Rapid Pomegranate Juice Authentication Using a Simple Sample-to-Answer Hybrid Paper/Polymer-Based Lab-on-a-Chip Device.

As a super fruit, pomegranate and its juice have attracted increased consumer demands during the past decades. Given the high production cost and market price, adulteration of pomegranate juice is highly likely to occur. To authenticate pomegranate juice and avoid the addition of cheaper fruit juices, such as apple and grape, an analytical method based on loop-mediated isothermal amplification (LAMP) was developed. This LAMP-based authentication method achieved highly sensitive (i.e., 10 pg for pomegranate DNA and 100 pg for grape and apple DNA) and specific detection of pomegranate, apple, and grape DNA present in fresh fruit juice. To further simplify the overall analysis, a hybrid paper/polymer-based lab-on-a-chip (LOC) platform was designed to integrate DNA extraction, LAMP reaction, and LAMP result visualization onto a single device. This LOC device was able to detect 2 μL of fresh pomegranate juice and 5 μL of fresh apple and grape juice. Using a homemade portable heating device, the overall analysis could be completed in ∼1 h in an almost instrument-free setting. The cost for each authentication test is estimated to be ∼4 USD and the reusable homemade portable heating device is ∼15 USD. This LAMP-based simple sample-to-answer hybrid paper/polymer-based LOC device has high potential to be adopted by government laboratories and the food industry to rapidly and routinely authenticate pomegranate juice even in a resource-limited environment.