Salivary diagnostics on paper microfluidic devices and their use as wearable sensors for glucose monitoring

摘要

Microfluidic paper-based devices (mu PADs) and wearable devices have been highly studied to be used as diagnostic tools due to their advantages such as simplicity and ability to provide instrument-free fast results. Diseases such as periodontitis and diabetes mellitus can potentially be detected through these devices by the detection of important biomarkers. This study describes the development of mu PADs through craft cutter printing for glucose and nitrite salivary diagnostics. In addition, the use of mu PADs integrated into a mouthguard as a wearable sensor for glucose monitoring is also presented. mu PADs were designed to contain two detection zones for glucose and nitrite assays and a sampling zone interconnected by microfluidic channels. Initially, the analytical performance of the proposed mu PADs was investigated and it provided linear behavior (r(2)>= 0.994) in the concentration ranges between 0 to 2.0mmolL(-1) and 0 to 400 mu molL(-1) for glucose and nitrite, respectively. Under the optimized conditions, the limits of detection achieved for glucose and nitrite were 27 mu molL(-1) and 7 mu molL(-1), respectively. Human saliva samples were collected from healthy individuals and patients previously diagnosed with periodontitis or diabetes and then analyzed on the proposed mu PADs. The results found using mu PADs revealed higher glucose concentration values in saliva collected from patients diagnosed with diabetes mellitus and greater nitrite concentrations in saliva collected from patients diagnosed with periodontitis, as expected. The results obtained on mu PADs did not differ statistically from those measured by spectrophotometry. With the aim of developing paper-based wearable sensors, mu PADs were integrated, for the first time, into a silicone mouthguard using a 3D-printed holder. The proof of concept was successfully demonstrated through the monitoring of the glucose concentration in saliva after the ingestion of chocolate. According to the results repo