X disease is a term coined by the World Health Organization (WHO) in 2018 to refer to a newly emerging pathogen or a previously known pathogen with newly acquired pandemic potential (Simpson et al., 2020). According to this definition, COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the first X disease, but another disease may emerge in the future. The most powerful and effective weapon against the threat of new viruses is to prevent their spread, with the key being accurate early diagnosis and effective isolation. Home testing typically reports results to public health authorities through smartphone applications and is a key tool in this strategy, enabling individuals to immediately identify infections without going to medical institutions, thereby reducing the risk of transmission and preserving personal protective equipment. However, current home testing, whether based on antigen detection or isothermal amplification, exhibits sensitivity limitations, especially in asymptomatic individuals, and requires users to collect nasal swab samples appropriately on their own. Obtaining high-quality samples remains a major challenge, as low-quality samples often lead to unreliable results. Although manufacturers provide visual aids and instructional videos to guide users, the ability to self collect varies greatly with age, especially for young children who require adult assistance to avoid damaging their nasal cavities due to improper handling. These challenges highlight the urgent need for more powerful and user-friendly home testing platforms to minimize operator dependence and improve testing accuracy, especially during asymptomatic infection periods. Therefore, an ideal respiratory virus home testing platform should integrate the following key features: (i) non-invasive and user-friendly sample collection, (ii) high sensitivity to detect pre symptomatic infections, (iii) fast detection time (

This article introduces EBCatch, an integrated system for label free electrochemical detection of respiratory viruses directly from exhaled breath condensate (EBC). This platform combines a semiconductor based condenser to efficiently collect EBC within 1 minute. It is an electrochemical biosensor based on carbon nanotubes, which has ACE2 function and does not require external reagents or complex sample pretreatment. EBCatch can achieve Flyk level sensitivity (the detection limit of pseudo virus is 1.6 fg/mL, far lower than the viral load in EBC samples of SARS-CoV-2 infected individuals), and can read the results from the sample collection within 8 minutes, proving high diagnostic accuracy with a sensitivity of up to 95.06%. The specificity is 97.30%, the overall accuracy is 96.13%, and it can be detected before symptoms and in the antigen negative stage. It is worth noting that the EBCatch response not only reflects viral load, but also viral activity, providing valuable insights into understanding infection status and transmission risk. This multifunctional and user-friendly platform represents a significant advancement in decentralized real-time monitoring of household respiratory infections, enabling timely intervention during emerging outbreaks.

Source: Sensor Expert Network