Porphyrinoids coated silica nanoparticles capacitive sensors for COVID-19 detection from the analysis of blood serum volatolome

The growing interest in analyzing human volatolome is among the primary motivations for developing gas sensors. Among the available sensor technologies, porphyrinoids coated quartz microbalance (QMBs) sensors demonstrate to be sensitive and selective enough to identify several diseases. Some drawbacks affect these transducers, such as difficult miniaturization and low-cost production. In this paper, we investigate capacitive sensors based on films of porphyrinoids functionalized silica nanoparticles as alternative and advantageous technology to match the performance of quartz microbalance sensors. The variation of sensor capacitance depended on the diffusion of airborne molecules into the sensing film, favoring the extraction of low-correlated dynamic features. As a demonstration of sensor properties, a three-sensor array has been used to measure the volatile compounds from blood serum to discriminate COVID-19 over other pathologies. Sensor data, processed by linear discriminant analysis, identified COVID-19 samples with 89% and 75% accuracy in training and test.