Coordination effect enhanced visualization of latent fingerprint with Eu (TTA)3phen-SiO2 microspheres.

Latent fingerprint (LFP) powders are crucial in the detection of LFPs in forensic science. However, it is often plagued by poor image resolution and low contrast. Herein, enhanced LFP fluorescence (FL) visualizations are achieved by doping Eu(III) coordination compound Eu(TTA)3phen directly into SiO2 microspheres instead of Eu(III) ions. Using the synthesized Eu(TTA)3phen-SiO2 microspheres, the fine characteristic structure of LFP can be seen and recognized under 365 nm irradiation, up to Level 3. However, the Eu3+-SiO2 microspheres were difficult to recognize the Level 2,3 fingerprint structure. The difference between the ridge and furrow gray values of Eu(TTA)3phen-SiO2 microspheres is 2.1 times that of Eu3+-SiO2 microspheres. The coordination effect increased the asymmetry around Eu(III) ions, resulting in the ultrasensitive 5D0→7F2 transition, thus increasing the FL intensity, and the uniform doping of the Eu(III) coordination compound into SiO2 also reduced the surface FL quenching due to shielding from oxygen. Under this dual effect, the LFP performance of Eu(TTA)3phen-SiO2 microspheres has been significantly improved. We believe that this novel and easy LFP visualization method is a promising routine in specific target detection including criminal investigation, customhouse check-in, and drug control.

Ligand Non-innocence and Single Molecular Spintronic Properties of AgII Dibenzocorrole Radical on Ag(111).

A facile method for the quantitative preparation of silver dibenzo-fused corrole Ag-1 is described. In contrast to the saddle conformation resolved by single-crystal X-ray analysis for Ag-1, it adopts an unprecedented domed geometry, with up and down orientations, when adsorbed on an Ag(111) surface. Sharp Kondo resonances near Fermi level, both at the corrole ligand and the silver center were observed by cryogenic STM, with relatively high Kondo temperature (172 K), providing evidence for a non-innocent AgII -corrole.2- species. Further investigation validates that benzene ring fusion and molecule-substrate interactions play pivotal roles in enhancing Ag(4d(x2 -y2 ))-corrole (π) orbital interactions, thereby stabilizing the open-shell singlet AgII -corrole.2- on Ag(111) surface. Moreover, this strategy used for constructing metal-free benzene-ring fused corrole ligand gives rise to inspiration of designing novel metal-corrole compound for multichannel molecular spintronics devices.

Recent Advances in Aggregation-Induced Electrochemiluminescence.

The emergence of the rising alliance between aggregation-induced emission (AIE) and electrochemiluminescence (ECL) is defined as aggregation-induced electrochemiluminescence (AIECL). The booming science of AIE has proved to be not only distinguished in luminescent materials but could also inject new possibility into ECL analysis. Especially in the aqueous phase and solid state for hydrophobic materials, AIE helps ECL circumvent the dilemma between substantial emission intensity and biocompatible media. The wide range of analytes makes ECL an overwhelmingly interesting analytical technique. Therefore, AIECL has gained potential in clinical diagnostics, environmental assays, and biomarker detections. This review will focus on introduction of the novel concept of AIECL, current applied luminophores, and related applications developed in recent years.

Spatiotemporal imaging of electrocatalytic activity on single 2D gold nanoplates via electrogenerated chemiluminescence microscopy.

Uncovering the relationship between the structure, surface properties and electrochemical activity of nanoparticles is of great importance for constructing novel nanocatalysts and highly efficient electrocatalytic devices. Here we report a study of the heterogeneously distributed electrocatalytic activity on individual 2D gold nanoplates. On the basis of electrogenerated chemiluminescence (ECL) microscopy, the size, shape, and site-specific catalytic activity of 2D nanocrystals could be directly imaged at the single particle level with submicron resolution. Since the microelectrode effect with higher fluxes at the perimeter was offset by diffusion of excited species of Ru(bpy)3 2+, calculated by finite element simulation, the ECL distribution was supposed to be uniform on the micro-sized plates. Therefore, it is highly possible that the observed nonuniform ECL distribution at single nanoplates reflected distinct surface electrocatalytic activities at different sites. Furthermore, ECL microscopy allows continuous in situ imaging, which elucidates the time-varying changes in the spatial distribution of electrocatalytic activity on individual nanoplates, indicating that the corners and edges with more defect sites exhibit higher reactivity, but lower stability than the flat facet. We believe that real-time and high-throughput ECL microscopy may lead to more comprehensive understanding of reactivity patterns of single nanocatalysts.

Novel mutations of AXIN2 identified in a Chinese Congenital Heart Disease Cohort.

