A Paper-Based Sensor for the Detection of Gastroesophageal Reflux Disease Utilizing a Cleavable Fluorescent Polymer.

Nowadays, gastroesophageal reflux disease (GERD) has emerged as one of the major hazards to the health of the upper gastrointestinal tract, and there is an urgent need for a low-cost, user-friendly, and non-invasive detection method. Herein, a paper-based sensor (CP sensor) for the non-invasive screening of GERD is proposed. The sensor is structured as a specially shaped cellulose paper strip embedded with fluorescent colloids, which are self-assembled from a cleavable synthetic fluorescent polymer (P4). Benefiting from the introduction of amide bonds and the unique assembled structure of the nanocolloids, the pepsin in the sample solution will hydrolyze the water-soluble branches in the micellar shell during detection, resulting in a corresponding output of the fluorescent signal. This responsiveness, which can be observed by the naked eye, is so sensitive with a minimum detectable concentration for pepsin as low as 0.3 ng·mL^-1. Clinical trials have further demonstrates that the designed paper sensor is capable of providing improved accuracy in the early diagnosis of GERD.