THREE NOVEL MOLECULAR GATE BIOSENSORS FOR THE RAPID AND ACCURATE DETECTION OF RESPIRATORY PATHOGENS: INFLUENZA A, SARS-COV-2 AND PSEUDOMONAS AERUGINOSA

Each year, about 4.8 million people die from infectious respiratory diseases, mainly of bacterial origin but also viral. Current detection methods are hindered by slow diagnosis, low specificity, and costly equipment. Rapid, accurate identification of viruses and bacterial is vital, especially since acute respiratory infections present overlapping symptoms, such as those from influenza A virus (IVA) and SARS-CoV-2. Additionally, the bacterium Pseudomonas aeruginosa causes severe infections in immunocompromised patients, with high mortality rates. The current gold standard, PCR testing, is limited by long turnaround times, need for specialized staff, and high cost. Three independent smart nanodevice-based biosensors with gated porous supports have been developed. Each one is designed to detect a specific pathogen. These biosensors combine molecular gates tailored to their target analytes with optical fluorescence transducers to amplify the signal. Specifically, the IVA-Biosensor detects IVA proteins, the SARS-Biosensor detects the Spike SARS-CoV-2 protein, and the Pae-Biosensor detects biomarkers of P. aeruginosa . The response of all three optical biosensors was monitored by the release of fluorescence cargo (Rodamine B) (λexc = 555 nm, λem = 585 nm). Additional high-resolution FESEM images and EDXS analysis of the materials' surface composition and absorption spectra were performed. All of the biosensors demonstrated high sensitivity even at low pathogen concentrations (0.7–1 nM for the IVA and SARS biosensors and 10–28 CFU/mL for the Pae-Biosensor), outperforming traditional molecular techniques. They also demonstrate high specificity and selectivity compared to other common nosocomial pathogens. Clinical tests showed promising accuracy. Nasopharyngeal samples differentiated infected patients from healthy ones for the viral biosensors, and urine samples confirmed the rapid (∼30 min) identification of P. aeruginosa . Finally, the Pae-Biosensor has been integrated into a lateral flow device with in situ fluorescent measurement, enabling one-minute sample discrimination. Three smart nanodevice-based biosensors, which are sensitive and selective, have been developed to detect the pathogens IVA, SARS-CoV-2 and P. aeruginosa in complex clinical samples in less than 30 minutes, based on new nanomaterials capped with molecular gates. These biosensors do not require complex laboratory equipment, pretreatment or highly specialised personnel, making them suitable for use in hospitals.