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Wound closure in surgeries is traditionally achieved using invasive methods such as sutures and staples. Adhesion‐based wound closure methods such as tissue adhesives, sealants, and hemostats are slowly replacing these methods due to their ease of application. Although several chemistries have been developed and used commercially for wound closure, there is still a need for better tissue adhesives from the point of view of toxicity, wet‐adhesion strength, and long‐term bonding. Catechol chemistry has shown great promise in developing wet‐set adhesives that meet these criteria. Herein, we have studied the biocompatibility of a catechol‐based copolymer adhesive, poly([dopamine methacrylamide]‐co‐[methyl methacrylate]‐co‐[poly(ethylene glycol) methyl ether methacrylate]) or poly(catechol‐MMA‐OEG), which is soluble in water. The adhesive was injected subcutaneously in a mouse model on its own and in combination with a sodium periodate crosslinker. After 72 h, 4 weeks, and 12 weeks, the mice were euthanized and subjected to histopathological analysis. Both adhesives were present and still palpable at the end of 12 weeks. The moderate inflammation observed for the poly(catechol‐MMA‐OEG) cohort at 72 h had reduced to mild inflammation at the end of 12 weeks. However, the moderate inflammatory response observed for the poly(catechol‐MMA‐OEG) + crosslinker cohort at 72 h had not subsided at 12 weeks. [ABSTRACT FROM AUTHOR]

NMR spectroscopy is used to investigate the reaction of trimethyl phosphate with four iron-sulfur complexes, (Fe4S4(SR)4)(super 2-), where R = C6H5, C2H5, Fe4S4(SC2H5)4](super 3-) and (Fe(SC2H5)4)(super 2-). Results show that the products vary depending upon starting iron complex. However, in each reaction, methylation occurs to release a thiolate ligand as the methyl thioether, CH3SR. There are also differences in nucleophilicity among the cour complexes as revealed by kinetic studies.

Incorporating catechols into polymers can provide strong adhesion even in moist environments, and these polymers show promise for use in several biomedical applications. Surgical adhesives must have strong bonds, be biocompatible, and function in a moist environment. Poly(lactic acid) (PLA) has a long history as a biocompatible material for hard tissue device fixation. By combining these concepts, catechol‐containing poly(lactic acid) (cPLA) polymers are created that are strongly adhesive and degrade in physiological environments. Here, we evaluated the cytocompatibility of cPLA with iron(III) or periodate (IO4−) cross‐linkers. Fibroblasts cultured in cPLA leachate or on cPLA films generally had slower growth and lower metabolism compared with PLA controls but no differences in viability. These results demonstrated that cPLA was not cytotoxic but that including catechols reduced cell health. When cPLA was cross‐linked with periodate, cells generally had reduced metabolism, slower cell growth, and poor actin fiber formation compared with PLA. These results are attributed to the cytotoxicity of periodate since cells cultured with periodate leachate had extremely low viability. Cells grown on the films of iron‐cross‐linked cPLA generally had high viability and metabolism but slower proliferation than PLA controls. These results indicate that the cPLA and iron‐cross‐linked cPLA systems are promising materials for biomedical adhesive applications. [ABSTRACT FROM AUTHOR]

1H, 31P(1H) and 199Hg(1H) NMR spectroscopic methods are used to investigate the reactions of ((CH3)4N)2(Hg(SC6H5)4) and ((C4H9)4N)(Hg(SC6H5)3) with (CH3O)3PO. Results show that the four-coordinate (Hg(SC6H5)4)(super 2-) readily dissociates a thiolate ligand, which demethylates (CH3O)3PO. The three-coordinate (Hg(SC6H5)3), however, does not dissociate a ligand and is less reactive. These results are used to explain th inactivity of the mercury derivative of Escherichia coli Ada DNA alkylation repair protein.

The reaction of ((CH3)4N)2(Zn(SC6H5)4) complex with (CH3O)3PO in the presence of DMSO was used as a model to understand the mechanism of repair of DNA alkylation damage rendered by the Ada protein of Escherichia coli. It was found that the reaction mimics the enzyme activity as the complex demethylates (CH3O)3PO. The active nucleophile in the reaction was identified to be a dissociated thiolate.

Author(s): Jonathan J. Wilker (corresponding author) [1] Ask beachgoers how mussels, barnacles and oysters attach themselves to rocks, and they will often guess that suction cups are involved. Actually, these [...]

Experimental studies were conducted to gain insight into the biomineralized adhesive material generated by the oyster for aggregating into large communities. The findings for the oyster cement could open new route to strategies to develop synthetic composite materials as well as better understand the components needed for healthy coastal environments.

The electron paramagnetic resonance spectra of iron bound by catecholate, tironate, and the Ac-Ala-DOPA-Thr-Pro-CON[H.sub.2] ('AdopaTP#) peptide in mono, bis, and tris coordination environments are presented. The data shows that Fe[(DOPA).sub.3] moieties and oxygen are needed to generate radical species and that protein-based radicals give a route to radical-radical coupling for generation of organic cross-links or protein-surface binding for the creation of surface bonding.