Stephen Moratti

• Professor at University of Otago

Objective: Rapid and efficacious haemostasis is paramount in neurosurgery. Assessing the efficacy and short- and long-term safety of haemostatic agents utilised within cerebral tissue is essential. This pilot study investigates the haemostatic efficacy and long-term safety of a novel beta-chitin patch against traditionally used agents, bipolar and...

Background & objectives: Ostial stenosis and persistent inflammation are the main reasons for revision endoscopic sinus surgery (ESS). Post-operative (PO) dressings can improve PO wound healing and patient outcomes after ESS. This study aimed to determine the safety and efficacy of Chitogel, with and without Deferiprone (Def) and Gallium Protoporph...

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 3...

Introduction Adhesions are often considered to be an inevitable consequence of abdominal and pelvic surgery, jeopardizing the medium and long-term success of these procedures. Numerous strategies have been tested to reduce adhesion formation, however, to date, no surgical or medical therapeutic approaches have been successful in its prevention. Thi...

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...

Hydroxyapatite (HA) derived from bovine bones garnered wider interest as a bone substitute due to their abundant availability as meat wastes and similarities in morphology and mineral composition to human bone. In our previous work, we developed an easy and reproducible method to prepare xenograft HA scaffolds from NZ bovine cancellous bones (BHA)....

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 o...

Introduction: Spinal laminectomy is a common procedure performed to relieve neural compression in patients suffering from myelopathy or radiculopathy. However, up to 40% of patients suffer from persistent post-operative pain and disability, a condition known as Failed Back Surgery Syndrome (FBSS). Excessive scarring in the surgical bed is implicat...

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 ge...

The title salt, C10H21N2O⁺·C7H12NO4S⁻, comprises a 3-methacryl­amido-N,N,N-tri­methyl­propan-1-aminium cation and a 2-acryl­amido-2-methyl­propane-1-sulfonate anion. The salt crystallizes with two unique cation–anion pairs in the asymmetric unit of the ortho­rhom­bic unit cell. The crystal studied was an inversion twin with a 0.52 (4):0.48 (4) doma...

In the title compound, the asymmetric unit comprises an N,N,N-trimethyl-1-(4-vinyl­phen­yl)methanaminium cation and a 4-vinyl­benzene­sulfonate anion, C12H18N⁺·C8H7O3S⁻. 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....

The reactions of py‐hz ligands (L1–L5) with Pb(CF3SO3)2⋅H2O resulted in some rare examples of discrete single‐stranded helical PbII complexes. L1 and L2 formed non‐helical mononuclear complexes [PbL1(CF3SO3)2]⋅CHCl3 and PbL2(CF3SO3)2][PbL2CF3SO3]CF3SO3⋅CH3CN, which reflected the high coordination number and effective saturation of PbII by the ligan...

The title compound C12H8Br2N2O, lies on an inversion centre in the space group P21/n. Doubts are cast on the report of a polymorph of this structure in the non-centrosymmetric space group P21 [Zhu, R.-T., Liu, J.-C., Jin, S., Liu, B. & Guo J.-P. (2006). Hecheng Huaxue (Chin. J. Synth. Chem.) 14, 591] as ADDSYM alerts point strongly to a centrosymme...

Objectives: Increasing antimicrobial resistance has presented new challenges to the treatment of recalcitrant chronic rhinosinusitis fuelling a continuous search for novel antibiofilm agents. This study aimed to assess the safety and efficacy of Chitogel (Chitogel®, Wellington New Zealand) combined with novel antibiofilm agents Deferiprone and Gall...

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. This study aims to determine the effect of the addition of budeson...

A new hydrogel network was designed to study its capability in hydrophilic drug delivery. Two sets of chemically cross-linked hydrogels were prepared under mild conditions with different cross-linking densities. The precursors obtained by modification of a natural polymer and a synthetic polymer. Oxidation of dextran, natural polymer, produced dext...

A systematic expansion of the well-known non-interpenetrated and robust MOF-11 was accomplished through a rediscovery of the ligand tetrakis(4-carboxyphenyl)adamantane (L). The combination of a rigid tetrahedral L and copper(II) paddle-wheel secondary building unit (SBU) resulted in a stable non-interpenetrated metal-organic framework, UOF-1 (UOF =...

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...

Use of 316L stainless steel, with its highly stable chromium oxide passive layer, is ubiquitous in medical and food industry environments. There is little data in the literature on the ability of stainless steel to absorb multifunctional polymer layers which might impart different surface properties. Current research in this area focuses on layer b...

Bone tissue engineering has emerged as one of the most indispensable approaches to address bone trauma in the past few decades. This approach offers an efficient and a risk-free alternative to autografts and allografts by employing a combination of biomaterials and cells to promote bone regeneration. Hydroxyapatite (HA) is a ceramic biomaterial tha...

