Synthesis of Meso-tetra (5-bromothiophen-2-yl) Porphyrins for Photodynamic Water Disinfection

Abstract

Pathogens in water continue to pose a danger to those who consume water. This is exacerbated by issues of water scarcity, antimicrobial resistance, toxic-by-products in water disinfection techniques and the cost of implementing water disinfection techniques. A remedy to these issues could be photodynamic water disinfection, a technique that utilises light to generate singlet oxygen, a cytotoxic species with no toxic by-products. In this study meso-tetra(5-bromothiophen-2-yl)porphyrin and its metallated analogues (zinc, indium, tin, iron, cobalt and nickel) were synthesised as its photosensitisers, characterised empirically and computationally via density functional theory. Four of the eight compounds synthesised were tested against carbapenem resistant Escherichia coli (CRE.coli) and methicillin resistant Staphylococcus aureus (MRSA) to determine their antimicrobial activity. The antimicrobial efficacy was conducted using broth-dilution method, which involved exposing the bacteria to varying concentrations of BTP and its metal analogues. Iron-BTP had the highest potency of the compounds tested against both bacteria. This was based on its 50% minimum inhibitory concentration (IC50), where for MRSA it was 33μM and for CRE.coli it was 87μM.