keyword
MENU ▼
Read by QxMD icon Read
search

crosslink

keyword
https://www.readbyqxmd.com/read/28222261/enhanced-release-of-molecules-upon-uv-light-irradiation-from-photoresponsive-hydrogels-prepared-from-bifunctional-azobenzene-and-four-arm-poly-ethylene-glycol
#1
Shiva Kumar Rastogi, Hailee E Anderson, Joseph Lamas, Scott L Barrett, Travis Cantu, Stefan Zauscher, William J Brittain, Tania Betancourt
Advances in biosensors and drug delivery depend on hydrogels that respond to external stimuli. In this work we de-scribe the preparation and characterization of photoresponsive hydrogels prepared by crosslinking of di-NHS ester of azobenzoic acid and four-armed, amine-terminated poly(ethylene glycol). The porous structure and composition of the hydrogels were confirmed by scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The reversible photoisomerization of the azobenzene-containing hydrogel crosslinkers in the gels was confirmed by ab-sorption spectroscopy...
February 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28221748/fe3-ph-thermo-responsive-supramolecular-hydrogel-with-multi-shape-memory-effect
#2
Xiaoxia Le, Wei Lu, He Xiao, Li Wang, Chunxin Ma, Jiawei Zhang, Youju Huang, Tao Chen
Poor, non-tunable mechanical properties as well as finite shape memory performance pose a barrier to shape memory hydrogels to realize practical applications. Here, a new shape memory hydrogel with tunable mechanical properties and multi-shape memory effect was presented. Three programmable reversible systems including PBA-diol ester bonds, AAc-Fe3+ and coil-helix transition of agar were applied to memorize temporary shapes and endow the hydrogel with outstanding multi-shape memory functionalities. Moreover, through changing the crosslinking densities, the mechanical properties of the as-prepared hydrogel can be adjusted...
February 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28221703/multiblock-copolymer-based-dual-dynamic-disulfide-and-supramolecular-crosslinked-self-healing-networks
#3
So Young An, Seung Man Noh, Jung Kwon Oh
A new multiblock copolymer self-healing strategy is reported that centers on the synthesis of block copolymers designed with different self-healing motifs incorporated into individual blocks. As a proof of concept, a novel pentablock copolymer (ABCBA) consisting of a poly(ethylene glycol) middle block and self-healable symmetric blocks of a polymethacrylate with pendant disulfide linkages and carboxylic acids is synthesized by a combination of consecutive controlled radical polymerization with hydrolytic cleavage...
February 21, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28220960/a-comparative-investigation-of-bombyx-mori-silk-fibroin-hydrogels-generated-by-chemical-and-enzymatic-crosslinking
#4
Traian V Chirila, Shuko Suzuki, Chloé Papolla
Fibroin, the major proteinaceous component of the silk fiber produced by larvae of the domesticated silk moth (Bombyx mori), has been widely investigated as a biomaterial for potential applications in tissue engineering and regenerative medicine. Following sol-gel transition, silk fibroin solutions can generate hydrogels that present certain advantages when employed as biomaterials, especially if they are crosslinked. The subject of this study was the self-crosslinking of silk fibroin through a process induced by the enzyme horseradish peroxidase (HRP) in the presence of hydrogen peroxide, a method only recently proposed and scarcely reported...
February 21, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28219689/in-vitro-drug-release-profiles-of-ph-sensitive-hydroxyethylacryl-chitosan-sodium-alginate-hydrogels-using-paracetamol-as-a-soluble-model-drug
#5
Pitchaya Treenate, Pathavuth Monvisade
The aim of this study is to investigate in vitro drug release profiles of pH-sensitive hydrogels composed of hydroxyethylacryl chitosan (HC) and sodium alginate (SA). The hydrogels were crosslinked by dipping method using different ionic crosslinkers (e.g., Ca(2+), Zn(2+) and Cu(2+)). The crosslinking reaction was confirmed by FT-IR. Swelling behavior and stability of the hydrogels in simulated digestive media were investigated. The result indicated that the combination between HC and SA could delay the degradation time of the hydrogels...
