Viral Identification from Cell Cultures by MALDI-TOF: Development, Application and Bioinformatic Assessment of an In-House Library—Understanding Strengths and Limitations

Well established long ago for bacterial and fungal detection, Matrix-Assisted Laser Desorption/Ionization–Time of Flight (MALDI-TOF) technique is not so well established in the virology field, and taking care of its advantages (speed, precision and low cost), this can be a powerful method for viral identification. To explore the feasibility and potential of MALDI-TOF for viral detection, this study shows the development of an in-house spectral library including several uninfected cell cultures and cultures infected with different clinically relevant viruses, such as SARS-CoV-2. This library was applied to the identification of viral infections directly on cell cultures, assessing the ability of the technique to discriminate between infected and non-infected profiles. Additionally, bioinformatic analyses were conducted to evaluate the structure, specificity, and reproducibility of the in-house library, and to understand its strengths and limitations. Sensitivity and specificity of the method were estimated by testing multiple culture batches from selected viruses included in the library. Together, these results provide a deeper understanding of the performance and applicability of MALDI-TOF in the virological context, highlighting its potential as a valuable research platform and a prospective tool for clinical viral detection.