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1.
Molecules ; 26(16)2021 Aug 17.
Article in English | MEDLINE | ID: mdl-34443571

ABSTRACT

Through variations in reaction solvent and stoichiometry, a series of S-diiodine adducts of 1,3- and 1,4-dithiane were isolated by direct reaction of the dithianes with molecular diiodine in solution. In the case of 1,3-dithiane, variations in reaction solvent yielded both the equatorial and the axial isomers of S-diiodo-1,3-dithiane, and their solution thermodynamics were further studied via DFT. Additionally, S,S'-bis(diiodo)-1,3-dithiane was also isolated. The 1:1 cocrystal, (1,4-dithiane)·(I2) was further isolated, as well as a new polymorph of S,S'-bis(diiodo)-1,4-dithiane. Each structure showed significant S···I halogen and chalcogen bonding interactions. Further, the product of the diiodine-promoted oxidative addition of acetone to 1,4-dithiane, as well as two new cocrystals of 1,4-dithiane-1,4-dioxide involving hydronium, bromide, and tribromide ions, was isolated.

2.
Talanta ; 221: 121482, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33076093

ABSTRACT

Membrane filters were coated with 10,12-pentacosadiynoic acid (PCDA) then polymerized on the filter for rapid bacterial detection and quantification. The polymerized PCDA (pPDCA)-coated filter changed color in response to Salmonella Typhimurium and Escherichia coli but not to Listeria innocua. The time required for color change of pPCDA-coated filters was determined by a visual panel. A simple linear regression model was generated to fit the observed data and was validated with goodness of fit analysis and residual analysis. The pPCDA-filter method estimated Salmonella Typhimurium populations of 8 to 3 log CFU ml-1 within 1.5-7.5 h, respectively.


Subject(s)
Listeria , Colony Count, Microbial , Food Microbiology , Polyacetylene Polymer
3.
Gels ; 6(2)2020 Apr 18.
Article in English | MEDLINE | ID: mdl-32325773

ABSTRACT

Hydrogels composed of calcium cross-linked alginate are under investigation as bioinks for tissue engineering scaffolds due to their variable viscoelasticity, biocompatibility, and erodibility. Here, pyrrole was oxidatively polymerized in the presence of sodium alginate solutions to form ionomeric composites of various compositions. The IR spectroscopy shows that mild base is required to prevent the oxidant from attacking the alginate during the polymerization reaction. The resulting composites were isolated as dried thin films or cross-linked hydrogels and aerogels. The products were characterized by elemental analysis to determine polypyrrole incorporation, electrical conductivity measurements, and by SEM to determine changes in morphology or large-scale phase separation. Polypyrrole incorporation of up to twice the alginate (monomer versus monomer) provided materials amenable to 3D extrusion printing. The PC12 neuronal cells adhered and proliferated on the composites, demonstrating their biocompatibility and potential for tissue engineering applications.

4.
Biofouling ; 31(6): 493-502, 2015.
Article in English | MEDLINE | ID: mdl-26218247

ABSTRACT

Diatoms are a major component of microbial biofouling layers that develop on man-made surfaces placed in aquatic environments, resulting in significant economic and environmental impacts. This paper describes surface functionalisation of the inherently conducting polymers (ICPs) polypyrrole (PPy) and polyaniline (PANI) with poly(ethylene glycol) (PEG) and their efficacy as fouling resistant materials. Their ability to resist interactions with the model protein bovine serum albumin (BSA) was tested using a quartz crystal microbalance with dissipation monitoring (QCM-D). The capacity of the ICP-PEG materials to prevent settlement and colonisation of the fouling diatom Amphora coffeaeformis (Cleve) was also assayed. Variations were demonstrated in the dopants used during ICP polymerisation, along with the PEG molecular weight, and the ICP-PEG reaction conditions, all playing a role in guiding the eventual fouling resistant properties of the materials. Optimised ICP-PEG materials resulted in a significant reduction in BSA adsorption, and > 98% reduction in diatom adhesion.