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 s...

Crystalline dibenzo-tetroxecin (I) has been prepared from a reaction between catechol and dichloromethane and its molecular and crystal structure, together with the Raman spectrum of the material in the solid state, is reported. The molecular structure shows the molecule adopts an anti or stepped conformation. Density functional theory (DFT) optimi...

In the title compound, C15H22O4, the fully substituted benzene ring carries a methyl propano­ate, two meth­oxy and three methyl substituents. Both meth­oxy substituents are almost orthogonal to the benzene ring plane. The methyl propano­ate group is almost planar, r.m.s. deviation 0.0138 Å, and is inclined to the benzene ring plane by 80.26 (14)°....

The closely related title compounds, 3-(2,5-dimeth­oxy-3,4,6-tri­methyl­phen­yl)propyl methacrylate, C18H26O4 (I), and 3-(2,4,5-trimethyl-3,6-dioxo­cyclo­hexa-1,4-dien­yl)propyl methacrylate, C16H20O4 (II), are monomers suitable for the preparation of redox polymers. They consist of a propyl­methacrylate group and three methyl substituents on di­me...

A rapid in-situ forming hydrogel was prepared as a potential carrier for the delivery of hydrophobic drugs. Schiff-base reaction between dextran aldehyde polymer (DA) and cyclodextrin-functionalized polyaspartamide with PEG pendants (PG) formed the gel. Two sets of hydrogels with different cross-linking densities and similar content of cyclodextrin...

Chitosan has emerged as an important biomaterial as it not only possesses a broad range of antimicrobial behavior but is also biodegradable with low mammalian toxicity. It is readily obtained from strong acid and basic treatment of chitinous materials such as crustacean shells. Its antimicrobial effect appears to arise from the interaction of the c...

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. Two sets of gels wer...

The design and synthesis of a Lonsdaleite (lon) network is an attractive and challenging supramolecular target. Our reticular synthesis strategy of slow diffusion of solutions of a simple rigid tetrahedral ligand and a Ag(I) metal ion, at room temperature and atmospheric pressure, resulted in both lon-MOFs and diamondoid (dia-MOFs) and associated 2...

Electroactive metallocene polymers are of inter­est due to the possibility that they offer a muscle-like response, and in gel systems very large volume changes are possible. The ferrocenyl moiety exhibits physical and electrochemical stability of the neutral and oxidized forms and could be a candidate for use as the redox-active group in these mate...

The isomeric derivatives 1,2-bis­(iodo­meth­yl)benzene, (I), and 1,3-bis­(iodo­meth­yl)benzene (II), both C8H8I2, were prepared by metathesis from their di­bromo analogues. The ortho-derivative, (I), lies about a crystallographic twofold axis that bis­ects the C—C bond between the two iodo­methyl substituents. The packing in (I) relies solely on C—...

Statement of significance: This work presents a new type of glue that is aimed at surgery applications using a water soluble star shaped polymer. It show excellent adhesion to skin and is tough and easy to use. We show that it is very biocompatible based on tests on live human cells, and could therefore in principle be used for internal surgery. C...

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,...

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...

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 show...

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 show...

There is considerable interest in the development of bifunctional ligand scaffolds for the group 7 metals due to potential biological applications. Building on our recent work in the development of “click” ligands and macrocycles, we show that a CuAAC “click” approach can be exploited for the synthesis of a small family of bioconjugated tridentate...

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 suc...

A composition suitable for use in wound healing, particularly for reducing post-surgical adhesions, containing cross-linked derivatives of chitosan and dextran polymers. A hydrogel forms when solutions of the polymers are combined.

The title compound, C12H20NO2, was synthesized from 4-hy­droxy-2,2,6,6-tetra­methyl­piperidin-1-oxyl (hy­droxy-TEMPO) and propargyl bromide. The six-membered ring adopts a flattened chair conformation and carries a propyn­yloxy substituent in an equatorial orientation at the 4-position. The N—O bond length of the piperidin-1-oxyl unit is 1.289 (3)...

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 conce...

Due to potential applications in the biological and material sciences there is considerable interest in the development of mechanically interlocked ligands (MILs). The mild functional-group tolerant copper(I)-catalysed azide-alkyne cycloaddition active-metal-template (CuAAC-AMT) method has been exploited to generate mono- and bi-functionalised [2]r...

The title compounds, [Co2(C8H11BrO3)(CO)6], (1), and [Co2(C12H16Br2O4)(CO)6], (2), result from the replacement of two carbonyl ligands from dicobalt octa­carbonyl by the alkynes 4-hy­droxy­but-2-ynyl 2-bromo-2-methyl­propano­ate and but-2-yne-1,4-diyl bis­(2-bromo-2-methyl­propano­ate), respectively. Both mol­ecules have classic tetra­hedral C2Co2...

