Viruses are a major threat to the wellbeing of humans, animals, and plants. The current diagnostics of viral RNA/DNA are largely dependent on polymerase chain reaction (PCR) and related concepts. ...Serological and immunological assays on the other hand aim to identify the presence of antibodies. Alternative approaches that consider non‐biological entities as part of the sensing set‐up might be a complementary path to alleviate the pressure on access to high‐quality biomolecules and PCR reagents. In this context, polydiacetylenes are widely explored as biosensors because these polymers can be synthesized in situ only with the assistance of light in the desired environment. In addition, this unique group of polymers can be utilized as biosensors to detect an assortment of biomolecules and pathogens with dual optical outputs. The detection of viruses and related biomolecules with polydiacetylenes have been explored over the course of the past three decades. This progress report aims to provide a comprehensive summary of polydiacetylene‐based biosensors for the detection of viruses and also related biomolecules, including nucleic acids and proteins. Given the current situation, this progress report will hopefully inspire scientists and contribute to the development of novel biosensors for the fast and effective detection of viruses.
The fast and effective detection of viruses and related biomolecules plays a critical role in combating viral infections and diseases. In this aspect, polydiacetylenes are potential candidates because of their facile synthesis and customizable stimuli‐responsiveness with dual‐signal optical output. The developments of utilizing polydiacetylenes as biosensors to detect viruses and related biomolecules are comprehensively summarized in this progress report.
A luminescent cadmium–pamoate metal–organic framework, Cd2(PAM)2(dpe)2(H2O)2⋅0.5(dpe) (1), has been synthesized under hydrothermal conditions by using π‐electron‐rich ligands ...4,4′‐methylenebis(3‐hydroxy‐2‐naphthalenecarboxylic acid) (H2PAM) and 1,2‐di(4‐pyridyl)ethylene (dpe). Its structure is composed of both mononuclear and dinuclear CdII building units, which are linked by the PAM and dpe ligands, resulting in a (4,8)‐connected 3D framework. The π‐conjugated dpe guests are located in a 1D channel of 1. The strong emission of 1 could be quenched efficiently by trace amounts of 2,4,6‐trinitrophenol (TNP), even in the presence of other competing analogues such as 4‐nitrophenol, 2,6‐dinitrotoluene, 2,4‐dinitrotoluene, nitrobenzene, 1,3‐dinitrobenzene, hydroquinone, dimethylbenzene, and bromobenzene. The high sensitivity and selectivity of the fluorescence response of 1 to TNP shows that this framework could be used as an excellent sensor for identifying and quantifying TNP. In the same manner, 1 also exhibits superior selectivity and sensitivity towards Cu2+ compared with other metal ions such as Zn2+, Mn2+, Mg2+, K+, Na+, Ni2+, Co2+, and Ca2+. This is the first MOF that can serve as a dual functional fluorescent sensor for selectively detecting trace amounts of TNP and Cu2+.
Sensing explosives: A luminescent, three‐dimensional cadmium–pamoate metal–organic framework has been synthesized. This material can serve as a selective sensor for the detection of 2,4,6‐trinitrophenol and Cu2+ (see figure).
Abstract The combined treatment of chemotherapeutant and microRNA (miR) has been proven to be a viable strategy for enhancing chemosensitivity due to its synergistic effect for tumor therapy. ...However, the co-delivery of drugs and genes remains a major challenge as they lack efficient co-delivery carriers. In this study, three amphiphilic star-branched copolymers comprising polylactic acid (PLA) and polydimethylaminoethyl methacrylate (PDMAEMA) with AB3 , (AB3 )2 ,and (AB3 )3 molecular architectures were synthesized respectively by a combination of ring-opening polymerization, atom transfer radical polymerization, and click chemistry via an “arm-first” approach. The star copolymers possessed a low critical micelle concentration (CMC) and formed nano-sized micelles with positive surface charges in water as well as exhibiting a much lower cytotoxicity than PEI 25 kDa. Nevertheless, their gene transfection efficiency and tumor inhibition ability showed a remarkable dependence on their molecular architecture. The (AB3 )3 architecture micelle copolymer exhibited the highest transfection efficiency, about 2.5 times higher than PEI. In addition, after co-delivering DOX and miR-21 inhibitor (miR-21i) into LN229 glioma cells, the micelles could mediate escaping miR-21i from lysosome degradation and the release of DOX to the nucleus, which significantly decreased the miR-21 expression. Moreover, co-delivery of DOX and miR-21i surprisingly exhibited an anti-proliferative efficiency compared with DOX or the miR-21i treatment alone. These results demonstrated that amphiphilic star-branched copolymers are highly promising for their combinatorial delivery of genes and hydrophobic therapeutants.
