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https://www.readbyqxmd.com/read/29161461/ruthenium-crosslinked-hydrogels-with-rapid-visible-light-degradation
#1
Teresa Rapp, Chris Highley, Brian Manor, Jason Burdick, Ivan J Dmochowski
Incorporation of photoresponsive molecules within soft materials can provide spatiotemporal control over bulk properties, and address challenges in targeted delivery and mechanical variability. However, the kinetics of in situ photochemical reactions are often slow and typically employ ultraviolet wavelengths. Here, we present a novel photoactive crosslinker Ru(bipyridine)2(3-pyridinaldehyde)2 (RuAldehyde), which was reacted with hydrazide-functionalized hyaluronic acid to form hydrogels capable of encapsulating protein cargo...
November 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29161020/deformation-drives-alignment-of-nanofibers-in-framework-for-inducing-anisotropic-cellulose-hydrogels-with-high-toughness
#2
Dongdong Ye, Qiaoyun Cheng, Qianlei Zhang, Yixiang Wang, Chunyu Chang, Liangbin Li, Haiyan Peng, Lina Zhang
Deformation driven alignment of molecules or nanofibers leading to anisotropy is a challenge in functional soft materials. Here, high toughness hydrogels with deformation-induced anisotropy are fabricated from cellulose solution in LiOH/urea, relying on successively designing a loose chemical crosslinking network and a dense physical network containing nanofibers and submicrobundles formed through parallel self-aggregation in dilute acid. The loose network acts as a large framework, whereas relatively dense physical networks are integrated inside, jointly constituting the hierarchical architecture...
November 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29160714/understanding-aqueous-stability-and-filtration-capability-of-mos2-membranes
#3
Zhongying Wang, Qingsong Tu, Sunxiang Zheng, Jeffrey J Urban, Shaofan Li, Baoxia Mi
Membranes made of layer-stacked two-dimensional molybdenum disulfide (MoS2) nanosheets have recently shown great promise for water filtration. At present, the reported water fluxes vary significantly while the accountable structure and properties of MoS2 nanochannels are largely unknown. This paper aims to mechanistically relate the performance of MoS2 membranes to the size of their nanochannels in different hydration states. We discovered that fully hydrated MoS2 membranes retained a 1.2-nm interlayer spacing (or 0...
November 21, 2017: Nano Letters
https://www.readbyqxmd.com/read/29160130/the-effect-of-bearing-type-on-the-outcome-of-total-hip-arthroplasty
#4
Rinne M Peters, Liza N Van Steenbergen, Martin Stevens, Paul C Rijk, Sjoerd K Bulstra, Wierd P Zijlstra
Background and purpose - Alternative bearing surfaces such as ceramics and highly crosslinked polyethylene (HXLPE) were developed in order to further improve implant performance of total hip arthroplasties (THAs). Whether these alternative bearing surfaces result in increased longevity is subject to debate. Patients and methods - Using the Dutch Arthroplasty Register (LROI), we identified all patients with a primary, non-metal-on-metal THA implanted in the Netherlands in the period 2007-2016 (n = 209,912). Cumulative incidence of revision was calculated to determine differences in survivorship of THAs according to bearing type: metal-on-polyethylene (MoPE), metal-on-HXLPE (MoHXLPE), ceramic-on-polyethylene (CoPE), ceramic-on-HXLPE (CoHXLPE), ceramic-on-ceramic (CoC), and oxidized-zirconium-on-(HXL)polyethylene (Ox(HXL)PE)...
November 21, 2017: Acta Orthopaedica
https://www.readbyqxmd.com/read/29159831/design-and-development-of-low-cost-polyurethane-biopolymer-based-on-castor-oil-and-glycerol-for-biomedical-applications
#5
A C W Tan, B J Polo-Cambronell, E Provaggi, C Ardila-Suárez, G E Ramirez-Caballero, V G Baldovino-Medrano, D M Kalaskar
In the current study, we present the synthesis of novel low cost bio-polyurethane compositions with variable mechanical properties based on castor oil and glycerol for biomedical applications. A detailed investigation of the physicochemical properties of the polymer was carried out by using mechanical testing, ATR-FTIR, and X-ray photoelectron spectroscopy (XPS). Polymers were also tested in short term in-vitro cell culture with human mesenchymal stem cells to evaluate their biocompatibility for potential applications as biomaterial...