Subject(s)
Aniline Compounds/chemistry , Biofouling/prevention & control , Diatoms/drug effects , Polyethylene Glycols/chemistry , Polymers/chemistry , Pyrroles/chemistry , Adsorption , Animals , Cattle , Diatoms/physiology , Molecular Weight , Polymerization , Quartz Crystal Microbalance Techniques , Serum Albumin, Bovine/chemistry , Surface Properties
5.
Biofouling ; 29(10): 1155-67, 2013.
Article in English | MEDLINE | ID: mdl-24063598

ABSTRACT

The ability to control the interaction between proteins and cells with biomaterials is critical for the effective application of materials for a variety of biomedical applications. Herein, the surface modification of the biological dopant dextran sulphate-doped polypyrrole (PPy-DS) with poly(ethylene glycol) to generate a biomaterial interface that is highly resistant to protein and cellular adhesion is described. Thiolated poly(ethylene glycol) (PEG-thiol) was covalently bound to PPy-DS backbone via a thiol-ene reaction. The surface resistance to an extracellular matrix protein fibronectin increased with increasing molecular weight and concentration of PEG-thiol, and was further optimised via increasing the reaction temperature and the pH of the reactant aqueous solution. Optimised surface modification conditions substantially reduced interfacial protein adsorption, with the complete inhibition of adhesion and colonisation by primary mouse myoblasts. PEG-thiol-modified inherently conducting polymers are highly protein resistant multifunctional materials that are promising compounds for a range of biomedical and aquatic applications.


Subject(s)
Biofouling/prevention & control , Biopolymers/chemistry , Cell Adhesion/drug effects , Polymers/chemistry , Proteins/chemistry , Pyrroles/chemistry , Microscopy, Atomic Force , Phosphenes , Polyethylene Glycols/chemistry , Sulfhydryl Compounds/chemistry , Surface Properties , Temperature
6.
Chem Commun (Camb) ; 46(11): 1854-6, 2010 Mar 21.
Article in English | MEDLINE | ID: mdl-20198231

ABSTRACT

Complementary halogen bonding and hydrogen bonding coexist in co-crystals of organoiodines with molecules containing the thioamide functionality. Thiourea.organoiodine co-crystals are shown to exhibit a remarkably reliable synthon with complementary N-H...S ribbons and S...I interactions.


Subject(s)
Halogens/chemistry , Iodine/chemistry , Sulfur/chemistry , Thioamides/chemistry , Crystallography, X-Ray , Hydrogen Bonding , Molecular Conformation
7.
ACS Appl Mater Interfaces ; 1(6): 1287-91, 2009 Jun.
Article in English | MEDLINE | ID: mdl-20355925

ABSTRACT

Polydiacetylene (PDA)-doped calcium alginate fibers were created by the solution blending of polymerized 10,12-pentacosadiynoic acid liposomes with sodium alginate in water prior to extrusion. The liposomes maintained their blue color during wet spinning and drying of the fibers but changed to red with exposure to specific external stimuli (heat, solvent, and chemical). In the latter case, the color change only occurred when the fibers were sufficiently permeable for the reacting species to reach the interior. A parameter termed the "Raman response" (RR) has been developed to quantify the amount of PDA liposomes in each of two critical conformations within the fibers. The RR attributes a quantitative measure of PDA response to individual stimuli. This method provides advantages over the commonly used "colorimetric response" in systems where sample limitations and chromophore activity make UV-vis spectroscopic measurements difficult or inaccurate. PDA liposomes are shown to effectively add a versatile sensing component to alginate fibers.


Subject(s)
Alginates/chemistry , Colorimetry/methods , Liposomes/chemistry , Polymers/chemistry , Polyynes/chemistry , Spectrum Analysis, Raman/methods , Color , Crystallization/methods , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Materials Testing , Polyacetylene Polymer
8.
J Nanosci Nanotechnol ; 2(5): 457-61, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12908278

ABSTRACT

Single-walled (SWNTs) and multiple-walled (MWNTs) carbon nanotubes were solubilized via the esterification of nanotube-bound carboxylic acids by oligomeric polyethylene glycol compounds. The water-soluble samples were used as starting materials in reactions with bovine serum albumin (BSA) protein in ambient aqueous solutions. The reaction conditions were designed for thermodynamically favorable transformation from ester to amide linkages, yielding SWNT-BSA and MWNT-BSA conjugates. The results show that the use of soluble starting nanotube materials in an indirect functionalization method represents a valuable approach to the biomodification of carbon nanotubes.


Subject(s)
Nanotubes, Carbon/chemistry , Serum Albumin, Bovine/chemistry , Water/chemistry , Esterification , Macromolecular Substances , Microscopy, Atomic Force , Microscopy, Electron , Molecular Conformation , Nanotechnology/methods , Polyethylene Glycols/chemistry , Protein Binding , Solubility , Solutions/chemistry , Spectrum Analysis , Surface Properties
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