Poly(ionic liquid)-coated membranes: Green solid-phase DNA extraction media for nucleic acid preparation applicable to point-of-care testing

초록

In this study, we synthesized an imidazolium-based ionic liquid (3-octyl-1-vinyl-1H-imidazol-3-ium bromide) and coated it on glass microfiber through in situ polymerization for bacterial lysis and DNA capture to be utilized for solid-phase DNA extraction media suitable for point-of-care testing applications. Poly(ionic liquid) (PIL) comprises of cationic vinyl imidazolium unit with a hydrophobic alkyl chain, which facilitates both cell disruption and nucleic acid adsorption. The released DNA was subsequently immobilized on the PIL surface due to electrostatic interaction. The synthesis of the ionic liquid and PIL was verified by spectroscopic and thermal analyses, while the interaction mechanism between the negatively-charged DNA and positively-charged vinyl imidazolium unit was studied using AutoDock Vina blind docking analysis. The properties of the PIL surface were studied by measuring the contact angle, and its antimicrobial performance was assessed using bacterial inhibition assays for bacterial lysis and DNA adsorption. Enterococcus faecium (E. faecium), an opportunistic nosocomial pathogen, was spiked into artificial urine, and the esp gene associated with biofilm formation and virulence was amplified under isothermal conditions at 65 degrees C for 45 min. Visual detection using Janus Green B produced a distinct color change from blue to purple, with a detection threshold of 102 CFU/mL. The entire procedure from DNA extraction to colorimetric detection was completed in less than 90 min, representing a cost-effective, rapid, and portable diagnostic approach for detecting bacterial infections, in this case, urinary tract infections to support clinical decision-making directly in clinical field settings.

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