November 21, 2017: Biopolymers
https://www.readbyqxmd.com/read/29159145/ph-responsive-cross-linked-polymeric-matrices-based-on-natural-polymers-effect-of-process-variables-on-swelling-characterization-and-drug-delivery-properties
#6
Fahad Naeem, Samiullah Khan, Aamir Jalil, Nazar Muhammad Ranjha, Amina Riaz, Malik Salman Haider, Shoaib Sarwar, Fareha Saher, Samrin Afzal
Introduction: The current work was aimed to design and synthesize novel crosslinked pH-sensitive gelatin/pectin (Ge/Pec) hydrogels using different polymeric ratios and to explore the effect of polymers and degree of crosslinking on dynamic, equilibrium swelling and in vitro release behavior of the model drug (Mannitol). Methods: The Ge/Pec based hydrogels were prepared using glutaraldehyde as the crosslinker. Various structural parameters that affect their release behavior were determined, including swelling study, porosity, sol-gel analysis, average molecular weight between crosslinks (Mc), volume fraction of polymer (V2,s), solvent interaction parameter (χ) and diffusion coefficient...
2017: BioImpacts: BI
https://www.readbyqxmd.com/read/29159144/thermoresponsive-graphene-oxide-starch-micro-nanohydrogel-composite-as-biocompatible-drug-delivery-system
#7
Mina Sattari, Marziyeh Fathi, Mansour Daei, Hamid Erfan-Niya, Jaleh Barar, Ali Akbar Entezami
Introduction: Stimuli-responsive hydrogels, which indicate a significant response to the environmental change (e.g., pH, temperature, light, …), have potential applications for tissue engineering, drug delivery systems, cell therapy, artificial muscles, biosensors, etc. Among the temperature-responsive materials, poly (N-isopropylacrylamide) (PNIPAAm) based hydrogels have been widely developed and their properties can be easily tailored by manipulating the properties of the hydrogel and the composite material...
2017: BioImpacts: BI
https://www.readbyqxmd.com/read/29158321/assembly-and-turnover-of-neurofilaments-in-growing-axonal-neurites
#8
Edward F Boumil, Rishel Vohnoutka, Sangmook Lee, Harish Pant, Thomas B Shea
Neurofilaments (NFs) are thought to provide stability to the axon. We examined NF dynamics within axonal neurites of NB2a/d1 neuroblastoma by transient transfection with green fluorescent protein-tagged NF-H (GFP-H) under the control of a tetracycline-inducible promoter. Immunofluorescent and biochemical analyses demonstrated that GFP-H expressed early during neurite outgrowth associated with a population of centrally-situated, highly-phosphorylated crosslinked NFs along the length of axonal neurites ("bundled NFs")...
November 20, 2017: Biology Open
https://www.readbyqxmd.com/read/29157200/swellix-a-computational-tool-to-explore-rna-conformational-space
#9
Nathan Sloat, Jui-Wen Liu, Susan J Schroeder
BACKGROUND: The sequence of nucleotides in an RNA determines the possible base pairs for an RNA fold and thus also determines the overall shape and function of an RNA. The Swellix program presented here combines a helix abstraction with a combinatorial approach to the RNA folding problem in order to compute all possible non-pseudoknotted RNA structures for RNA sequences. The Swellix program builds on the Crumple program and can include experimental constraints on global RNA structures such as the minimum number and lengths of helices from crystallography, cryoelectron microscopy, or in vivo crosslinking and chemical probing methods...
November 21, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/29156637/synthesis-and-improved-cross-linking-properties-of-c5-modified-furan-bearing-pnas
#10
Joke Elskens, Alex Manicardi, Valentina Costi, Annemieke Madder, Roberto Corradini
Over the past decades, peptide nucleic acid/DNA (PNA:DNA) duplex stability has been improved via backbone modification, often achieved via introducing an amino acid side chain at the α- or γ-position in the PNA sequence. It was previously shown that interstrand cross-linking can further enhance the binding event. In this work, we combined both strategies to fine-tune PNA crosslinking towards single stranded DNA sequences using a furan oxidation-based crosslinking method; for this purpose, γ-l-lysine and γ-l-arginine furan-PNA monomers were synthesized and incorporated in PNA sequences via solid phase synthesis...
November 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29155013/3-4-dihydroxyphenylacetaldehyde-synthase-and-cuticle-formation-in-insects
#11
Chenghong Liao, Archana Upadhyay, Jing Liang, Qian Han, Jianyong Li
Cuticle is the most important structure that protects mosquitoes and other insect species from adverse environmental conditions and infections of microorganism. The physiology and biochemistry of insect cuticle formation have been studied for many years and our understanding of cuticle formation and hardening has increased considerably. This is especially true for flexible cuticle. The recent discovery of a novel enzyme that catalyzes the production of 3,4-dihydroxyphenylacetaldehyde (DOPAL) in insects provides intriguing insights concerning the flexible cuticle formation in insects...