February 17, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28219688/mesoporous-phenylalanine-ammonia-lyase-microspheres-with-improved-stability-through-calcium-carbonate-templating
#6
Jiandong Cui, Yamin Zhao, Zhilei Tan, Cheng Zhong, Peipei Han, Shiru Jia
Cross-linked enzyme aggregates (CLEAs) have recently emerged as a promising method for enzyme immobilization due to its simplicity and low cost. However, a lack of good size and morphological control over the as-prepared CLEAs has limited their practical applications in some cases. Here, monodisperse spherical CLEAs of phenylalanine ammonia lyase (PAL microspheres) were prepared based on CaCO3 microtemplates. The preparation procedure involves filling porous CaCO3 microtemplates with the protein by salt precipitation, glutaraldehyde crosslinking, and dissolution of the microtemplates...
February 17, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28218841/the-mechanism-of-human-apohemoglobin-unfolding
#7
Premila P Samuel, William Christopher Ou, George N Phillips, John Steven Olson
Removal of heme from human hemoglobin (Hb) results in formation of an apoglobin heterodimer. Titration of this apo-dimer with GdnHCl leads to biphasic unfolding curves indicating two distinct steps. Initially the heme pocket unfolds and generates a dimeric intermediate in which ~50% of the original helicity is lost, but the α1β1 interface is still intact. At higher [GdnHCl], this intermediate dissociates into unfolded monomers. This structural interpretation was verified by comparing GdnHCl titrations for adult human hemoglobin A (HbA), recombinant fetal human hemoglobin (HbF), recombinant Hb crosslinked with a single glycine linker between the α chains (rHb0...
February 20, 2017: Biochemistry
https://www.readbyqxmd.com/read/28218515/chlorinated-glycopeptide-antibiotic-peptide-precursors-improve-cytochrome-p450-catalyzed-cyclization-cascade-efficiency
#8
Madeleine Peschke, Clara Brieke, Rob Goode, Ralf Schittenhelm, Max J Cryle
The activity of glycopeptide antibiotics depends upon important structural modifications to their precursor heptapeptide backbone: specifically, the Cytochrome P450-catalyzed oxidative crosslinking of aromatic side chains as well as the halogenation of specific residues within the peptide. The timing of halogenation and its effect on the cyclization of the peptide is currently unclear. Our results show that chlorination of peptide precursors improves their processing by P450 enzymes in vitro, which provides support for GPA halogenation occurring prior to peptide cyclization during non-ribosomal peptide synthesis...
February 20, 2017: Biochemistry
https://www.readbyqxmd.com/read/28216463/successful-application-of-large-microneedle-patches-by-human-volunteers
#9
Anastasia Ripolin, James Quinn, Eneko Larrañeta, Eva Maria Vicente-Perez, Johanne Barry, Ryan F Donnelly
We describe, for the first time, the design, production and evaluation of large microneedle patches. Such systems, based on 16 individual microneedle arrays (needle height 600μm), were prepared from aqueous blends of 15% w/w Gantrez(®) S97 and 7.5% w/w poly(ethyleneglycol) 10,000Da. Ester-based crosslinking was confirmed by FTIR and mechanical strength was good. Insertion depths in a validated skin model were approximately 500μm. Ten human volunteers successfully self-inserted the microneedles of these larger patches in their skin, following appropriate instruction, as confirmed by transepidermal water loss measurements...
February 16, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28215070/influence-of-hierarchical-interfacial-assembly-on-lipase-stability-and-performance-in-deep-eutectic-solvent
#10
Stephanie M Andler, Li-Sheng Wang, Vincent M Rotello, Julie M Goddard
Hierarchical systems that integrate nano- and macroscale structural elements can offer enhanced enzyme stability over traditional immobilization methods. Microparticles were synthesized using interfacial assembly of lipase B from Candida antarctica with (CLMP-N) and without (CLMP) nanoparticles around a crosslinked polymeric core, to characterize the influence of the hierarchical assembly on lipase stability in extreme environments. Kinetic analysis revealed the turnover rate (kcat) significantly increased after immobilization...