The extensive involvement of miRNAs in cancer pathobiology has opened avenues for drug development based on oncomir inhibition. Dicer is the core enzyme in miRNA processing that cleaves the terminal ...loop of precursor microRNAs (pre-miRNAs) to generate mature miRNA duplexes. Using the three-dimensional structure of the Dicer binding site on the pre-miR-21 oncomir, we conducted an in silico high-throughput screen for small molecules that block miR-21 maturation. By this method, we identified a specific small-molecule inhibitor of miR-21, termed AC1MMYR2, which blocked the ability of Dicer to process pre-miR-21 to mature miR-21. AC1MMYR2 upregulated expression of PTEN, PDCD4, and RECK and reversed epithelial-mesenchymal transition via the induction of E-cadherin expression and the downregulation of mesenchymal markers, thereby suppressing proliferation, survival, and invasion in glioblastoma, breast cancer, and gastric cancer cells. As a single agent in vivo, AC1MMYR2 repressed tumor growth, invasiveness, and metastasis, increasing overall host survival with no observable tissue cytotoxicity in orthotopic models. Our results offer a novel, high-throughput method to screen for small-molecule inhibitors of miRNA maturation, presenting AC1MMYR2 as a broadly useful candidate antitumor drug.
Nested concentric structures widely exist in nature and designed systems with circles, polygons, polyhedra, and spheres sharing the same center or axis. It still remains challenging to construct ...discrete nested architecture at (supra)molecular level. Herein, three generations (G2-G4) of giant nested supramolecules, or Kandinsky circles, have been designed and assembled with molecular weight 17,964, 27,713 and 38,352 Da, respectively. In the ligand preparation, consecutive condensation between precursors with primary amines and pyrylium salts is applied to modularize the synthesis. These discrete nested supramolecules are prone to assemble into tubular nanostructures through hierarchical self-assembly. Furthermore, nested supramolecules display high antimicrobial activity against Gram-positive pathogen methicillin-resistant Staphylococcus aureus (MRSA), and negligible toxicity to eukaryotic cells, while the corresponding ligands do not show potent antimicrobial activity.
Non-orthogonal multiple access (NOMA) and heterogeneous network (HetNet) are two significant and promising enabling techniques to further improve overall system performance for nextgeneration mobile ...communication systems. In this paper, we develop a novel NOMA HetNet through applying NOMA technique to both macrocell and small-cell of conventional HetNet, which improves the spectral efficiency whereas results in a more complex interference environment. To tackle this complicated interference problem and maximize the overall throughput of this NOMA HetNet, meanwhile ensure the desired quality of service (QoS) of each user, we mathematically formulate a power allocation problem which proves to be an NP-hard problem. Then, to deal with this optimization problem, we propose a users scheduling scheme and an iterative distributed power control algorithm. The simulation results demonstrate that compared with the conventional orthogonal multiple access (OMA) HetNet systems and single-tier NOMA networks, the combination of OMA technique and HetNet with the proposed algorithm can greatly improve the system performance in terms of spectral efficiency and outage performance.
•An integrated catalytic process was developed to produce biodiesel from chicken fat.•The catalytic composite membrane present a high FFAs conversion and stability.•The conversion of ...transesterification carried out by sodium methoxide was 98.1%.•The main properties of the biodiesel met the international standards.
