No abstract

Biomacromolecules usually form complex superstructures in natural biotissues, such as different alignments of collagen fibres in articular cartilages, for multifunctionalities. Inspired by nature, there are efforts towards developing multiscale ordered structures in hydrogels (recognized as one of the best candidates of soft biotissues). However, creating complex superstructures in gels are hardly realized because of the absence of effective approaches to control the localized molecular orientation. Here we introduce a method to create various superstructures of rigid polyanions in polycationic hydrogels. The control of localized orientation of rigid molecules, which are sensitive to the internal stress field of the gel, is achieved by tuning the swelling mismatch between masked and unmasked regions of the photolithographic patterned gel. Furthermore, we develop a double network structure to toughen the hydrogels with programmed superstructures, which deform reversibly under large strain. This work presents a promising pathway to develop superstructures in hydrogels and should shed light on designing biomimetic materials with intricate molecular alignments.

Zinc enzymes are ubiquitous in nature and are frequently used to catalyze the hydrolysis of carboxylic acid esters, phosphate esters, and amides. Although many models and mimics of zinc enzymes have been reported, it remains difficult to construct active sites with accurately positioned catalytic groups and tunable substrate selectivity. By imprinting a substrate-like amino template coordinated to a polymerizable zinc complex inside cross-linked micelles, we prepared water-soluble nanoparticles with well-defined active sites. The position of the zinc ion could be tuned systematically with respect to the ester bond to be cleaved in the substrate (p-nitrophenyl esters), as well as the rigidity of the active site. Our imprinted zinc catalysts were able to distinguish substrates that differed by the position of a single methyl group, chain length of the acyl chain, and substitution of the phenyl ring. The turnover number (>460 at pH 7) was 1 order of magnitude higher than those previously reported for artificial zinc enzymes in the literature.

A millimeter-scaled periodic structure is created in a polyelectrolyte hydrogel by the rapid-heterogeneous swelling process, and is frozen by the polyion complexation of the polyelectrolyte network with the oppositely charged, semi-rigid polyelectrolyte. The hydrogel is synthesized from a cationic monomer, N- [3-(N,N-dimethylamino)propyl] acrylamide methyl chloride quaternary (DMAPAA-Q), in the presence of a small amount of the oppositely charged poly(2,2'-disulfonyl-4,4'-benzidine terephthalamide) (PBDT) that has a semi-rigid nature. During swelling process, surface creasing due to the large mismatching of swelling degree between the surface layer and the inner one of the poly DMAPAA-Q (PDMAPAA-Q) gel occurs, which induces highly oriented semi-rigid PBDT molecules along the tensile direction of the crease pattern. In accompany with the evolution of surface creasing, a lattice-like periodic birefringence pattern is formed, which is frozen permanently by the strong polyion complex formation, even after the surface instability pattern of the gel disappears completely throughout the dynamic coalescence. In this work we rationally clarified that formation of such a long-range ordered non-equilibrium structure in the polyelectrolyte hydrogel by the rapid-heterogeneous swelling process requires the following three indispensable conditions: (i) swelling-induced surface creasing; (ii) polyion complex formation; and (iii) a semi-rigid or rigid dopant. This sort of non-equilibrium structure formation mechanism may help understand how biomacromolecules that are rigid polyelectrolytes, such as microtubules and actin filaments, form rich architectures during the growth of biological organs.

We report a novel giant oriented structure observed in plate hydrogels synthesized by photo-polymerization of cationic monomers with cross-linker in the presence of a semi-rigid polyanion as dopant. The giant structure, formed via self-assembly of the semi-rigid polyion complex, consists of millimeter-scale concentric cylindrical domains in cubic packing that are sandwiched by two homeotropically aligned outer layers. A universal relationship between the diameter of the cylinders D and the thickness of the swollen gel T is observed, as D=0.5T, regardless the change in the concentrations of the polyanion and precursor cationic monomer. This result permits us to induce giant concentric structure into hydorgels with the tunable cylindrical size.

Isatin derivatives potentially act on various biological targets. In this article, a series of novel isatin-hydrazones were synthesized in excellent yields. Their cytotoxicity was tested against human breast adenocarcinoma (MCF7) and human ovary adenocarcinoma (A2780) cell lines using MTT assay. Compounds 4j (IC50 = 1.51 ± 0.09 µM) and 4k (IC50 = 3.56 ± 0.31) showed excellent activity against MCF7, whereas compound 4e showed considerable cytotoxicity against both tested cell lines, MCF7 (IC50 = 5.46 ± 0.71 µM) and A2780 (IC50 = 18.96± 2.52 µM), respectively. Structure-activity relationships (SARs) revealed that, halogen substituents at 2,6-position of the C-ring of isatin-hydrazones are the most potent derivatives. In-silico absorption, distribution, metabolism and excretion (ADME) results demonstrated recommended drug likeness properties. Compounds 4j (IC50 = 0.245 µM) and 4k (IC50 = 0.300 µM) exhibited good inhibitory activity against the cell cycle regulator CDK2 protein kinase compared to imatinib (IC50 = 0.131 µM). A molecular docking study of 4j and 4k confirmed both compounds as type II ATP competitive inhibitors that made interactions with ATP binding pocket residues, as well as lacking interactions with active state DFG motif residues.

Palm oil is one of the leading agricultural crops in the world, as it dominates 34% of the global vegetable oil market, with approximately 64.6*103 million kgs of production in 2017. However, along with its breakthrough, the generation of palm oil mill effluent (POME) as uncontrolled waste has become a serious matter and requires proper management to reduce its negative effects on the environment. Subsequently, the high organic content of POME makes it possible to convert waste into value-added products, such as biogas. A ratio of 0.5 for biological oxygen demand to chemical oxygen demand (BOD/COD) indicates a high possibility for biological treatment. Recently, the utilisation of POME as a cheap source for biogas production has gained an extraordinary amount of attention, and intensive research has been conducted on the upstream to downstream process. Finding the most suitable and efficient pretreatment technique and reactor configuration are vital parameters for the treatment and conversion of POME to biogas. This review describes existing pretreatment processes for POME and recommends recently manufactured high-rate anaerobic reactors as the most suitable and efficient pretreatment technique for maximising the extraction of biogas from POME.

INTRODUCTION Nucleosides are key compounds involved in major biological processes, such as nucleic acids and proteins synthesis, cell signaling, enzyme regulation, and metabolism. Nucleoside and their derivatives have emerged as molecules with ABSTRACT In search of new leads toward potent antibacterial agents; therefore, a series of thymidine analogues were synthesized by direct acylation method and furnished the 5´-O-acyl thymidine derivatives in good yield. A number of acyl derivatives were prepared in order to obtain a series of newer components for antibacterial screening experiments. The synthesized compounds were characterized by their FTIR, 1 HNMR spectral data and elemental analysis. These thymidine derivatives were evaluated for in vitro antibacterial screening studies against a number of human pathogenic microorganisms by disc diffusion method. The study revealed that most of the tested chemicals exhibited moderate to good antibacterial activities. It was also observed that the test chemical 2-bromobenzoyl derivative 11 very significantly inhibited the growth of all Gram-positive and Gram-negative bacterial strains used. For comparative studies, antibacterial activity of standard antibiotics, Azithromycin was also carried out against these microorganisms. Hence, these thymidine derivatives can be used to discover antibacterial agents that may serve as leads in the development of new pharmaceuticals research activities.