventricular septal defect (VSD) in humans. The present study was to define the chromosome region assignment by transmission disequilibrium test (TDT), and to identify the important candidate gene by family-based association study and haplotype analysis. METHODS: Surrounding D12S1056, ten microsatellite markers including D12S329, D12S305, D12S1662, D12S1056, D12S1293, D12S334, D12S102, D12S83, D12S1655 and D12S1691 were chosen, and TDT was performed in 62 nuclear family trios each consisting of an affected child and two healty parents. Subsequently, the GLI gene, a positional candidate gene that maps to the target region, was selected for further analysis. Three single nucleotide polymorphisms (SNPs), G11888C, G11388A, and G11625T, were selected for family-based association study and haplotype analysis. RESULTS: VSD was significantly associated with all selected markers except D12S1691 [72.2 centi morgen (cM)] and D12S1700 (75.76 cM). VSD was also significantly associated with G11888C (chi(2) = 5.918, P = 0.015), G11388A (chi(2) = 8.067, P = 0.005), and G11625T (chi(2) = 11.842, P = 0.001). Haplotype analysis showed a strong linkage disequilibrium between G11888C and G11388A (D' = 0.999), but in significant (chi(2) = 1.035, df = 2, P > 0.05). CONCLUSIONS: The susceptibility gene of VSD was mapped to 3.56 cM in 12q13 by TDT, and the GLI gene, an important candidate in the target region, was associated with VSD.

Isolation of differentially expressed genes in human heart tissues.

We applied RNA arbitrarily primed-PCR (RAP-PCR) to screen the genes differentially expressed between common congenital heart defects (CHD) [atrial septal defect, ventricular septal defect, Tetrology of Fallot (TOF)] and normal human heart samples. Three of these differentially amplified fragments matched cDNA sequences coding for proteins of unknown function in humans: hCALO (human homologue of calossin), NP79 (coding for a nuclear protein of 79KD) and SUN2 (Sad-1 unc-84 domain protein 2). The other four fragments were from known human genes: apolipoprotein J, titin, dystrophin and protein kinase C-delta. Northern blot analysis confirmed that all of these genes are expressed in the human heart. The results of RAP-PCR were reconfirmed by quantitative RT-PCR in TOF and control heart samples. Both techniques showed the levels of expression of hCALO, NP79 and SUN2 to be comparable in TOF and control samples and the level of expression of dystrophin and titin, both coding for cytoskeletal proteins, to be significantly upregulated in TOF samples. In summary, we have shown that the RAP-PCR technique is useful in the identification of differentially expressed gene from biopsy samples of human CHD tissues. In this manner, we have identified three novel genes implicated in the normal function of the human heart and two known genes upregulated in TOF samples.