November 15, 2017: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/29154874/preparation-and-characterization-of-three-dimensional-scaffolds-based-on-hydroxypropyl-chitosan-graft-graphene-oxide
#12
P R Sivashankari, A Moorthi, K Mohamed Abudhahir, M Prabaharan
Hydroxypropyl chitosan (HPCH), a water soluble derivative of chitosan, is widely considered for tissue engineering and wound healing applications due to its biocompatibility and biodegradability. Graphene oxide (GO) is a carbon-based nanomaterial which is capable of imparting desired properties to the scaffolds. Hence, the integration of GO into HPCH could allow for the production of HPCH-based scaffolds with improved swelling character, mechanical strength, and stability aimed at being used in tissue engineering...
November 14, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29154021/diagnosis-of-fanconi-anaemia-by-ionising-radiation-or-mitomycin-c-induced-micronuclei
#13
Flavia Zita Francies, Rosalind Wainwright, Janet Poole, Kim De Leeneer, Ilse Coene, Greet Wieme, Hélène A Poirel, Bénédicte Brichard, Stephanie Vermeulen, Anne Vral, Jacobus Slabbert, Kathleen Claes, Ans Baeyens
Fanconi Anaemia (FA) is an autosomal recessive disorder characterised by defects in DNA repair, associated with chromosomal instability and cellular hypersensitivity to DNA cross-linking agents such as mitomycin C (MMC). The FA repair pathway involves complex DNA repair mechanisms crucial for genomic stability. Deficiencies in DNA repair genes give rise to chromosomal radiosensitivity. FA patients have shown increased clinical radiosensitivity by exhibiting adverse normal tissue side-effects. The study aimed to investigate chromosomal radiosensitivity of homozygous and heterozygous carriers of FA mutations using three micronucleus (MN) assays...
November 8, 2017: DNA Repair
https://www.readbyqxmd.com/read/29152858/in-vitro-evaluation-of-anti-aggregation-and-degradation-behavior-of-pegylated-polymeric-nanogels-under-in-vivo-like-conditions
#14
Yinan Chen, George R Dakwar, Kevin Braeckmans, Twan Lammers, Wim E Hennink, Josbert M Metselaar
The in vivo stability and biodegradability of nanocarriers crucially determine therapeutic efficacy as well as safety when used for drug delivery. This study aims to evaluate optimized in vitro techniques predictive for in vivo nanocarrier behavior. Polymeric biodegradable nanogels based on hydroxyethyl methacrylamide-oligoglycolates-derivatized poly(hydroxyethyl methacrylamide-co-N-(2-azidoethyl)methacrylamide) and with various degrees of PEGylation and crosslinking densities are prepared. Three techniques are chosen and refined for specific in vitro evaluation of the nanocarrier performance: (1) fluorescence single particle tracking (fSPT) to study the stability of nanogels in human plasma, (2) tangential flow filtration (TFF) to study the degradation and filtration of nanogel degradation products, and (3) fluorescence fluctuation spectroscopy (FFS) to evaluate and compare the degradation behavior of nanogels in buffer and plasma...
November 20, 2017: Macromolecular Bioscience
https://www.readbyqxmd.com/read/29150765/finite-element-design-optimization-of-a-hyaluronic-acid-based-hydrogel-drug-delivery-device-for-improved-retention
#15
Jourdan Colter, Barbara Wirostko, Brittany Coats
Drug-loaded hydrogel devices are emerging as an effective means of localized and sustained drug delivery for the treatment of corneal conditions and injuries. One such device uses a novel, thiolated crosslinked carboxymethylated, hyaluronic acid-based hydrogel (CMHA-S) film to deliver drug to the ocular surface upon placement into the inferior fornix of the eye. While proven to be very safe and effective, the CMHA-S film tends to dislodge in the highly-lubricated ocular environment, thereby reducing drug delivery efficiency and drug efficacy...
November 17, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/29150605/global-role-of-the-bacterial-post-transcriptional-regulator-csra-revealed-by-integrated-transcriptomics
#16
Anastasia H Potts, Christopher A Vakulskas, Archana Pannuri, Helen Yakhnin, Paul Babitzke, Tony Romeo
CsrA is a post-transcriptional regulatory protein that is widely distributed among bacteria. This protein influences bacterial lifestyle decisions by binding to the 5' untranslated and/or early coding regions of mRNA targets, causing changes in translation initiation, RNA stability, and/or transcription elongation. Here, we assess the contribution of CsrA to gene expression in Escherichia coli on a global scale. UV crosslinking immunoprecipitation and sequencing (CLIP-seq) identify RNAs that interact directly with CsrA in vivo, while ribosome profiling and RNA-seq uncover the impact of CsrA on translation, RNA abundance, and RNA stability...
