Atomically Precise Chiral Metal Nanoclusters for Circularly Polarized Light Detection.

Circularly polarized light (CPL) detection is of great significance in various applications such as drug identification, sensing and imaging. Atomically precise chiral metal nanoclusters with intense circular dichroism (CD) signals are promising candidates for CPL detection, which can further facilitate device miniaturization and integration. Herein, we report the preparation of a pair of optically active chiral silver nanoclusters [Ag7(R/S-DMA)2(dpppy)3] (BF4)3 (R/S-Ag7) for direct CPL detection. The crystal structure and molecular formula of R/S-Ag7 clusters are confirmed by single-crystal x-ray diffraction and high-resolution mass spectrometry. R/S-Ag7 clusters exhibit strong CD spectra and CPL luminescence both in solution and solid states. When used as the photoactive materials in photodetectors, R/S-Ag7 enables effective discrimination between left-handed circularly polarized and right-handed circularly polarized light at 520 nm with short response time, high responsivity and considerable discrimination ratio. This study is the first report on using atomically precise chiral metal nanoclusters for CPL detection.

[The Roles of RUNX1 in the Proliferation and Osteogenic and Adipogenic Differentiation of Dental Pulp Stem Cells].

OBJECTIVE: To investigate the influence of Runt-related transcription factor 1 (RUNX1) on the proliferation, osteogenic differentiation and adipogenic differentiation of dental pulp stem cells (DPSC) in vitro. METHODS: DPSCs were transfected through lentiviral vector carrying the target gene RUNX1 and green fluorescent protein (GFP). After 48 h, transfection efficiency was determined with the fluorescent marking of GFP and Western blot. The effect of the overexpression of RUNX1 on DPSC proliferation and colony formation was determined with CCK-8 and colony formation assay; cell cycle of DPSC was detected by flow cytometry. RUNX1 siRNA was transfected into the DPSCs. After mineralized induction, the effect of RUNX1 overexpression/silencing on the osteogenetic differentiation of DPSC was tested by alkaline phosphatase (ALP) staining and alizarin red staining. After adipogenic induction, oil red O staining was done in order to observe the effect of overexpression/silencing of RUNX1 on the adipogenic differentiation of DPSC. RESULTS: RUNX1 protein was overexpressed in DPSC after lentiviral transfection. Fluorescent test showed successful transfection of lentiviral transfection and over 70% of the cells showed stable expression of GFP protein. The proliferation and colony-formation efficiency of DPSC was enhanced significantly and the proportion of DPSCs in the S phase was significantly increased in the RUNX1-overexpessed group ( P<0.05). ALP activity and mineralized nodule formation ability increased, while lipid droplets decreased in the RUNX1-overexpessed group ( P<0.05). ALP activity and mineralized nodule formation ability decreased, while lipid droplets increased in the RUNX1 knockdown group ( P<0.05) . CONCLUSION: RUNX1 promotes DPSC proliferation and osteogenic differentiation while it inhibits DPSC adipogenic differentiation.

[Synergistic Antibacterial Activity of Berberine in Combination with Amylmetacresol Against Enterococcus faecalis in vitro].

OBJECTIVE: To study the antibacterial effect of berberine combined with amylmetacresol on Enterococcus faecalis. METHODS: Both dilution method and live bacteria CFU were used to determine the minimum inhibitory concentration (MIC) of berberine and amylmetacresol on E. faecalis. The killing effect of berberine and amylmetacresol on planktonic E. faecalis was detected by suspension quantitative germicidal test and live/dead bacteria staining. The effects of berberine and amylmetacresol on the structure of mature biofilm of E. faecalis was observed by scanning electron microscopy (SEM). The toxicity of berberine and amylmetacresol on human oral keratinocytes (HOK) was determined by CCK-8 cell proliferation and cytotoxicity assay and cytotoxicity LDH assay. RESULTS: The MIC of berberine was 512 µg/mL, and the MIC of amylmetacresol was 0.023 3%. 512 µg/mL berberine and 0.002 33% amylmetacresol had a weak killing effect on planktonic E. faecalis alone, while they showed a synergistic antibacterial effect in combination. Cell survival in the biofilm was only slightly changed by berberine and amylmetacresol. The structure of biofilm was obviously changed by berberine and amylmetacresol. 512 µg/mL berberine and 0.002 33% amylmetacresol alone or in combination showed the survival rate was much higher than the injury rate, suggesting berberine and amylmetacresol had a low cytotoxicity. CONCLUSION: Berberine and amylmetacresol had synergism against E. faecalis, and the biological safety of the combination use was better.

Filling the gaps in icosahedral superatomic metal clusters.

Chemically modified superatoms have emerged as promising candidates in the new periodic table, in which Au13 and its doped M n Au13- n have been widely studied. However, their important counterpart, Ag13 artificial element, has not yet been synthesized. In this work, we report the synthesis of Ag13 nanoclusters using strong chelating ability and rigid ligands, that fills the gaps in the icosahedral superatomic metal clusters. After further doping Ag13 template with different degrees of Au atoms, we gained insight into the evolution of their optical properties. Theoretical calculations show that the kernel metal doping can modulate the transition of the excited-state electronic structure, and the electron transfer process changes from local excitation (LE) to charge transfer (CT) to LE. This study not only enriches the families of artificial superatoms, but also contributes to the understanding of the electronic states of superatomic clusters.

Orexin-A aggravates cognitive deficits in 3xTg-AD mice by exacerbating synaptic plasticity impairment and affecting amyloid ß metabolism.

Dementia is the main clinical feature of Alzheimer's disease (AD). Orexin has recently been linked to AD pathogenesis, and exogenous orexin-A (OXA) aggravates spatial memory impairment in APP/PS1 mice. However, the effects of OXA on other types of cognitive deficits, especially in 3xTg-AD mice exhibiting both plaque and tangle pathologies, have not been reported. Furthermore, the potential electrophysiological mechanism by which OXA affects cognitive deficits and the molecular mechanism by which OXA increases amyloid ß (Aß) levels are unknown. In the present study, the effects of OXA on cognitive functions, synaptic plasticity, Aß levels, tau hyperphosphorylation, BACE1 and NEP expression, and circadian locomotor rhythm were evaluated. The results showed that OXA aggravated memory impairments and circadian rhythm disturbance, exacerbated hippocampal LTP depression, and increased Aß and tau pathologies in 3xTg-AD mice by affecting BACE1 and NEP expression. These results indicated that OXA aggravates cognitive deficits and hippocampal synaptic plasticity impairment in 3xTg-AD mice by increasing Aß production and decreasing Aß clearance through disruption of the circadian rhythm and sleep-wake cycle.