February 20, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28214743/tio2-nanowire-arrays-modified-with-a-simultaneous-etching-doping-and-deposition-technique-for-ultrasensitive-amperometric-immunosensing
#11
Xiaoqiang Liu, Xiaohe Huo, Peipei Liu, Yunfei Tang, Jun Xu, Huangxian Ju
In this work, an ultrasensitive immunosensing scaffold was structured with TiO2 nanowire (TiNW) arrays modified with molybdenum (Mo) and MoS2 flakes by a triplex "etching, doping and deposition" technique. The triply modification of TiNW arrays improved their electron transfer, and the decoration of MoS2 flakes on TiNW arrays increased both the conductivity and the specific surface area of TiNW. Accordingly, the triply modified TiNW arrays provided a biocompatible microenviroment for the biomolecules and high specific surface area to load big amount of biomolecules...
February 14, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28213846/fixation-of-bovine-pericardium-based-tissue-biomaterial-with-irreversible-chemistry-improves-biochemical-and-biomechanical-properties
#12
H Tam, W Zhang, D Infante, N Parchment, M Sacks, N Vyavahare
Bioprosthetic heart valves (BHVs), derived from glutaraldehyde crosslinked (GLUT) porcine aortic valve leaflets or bovine pericardium (BP), are used to replace defective heart valves. However, valve failure can occur within 12-15 years due to calcification and/or progressive structural degeneration. We present a novel fabrication method that utilizes carbodiimide, neomycin trisulfate, and pentagalloyl glucose crosslinking chemistry (TRI) to better stabilize the extracellular matrix of BP. We demonstrate that TRI-treated BP is more compliant than GLUT-treated BP...
February 17, 2017: Journal of Cardiovascular Translational Research
https://www.readbyqxmd.com/read/28213523/identification-of-regions-in-the-spt5-subunit-of-dsif-that-are-involved-in-promoter-proximal-pausing
#13
Yijun Qiu, David S Gilmour
DRB-sensitivity inducing factor (DSIF(2), or Spt4/5) is a conserved transcription elongation factor that both inhibits and stimulates transcription elongation in metazoans. In Drosophila and vertebrates, DSIF together with negative elongation factor (NELF) associates with RNA polymerase II (Pol II) during early elongation and causes Pol II to pause in the promoter proximal region of genes. The mechanism of how DSIF establishes pausing is not known. We constructed Spt5 mutant forms of DSIF and tested their capacity to restore promoter proximal pausing to DSIF-depleted Drosophila nuclear extracts...
February 17, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28211205/locking-interconversion-of-aromatic-oligoamide-foldamers-by-intramolecular-side-chain-crosslinking-toward-absolute-control-of-helicity-in-synthetic-aromatic-foldamers
#14
Lu Zheng, Chengyuan Yu, Yulin Zhan, Xuebing Deng, Ying Wang, Hua Jiang
A series of foldamers of 8-amino-2-quinolinecarboxylic acid were stapled by intramolecular ring-closing olefin metathesis to generate the constrained aromatic foldamers with varying lengths of hydrocarbon side-chains. Investigations clearly revealed that the side-chain crosslinkers are capable of completely locking the interconversions of the stapled aromatic foldamers over a wide range of temperature in CDCl3, even in C2D2Cl4. Hence, the stapled foldamers with the short hydrocarbon crosslinker can be easily separated by silica gel chromatography to generate foldamers with stable, absolute one-handed helicity...
February 16, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28210379/two-crosslinking-technologies-for-superficial-reticular-dermis-injection-a-comparative-ultrasound-and-histologic-study
#15
Patrick Micheels, Stéphanie Besse, Didier Sarazin
Background: Few hyaluronic acid fillers have been developed for superficial injection. Objective: To compare the diffusion and integration properties of cohesive polydensified matrix and Vycross® technology hyaluronic acid fillers with lidocaine following injection into the superficial reticular dermis. Methods and materials: Two subjects received two injections each of cohesive polydensified matrix and Vycross® hyaluronic acid (0.2mL/site) in the superficial reticular dermis of the buttock under ultrasound control...
