Recent advances in on-site mass spectrometry analysis for clinical applications

In recent years, mass spectrometry (MS) is increasingly attracting interests for clinical applications, which also calls for technical innovations to make a transfer of MS from conventional analytical laboratories to clinics. The system design and analysis procedure should be friendly for novice users and applicable for on-site clinical diagnosis. In addition, the analysis result should be auto-interpreted and reported in formats much simpler than mass spectra. This motivates new ideas for developments in all the aspects of MS. In this review, we report recent advances of direct sampling ionization and miniature MS system, which have been developed targeting clinical and even point-of-care analysis. We also discuss the trend of the development and provide perspective on the technical challenges raised by diseases such as coronavirus SARS-CoV-2.

MS is powerful tool in analytical chemistry and is experiencing a translation from analytical chemistry to clinical applications. Ambient ionizations allow biological samples to be sampled directly in their native environment without pretreatment. Meanwhile, the soft nature of ambient ionization guarantees minimal destructions to the biological samples and invasions to the patients. This is a prerequisite that MS technique could be transferred to non-expert users and used in clinical settings, such as nurses and physicians in clinical office and operation room. Another difficulty for the technical translation is the size and mobility of the MS systems, which prevent the application of MS in on-site scenarios, such as ambulances and outdoors for POC diagnosis. Miniature MS systems with an adequate performance can well fill the gap. Instead of pursuing ultimate high performance as large-scale instruments, the system design for miniature MS systems is intended to achieve a balance among the size reduction, ease of use and required performance of specific applications. With highly specific molecular information in hand, miniature MS systems incorporated with direct sampling methods are expected to provide POC service and personalized treatment for patients in future.