ACS Nanoscience Au最新文献

Metalorganic chemical vapor deposition (MOCVD) has become a pivotal technique for developing wafer-scale transition metal dichalcogenide (TMD) 2D materials. This study investigates the impact of MOCVD growth conditions on achieving uniform and selective polymorph phase control of MoTe₂ over large wafers. We demonstrated the controlled and uniform growth of few-layer MoTe₂ in pure 2H, 1T', and mixed phases at various temperatures on up to 4 in. C-plane sapphire wafers with hexagonal boron nitride templates. At 600 °C, high-quality 2H-MoTe₂ was obtained within a narrow temperature window, verified with absorption and TEM analysis. In addition, we observed strong exciton-phonon coupling effects in multiwavelength Raman spectroscopy when the excitation wavelength was in resonance with the C-exciton. Our findings indicate that temperature-induced Te vacancies play a crucial role in determining the MoTe₂ phase. This study highlights the importance of precise control over the MOCVD growth temperature to engineer the MoTe₂ phase of interest for device applications.

Heavy water (D₂O) has found extensive application as a moderator in nuclear reactors. Additionally, it serves as a substitute for regular water (H₂O) in biological or spectroscopic experiments, providing a deuterium source and addressing challenges related to solvent opacity or contrast. This is particularly relevant in experiments involving neutron scattering, infrared absorption, or nuclear magnetic resonance. However, replacing H₂O with D₂O is not always a straightforward or harmless substitution and can instead have unintended chemical consequences. In this study, we highlight the significant impact of solvent deuteration on two common gold nanoparticle syntheses-borohydride reduction and ascorbic acid reduction-by comparing reactions in D₂O and H₂O and mixtures thereof. The resulting colloids exhibit differences in size and spectral characteristics, and their effectiveness as nanocatalysts in the widely used 4-nitrophenol reduction benchmark reaction is adversely affected by the presence of D₂O during both particle synthesis and as the catalytic medium. Ultimately, these results underscore a critical awareness often overlooked by scientists and engineers: despite its widespread and sometimes indispensable use in analytical spectroscopy, cellular imaging, biophysics, and organic chemistry, D₂O cannot truly replace H₂O without significantly altering the chemical environment of a reaction.

Cancer is commonly caused by a gain of function in proto-oncogenes and a simultaneous loss of function in tumor suppressor genes. Advanced prostate cancer (PCa) is often linked with changes in the activity or expression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), a well-known tumor suppressor, and androgen receptor (AR), a pro-tumorigenic transcription factor. However, no therapies exist for the simultaneous correction of tumorigenic promotion and suppressor depletion. Here, we report that concurrent PTEN restoration and AR silencing by lipid nanoparticle (LNP) delivery of PTEN messenger RNA (mPTEN) and AR small interfering RNA (siAR) elicited synergistic therapeutic effects in PCa cells. We screened various LNP formulations for the optimal delivery of both RNAs. In C4-2 and LNCaP cells, both of which are AR-positive and PTEN-null PCa cell lines, the combinatorial treatment of siAR and mPTEN LNPs resulted in much stronger cytotoxicity in vitro than the treatment of either alone. Western blot analyses revealed concurrent regulation of phosphatidylinositol 3-kinase-protein kinase B (PI3K-AKT) and extracellular signal-regulated kinase (ERK) pathways, leading to increased caspase-3 cleavage-mediated apoptosis. Our findings suggest that the strategy of RNA-mediated concurrent restoration of tumor suppressors and inhibition of tumorigenic drivers could lead to the more effective treatment of PCa and potentially other malignancies.