Pop-up paper-based and fully integrated microdevice for point-of-care testing of vancomycin-resistant Enterococcus

Abstract

This study presents a pop-up greeting card-inspired paper-based microdevice fully integrating DNA extraction, loop-mediated isothermal amplification (LAMP), and pH-dependent colorimetric detection for vancomycin-resistant Enterococcus (VRE) identification. The microdevice has a 3D paper platform that allows folding to mix the sample and reagents for sequential DNA purification and amplification. An FTA card was used for DNA extraction from intact bacteria in several samples, including bacterial cell culture, milk, and sausage. The extraction zone was then folded to transfer purified DNA in the FTA card to the reaction chamber for the LAMP reaction performed at 65 °C. After 45 min, a newly synthesized chemosensor was added to the reaction chamber for the colorimetric detection of the LAMP reaction based on pH changes. The color of the FTA card and LAMP solution turned yellow which indicated the absence of target DNA, whereas the colorless FTA card indicated the presence and successful amplification of target DNA. A highly sensitive detection with the limit of VRE detection of 102 CFU/mL in milk was achieved using this microdevice. The portable and integrated microdevice presented in this study holds significant promise for point-of-care applications to accurately and rapidly diagnose and control VRE not only in food but also in healthcare settings. © 2021 Elsevier B.V.