Critical Calibration of Mass Photometry for Higher-Mass Samples Such as Adeno-Associated Virus Vectors

Mass photometry (MP) is a label-free, single-molecule technique that can determine molecular mass distribution with very low sample consumption in a short time. Because of the established experimental instrument and analytical software, MP measurements may be readily obtained; thus, the application of MP is expanding, especially in the fields of bioscience and biotechnology. However, because the MP data quality is strongly focus-dependent, optical settings must be intrinsically strict. In this study, we report the importance of the critical calibration of the mass photometer, which is required for the accurate estimation of high–molecular mass samples, such as adeno-associated virus vectors. Additionally, a method for optimizing the instrument settings, including the calibration of the stage, is presented.