Latest ArticlesThe detection of biomarkers is of great significance in the diagnosis of numerous diseases, especially cancer. Herein, we developed a sensitive and universal fluorescent aptasensor strategy based on magnetic beads, DNA G-quadruplex, and exonuclease Ⅲ (Exo Ⅲ). In the presence of a target protein, a label-free single strand DNA (ssDNA) hybridized with the aptamer was released as a trigger DNA due to specific recognition between the aptamer and target. Subsequently, ssDNA initiates the Exo Ⅲ-aided recycling to amplify the fluorescence signal, which was caused by N-methylmesoporphyrin Ⅸ (NMM) insertion into the G-quadruplex structure. This proposed strategy combines the excellent specificity between the aptamer and target, high sensitivity of the fluorescence signal by G-quadruplex and Exo Ⅲaided recycling amplification. We selected (50-1200 nmol/L) MUC1, a common tumor biomarker, as the proof-of-concept target to test the specificity of our aptasensor. Results reveal that the sensor sensitively and selectively detected the target protein with limits of detection (LODs) of 3.68 and 12.83 nmol/L in buffer solution and 10% serum system, respectively. The strategy can be easily applied to other targets by simply substituting corresponding aptamers and has great potential in the diagnosis and monitoring of several diseases.
A ruthenium based catalytic system ([Ru(p-cymene)Cl2]2/XantPhos with substoichiometric Cs2CO3) has been established to effectively achieve the first direct amination cyclization of 1, 2, 4-butanetriol with primary aromatic amines. The product of this sustainable hydrogen autotransfer process is valuable Naryl-3-pyrrolidinol.
The construction of N-methyl amine moieties is an important reaction that has found numerous applications. Development of new methylation agents that are more environmentally benign than classical agents, such as iodomethane and methyl sulfate, is still highly desirable. Herein, we report a convenient protocol for direct reductive N-methylation of amines using formic acid as the methylation agent via simple inorganic base catalysis. The present protocol operates under transition-metal-free and air-tolerant conditions. Both the catalyst, K2HPO4, and the reductant, polymethylhydrosiloxane (PMHS), are cheap and easily separable from the crude reaction product mixture. Mechanistic investigations suggest that the reaction occur through the formation of an acetal intermediate followed by the C-N bond formation.
Efficient catalytic system with low energy consumption exhibits increasing importance due to the upcoming energy crisis. Given this situation, it should be an admirable strategy for reducing energy input by effectively utilizing incident solar energy as a heat source during catalytic reactions. Herein, aza-fused π-conjugated microporous polymer (aza-CMP) with broad light absorption and high photothermal conversion efficiency was synthesized and utilized as a support for bimetallic AuPd nanocatalysts in light-driven benzyl alcohol oxidation. The AuPd nanoparticles anchored on aza-CMP (aza-CMP/AuxPdy) exhibited excellent catalytic performance for benzyl alcohol oxidation under 50 mW/cm2 light irradiation. The improved catalytic performance by the aza-CMP/AuxPdy is attributed to the unique photothermal effect induced by aza-CMP, which can promote the catalytic benzyl alcohol oxidation occurring at AuPd. This work presents a novel approach to effectively utilize solar energy for conventional catalytic reactions through photothermal effect.
The preparation of silver nanoparticles (AgNPs) with microbe or plant tissues as bio-template offers green approach, while it suffers from low harvest and purification is needed. Herein, we propose a facile protocol for one-pot preparation of AgNPs using M13 phage as bio-template by simply mixing AgNO3 solution with alkali M13 phage. In the obtained AgNPs-M13 phage composite, Cr(Ⅲ) selectively coordinates with the amino residues on phage surface and leads to the aggregation of AgNPs through the bridging of M13 phages. This makes it feasible for colorimetric sensing of Cr(Ⅲ) by measuring the absorbance ratio of AgNPs at 600 and 405 nm, which provides a LOD of 14 nmol/L. The composite also showed favorable bactericidal activity for both Gram-positive and Gram-negative bacteria, making it a promising candidate as antibacterial film in chromium-containing dental alloys and meanwhile serve as a sensing probe for monitoring the corrosion of the dental alloys.
Highly luminescent colloidal nanocrystals have wide applications in bioimaging and various optoelectronic devices. Herein we report a facile and mild procedure by combining S2- treatment and binary ligand passivation, which can efficiently enhance the luminescent property of CdSe nanocrystals at room temperature. The photoluminescence quantum yield of as-treated CdSe nanocrystals exhibits drastic enhancement (e.g., 188 times for CdSe nanorods) after this dual-passivation treatment. The methodology proposed here can be applied to various CdSe nanocrystals, regardless of their sizes, shapes, and crystal structures.
A novel channel-wall engineering strategy of the porous materials cationic covalent organic frameworks (COFs) is established based on rapid microwave-assisted anion exchange reaction and utilized to prepare a set of new COFs. Due to the interaction between the carbon dioxide (CO2) and the acetate anion, the resulting SJTU-COF-AcO shows greatly enhanced carbon dioxide capacity up to 1.7 times of the pristine COF. The effect of the counter anions to CO2 capacity in the cationic COFs is investigated for the first time, which demonstrates that our channel-wall engineering strategy is a promising way to tailor the property of COFs for high CO2 capacity.
Fourteen avermectin B2a aglycon derivatives were designed and synthesized after removing the oleandrose disaccharide of avermectin B2a. Their structures were characterized by 1H NMR, 13C NMR, HMRS. Preliminary bioassays indicated that these compounds exhibited good insecticidal activity against diamondback moth at 200 mg/L, with mortality no less than 90%. Compounds 10b, 12a, 12c, 17 demonstrated good acaricidal activity against the adult mites, larvae, and good inhibition rate of hatching to mite eggs of Tetranychus cinnabarinus. Compounds 5, 10b, 10c exhibited excellent fungicidal activity against fourteen fungal pathogens in vitro. 3D-QSAR analysis showed that the fungicidal activity of avermectin B2a aglycon derivatives would be increased when a negatively charged and bulky group was introduced at 13-position, which will be instructive for the further modification of avermectin B2a aglycon.
The development of polymeric optical materials with a higher refractive index, transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as microlenses, image sensors, and organic light-emitting diodes. Most acrylates have a low refractive index (around 1.50) which does not meet the high performance requirements of advanced optical materials. In this research, three novel acrylates were synthesized via a facile one-step approach and used to fabricate optical transparent polymers. All of the polymers reveal good optical properties including high transparency (≥90%) in the visible spectrum region and high refractive index values (1.6363) at 550 nm. Moreover, nanostructures of these acrylate polymers with various feature sizes including nanogratings and photonic crystals were successfully fabricated using nanoimprint lithography. These results indicate that these acrylates can be used in a wide range of optical and optoelectronic devices where nanopatterned films with high refractive index and transparency are required.
Graphene oxide (GO) is widely used in the construction and application of various 2D membrane-based materials due to its unique colloidal structure. Herein, we demonstrate that micrometer-sized particles can make up freestanding membranes enabled by the extraordinary amphiphilic and polymer-like properties of graphene oxide through freeze casting. The 2D macromolecule, GO could well wrap the particles for better uniformity and stability in either dispersion or membrane. Importantly, freeze casting plays an important role in avoiding the severe aggregation of micrometer-sized particles in the solventremoving process. After reduction, the membrane exhibits good electrical conductivity while maintaining its integral structure, which can be directly used as a freestanding binder-free electrode. This work provides a universal approach to fabricate freestanding membranes with various micrometersized materials for energy storage.
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