Temporal-spatially transformed synthesis and formation mechanism of gold bellflowers

Chloride-ion-directed synthesis of plate-like Cu2O mesocrystals for effective nitrogen fixation

Cuprous oxide (Cu₂O) mesocrystals, which are composed of numerous nanocrystals with a common crystallographic orientation, are supposed to possess superior photocatalytic abilities than the normal constructions, but very few of them have been reported to date. In this work, plate-like Cu₂O mesocrystals were successfully fabricated via a facile one-pot wet chemical strategy. Unlike the commonly used polymers or small molecules, chloride ions (Cl^-) were employed as structure-directing agents and played the main role in the Cu₂O mesocrystal formation. The formation mechanism was interpreted as follows: the presence of Cl^- inhibited the formation of CuO and Cu by forming the intermediate product CuCl, which was further hydrolyzed to Cu₂O nanocrystals. Cl^- tended to adsorb on the (111) facets of the formed Cu₂O nanocrystals and stabilize them. Then the Cu₂O nanocrystals were aligned side by side through the unabsorbed side faces, leading to mutual nanocrystals orientation and crystallographic lock-in, facilitating the formation of plate-like Cu₂O mesocrystals. The polymer, polyacrylamide (PAM), also promoted the mesocrystals formation by serving as a stabilizer and fixed the crystallographic orientation of the Cu₂O nanocrystals during their orderly stacking process. The plate-like Cu₂O mesocrystals showed a long decay time and pronounced performance toward the visible-light-driven photocatalytic reduction of N₂ into NH₃. This research may stimulate in-depth investigations into the exploration of new synthetic methods for the design and construction of novel mesocrystals.

Gold Nanostars Combined with the Searched Antibody for Targeted Oral Squamous Cell Carcinoma Therapy

Oral squamous cell carcinoma (OSCC) is the most common cancer in the oral and maxillofacial region. Due to the special physiological and anatomical position of the oral cavity, the disease often has a significant impact on the chewing, swallowing, language, and breathing functions of patients. In recent years, with the development of medical molecular biology, molecular targeted therapy has received increasing clinical attention and has gradually become a new method for the treatment of malignant tumors. In this research, gold nanostars with a high photothermal effect combined with the searched targeted antibody were used for OSCC therapy. We use the data set in the public database and construct a gene co-expression module by weighted gene co-expression network analysis (WGCNA). It was found that the turquoise module and the midnight blue module had the greatest connection to tumorigenesis. Cytoscape software was used to analyze the important modules, and the top 10 genes of each module were selected; the survival analysis of the top 10 genes was carried out by gene expression profiling interactive analysis (GEPIA), which indicated that these genes (SERPINH1, MMP11, ADAM12, FADS3, SLC36A2, C1QTNF7, SCRG1, and APOBEC2) have statistical significance as key genes that are related to the tumorigenesis of OSCC. Then, the anti-SERPINH1 antibody targeted to SERPINH1 was chosen as the inhibitor and combined with gold nanostars for photothermal assisted targeted therapy. Thus, the searched key genes can be regarded as biomarkers and therapeutic targets for further precise diagnosis.

Strategies to improve the photothermal capacity of gold-based nanomedicines

The plasmonic photothermal properties of gold nanoparticles have been widely explored in the biomedical field to mediate a photothermal effect in response to the irradiation with an external light source. Particularly, in cancer therapy, the physicochemical properties of gold-based nanomaterials allow them to efficiently accumulate in the tumor tissue and then mediate the light-triggered thermal destruction of cancer cells with high spatial-temporal control. Nevertheless, the gold nanomaterials can be produced with different shapes, sizes, and organizations such as nanospheres, nanorods, nanocages, nanoshells, and nanoclusters. These gold nanostructures will present different plasmonic photothermal properties that can impact cancer thermal ablation. This review analyses the application of gold-based nanomaterials in cancer photothermal therapy, emphasizing the main parameters that affect its light-to-heat conversion efficiency and consequently the photothermal potential. The different shapes/organizations (clusters, shells, rods, stars, cages) of gold nanomaterials and the parameters that can be fine-tuned to improve the photothermal capacity are presented. Moreover, the gold nanostructures combination with other materials (e.g. silica, graphene, and iron oxide) or small molecules (e.g. indocyanine green and IR780) to improve the nanomaterials photothermal capacity is also overviewed.

