title: An investigation of the biochemical properties of tetrazines as potential coating additives.
abstract: 1,2,4,5-Tetrazine and its 3,6-disubstituted derivatives are currently used for a range of industrial and medical applications as they exhibit particular coordination chemistries, characterised by electron and charge transfer phenomena. The aim of the present work is to synthesise two tetrazine derivatives, namely 3,6-dihydrazino-1,2,4,5-tetrazine (DHDTZ) and 1,2,4,5-tetrazine dicarboxylic acid (DCTZ), and determine their antibacterial, antioxidant and anticorrosion characteristics as additives in a sol-gel coating on SS316L steel. The structure of the tetrazines was confirmed by NMR and FTIR while the surface morphology of bacterial cells in their presence was observed by AFM. Their ability to inhibit corrosion on 316L stainless steel was electrochemically determined using a potentiodynamic scanning (PDS) technique. The corrosion inhibition results showed that the acidic DCTZ provided the best corrosion protection. The concentration-dependent antioxidant capacity of the tetrazines was confirmed by both DPPH radical scavenging activity and FRAP assays, showing higher activity for DHDTZ than DCTZ. Furthermore, a DHDTZ doped sol-gel solution was prepared and curing parameter (temperature and time) was optimised for coating on microtitre wells and stainless steel panel. The antibacterial activity of the coated surfaces against Pseudomonas aeruginosa ATCC 27853 and the biofilm forming bacteria Staphylococcus epidermidis CSF 41498 was determined. DHDTZ showed significantly higher antibacterial activities with MIC as low as 31 ppm compared to 250 ppm for DCTZ.
authors.affiliation: School of Biological Sciences, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland.
authors.forename: Swarna
authors.initials: S
authors.lastname: Jaiswal
authors.forename: P C Rajath
authors.initials: PC
authors.lastname: Varma
authors.forename: Luke
authors.initials: L
authors.lastname: O'Neill
authors.forename: Brendan
authors.initials: B
authors.lastname: Duffy
authors.forename: Patrick
authors.initials: P
authors.lastname: McHale
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000975:Antioxidants / Q000378:metabolism; D001422:Bacterial Adhesion / Q000187:drug effects; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D055664:Electrochemical Techniques; D036681:Fluorescence Recovery After Photobleaching; D006090:Gram-Negative Bacteria / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D006573:Heterocyclic Compounds, 1-Ring / Q000494:pharmacology*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008315:Malondialdehyde / Q000378:metabolism; D008422:Materials Testing; D008826:Microbial Sensitivity Tests; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D020099:Coated Materials, Biocompatible; D006573:Heterocyclic Compounds, 1-Ring; D008315:Malondialdehyde