The synthesis and characterisation by IR spectroscopy and elemental analysis of ten new Ag(I)-L complexes are described. Of these complexes, nine are characterised by single crystal X-ray diffraction: {[Ag(L)](CF3SO3)·1/2H2O}∞ (1), {[Ag(L)](ClO4)·1/2H2O}∞ (2), {[Ag2(L)2(CH3CN)](ClO4)2·2CH3CN·H2O}∞ (3), {[Ag2(L)2(CH3CN)2](ClO4)2·CH3CN}∞ (4), {[Ag2(L...

[28230-32-2] C7H5N3O2 (MW 163.15)1S/C7H5N3O2/c11-7-5-3-1-2-4-6(5)8-9-10(7)12/h1-4,12HInChIKey = HJBLUNHMOKFZQX-UHFFFAOYSA-N(additive to improve yields and decrease racemization in DCC-promoted peptide synthesis1)Alternate Names: Dhbt-OH; 3-hydroxy-4-keto-3,4-dihydro-1,2,3-benzotriazine, 3-hydroxy-1,2,3-benzotriazin-4(3H)-one; 3,4-dihydro-3-hydroxy-...

Two "small" 22- and 24-membered exo-alcohol functionalised pyridyl macrocycles are exploited in the CuAAC active-template synthesis of [2]rotaxanes. The 24-membered macrocycle forms [2]rotaxanes in good yields while the smaller 22-membered macrocycle does not lead to interlocked products.

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

The symmetrical, homoditopic, pyrimidine-hydrazone (pym-hyz) ligand L1 was used to synthesise three new heterobimetallic complexes, CuPbL1(ClO4)(4), CuAgL1(SO3CF3)(3), and CuZnL1(SO3CF3)(4). Each of the complexes was produced in a one-pot reaction in CH3CN, and was isolated in high yield and purity simply by precipitation through the addition of di...

A new hydroxymethyl terminated pyrimidine-hydrazone (pym-hyz) ligand (L1) was synthesized with a central hyz-pyridine-hyz (hyz-py-hyz) motif replacing the usual hyz-pym-hyz unit, to create a molecular strand that underwent metal-induced isomerization with a minimal net change in ligand length. NMR spectroscopy showed that L1 had a horseshoe shape d...

Background: Stenosis of sinus ostia following endoscopic sinus surgery (ESS) is the most common reason for revision surgery. Chitosan-dextran (CD) gel has been shown to be an effective hemostatic agent; however, its effects on ostial stenosis are unknown. This study aims to quantify the effect of CD gel on circumferential scarring following ESS....

The title compounds, C11H11BrO3, (I), and C11H11NO5, (II), respectively, are derivatives of 6-hy­droxy-5,7,8-trimethyl­chroman-2-one substituted at the 5-position by a Br atom in (I) and by a nitro group in (II). The pyran­one rings in both mol­ecules adopt half-chair conformations, and intra­molecular O—H⋯Br [in (I)] and O—H⋯Onitro [in (II)] hydro...

A new ditopic pyrimidine-hydrazone ligand, 6-hydroxymethylacryloyl-2-pyridinecarboxaldehyde, 2,2'-[2,2'-(2-methyl-4,6-pyrimidinediyl)bis(1-methylhydrazone)] (L2), was synthesized with terminal acryloyl functional groups to allow incorporation into copolymer gel actuators. NMR spectroscopy was used to show that L2 adopted a horseshoe shape with tran...

The synthesis and performance of novel redox-controlled gel actuators are described. The gels are constructed with quinone groups that can be reversibly oxidised or reduced, producing a marked change in the swelling of the gel. The use of highly sterically hindered quinones means that they can be polymerised directly without protection. Incorporati...

A chitosan dextran-based (CD) hydrogel, developed for use in endoscopic sinus surgery, was tested for antimicrobial activity in vitro against a range of pathogenic microorganisms. The microdilution technique was used to determine minimum inhibitory, minimum bactericidal, and minimum fungicidal concentrations. In addition, the time-kill efficacy of...

Poly(ethylene oxide) (PEO) polymers have been of great interest to biomaterial scientists for many years due to their biocompatible properties. PEOs with a broad range of end-functions are found in wide variety of applications such as drug delivery, tissue engineering scaffolds, surgical gel sealants and others. In this work we aim at synthesizing...

The title compound, C11H12O3, is essentially planar, with an r.m.s. deviation of 0.179 Å from the mean plane through the 14 non-H atoms in the mol­ecule. The benzene ring and the pyranone mean plane are inclined at 13.12 (6)° to one another and the pyran­one ring adopts a flattened chair conformation. In the crystal, O—H⋯O hydrogen bonds and C—H⋯O...