Congenital heart defects (CHDs), the most common congenital human birth anomalies, involves complex genetic factors. Wnt/ß-catenin pathway is critical for cardiogenesis and proved to be associated with numerous congenital heart abnormities. AXIN2 has a unique role in Wnt/ß-catenin pathway, as it is not only an important inhibitor but also a direct target of Wnt/ß-catenin pathway. However, whether AXIN2 is associated with human CHDs has not been reported. In our present study, we found a differential expression of Axin2 mRNA during the development of mouse heart, indicating its importance in mouse cardiac development. Then using targeted next-generation sequencing, we found two novel case-specific rare mutations [c.28 C > T (p.L10F), c.395 A > G (p.K132R)] in the sequencing region of AXIN2. In vitro functional analysis suggested that L10F might be a loss-of-function mutation and K132R is a gain-of-function mutation. Both mutations disrupted Wnt/ß-catenin pathway and failed to rescue CHD phenotype caused by Axin2 knockdown in zebrafish model. Collectively, our study indicates that rare mutations in AXIN2 might contribute to the risk of human CHDs and a balanced canonical Wnt pathway is critical for cardiac development process. To our knowledge, it is the first study of AXIN2 mutations associated with human CHDs, providing new insights into CHD etiology.

Aggregation-Induced Electrochemiluminescence of Carboranyl Carbazoles in Aqueous Media.

The aggregation-induced electrochemiluminescence (AIECL) of carboranyl carbazoles in aqueous media was investigated for the first time. Quantum yields, morphologies, and particle sizes were observed to determine the electrochemiluminescence (ECL) performance of these aggregated organic dots (ODs). All compounds exhibit much higher ECL stability and intensity than the carborane-free compound, demonstrating the essential role of the carboranyl motif. Moreover, the results of cyclic voltammetry (CV) suggest that oxidation/reduction reactions take place at the carboranyl motif. The excited states of ODs were proposed to be generated by the mechanism of surface state transitions. More importantly, these compounds show a reductive-oxidative mechanism in contrast to other organic materials that show oxidative-reductive mechanisms. Our experiments and data have established the relation between AIE organic structures and ECL properties that has a strong potential for biological and diagnostic applications.

Electrogenerated Chemiluminescence Imaging of Electrocatalysis at a Single Au-Pt Janus Nanoparticle.

Noble metal nanoparticles are promising catalysts in electrochemical reactions, while understanding the relationship between the structure and reactivity of the particles is important to achieve higher efficiency of electrocatalysis, and promote the development of single-molecule electrochemistry. Electrogenerated chemiluminescence (ECL) was employed to image the catalytic oxidation of luminophore at single Au, Pt, and Au-Pt Janus nanoparticles. Compared to the monometal nanoparticles, the Janus particle structure exhibited enhanced ECL intensity and stability, indicating better catalytic efficiency. On the basis of the experimental results and digital simulation, it was concluded that a concentration difference arose at the asymmetric bimetallic interface according to different heterogeneous electron-transfer rate constants at Au and Pt. The fluid slip around the Janus particle enhanced local redox reactions and protected the particle surface from passivation.

A novel DNA tetrahedron-hairpin probe for in situ"off-on" fluorescence imaging of intracellular telomerase activity.

A novel three-dimensionally structured DNA probe is reported to realize in situ"off-on" imaging of intracellular telomerase activity. The probe consists of a DNA tetrahedron and a hairpin DNA on one of the vertices of the DNA tetrahedron. It is composed of four modified DNA segments: S1-Au nanoparticle (NP) inserting a telomerase strand primer (TSP) and S2-S4, three Cy5 dye modified DNA segments. Fluorescence of Cy5 at three vertices of the DNA tetrahedron is quenched by the Au NP at the other vertex due to the effective fluorescence resonance energy transfer (FRET) ("off" state). When the probe meets telomerase, the hairpin structure changes to rod-like through complementary hybridization with the telomerase-triggered stem elongation product, resulting in a large distance between the Au NP and Cy5 and the recovery of Cy5 fluorescence ("on" state). The molar ratio of 3 : 1 between the reporter (Cy5) and the target related TSP makes the probe show high sensitivity and recovery efficiency of Cy5 in the presence of telomerase extracted from HeLa cells. Given the functional and compact nanostructure, the mechanically stable and noncytotoxic nature of the DNA tetrahedron, this FRET-based probe provides more opportunities for biosensing, molecular imaging and drug delivery.

Mesoporous silica film-assisted amplified electrochemiluminescence for cancer cell detection.

A mesoporous silica film-assisted amplification method is reported for the first time for the sensitive electrochemiluminescence detection of cancer cells.