An integrated process of catalytic composite membranes (CCMs) and sodium methoxide was developed to produce biodiesel from waste chicken fat. The free fatty acids (FFAs) in the chicken oil were converted to methyl esters by esterification with methanol using a novel sulfonated polyethersulfone (SPES)/PES/non-woven fabric (NWF) CCMs in a flow-through catalytic membrane reactor. The CCM is that the NWF fibers were fully embedded in SPES/PES with a homogeneous and microporous structure. The oil obtained after esterification was carried out by transesterification of sodium methoxide. The results showed that the FFAs conversion obtained by CCMs with the acid capacity of 25.28mmol (H+) was 92.8% at the residence time 258s. The CCMs present a good stability during the continuous running of 500h. The conversion of transesterification was 98.1% under the optimum conditions. The quality of the biodiesel met the international standards.
An explosive growth in vehicular wireless applications gives rise to spectrum resource starvation. Cognitive radio has been used in vehicular networks to mitigate the impending spectrum starvation ...problem by allowing vehicles to fully exploit spectrum opportunities unoccupied by licensed users. Efficient and effective detection of licensed user is a critical issue to realize cognitive radio applications. However, spectrum sensing in vehicular environments is a very challenging task due to vehicle mobility. For instance, vehicle mobility has a large effect on the wireless channel, thereby impacting the detection performance of spectrum sensing. Thus, gargantuan efforts have been made in order to analyze the fading properties of mobile radio channel in vehicular environments. Indeed, numerous studies have demonstrated that the wireless channel in vehicular environments can be characterized by a temporally correlated Rayleigh fading. In this paper, we focus on energy detection for spectrum sensing and a counting rule for cooperative sensing based on Neyman-Pearson criteria. Further, we go into the effect of the sensing and reporting channel conditions on the sensing performance under the temporally correlated Rayleigh channel. For local and cooperative sensing, we derive some alternative expressions for the average probability of misdetection. The pertinent numerical and simulating results are provided to further validate our theoretical analyses under a variety of scenarios.
► The conversion obtained by CCM was over 98.0% during the continuous esterification. ► The external mass transfer resistance was related to the flow rate. ► The internal mass transfer resistance was ...related to the membrane thickness. ► A kinetic model was established to predict the conversion.
A novel composite catalytic membrane (CCM) was prepared from sulfonated polyethersulfone (SPES) and polyethersulfone (PES) blend supported by non-woven fabrics, as a heterogeneous catalyst to produce biodiesel from continuous esterification of oleic acid with methanol in a flow-through mode. A kinetic model of esterification was established based on a plug-flow assumption. The effects of the CCM structure (thickness, area, porosity, etc.), reaction temperature and the external and internal mass transfer resistances on esterification were investigated. The results showed that the CCM structure had a significant effect on the acid conversion. The external mass transfer resistance could be neglected when the flow rate was over 1.2mlmin−1. The internal mass transfer resistance impacted on the conversion when membrane thickness was over 1.779mm. An oleic acid conversion kept over 98.0% for 500h of continuous running. The conversions obtained from the model are in good agreement with the experimental data.
Nano/micromotors are self‐propelled particles that use external stimuli to gain locomotion outperforming Brownian motion. Here, three different polymers are employed that are conjugated to silica ...particles through a pH‐labile linker. At slightly acidic pH, the linkers hydrolyze and release the polymeric chains, resulting in enhanced locomotion. The motors show a maximum velocity of ≈3 µm s−1 in cell media when poly(ethylene glycol) methyl ether methacrylate is asymmetrically distributed on the surface of the particles. Further, the motor internalization by RAW 264.7 macrophages was compared between motors, which have the polymer conjugated via a pH‐labile linker, and the irresponsive particles. Preliminary data indicate enhanced uptake, but further efforts are required to use responsive polymers to propel motors inside mammalian cells.
Janus motors decorated with pH‐responsive polymers show environmentally‐triggered enhanced locomotion. These motors increase the cell mean fluorescence in shorter times due to their internalization.
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