A one-pot, multi-component CuAAC reaction was exploited for the safe generation of an exo alcohol-functionalised pyridyl-1,2,3-triazole ‘click’ macrocycle in good yield. The macrocycle was characterised by elemental analysis, HR-ES-MS, H and C NMR spectrometry, and the molecular structure was confirmed by X-ray crystallography. Efforts to use the ‘...

The title mol­ecule, C14H14O4, lies on a twofold rotation axis that bis­ects the central benzene ring, with only one half-mol­ecule in the asymmetric unit. The pyran­one systems adopt distorted twist- boat conformations, with the two methyl­ene C atoms displaced by 0.537 (1) and 0.163 (2) Å from the best-fit plane through the remaining five C and O...

A neoteric correlation between the cyclopentadienyl (Cp)-aryl dihedral angle and crystal packing arrangement is confirmed in the structural determination of three ethynylferrocene substituted naphthalenes. Two of the naphthalenes have approximately orthogonal Cp and aryl ring systems and feature an inversion dimer motif with CHπ(alkyne) short conta...

Metal complexation studies were performed with AgSO(3)CF(3) and AgBF(4) and the ditopic pyrimidine-hydrazone ligand 6-(hydroxymethyl)pyridine-2-carboxaldehyde (2-methylpyrimidine-4,6-diyl)bis(1-methylhydrazone) (1) in both CH(3)CN and CH(3)NO(2) in a variety of metal-to-ligand ratios. The resulting complexes were studied in solution by NMR spectros...

The title compound, C(7)H(6)OS, crystallizes with two similar mol-ecules, 1 and 2, in the asymmetric unit. Both mol-ecules are essentially planar with r.m.s. deviations of 0.0193 and 0.0107 Å for the planes through the nine non-H atoms of mol-ecules 1 and 2, respectively. The thio-phene and 4,5-dihydro-cyclo-penta-dienone rings are inclined at 2.40...

The invention relates to a polymeric gel actuator. The polymeric gel actuator comprises a polymeric gel in contact with solvent. The polymer contains redox components. Redn. or oxidn. of the redox components change the affinity of the polymer for the solvent, changing the vol. of the polymeric gel. The vol. change of the polymeric gel can be used t...

By using electroactive monomers it is possible to produce gels that respond to oxidation or reduction by swelling and deswelling in the presence of solvent. By the inclusion of an appropriate biasing element such as a spring, it is possible to produce linear, reversible actuation. The process can be driven electrochemically in a standard cell, with...

Hydrogels are swollen, crosslinked networks that have great potential for use in biomedicine. Their softness, biocompatibility and ability for rapid diffusion of molecules make them useful for drug delivery, cell culture, wound healing and sensing applications. The chemical functionality of the gels can be easily modified to provide signalling and...

The title compound, C15H24N2O2, crystallizes with two unique mol­ecules, (I) and (II), in the asymmetric unit, differing in the orientation of the acryloyl units with respect to the piperidine rings. The acryl­amide units are essentially planar in both mol­ecules (r.m.s. deviations = 0.042 and 0.024 Å, respectively), as are the C3N chains of the ac...

In the title mol-ecule, C(16)H(14)O(4)S, the dihydro-cyclo-penta-thio-phenone ring system is almost planar, with an r.m.s. deviation of 0.060 Å from the best fit plane through all nine non-H atoms. The cyclo-penta-none ring adopts a severely flattened envelope conformation with the C atom carrying the OH and ethylcarboxylate substituents at the fla...

Metal complexation studies were performed with the ditopic pyrimidine-hydrazone (pym-hyz) strand 6-hydroxymethylpyridine-2-carboxaldehyde (2-methyl-pyrimidine-4,6-diyl)bis(1-methylhydrazone) (1) and Pb(ClO(4))(2)·3H(2)O, Pb(SO(3)CF(3))(2)·H(2)O, Zn(SO(3)CF(3))(2), and Zn(BF(4))(2) to examine the ability of 1 to form various supramolecular architect...

In the title mol­ecule, C11H11ClO3, the fused pyran ring adopts a half-chair conformation. In the crystal, inter­molecular O—H⋯O hydrogen bonds link mol­ecules into chains along [100]. These chains are inter­connected by weak inter­molecular C—H⋯O contacts which generate R2²(8) ring motifs, forming sheets parallel to (001). Tetra­gonal symmetry gen...

The title compound, C12H14O3, consists of a chromanone unit with an –OH substituent at the 4-position and methyl substituents on the remaining C atoms of the aromatic ring. The fused pyran­one ring adopts a distorted envelope conformation with the methyl­ene group adjacent to the carbonyl carbon as the flap atom. The crystal structure is stabilized...