The effect of chemical and structural modifiers on the haemostatic process and cytotoxicity of the beta-chitin patch.

Beta-chitin patch has previously been proven to be an effective haemostat, but whether modifying the patch affects its efficacy and safety, remains unanswered. In this study, the patch was modified using polyethylene oxide, Pluronic-F127, calcium, increased thickness or polyphosphate, and their effect on the process of haemostasis and cytotoxicity was tested and compared with standard-of-care, Surgicel and FloSeal. Whole blood collected from volunteers was applied to the patches to test their whole blood clotting and thrombin generation capacities, whilst platelet isolates were used to test their platelet aggregation ability.

Preparation, Properties and Cell Biocompatibility of Room Temperature LCST-Hydrogels Based on Thermoresponsive PEO Stars.

A series of star and linear polymers based on a poly(ethylene oxide) core and poly(diethylene glycol ethyl ether acrylate) outer arms were synthesised by atom-transfer radical polymerization. The polydispersity of the polymers were low, showing good control of initiation and growth. They all showed lower critical solution (LCST) behaviour, and at 30% concentration most gelled at or below room temperature.

Formation of a robust, double-walled LiMOF from an L-shaped di-substituted N-heterocyclic adamantane-based ligand.

The properties of adamantane render it an attractive building block towards the synthesis of robust frameworks. This work describes the synthesis of the L-shaped 1,3-bis(3'-carboxypyridine)adamantane (L1) ligand and the corresponding Li(i), Zn(ii) and Cu(ii) frameworks. Three topologically analogous Li(i) frameworks LiMOF12, LiMOF30 and LiMOF50 are reported, with calculated solvent accessible void volumes of 46, 43 and 36%, respectively.

Tough polymeric hydrogels using ion-pair comonomers.

Hydrogels with excellent mechanical properties were synthesized by radical photo-polymerization of three different types of ion-pair comonomers (IPC), without requiring any chemical cross-linking agent. Insoluble gels formed only at a specific solution concentration range, which was unique to the particular salt. The gels changed properties after one day soaking in water, becoming less stiff and more extendible, but remained stable after that.

The structure and Hirshfeld surface analysis of the salt 3-methacryl-amido-,,-tri-methyl-propan-1-aminium 2-acryl-amido-2-methyl-propane-1-sulfonate.

The title salt, CHNO·CHNOS, comprises a 3-methacryl-amido-,,-tri-methyl-propan-1-aminium cation and a 2-acryl-amido-2-methyl-propane-1-sulfonate anion. The salt crystallizes with two unique cation-anion pairs in the asymmetric unit of the ortho-rhom-bic unit cell. The crystal studied was an inversion twin with a 0.

Gel actuators based on polymeric radicals.

Low-voltage electrochemical actuation of radical polymer gels has been demonstrated in an organic electrolyte. Polymer gels were prepared by post-modification of active-ester precursor gels with an amine-functionalised radical. A combination of few-layer graphene and multiwall carbon nanotubes gave high conductivity and improved actuation in the gels, with 32% linear actuation.

Structure and Hirshfeld surface analysis of the salt ,,-trimethyl-1-(4-vinyl-phen-yl)methanaminium 4-vinyl-benzene-sulfonate.

In the title compound, the asymmetric unit comprises an ,,-trimethyl-1-(4-vinyl-phen-yl)methanaminium cation and a 4-vinyl-benzene-sulfonate anion, CHN·CHOS. The salt has a polymerizable vinyl group attached to both the cation and the anion. The methanaminium and vinyl substituents on the benzene ring of the cation subtend angles of 86.

A Design Strategy for Single-Stranded Helicates using Pyridine-Hydrazone Ligands and Pb.

The reactions of py-hz ligands (L1-L5) with Pb(CF SO ) ⋅H O resulted in some rare examples of discrete single-stranded helical Pb complexes. L1 and L2 formed non-helical mononuclear complexes [PbL1(CF SO ) ]⋅CHCl and PbL2(CF SO ) ][PbL2CF SO ]CF SO ⋅CH CN, which reflected the high coordination number and effective saturation of Pb by the ligands. The reaction of L3 with Pb resulted in a dinuclear meso-helicate [Pb L3(CF SO ) Br]CF SO ⋅CH CN with a stereochemically-active lone pair on Pb .

The efficacy of a novel budesonide chitosan gel on wound healing following endoscopic sinus surgery.

Background: Adhesion formation and ostial stenosis are common causes of surgical failure after endoscopic sinus surgery (ESS). Postoperative topical steroid application has been shown to improve wound healing. Chitosan-dextran gel (CD gel) is an effective hemostatic nasal dressing.

A mechanically strengthened polyacrylamide gel matrix fully compatible with electrophoresis of proteins and nucleic acids.

