wileyonlinelibrary.comhydrogels exhibit slow macroscale response with a magnitude of minutes to hours. [10][11][12][13] Meanwhile, they are typically mechanically weak or brittle, [ 14,15 ] resulting in unstable performance after cycles of stimulation. In addition, most of these hydrogels possess isotropic porous structures, showing size changes evenly, making desirable locomotion (e.g., bending, twisting, and folding) diffi cult to achieve. [ 16,17 ] Modulation of pores size and their distributions is essential for manipulating hydrogels properties. Several strategies including gas foaming, [ 18 ] fi ber bonding, [ 19 ] and porogen leaching [ 20 ] were developed to fabricate homo geneous macropore sized hydrogels for rapid responses. However, the orientation responses of such materials were limited, causing diffi culties in anisotropic locomotion. Moreover, mechanical strength of these hydrogels was relatively weak due to the fragile macrosized pore structures. On the other hand, electrophoresis-assisted porogen leaching and hydrogel layering methods [21][22][23][24] have been developed to produce responsive hydrogels with stepwisedistributed pore structures to enable their anisotropic responsive capabilities. However, these hydrogels have some adverse properties including less pore interconnectivity, decelerated mass transport, and being prone to delamination, causing their slow response to stimuli and poor mechanical properties. To date, synthesis of hydrogels with simultaneously rapid thermal response kinetics, robust mechanical strength, and desirable anisotropic locomotion remains an unsolved challenge.In this study, we presented a heterobifunctional crosslinker enabled hydrothermal process, forming hydrogels with gradient porous structure to address these issues. The hydrothermal synthesis is performed in closed systems of relatively high temperatures and pressures, in which only water is used as the reactive medium. At elevated temperatures, hydrothermal process can prompt a variety of chemical reactions such as vinyl polymerizations and intermolecular dehydration. [25][26][27] N -isopropylacrylamide (NIPAM), a well-known thermo-responsive material bearing two highly reactive double bonds, [ 28,29 ] was used as monomer. 4-hydroxybutyl acrylate (4HBA), an acrylic ester possessing a reactive double bond and a less reactive hydroxyl group at either end of the molecule, was innovatively applied Programmable locomotion of responsive hydrogels has gained increasing attention for potential applications in soft robotics, microfl uidic components, actuators, and artifi cial muscle. Modulation of hydrogel pore structures is essential for tailoring their mechanical strength, response speeds, and motion behaviors. Conventional methods forming hydrogels with homogeneous or stepwise-distributed pore structures are limited by the required compromise to simultaneously optimize these aspects. Here, a heterobifunctional crosslinker enabled hydrothermal process is introduced to synthesize responsive hydrogels with well-defi...
In nature, individual cells contain multiple isolated compartments in which cascade enzymatic reactions occur to form essential biological products with high efficiency. Here, we report a cell-inspired design of functional hydrogel particles with multiple compartments, in which different enzymes are spatially immobilized in distinct domains that enable engineered, one-pot, tandem reactions. The dense packing of different compartments in the hydrogel particle enables effective transportation of reactants to ensure that the products are generated with high efficiency. To demonstrate the advantages of micro-environmental modifications, we employ the copolymerization of acrylic acid, which leads to the formation of heterogeneous multi-compartmental hydrogel particles with different pH microenvironments. Upon the positional assembly of glucose oxidase and magnetic nanoparticles, these hydrogel particles are able to process a glucose-triggered, incompatible, multistep tandem reaction in one pot. Furthermore, based on the high cytotoxicity of hydroxyl radicals, a glucose-powered therapeutic strategy to kill cancer cells was approached.
Phospholipids are used as an additive in capillary electrophoresis to enhance the separation of glycans derived from alpha1-acid glycoprotein, fetuin, and ribonuclease B. The properties of phospholipid preparations are dependent upon composition, hydration, and temperature. Separation performance is evaluated as a function of these variables. A preparation of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC), with [DMPC]/[DHPC] = 2.5, in 10% lipid/aqueous buffer at 25 degrees C provides the best separation efficiency at an electric field strength of 400 V/cm. Resolution is enhanced with the additive. Concanavalin A, a lectin selective for high mannose and mannose branching glycans, and alpha1-2,3 mannosidase, an enzyme that cleaves 1-2 and 1-3 mannopyranosyl residues, are incorporated in the separation to provide additional selectivity and to expand the application of phospholipid additives for glycan separation.
We previously reported the design of spirooxindoles with two identical substituents at the carbon-2 of the pyrrolidine core as potent MDM2 inhibitors. In this paper we describe an extensive structure–activity relationship study of this class of MDM2 inhibitors, which led to the discovery of 60 (AA-115/APG-115). Compound 60 has a very high affinity to MDM2 (Ki < 1 nM), potent cellular activity, and an excellent oral pharmacokinetic profile. Compound 60 is capable of achieving complete and long-lasting tumor regression in vivo and is currently in phase I clinical trials for cancer treatment.
Microbial polyhydroxyalkanoates (PHA) were proposed for the first time as a new type of biofuel. In this paper, poly-R-3-hydroxybutyrate (PHB) and medium chain length PHA (mcl PHA) were, respectively, esterified to become R-3-hydroxybutyrate methyl ester (3HBME) and medium chain length hydroxyalkanoate methyl ester (3HAME) via acid-catalyzed hydrolysis. The recovery percentages of 3HBME and 3HAME were 52 and 65%, respectively. The purities of 3HBME and 3HAME were 97 and 96%, respectively. Combustion heats of 3HBME, 3HAME, ethanol, n-propanol, n-butanol, 0(#) diesel, 90(#) gasoline, and 3HBME-based and 3HAME-based blended fuels were investigated and compared, respectively. It was found that 3HBME and 3HAME had combustion heats valuing 20 and 30 KJ/g, respectively. Ethanol has a combustion heat of 27 KJ/g, while addition of 10% 3HBME or 3HAME enhanced the combustion heat of ethanol to 30 and 35 KJ/g, respectively. The addition of 3HBME or 3HAME into n-propanol and n-butanol led to a slight reduction of their combustion heats. Combustion heats of blended fuels 3HBME/diesel or 3HBME/gasoline and of 3HAME/diesel or 3HAME/gasoline were lower than that of the pure diesel or gasoline. It was roughly estimated that the production cost of PHA-based biofuels should be around US$1200 per ton.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.