Implementation of Chemiluminescence and Color-Based Detection in Smartphone for Bioassays

The activity carried out during my PhD was principally addressed to the development and characterization of new detection systems based on chemical luminescence (CL) for the implementation into smartphone based-biosensors for point of care (POC) and point of need applications. The aim of this research has been to determine the feasibility of combining smartphone detection capabilities with CL dependent assay results. In particular, my work has concerned the development of two smartphone-based assays to image and quantify chemiluminescence coupled biospecific enzymatic reactions to detect total cholesterol in serum and lactate in oral fluid and sweat. The devices were produced using a low-cost 3D printing technology and include a disposable analytical minicartridge, a mini dark box to avoid interference from ambient light measurement, and a holder to connect the dark box to a smartphone. The performances of these systems were compared with those obtained with a reference laboratory instrumentation (thermoelectrically cooled MZ-2PRO CCD camera). Finally, it was developed an alternative non-invasive smartphone-based assay to quantify lactate in oral fluid using a reagentless bioactive paper-based solid-phase biosensor integrated in smartphone-based device, employing light reflectance to measure an end-point enzymatic chemical reaction. The quantitative information is obtained from the change of color, due to variability of amount, intensity and brightness of light reflected from surface where assay has occurred. The proposed approaches based on the use of smartphone as detector paves the way for a new generation of analytical devices in the clinical diagnostic field. Moreover, the connectivity and data processing offered by smartphones can be exploited to perform analysis directly at home with simple procedures. The extreme simplicity of the device widens it applicability and makes it suitable for the detection of many analytes of clinical interest, for instance H2O2 producing all kind of oxidases.