Polyacrylamide gel electrophoresis is a universal tool in a biochemist's toolkit for protein and nucleic acid separation and subsequent visualisation and analysis. The standard formulation of polyacrylamide gels consists of acrylamide (ACM) monomer crosslinked with bisacrylamide (MBA) which creates a gel with excellent sieving properties but which is mechanically fragile and prone to tearing during post-electrophoresis manipulations involved in visualisation and analysis. By adding a poly(ethylene oxide) macro-crosslinker to the standard gel formulation, we have created a tough gel matrix that can be used to fractionate proteins and nucleic acids by polyacrylamide gel electrophoresis.

Crystal structures of the polymer precursors 3-(2,5-dimeth-oxy-3,4,6-tri-methyl-phen-yl)propyl methacrylate and 3-(2,4,5-trimethyl-3,6-dioxo-cyclo-hexa-1,4-dien-yl)propyl methacrylate.

The closely related title compounds, 3-(2,5-dimeth-oxy-3,4,6-tri-methyl-phen-yl)propyl methacrylate, CHO (I), and 3-(2,4,5-trimethyl-3,6-dioxo-cyclo-hexa-1,4-dien-yl)propyl methacrylate, CHO (II), are monomers suitable for the preparation of redox polymers. They consist of a propyl-methacrylate group and three methyl substituents on di-meth-oxy-benzene and quinone cores, respectively. Both crystal structures feature weak C-H⋯O hydrogen bonds and C-H⋯π(ring) contacts between methyl groups and the six-membered rings.

Hyperelastic Tough Gels through Macrocross-Linking.

The wet and soft nature of hydrogels makes them useful as a mimic for biological tissues, and in uses such as actuators and drug delivery vehicles. For many applications the mechanical performance of the gel is critical, but gels are notoriously weak and prone to fracture. Free radical polymerization is a very powerful technique allowing for fine spatial and temporal control of polymerization, but also allows for the use of a wide range of monomers and mixtures.

Antimicrobial Properties of Tris(homoleptic) Ruthenium(II) 2-Pyridyl-1,2,3-triazole "Click" Complexes against Pathogenic Bacteria, Including Methicillin-Resistant Staphylococcus aureus (MRSA).

A series of tris(homoleptic) ruthenium(II) complexes of 2-(1-R-1H-1,2,3-triazol-4-yl)pyridine "click" ligands (R-pytri) with various aliphatic (R = butyl, hexyl, octyl, dodecyl, and hexdecyl) and aromatic (R = phenyl and benzyl) substituents was synthesized in good yields (52%-66%). The [Ru(R-pytri)](X) complexes (where X = PF or Cl) were characterized by elemental analysis, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), H and C nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies, and the molecular structures of six of the compounds confirmed by X-ray crystallography. H NMR analysis showed that the as-synthesized materials were a statistical mixture of the mer- and fac-[Ru(R-pytri)] complexes.

Cyclodextrin-polyhydrazine degradable gels for hydrophobic drug delivery.

An injectable and biocompatible hydrogel system was designed for hydrophobic drug delivery. This hydrogel consisted of degradable polymers with cyclodextrin (CD) moieties. CD groups were used to increase the solubility of a hydrophobic molecule (nicardipine) in an aqueous solution through the formation of the inclusion complex.

Crystal structures of two bis-(iodo-meth-yl)benzene derivatives: similarities and differences in the crystal packing.

The isomeric derivatives 1,2-bis-(iodo-meth-yl)benzene, (I), and 1,3-bis-(iodo-meth-yl)benzene (II), both C8H8I2, were prepared by metathesis from their di-bromo analogues. The ortho-derivative, (I), lies about a crystallographic twofold axis that bis-ects the C-C bond between the two iodo-methyl substituents. The packing in (I) relies solely on C-H⋯I hydrogen bonds supported by weak parallel slipped π-π stacking inter-actions [inter-centroid distance = 4.

Synthesis of triphenylphosphonium vitamin E derivatives as mitochondria-targeted antioxidants.

A series of mitochondria-targeted antioxidants comprising a lipophilic triphenylphosphonium cation attached to the antioxidant chroman moiety of vitamin E by an alkyl linker have been prepared. The synthesis of a series of mitochondria-targeted vitamin E derivatives with a range of alkyl linkers gave compounds of different hydrophobicities. This work will enable the dependence of antioxidant defence on hydrophobicity to be determined in vivo.

Strong poly(ethylene oxide) based gel adhesives via oxime cross-linking.

Unlabelled: There is a demand for materials to replace or augment the use of sutures and staples in surgical procedures. Currently available commercial surgical adhesives provide either high bond strength with biological toxicity or polymer and protein-based products that are biologically acceptable (though with potential sensitizing potential) but have much reduced bond strength. It is desirable to provide novel biocompatible and biodegradable surgical adhesives/sealants capable of high strength with minimal immune or inflammatory response.

Structure and packing of aminoxyl and piperidinyl acrylamide monomers.