The application of small organic π-conjugated discotic derivatives in photoacoustic imaging and photothermal conversion

Near-infrared absorbing dyes are catching people's attention as they are committed to find materials with greater photoacoustic (PA) and photothermal (PT) effect. In this study, a new series of organic π-conjugated discotic derivatives synthesized via [2 + 2] click chemistry were introduced. The PA intensity and PT conversion effect of the derivatives were monitored. It was found that the π-conjugated discotic derivatives had a proper absorption peak and PA intensity by introducing the click regents. Furthermore, the PA intensity remained relatively high, while B12 molecules were embedded in hydrophobic phospholipid bilayer of liposomes (B12⊂L). The application in biological therapy for tumors become possible as the toxicity of B12⊂L was low. What's more, when B12 molecules embedded in poly (N-isopropylacrylamide)-block-poly (2-nitrobenzyl methacrylate) (PNIPAM-b-PNBM) thermosensitive micelles were irradiated by laser, the molecules could take the place of direct temperature stimulus. This work affords us a way to solve the problem in which direct temperature stimulus is inapplicable.

A ratiometric electrochemical strategy for sensitive determination of Furin activity based on dual signal amplification and antifouling nanosurfaces

Developing a sensitive and accurate method for Furin activity is still the bottleneck for understanding the role played by Furin in cell-surface systems and even in Alzheimer's disease. In this work, a ratiometric electrochemical biosensor was developed for sensitive and accurate determination of Furin activity in the cell based on dual signal amplification stemming from a peptide with multiple response sites and the antifouling gold nano-bellflowers (GBFs). A new peptide, HS-CMRVRR↓YKDFDFG (P3), was designed for the first time to be selectively cleaved by Furin at site↓. More importantly, this peptide P3 constitutes three amino acid residues with the -COOH group subsequently used to bind with the response molecule of ferrocene, and can remarkably improve the determination sensitivity by about 2.3 fold. Meanwhile, GBFs stabilized by PEG were taken as a second element to magnify the signal of the ferrocene group via a large ratio surface area and good conductivity, as well as an antibiofouling nanosurface to reduce the biofouling of the electrode surface in cells. This double amplification strategy can greatly enhance the sensitivity of Furin detection by 6.5-fold, which is favorable for detection of low amounts of Furin. In addition, 5'-MB-GGCGCGA(T)₁₃-SH-3' was co-assembled as an inner reference to provide a built-in element to correct the determination error resulting from a complicated analysis environment. Finally, this sensitive and accurate Furin biosensor was successfully applied to detect Furin activity in Furin overexpressed U251 and MDA-MB-468 cells. As far as we know, this is the first report to mention an electrochemical strategy to detect Furin activity in cells.

Ligand Controlled Morphology Evolution of Active Intermediates for the Syntheses of Gold Nanostars

Gold nanostars have unique plasmonic properties that are related to the highly branched nanostructures. However, it is challenging to precisely control these branches. Here we studied the reaction kinetics on the seed-mediated growth process of gold nanostars using in situ UV-vis spectroscopy. The impact of hydroquinone ligands on the formation and evolution of active intermediates was systematically explored. In addition, we improved the classical seed-mediated method to achieve a much better control on the final morphology of gold nanostars by a sudden addition of a high concentration ligand solution. Our method can significantly advance the syntheses of gold nanostars and provide numerous opportunities to prepare nanomaterials with unique morphology and plasmonic properties.