January 2017: Journal of Clinical and Aesthetic Dermatology
https://www.readbyqxmd.com/read/28209516/movement-of-the-%C3%AE-hairpin-in-the-third-zinc-binding-module-of-uvra-is-required-for-dna-damage-recognition
#16
Thanyalak Kraithong, Ketsaraphorn Channgam, Ornchuma Itsathitphaisarn, Montip Tiensuwan, David Jeruzalmi, Danaya Pakotiprapha
Nucleotide excision repair (NER) is distinguished from other DNA repair pathways by its ability to process various DNA lesions. In bacterial NER, UvrA is the key protein that detects damage and initiates the downstream NER cascade. Although it is known that UvrA preferentially binds to damaged DNA, the mechanism for damage recognition is unclear. A β-hairpin in the third Zn-binding module (Zn3hp) of UvrA has been suggested to undergo a conformational change upon DNA binding, and proposed to be important for damage sensing...
February 7, 2017: DNA Repair
https://www.readbyqxmd.com/read/28209339/vitamin-e-stabilized-highly-crosslinked-polyethylenes-the-role-and-effectiveness-in-total-hip-arthroplasty
#17
Kengo Yamamoto, Toshiyuki Tateiwa, Yasuhito Takahashi
Morphology and design of ultra-high molecular weight polyethylene (UHMWPE or simply PE) acetabular components used in total hip arthroplasty (THA) have been evolving for more than half a century. Since the late-1990s, there were two major technological innovations in PE emerged from necessity to overcome the wear-induced periprosthetic osteolysis, i.e., the development of highly crosslinked PEs (HXLPEs). There are many literature reporting that radiation crosslinked and remelted/annealed (first-generation) HXLPEs markedly reduced the incidence of osteolysis and aseptic loosening...
February 10, 2017: Journal of Orthopaedic Science: Official Journal of the Japanese Orthopaedic Association
https://www.readbyqxmd.com/read/28208644/novel-magnetic-cross-linked-cellulase-aggregates-with-a-potential-application-in-lignocellulosic-biomass-bioconversion
#18
Junqi Jia, Weiwei Zhang, Zengjie Yang, Xianling Yang, Na Wang, Xiaoqi Yu
The utilization of renewable biomass resources to produce high-value chemicals by enzymatic processes is beneficial for alternative energy production, due to the accelerating depletion of fossil fuels. As immobilization techniques can improve enzyme stability and reusability, a novel magnetic cross-linked cellulase aggregate has been developed and applied for biomass bioconversion. The crosslinked aggregates could purify and immobilize enzymes in a single operation, and could then be combined with magnetic nanoparticles (MNPs), which provides easy separation of the materials...
February 10, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28207270/intracellular-delivery-colloidally-stable-core-crosslinked-triblock-copolymer-micelles-with-glutathione-responsive-enhanced-drug-release-for-cancer-therapy
#19
Jung Kwon Oh, Depannita Biswas, So Young An, Yijing Li, Xiangtao Wang
Design and development of amphiphilic block copolymer-based nanocarriers exhibiting enhanced colloidal stability upon dilution in the blood and cellular glutathione-responsive rapid drug release is highly desired for tumor-targeting chemotherapy. Herein, we report a novel ABA-type triblock copolymer consisting of a hydrophilic central poly(ethylene glycol) block and two terminal hydrophobic blocks of a polymethacrylate having pendant disulfides (PHMssEt), thus PHMssEt-b-PEG-b-PHMssEt (ssTP). Aqueous self-assembly and following disulfide-exchange reaction of the resulting ssTP allows for formation of core-crosslinked micelles (CCMs) through the formation of new disulfide linkages, retaining enhanced colloidal stability in physiological condition and in the presence of proteins...
February 16, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28207251/cross-linked-micellar-spherical-nucleic-acids-from-thermoresponsive-templates
#20
Resham J Banga, Brian Meckes, Suguna P Narayan, Anthony J Sprangers, SonBinh T Nguyen, Chad A Mirkin
A one-pot synthesis of micellar spherical nucleic acid (SNA) nanostructures using Pluronic F127 as a thermoresponsive template is reported. These novel constructs are synthesized in a chemically straightforward process that involves intercalation of the lipid tails of DNA amphiphiles (CpG motifs for TLR-9 stimulation) into the hydrophobic regions of Pluronic F127 micelles followed by chemical cross-linking and subsequent removal of non-crosslinked structures. The dense nucleic acid shell of the resulting cross-linked micellar SNA enhances their stability in physiological media and facilitates their rapid cellular internalization making them effective TLR-9 immunomodulatory agents...
February 16, 2017: Journal of the American Chemical Society
keyword
keyword
36416
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"