The closely related title compounds, 4-acrylamido-2,2,6,6-tetramethylpiperidine-1-oxyl, C12H21N2O2, (I), and N-(2,2,6,6-tetramethylpiperidin-4-yl)acrylamide monohydrate, C12H22N2O·H2O, (II), are important monomers in the preparation of redox-active polymers. They comprise an acrylamide group of the usual s-cis configuration appended to a 2,2,6,6-tetramethyl-substituted piperidine-1-oxyl radical or a piperidinyl chair, respectively. The adjacent amide and piperidinyl H atoms are approximately trans across the C-N bond.

Reducing the Oxidation Level of Dextran Aldehyde in a Chitosan/Dextran-Based Surgical Hydrogel Increases Biocompatibility and Decreases Antimicrobial Efficacy.

A highly oxidized form of a chitosan/dextran-based hydrogel (CD-100) containing 80% oxidized dextran aldehyde (DA-100) was developed as a post-operative aid, and found to significantly prevent adhesion formation in endoscopic sinus surgery (ESS). However, the CD-100 hydrogel showed moderate in vitro cytotoxicity to mammalian cell lines, with the DA-100 found to be the cytotoxic component. In order to extend the use of the hydrogel to abdominal surgeries, reformulation using a lower oxidized DA (DA-25) was pursued.

Characterization of the in vivo host response to a bi-labeled chitosan-dextran based hydrogel for postsurgical adhesion prevention.

In developing a chitosan/dextran-based (CD) hydrogel as an adhesion prevention postsurgical aid, the in vivo biodegradation rate, biodistribution, and inflammatory response are important parameters to the biomedical device design. Herein, for the first time, a CD hydrogel was prepared by mixing aqueous solutions of a near infrared (NIR) labeled succinylated chitosan (SC) and tritiated [(3) H] oxidized dextran (DA). The biodegradation and biodistribution of the NIR/[(3) H]-CD hydrogel was tracked noninvasively using NIR fluorescence imaging, and by liquid scintillation counting (LSC) of organs/tissues after subcutaneous injection in BALB/c mice.

Crystal structure of 4-(prop-2-yn-yloxy)-2,2,6,6-tetra-methyl-piperidin-1-ox-yl.

The title compound, C12H20NO2, was synthesized from 4-hy-droxy-2,2,6,6-tetra-methyl-piperidin-1-oxyl (hy-droxy-TEMPO) and propargyl bromide. The six-membered ring adopts a flattened chair conformation and carries a propyn-yloxy substituent in an equatorial orientation at the 4-position. The N-O bond length of the piperidin-1-oxyl unit is 1.

The use of chitosan-dextran gel shows anti-inflammatory, antibiofilm, and antiproliferative properties in fibroblast cell culture.

Background: Chitosan-dextran gel has been used as an antihemostatic agent and antiadhesive agent after endoscopic sinus surgery. Because Staphylococcus aureus biofilms have been implicated in recalcitrant chronic rhinosinusitis, this study aimed to further investigate the (i) anti-inflammatory, (ii) bacterial biofilm inhibition, (iii) antiproliferative effects, and (iv) wound-healing properties of chitosan and chitosan-dextran gel.

Methods: Fibroblasts were isolated from human nasal tissue and were used to determine the effects of chitosan and chitosan-dextran gel on (i) cell proliferation, (ii) wound healing, (iii) inflammation in fibroblast cultures challenged with superantigens S.

Synthesis, physiochemical characterization, and biocompatibility of a chitosan/dextran-based hydrogel for postsurgical adhesion prevention.

An amine-functionalized succinyl chitosan and an oxidized dextran were synthesized and mixed in aqueous solution to form an in situ chitosan/dextran injectable, surgical hydrogel for adhesion prevention. Rheological characterization showed that the rate of gelation and moduli were tunable based on amine and aldehyde levels, as well as polymer concentrations. The CD hydrogels have been shown to be effective post-operative aids in prevention of adhesions in ear, nose, and throat surgeries and abdominal surgeries in vivo.

In vitro biocompatibility and cellular interactions of a chitosan/dextran-based hydrogel for postsurgical adhesion prevention.

In this paper, we report the in vitro biocompatibility and cellular interactions of a chitosan/dextran-based (CD) hydrogel and its components as determined by mutagenicity, cytotoxicity, cytokine/chemokine response, and wound healing assays. The CD hydrogel, developed for postsurgical adhesion prevention in ear, nose, and throat surgeries, was shown by previously published experiments in animal and human trials to be effective. The hydrogel was synthesized from the reaction between succinyl chitosan (SC) and oxidized dextran (DA).

Tetratopic pyrimidine-hydrazone ligands modified with terminal hydroxymethyl and acryloyl arms and their Pb(II), Zn(II), Cu(II) and Ag(I) complexes.

The first tetratopic pyrimidine-hydrazone (pym-hyz) molecular strands containing terminal hydroxymethyl (L1) and acryloyl (L2) functional groups have been synthesised. L1 was produced by step-wise imine condensation reactions, starting with 6-hydroxymethyl-2-pyridinecarboxaldehyde. L2 was then synthesised through the treatment of L1 with acryloyl chloride.