November 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/29150150/biocompatible-hollow-polymeric-particles-produced-by-a-mild-solvent-and-template-free-strategy
#17
Eustolia Rodríguez-Velázquez, Pablo Taboada, Manuel Alatorre-Meda
Macroscopic hollow polymeric particles are attractive materials for various applications such as surgery, food industry, agriculture, etc. However, protocols reporting their synthesis have hitherto made use of organic solvents and/or sacrificial templates, compromising the encapsulation of different bioactive compounds and the process yield. Here, millimeter-size, hollow polymeric particles were synthesized, for the first time, in a solvent- and template free manner onto superhydrophobic surfaces (SHS). The particles were produced upon assembly and double superficial crosslinking of liquid droplets of DNA and methacrylamide chitosan aqueous solutions (CH:MA), leading to liquid-core particles with a hardened hydrogel shell...
November 14, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/29148982/a-dentin-derived-hydrogel-bioink-for-3d-printing-of-cell-laden-scaffolds-for-regenerative-dentistry
#18
Avathamsa Athirasala, Anthony Tahayeri, Greeshma Thrivikraman, Cristiane Miranda Franca, Nelson Monteiro, Victor Tran, Jack Ferracane, Luiz Bertassoni
Recent studies in tissue engineering have adopted extracellular matrix (ECM) derived scaffolds as natural and cytocompatible microenvironments for tissue regeneration. The dentin matrix, specifically, has been shown to be associated with a host of soluble and insoluble signaling molecules that can promote odontogenesis. Here, we have developed a novel bioink, blending printable alginate (3% w/v) hydrogels with the soluble and insoluble fractions of the dentin matrix. We have optimized the printing parameters and the concentrations of the individual components of the bioink for print accuracy, cell viability and odontogenic potential...
November 17, 2017: Biofabrication
https://www.readbyqxmd.com/read/29148732/photocontrolled-release-of-doxorubicin-conjugated-through-a-thioacetal-photocage-in-folate-targeted-nanodelivery-systems
#19
Pamela T Wong, Shengzhuang Tang, Jayme Cannon, Dexin Chen, Rachel Sun, Jennifer Lee, James Phan, Ke Tao, Kang Sun, Biqiong Chen, James R Baker, Seok Ki Choi
Despite their proven ability for precise and targeted release, nanoplatform systems for photocontrolled delivery often face formidable synthetic challenges, in part, due to the paucity of advanced linker strategies. Here we report on a novel linker strategy using a thioacetal ortho-nitrobenzaldehyde (TNB) cage, demonstrating its application for delivery of doxorubicin (Dox) in two nanoscale systems. This photocleavable linker, TNB(OH), which presents two identical arms, each terminated with a hydroxyl functionality, was prepared in a single step from 6-nitroverataldehyde...
November 17, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/29147871/an-optimized-and-feasible-preparation-technique-for-the-industrial-production-of-hydrogel-patches
#20
Wei-Ze Li, Wen-Xia Han, Xu-Liang Hao, Ning Zhao, Xi-Feng Zhai, Li-Bin Yang, Shu-Miao He, Yu-Chuan Cheng, Han Zhang, Li-Na Fu, Yan Zhang, Ze Liang
For hydrogel patches, the laboratory tests could not fully reveal the existing problems of full scale of industrial production, and there are few studies about the preparation technique for the industrial manufacturing process of hydrogel patches. So, the purpose of this work was to elucidate the effects of mainly technological operation and its parameters on the performance of hydrogel patches at the industrial-scale production. The results revealed the following: (1) the aqueous phase was obtained by polyvinylpyrrolidone (PVP) along with tartaric acid dissolved in purified water, then feeding this into a vacuum mixer as a whole in one batch, thus extended the crosslinking reaction time of hydrogel paste (matrix) and allowed the operation of coating/cutting-off to be carried out easily, and there was no permeation of backing layer; (2) the gel strength of the hydrogel patches increased with the increase of working temperature, however, once the temperature exceeded 35 ± 2 °C, the hydrogel paste would lose water severely and the resultant physical crosslinking structure which has lower gel/cohesive strength would easily bring gelatinization/residues during application; (3) the relative humidity (RH) of the standing-workshop was dynamically controlled (namely at 35 ± 2 °C, keeping the RH at 55 ± 5% for 4 days, then 65 ± 5% for 2 days), which would make patches with satisfactory characteristics such as better flexibility, higher adhesive force, smooth flat matrix surface, and without gelatinization/residues and warped edge during the using process; (4) the aging of the packaged hydrogel patches was very sensitive to storage temperature, higher temperature, higher gel strength and lower adhesiveness...
November 16, 2017: AAPS PharmSciTech
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